AstroSat-CZTI Detection of Variable Prompt Emission Polarization in GRB 171010A

The emission mechanisms of gamma-ray bursts (GRBs) and the radiation processes involved in producing the complex structure during the prompt phase have eluded a complete understanding even though these energetic cosmological events have been studied for more than five decades. Based on the duration of the observed prompt emission, GRBs are broadly classified into two families called long and short GRBs with a demarcation at 2 s. The long GRBs are found to be associated with with type Ic supernovae, which indicates that they originated from a massive star. To efficiently extract energy to power a GRB, such a collapse results in a black hole or a rapidly spinning and highly magnetized neutron star (Woosley & Bloom 2006; Cano et al. 2017). The recent groundbreaking discovery of gravitational waves and their electromagnetic counterpart object (a short GRB) resolved the problem of identifying progenitors of short GRBs at least for the case of one joint GW/GRB detection (Abbott et al. 2016). The commonly accepted scenario for the production of the emerging radiation is based on the premise that relativistic jets are launched from the central engine. When the jet pierces an ambient medium that is either a constant-density interstellar medium (ISM) or a wind-like medium whose density varies with distance, external shocks are formed and the generated radiation receives contributions from both the forward and the reverse shocks. The resultant emission constitutes the widely observed afterglows in GRBs (Rees & Meszaros 1992; Meszaros & Rees 1993; Mészáros & Rees 1997, 1999; Akerlof et al. 1999). A plateau phase in the X-ray emission is, however, thought to be associated with a long-term central engine activity; alternatively, the stratification in the Lorentz factor of the ejecta could also provide an extended energy injection (Dai & Lu 1998; Zhang et al. 2006).

The prompt emission can arise as a result of various mechanisms, the leading candidates of which are (i) increase in jet Lorentz factor with time, leading to the collision of the inner with the outer layers, which generates internal shocks that produce nonthermal synchrotron emission as the electrons gyrate in the existing magnetic field (Narayan et al. 1992; Rees & Meszaros 1994). A variant of the internal shock model is the internal-collision-induced magnetic reconnection and turbulence (ICMART) model, where abrupt dissipation occurs through magnetic reconnections in a jet dominated by Poynting flux (Zhang & Yan 2011). (ii) Prompt emission can also arise through dissipation that occurs within a fuzzy photosphere; the photosphere is especially invoked to explain the quasi-thermal shape of the spectrum. The process manifests itself in such a way that it can produce a nonthermal shape of the spectrum as well (Beloborodov 2017). (iii) Gradual magnetic dissipation that occurs within the photosphere of a jet dominated by Poynting flux can trigger a prompt emission (Beniamini & Giannios 2017), and (iv) Comptonization of soft corona photons off the electrons in the outgoing relativistic ejecta is another mechanism (Titarchuk et al. 2012; Frontera et al. 2013). These models are designed to explain the spectral properties of the prompt emission of GRBs and are successful to a certain extent. Some prominent features such as the evolution of the spectral parameters and correlations among GRB observables are not well understood, and most of them remain unexplained within the framework of a single model.

Another crucial information that can be added to the existing plethora of observations of the prompt emission, such as the spectral and timing properties, afterglows, and associated supernovae, is the polarization of the prompt emission. The detection of polarization therefore provides an additional tool for testing the theoretical models of the mechanism of GRB prompt emission. However, this has remained a rarely explored avenue because no dedicated polarimeters and reliable polarization measurements are available. The Cadmium Zinc Telluride Imager (CZTI) on board AstroSat offers a new opportunity to reliably measure polarization of bright GRBs in the hard X-rays (Chattopadhyay et al. 2014; Vadawale et al. 2015; Chattopadhyay et al. 2017). The polarization expected from different models of prompt emission is not only different in magnitude, but also in the expected pattern of temporal variability, depending on the emission mechanism, jet morphology, and view geometry (see, e.g., Covino & Gotz 2016). A study of the time-variability characteristics is very important because bright GRBs whose spectra have been studied in great detail have often been found to have spectra that significantly deviate from the standard Band function that is conventionally used to model the GRB spectra (Abdo et al. 2009; Ackermann et al. 2010; Izzo et al. 2012; Wang et al. 2017; Vianello et al. 2018).

GRB 171010A is a bright GRB, and it presents an opportunity for a multi-pronged approach to understand the GRB prompt emission. It has been observed by both Fermi and AstroSat-CZTI. Afterglows in gamma-rays (Fermi/LAT), X-rays (Swift-XRT), and optical have been detected, and the associated supernova SN 2017htp has been found on the tenth day of the prompt emission. A redshift z = 0.33 has been measured spectroscopically by the extended Public ESO Spectroscopic Survey for Transient Objects optical observations (Kankare et al. 2017). We present here a comprehensive analysis of this GRB using the Fermi observation for spectral properties and attempt to relate the prompt spectral properties to the detection of variable high polarization using AstroSat-CZTI. We present a summary of the observations in Section 2. The Fermi light curves and spectra are constructed in various energy bands and time bins, respectively, and they are presented in Sections 2–4. The polarization measurements in different time intervals and energies are presented in Section 6. We discuss our results and derive conclusions in Section 7. The cosmological parameters chosen were Ω_λ = 0.73, Ω_m = 0.27 and H₀ = 70 km Mpc⁻¹ s⁻¹ (Komatsu et al. 2009).

GRB 171010A triggered the Fermi-LAT and Fermi-GBM at 19:00:50.58 UT (T₀) on 2017 October 10 (Omodei et al. 2017; Poolakkil & Meegan 2017). The observed high peak flux generated an autonomous re-point request (ARR) in the GBM flight software and the Fermi telescope slewed to the GBM in-flight location. A target of opportunity (ToO) observation was carried out by the Niel Gehrels Swift Observatory (Evans 2017), and the Swift-XRT localized the burst to R.A.(J2000): 6658092, and decl.: −1046325 (D'Ai et al. 2017). Swift-XRT followed the burst for ∼2 × 10⁶ s.¹⁰ The prompt emission was also observed by Konus-Wind (Frederiks et al. 2017). The fluence observed in the Fermi-GBM 10–1000 keV band from T₀ + 5.12 s to T₀ + 151.55 s is (6.42 ± 0.05) × 10⁻⁴ erg cm⁻² (Poolakkil & Meegan 2017). Here T₀ is the trigger time in the Fermi-GBM. The first photon in LAT (>100 MeV) with a probability 0.9 of its association with the source is received at ∼T₀ + 374 s and has an energy ∼194 MeV, and a photon with energy close to 1 GeV (930 MeV) is detected at ∼404 s. The highest energy photon (∼19 GeV) in the Fermi-LAT is detected at ∼2890 s. The rest frame energy of this photon is ∼25 GeV.

We examined the light curves of the GRB as obtained from all 12 NaI detectors and found that detectors n7, n8, and nb (using the common naming conventions) have significant detections (source angles are n7: 69°, n8: 31°, and nb: 40°). We have used data from all three detectors to examine the broad emission features of the GRB. For the wide-band temporal and spectral analysis, however, we chose n8 and nb, which have higher count rates than the other detectors, and the angles made with the source direction for these two detectors are lower than 50 degrees. The timescale used throughout this paper is relative to the Fermi-GBM trigger time, i.e., t = T − T₀. Of the two BGO scintillation detectors, the detector BGO 1 (b1), which is positioned on the same side on the satellite as the selected NaI detectors, is chosen for further analysis.

The light curve is shown in Figure 1, and it shows two episodes of emission (a) beginning at ∼−5 s of the main burst and lasts up to ∼205 s, followed by a quiescent state when the emission level meets the background level, and (b) the emission becomes active again after a short period at ∼246 s and radiation from the burst is detected until ∼278 s. We call these emission phases Episodes 1 and 2. In Figure 1 we also show the light curve in the 100–400 keV region (the energy range of AstroSat-CZTI observations), and we use this light curve to divide the data for the time-resolved spectral analysis. The blocks of constant rate (Bayesian blocks) are constructed from the light curves and are overplotted on the count-rate light curves to show statistically significant changes in them (Scargle et al. 2013).

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The light curves summed over the chosen GBM detectors (n8 and nb) in six different energy ranges are shown in Figure 2. The GRB has a complex structure with multiple peaks, and the high-energy emission (above 1 MeV) is predominant until about 50 s, as seen in the light curve for >1 MeV. Bayesian blocks are constructed from the light curves and are overplotted on the count rate.

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The burst is very bright, and even with a signal-to-noise ratio of 50, we are able to construct more than 150 time bins. We therefore created time bins from the Bayesian blocks constructed from the light curve in the energy range 100–400 keV where CZTI is sensitive for polarization measurements. These bins (large number of Bayesian blocks) track significantly varying features in the light curve and will also be sufficient to give a substantial idea about the energetics of the burst. The spectra are reduced using the Fermi Science tools software rmfit¹¹ by the standard method that is described in the tutorial.¹²

GRB prompt emission spectra generally show a typical shape described by the Band function (Band et al. 1993), but for a number of bursts, additional components are observed in the spectra, such as quasi-thermal components modeled by a blackbody (BB) function (Ryde 2005; Guiriec et al. 2011; Page et al. 2011; Basak & Rao 2015), or they show additional nonthermal components modeled by a power law or a power law with an exponential cutoff (Abdo et al. 2009; Ackermann et al. 2013). Additionally, for a few cases, spectra with a top-hat shape are also observed and modeled by a Band function with an exponential roll-off at higher energies (Wang et al. 2017; Vianello et al. 2018).

The above models are driven by data and phenomenology. The physical models devised to explain the GRB prompt emission radiation have the synchrotron emission or the Compton scattering as the core processes. The synchrotron spectrum for a power-law distribution of electrons consists of power laws that are joined at energies that depend upon cooling frequency (ν_c), minimum-injection frequency (ν_m), and absorption frequency (ν_a). The Comptonization models include inverse Compton scattering as a primary mechanism (Lazzati et al. 2000; Titarchuk et al. 2012). Comptonization signatures (XSPEC grbcomp model) have been detected for a set of GRBs observed by the Burst and Transient Source Experiment on board the Compton Gamma Ray Observatory (Frontera et al. 2013). The grbcomp model differs from the other Comptonization model, the Compton drag model. In the Compton drag model, the single inverse Compton scatterings of thermal photons shape the spectrum, while in the grbcomp model, multiple Compton scatterings are assumed. Another major difference is that the scattering is off the outflow, which is subrelativistic in the grbcomp model and relativistic in the Compton drag model.

We apply this prior knowledge of spectral shapes from the previous observations of GRBs to study GRB 171010A. The spectra are modeled by various spectroscopic models available in XSPEC (Arnaud 1996). The statistics pgstat is used for optimizing and testing the various models.¹³ We start with the Band function, and use the other models based upon the residuals of the data and model fit. The functional form of the Band model used to fit the photon spectrum is given in Equation (1) (Band et al. 1993),

$$\begin{eqnarray}&&\begin{array}{l}{N}_{\mathrm{Band}}(E)\,=\,\left\{\begin{array}{l}{K}_{B}{\left(E/100\right)}^{\alpha }\exp \left(-E\left(2+\alpha \right)/{E}_{{\rm{p}}}\right)\ \ E\lt {E}_{{\rm{b}}}\\ {K}_{B}{\left\{\left(\alpha -\beta \right){E}_{{\rm{p}}}/\left[100\left(2+\alpha \right)\right]\right\}}^{\left(\alpha -\beta \right)}\exp \left(\beta -\alpha \right){\left(E/100\right)}^{\beta }\ \ E\geqslant {E}_{{\rm{b}}}\end{array}\right..\end{array}\end{eqnarray} \tag{ 1 }$$

Other models include blackbody¹⁴ (BB) and a power law with two breaks (bkn2pow)¹⁵ to model the broad-band spectrum.

$$\begin{eqnarray}{N}_{\mathrm{bkn}2\mathrm{pow}}(E)=\left\{\begin{array}{cc}{{KE}}^{-{\alpha }_{1}}, & E\leqslant {E}_{1}\\ {{KE}}_{1}^{{\alpha }_{2}-{\alpha }_{1}}{E}^{-{\alpha }_{2}}, & {E}_{1}\leqslant E\leqslant {E}_{2}\\ {{KE}}_{1}^{{\alpha }_{2}-{\alpha }_{1}}{E}_{2}^{{\alpha }_{3}-{\alpha }_{2}}{E}^{-{\alpha }_{3}}, & E\geqslant {E}_{3}\end{array}\right..\end{eqnarray} \tag{ 2 }$$

For the Comptonization model proposed by Titarchuk et al. (2012), the XSPEC local model grbcomp is fit to the photon spectrum.¹⁶ The pivotal parameters of this model are the temperature of the seed BB spectrum (kT_s), the bulk outflow velocity of the thermal electrons (β), the electron temperature of the subrelativistic outflow (kT_e), and the energy index of the Green function with which the formerly Comptonized spectrum is convolved (α_b). Using the normalization of the grbcomp model, we can obtain the apparent BB radius. To avoid degeneracy in the parameters or the case when parameters are difficult to constrain, we froze some of the parameters.

To fit the spectra with synchroton radiation model, we implemented a table model for XSPEC. We assumed a population of electrons with a power-law energy distribution (as a result of acceleration) dN/dγ ∝ γ^−p for γ > γ_m, where γ_m is the minimum Lorentz factor of electrons. The cooling of electrons by synchrotron radiation is considered in slow- and fast-cooling regimes depending on the ratio between γ_m and the cooling Lorentz factor γ_c (Sari et al. 1998). We computed the resulting photon spectrum of the electron population assuming that the average electron distribution at a given time is dN/dγ ∝ γ⁻² for γ_c < γ < γ_m and dN/dγ ∝ γ^−p−1 for γ > γ_m in the fast-cooling regime and dN/dγ ∝ γ^−p for γ_m < γ < γ_c and dN/dγ ∝ γ^−p−1 for γ > γ_c in the slow-cooling regime. The synchrotron model is made of four free parameters: the ratio between the characteristic Lorentz factors γ_m/γ_c; the peak energy of the F_ν spectrum E_c, which is simply the energy that corresponds to the cooling frequency; the power-law index of electrons distribution p; and the normalization. We built the table model for the range of 0.1 ≤ γ_m/γ_c ≤ 100 and 2 ≤ p ≤ 5.

To fit the time-integrated spectrum of Episode 1, we use the four models described above: (i) Band, (ii) Band + BB, (iii) broken power-law (bkn2pow), and (iv) the Comptonization model (grbcomp). The best-fit parameters of the tested models are reported in Table 1. The νF_ν plots, along with the residuals, are shown in Figure 3 for the four models we used. The Band fit shows deviations at lower energies, which signify deviations from the power law that is used to model the spectra from the low-energy threshold of 8 keV to the peak energy of the Band function (∼150 keV). We have examined these residuals in detail by progressively raising the low-energy threshold to 40 keV (greater than the energy in which the deviations are seen) and extrapolating the model to the low energies. The low-energy features could still be seen. An anomaly like this has been found in previous studies (Tierney et al. 2013), and we conclude that a separate low-energy feature in the spectra can exist. We included a BB along with the Band model for higher energies, but the residuals still showed a systematic hump. We also tried another model for this feature of the spectrum: a power law with two breaks (bkn2pow model). The bkn2pow model is preferable as the pgstat is much lower for the same number of parameters (Δpgstat = 41). The presence of a narrow residual hump also requires a sharper break than a smooth BB curvature. This also indicates that the break does not evolve much in time and is thus not smeared out. The Comptonization model (grbcomp), however, gives the best fit for the time-integrated spectrum of Episode 1. All the parameters of this model except for β, fbflag, and log(A) were left free. The parameter β was frozen to the value 0.2 to ignore terms O(∼β²), and fbflag was set to zero to include only the first-order bulk Comptonization term. A value of 3.9 for γ shows deviation for the seed photons from the seed BB spectrum. However, during the time-resolved spectral analysis, as reported in the next subsection, we kept it fixed to 3 to consider a BB spectrum for the seed photons.

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Table 1.  The Best-fit Parameters for the Time-integrated Spectrum of GRB 171010A, Episode 1

Model
Band	α	β	Ep (keV)	pgstat/dof
	$-{1.15}_{-0.01}^{+0.01}$	$-{2.40}_{-0.03}^{+0.03}$	${163}_{-3}^{+3}$	2786/335
BB+Band	α	β	Ep (keV)	kTBB (keV)	pgstat/dof
	$-{0.75}_{-0.03}^{+0.04}$	$-{2.40}_{-0.03}^{+0.04}$	${150.0}_{-2.6}^{+2.5}$	${5.8}_{-0.1}^{+0.1}$	1465/333
bkn2pow	α1	α2	α3	E1 (keV)	E2 (keV)	pgstat/dof
	${0.48}_{-0.07}^{+0.06}$	${1.464}_{-0.005}^{+0.006}$	${2.33}_{-0.02}^{+0.02}$	${17.2}_{-0.4}^{+0.4}$	${132.7}_{-2.3}^{+2.3}$	1421/333
grbcomp	kTs (keV)	kTe (keV)	τ	αb	Rph (1010 cm)	pgstat/dof
	${4.8}_{-0.4}^{+0.5}$	${55}_{-3}^{+3}$	${4.15}_{-0.15}^{+0.18}$	${1.52}_{-0.04}^{+0.04}$	${8.0}_{-2.0}^{+2.2}$	1281/332
Synchrotron model	γm/γc	Ec (keV)	p	pgstat/dof
	${4.06}_{-0.08}^{+0.03}$	${21.6}_{-0.4}^{+0.2}$	>4.82	2520/335

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The isotropic energy (E_γ,iso) is calculated in the cosmological frame of the GRB by integrating the observed energy spectrum over 1 keV/(1 + z) to 10 MeV/(1 + z). The tested models differ significantly only at low energies and yield similar E_γ,iso. We have E_γ,iso = 2.2 × 10⁵³ erg for the best-fit model grbcomp. The Γ₀ − E_γ,iso correlation between the initial Lorentz factor and the isotropic energy can be used to estimate Γ₀ of the fireball ejecta (Liang et al. 2010). The estimated Γ₀ is ${392}_{-34}^{+38}$. The errors are propagated from the normalization and slope of the correlation. Episode 2 could be spectrally well described by a simple power-law, and the best-fit power-law index is ${1.90}_{-0.06}^{+0.07}$ for pgstat 274 for 229 degrees of freedom.

4.1. Parameter Evolution

We performed a time-resolved analysis to capture the variations in the spectral properties by dividing the data into time segments based on the Bayesian blocks made from the 100–400 keV light curve. We test the models that were used for the time-integrated analysis. The deviation from Band spectrum at low energies observed in the time-integrated spectrum is also present in the time-resolved bins, thus justifying the need to use more complex models than the simple Band function. However, we find that the three additional models (Band+BB, bknpwl, and grbcomp) represent the time-resolved spectral data equally well. The evolution of the model parameters is shown in Figure 4. In Fermi-GBM, the energy range 8–20 keV is divided into 12 energy channels, and thus it provided sufficient data points to constrain the power law or BB temperature when the BB peak or low-energy break falls well within these energy channels. In case of bkn2pow, the low-energy index is very steep (∼−3) when the break energy E₁ is found to be close to the lower edge of the detection band. For such cases, we froze the index to −3 to obtain constraints on the other parameters of the model. When we fit with the Band function, the peak energy E_p shows three pulse-like structures in their temporal evolution, and these can be identified as showing a hard-to-soft evolution for peaks in the photon flux. The first structure in E_p (at ∼10 s) can be associated with the enhancement seen in the <1 MeV flux (Figure 2, top panel). When the low-energy feature is modeled using bkn2pow, almost all the peak energies fall below 200 keV. The variation in the low-energy break (E₁) remains concentrated in a very narrow band (10–20 keV). The best-fit parameters for all the models are presented in the Appendix.

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The evolution of the derived parameters of the grbcomp model such as photospheric radius (R_ph) and bulk parameter (δ) is shown in Figure 6.

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4.1.1. Parameter Distribution

Although the best fit to the time-integrated spectrum is the Comptonization model (grbcomp), we have tested the models (i) Band, (ii) bkn2pow, (iii) BB+Band, and (iv) grbcomp for the time-resolved spectra. The distribution of the parameters is presented in Figure 7 and summarized here.

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For the Band function, the low-energy index α is distributed with a mean value −1 (σ = 0.13). The maximum value observed is −0.25 for a few time bins, and in the other cases, α remains mostly below −0.8. The values of the low-energy index agree with what is typically observed for long GRBs ($\langle \alpha \rangle$ = −1), which is, however, known to be harder than the synchrotron radiation in the fast-cooling regime. The high-energy index follows a bimodal distribution with a mean value of −2.7 (σ = 0.3) for the main chunk, which is concentrated around −3 < β < −2 and can be interpreted as values normally observed for GRBs. The peak energy E_p is between 32 and 365 keV with a median ∼140 (σ = 83) keV. Its distribution also shows a bimodal nature, which reflects the evolution of E_p.

In the case of bkn2pow, we observed that when the lower break energy E₁ is near the lower edge of the detection band, the power-law index below E₁ is very steep. This is expected because there are only a few channels here and the fit probably gives an unphysical result. We thus fixed the values to −3 because they are difficult to constrain by the fits and also hamper the overall fitting process. Note that the bkn2pow model is defined with an a priori negative sign, and we have to be cautious when we compare it with the Band function, where the indices are defined without a negative sign. For the purpose of comparison, we explicitly reverse the signs of the bkn2pow indices. The mean value of −α₁ is ∼0.3 (σ = 0.65). Here, we have ignored values <1.5 as they form another part of the bimodal distribution with low E₁, during the time when E₁ is near the lower edge of the GBM energy band. The mean value of −α₂ is ∼−1.4 (σ = 0.22). This forms the second power law from E₁ to E₂. The third segment of the emission has a power-law index −α₃ with a mean of ∼−2.6 (σ = 0.23). The low-energy break E₁ has a mean ∼16 (σ = 2.3) keV, and it falls in a narrow range of 11–20 keV. The mean E₂ is ∼140 (σ = 32) keV, comparable to the mean of the Band function peak energy with a unimodal distribution. The E₂ values are concentrated in the range 93–350 keV.

When a BB is added, the fit statistics is better than the Band function throughout the burst (see Figure 5). The BB temperature varies between 4 and 10 keV with a median of ∼6.3 (σ = 1.12) keV. The α distribution has harder values, while E_p and β are similar to the distributions of their counterparts in the Band function. The presence of a BB does not seem to move the peak energies significantly, but an upward shift is noticeable. In the grbcomp model, the average temperature of the seed photons was 6.8 (σ = 0.8) keV. The electron temperature kT_e was found to be 55 (σ = 21) keV. We derived the photospheric radius from the normalization of the model. We found the photospheric radius to be ∼10¹¹ cm. The grbcomp model parameters are reasonable, and a photospheric radius of 10¹¹ cm is consistent with the predictions (Frontera et al. 2013).

4.1.2. Parameter Correlations

We explore two parameter correlations and present the graphs in Figure 8.

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(i) kT_BB versus E_p: Thermal components observed in a set of bright Fermi single-pulse GRBs are correlated to the peak of nonthermal emission (Burgess et al. 2014b). The exponent of the power-law relation (E_p ∝ T^q) indicates the position of the photosphere if it is in the coasting phase or acceleration phase. The jet is dominated by magnetic fields when q is 2 and baryonic if q is nearly 1. However, these results were found in GRBs with single pulses, and for GRBs made up of overlapping pulses, these criteria may not be valid. For GRB 171010A, a positive correlation (E_p ∝ T^2.2) between E_p and kT_BB is found with a log-linear Pearson correlation coefficient of 0.81 and a p-value ∼10⁻¹⁵. The index therefore points out a magnetically dominated jet with a photosphere below the saturation radius. We discuss this result coupled with the polarization results in Section 7. The peak energy from the Band function and BB + Band function is also found to be correlated, ${E}_{{\rm{p}},\mathrm{Band}}\propto {E}_{{\rm{p}},\mathrm{BB}+\mathrm{Band}}^{1.2}$.

(ii) Correlations of the grbcomp parameters: Correlations between the grbcomp model parameters and other model parameters are reported in Frontera et al. (2013). We found a strong correlation between the peak energy of the Band function and the bulk parameter (δ), with a log-linear Pearson coefficient and a p-value r(p) of −0.68 (∼10⁻⁹). The seed photon temperature kT_BB and photospheric radius R_ph are uncorrelated, in contrast to the strong anticorrelation reported in Frontera et al. (2013). The seed BB temperature and the electron temperature are not correlated, consistent with the predictions of the grbcomp model. The parameter ${{kT}}_{e}$ and the peak energy of the BB+Band model are correlated, with ${{kT}}_{e}\propto {E}_{{\rm{p}},\mathrm{BB}+\mathrm{Band}}^{1}$.

We have analyzed the afterglow data of GRB 171010A in gamma-rays (Fermi-LAT) and X-rays (Swift-XRT), and the results are shown in Figures 9 and 10.

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5.1. γ-ray Afterglows

A 12° region of interest was selected around the refined Swift-XRT coordinates and an angle of 100° between the GRB direction and Fermi zenith was selected based on the navigation plots. The zenith cut is applied to reduce the contamination from γ-rays of the Earth albedo. The transient event class and its instrument response function P8R2_TRANSIENT020E_V6 is used because it is appropriate for GRB durations. Details about the LAT analysis methods and procedures can be found in the Fermi-LAT GRB catalog (Ackermann et al. 2013).

A simple power-law temporal decay is observed for the LAT light curve with a hint of a momentary increase or steady emission in both energy and photon fluxes during the first and second time bins: 346–514 s and 514–635 s. The LAT photon flux varies with time as a power law with an index −1.56 ± 0.40, and the energy flux varies as a power law with an index −1.37 ± 0.45. The photon index of LAT-HE is Γ_L = −2.0 ± 0.1 from a spectral fit obtained by fitting the first 10⁵ s data. This gives a spectral index β_L = Γ_L + 1 to be −1.0 ± 0.1. The time-resolved spectra show no variation in the photon index in the first four bins. The parameters are reported in Table 2, and the evolution of the flux and photon index is shown in Figure 9.

In the external shock model, for ν > max {ν_m, ν_c}, which is generally true for reasonable shock parameters, we can derive the power-law index of the shocked electrons by f_ν ∝ ν^−p/2. We have a synchrotron energy flux ${f}_{L}\propto {\nu }^{-{\beta }_{L}}{t}^{-{\alpha }_{L}}$ (see the LAT light curve in Figure 9). We found α_L = 1.37 ± 0.45 and β_L = 1.0 ± 0.1. The value of β_L gives us p = 2.0 ± 0.2. Thus, the power-law index for the energy flux decay can be predicted using f_L ∝ t^(2–3p)/4. The calculated value of α_L is −1.0 ± 0.2, which agrees well with the observed value of −1.37 ± 0.45. We can therefore conclude that for GRB 171010A, the LAT high-energy afterglows are formed in an external forward shock.

For the thin-shell case in a homogeneous medium and assuming that the peak of the LAT afterglow (t_p) occurs either before or in the second time bin, we find t_p < 530 s, and we can constrain the initial Lorentz factor (Γ₀) of the GRB jet (see, e.g., Sari & Piran 1999; Molinari et al. 2007) using

$$\begin{eqnarray}&&{{\rm{\Gamma }}}_{0}\gt 193{\left(n\eta \right)}^{-1/8}\times {\left(\displaystyle \frac{{E}_{\gamma ,52}}{{t}_{{\rm{p}},z,2}^{3}}\right)}^{1/8},\end{eqnarray} \tag{ 3 }$$

where m_p is the proton mass, η is the radiation efficiency, t_p is the time when the afterglow peaks, and E_γ,52 is the k-corrected rest-frame energy of the GRB in the 1–10,000 keV band. For a typical density n = 0.1 cm⁻³ of the homogeneous ambient medium and η = 0.5, we can constrain the initial Lorentz factor Γ₀ > 330. This limit is consistent with Γ₀ found in Section 4 from the Γ₀ − E_γ,iso correlation.

The photon index hardens in the 2150–6650 s time bin, and the flux also seems to deviate from the power-law fit. This indicates a contribution from an inverse Compton component. The highest energy photon with a rest-frame energy of ∼25 GeV is also observed during this interval.

5.2. X-ray Afterglows

The primary goal of the Swift satellite is to detect GRBs and observe the afterglows in X-ray and optical wavelengths. If a GRB is not detected by Swift but is detected by some other mission (e.g., Fermi ), ToO mode observations can be initiated in Swift for very bright bursts. For such bursts, the prompt phase is missed by Swift and afterglow observations are also inevitably delayed. However, the detection of X-ray afterglows with Swift-XRT not only allows us to study the delayed afterglow emissions, but also allows us to precisely localize the GRB for further ground- and space-based observations at longer wavelengths. The X-ray afterglow of GRB 171010A was observed by Swift ∼24,300 s (∼0.3 days) after the burst. We have used the XRT products and light curves from the XRT online repository¹⁷ to study the light curve and spectral characteristics. The statistically preferred fit to the count-rate light curve in the 0.3–10 keV band has three power-law segments with two breaks. The temporal power-law indices and the break times in the light curve, as given in the GRB online repository, are listed in Table 3. The data are also consistent with three breaks (Table 3). The light curve with three breaks resembles the canonical GRB light curves observed in XRT (Nousek et al. 2006; Zhang et al. 2006). We have analyzed the XRT spectral data and generated the energy-flux light curve shown in Figure 10. The flux light-curve in the 0.3–10 keV energy band is fit with a single power-law and a broken power-law with a single break at time t_b. The best-fit single power-law shows a decay index of f_X ∝ t^{−1.44±0.03}, while in the broken power-law, the pre- and post-break decay indices are 1.29 ± 0.05 and 1.97 ± 0.24, respectively, with the break at t_b = (3.37 ± 1.03) × 10⁵ s. These values are consistent with the fits for the count-rate light curves given in Table 3.

Table 3.  Best-fit Parameters for Power-law Fits with Multiple Breaks for the Low-energy Light Curve from XRT

Breaks	α1	tb,1	α2	tb,2	α3	tb,3	α4
		(104 s)		(105 s)		(105 s)
1	${1.30}_{-0.08}^{+0.07}$	${34.0}_{-15.0}^{+0.0}$	${2.0}_{-0.0}^{+0.0}$	⋯	⋯	⋯	⋯
2	${2.37}_{-0.17}^{+0.32}$	${8.6}_{-5.0}^{+1.6}$	$-{0.95}_{-0.55}^{+2.13}$	${1.58}_{-0.14}^{+1.57}$	${1.85}_{-0.14}^{+0.14}$	⋯	⋯
3	${2.37}_{-0.16}^{+0.39}$	${7.0}_{+3.0}^{+0.0}$	${0}_{-2}^{+1}$	${1.8}_{-0.4}^{+0.0}$	${2.0}_{-0.5}^{+6.0}$	${8.0}_{-6.0}^{+0.0}$	${1}_{-3}^{+7}$

Note. Power law with two breaks is the best-fit model.

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Table 4.  Spectral Fit to the XRT Spectra at Different Time Intervals Using the Power-law (PL) Model

Time	Model	nH,i	αpo	CSTAT/dof
(104 s)	PL	1022
Phase 1
(2.43–17.5)			${1.9}_{-0.1}^{+0.1}$
Phase 2		${0.27}_{-0.05}^{+0.05}$		513/566
(17.5, 132.2)			${2.0}_{-0.2}^{+0.2}$
Phase 1	PL	αpo	CSTAT/dof
(2.43, 2.58)		${1.45}_{-0.70}^{+0.32}$	179/222
(3.03, 3.17)		${1.7}_{-0.1}^{+0.1}$	211/246
(3.59, 4.16)		${1.71}_{-0.15}^{+0.15}$	204/205
(13.3, 17.5)		${1.9}_{-0.2}^{+0.2}$	109/135
Phase 2
(17.5, 77.2)		${1.8}_{-0.2}^{+0.2}$	151/188
(85, 132.2)		${1.4}_{-0.4}^{+0.5}$	45/41

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We call the two segments of the light curve with three breaks phase 1 (see Table 3) before t_b,2 and phase 2 after t_b,2. Phase 1 is subjectively divided into three time bins to track the evolution of the spectral parameters during this phase. Phase 2 is also divided at t_b,3 to inspect the spectral change with the apparent rise in the light curve after this point.

We froze the equivalent hydrogen column density (n_H) to its Galactic value (Willingale et al. 2013). Another absorption model, tbabs in XSPEC, is used to model intrinsic absorption, and n_H corresponding to it is frozen to the value obtained from the time-integrated fit. A simple power law fits the spectrum for both the phases and the parameters are reported in Table 4.

The photon index in the XRT band is found to be Γ_X = −1.9 ± 0.1 for phase 1 and ${{\rm{\Gamma }}}_{{\rm{X}}}=-{1.7}_{-0.6}^{+0.3}$ for phase 2. The evolution of energy flux in 0.3–10 keV and the photon index are shown in Figure 10. Similar to LAT, it also predicts p ∼ 2 when both ν_m and ν_c evolve to energies that lie below the XRT band. When we consider p ∼ 2.2 (see, e.g., Nousek et al. 2006; Zhang et al. 2006), which will be nearly consistent with the p inferred from the LAT afterglow and is also near to the XRT-afterglow value. For the late-time decay, we therefore have α_X ∼ −1.15. When the light curve is modeled by a broken power-law, we obtain f_X ∝ t^{−1.29±0.05} before the break and f_X ∝ t^{−1.97±0.24} thereafter. This means that the predicted α_X ∼ −1.15 is nearly consistent with α_X ∼ 1.29 ± 0.05 (three times the error bar). The α_X before and after the break are consistent with the late-time decay in the external shock model. The observed break can also be identified as a jet break (t_break = 3.4 × 10⁵ s) and can be used to determine the opening angle (θ_j) of the jet as given by Equation (4) (Frail et al. 2001). However, an achormatic break at all wavelengths in the light curves is required to claim that it is as a jet break. The absence of a break until the last data point observed in XRT can also be used to place a lower limit on the jet break (see, e.g., Wang et al. 2018). This means that any break before that corresponds to the last data point in XRT will also respect that limit because for a given initial Lorentz factor (Γ₀), the jet break will occur later for a wider jet,

$$\begin{eqnarray}\begin{array}{rcl}{\theta }_{j} & \approx & 0.057{\left(\displaystyle \frac{{t}_{j}}{\mathrm{86,400}{\rm{s}}}\right)}^{3/8}{\left(\displaystyle \frac{1+z}{2}\right)}^{-3/8}\\ & & \times \ {\left(\displaystyle \frac{{E}_{\mathrm{iso}}}{{10}^{53}\mathrm{erg}}\right)}^{-1/8}{\left(\displaystyle \frac{\eta }{0.2}\right)}^{1/8}{\left(\displaystyle \frac{n}{0.1{\mathrm{cm}}^{-3}}\right)}^{1/8}.\end{array}\end{eqnarray} \tag{ 4 }$$

We obtain θ_j = 0.11 rad (=63) using Equation (4). The beaming angle can be estimated using the Lorentz factor Γ₀ with θ_beam = 1/Γ₀. For Γ₀ = 330, we have θ_beam = 0.003 rad (=017). Thus, we have a wide bright jet with a narrow beaming angle. The Lorentz factor estimated above holds for the final merged shells propagating to the circum-burst medium and forming an external shock. The Lorentz factor for individual shells can be even higher than our estimate. The jet energy corrected for collimation is 1.37 × 10⁵¹ erg.

GRB 171010A is one of the brightest GRBs detected in CZTI with an observed fluence <10⁻⁴ erg cm⁻². This makes the GRB a candidate for polarization measurement. CZTI works as a Compton polarimeter, where polarization is estimated from the azimuthal angle distribution of the Compton-scattering events between the CZTI pixels at energies beyond 100 keV. The polarization measurement capability of CZTI has been demonstrated experimentally during its ground calibration (Chattopadhyay et al. 2014; Vadawale et al. 2015). First on-board verification of its X-ray polarimetry measurement capability came with the detection of high polarization in Crab in 100–380 keV (Vadawale et al. 2017). Crab was observed for ∼800 ks in two years after its launch, and this was statistically the most significant polarization measurement to date in hard X-rays. The polarimetric sensitivity of CZTI for off-axis GRBs is expected to be lower than that for on-axis sources (e.g., Crab), but the high ratio of signal to background noise for GRBs and the availability of pre-GRB and post-GRB background makes CZTI equally sensitive to polarization measurements of GRBs. Recently, we reported systematic polarization measurement for 11 GRBs, with ∼3σ detection for 5 GRBs and ∼2σ detection for 1 GRB, and an upper limit estimation for the remaining 5 GRBs. GRB 171010A is a bright GRB for which ∼2000 Compton events were registered in CZTI. It is the second-brightest GRB in terms of the number of Compton events after GRB 160821A, and therefore is a candidate for polarization analysis.

The details of the polarization measurement of GRBs with CZTI can be found in Chattopadhyay et al. (2017). Here we briefly describe the different steps involved in the analysis procedure.

• 1.  
  The first step is to identify and select the valid Compton events. We select the double-pixel events during the prompt emission by identifying events that occur within a 40 μs time window. The double-pixel events are then filtered against various Compton kinematics criteria to finally obtain the Compton-scattered events.
• 2.  
  The selection of Compton events is confined within the 3 × 3 pixel block of CZTI modules, which results in an 8 bin azimuthal scattering angle distribution. We compute the azimuthal scattering angles for events during both the GRB prompt emission and the background before and after the prompt emission. The combined pre- and post-GRB azimuthal distribution is used for background subtraction to finally obtain the azimuthal distribution for the GRB.
• 3.  
  The background-corrected prompt emission azimuthal distribution shows some modulation due to (a) the asymmetry in the solid angles subtended by the edge and the corner pixels to the central scattering pixel, and (b) the off-axis viewing angle of the burst. These two factors are corrected by normalizing the azimuthal angle distribution with a simulated distribution for the same GRB spectra at the same off-axis angle assuming that the GRB is completely unpolarized. The simulation is performed in Geant4 with a full mass model of CZTI and AstroSat.
• 4.  
  We fit the background- and geometry-corrected azimuthal angle distribution using a Markov chain Monte Carlo (MCMC) simulation to estimate the modulation factor and polarization angle (PA; in the CZTI plane). This is followed up by detailed statistical tests to determine whether the GRB is truly polarized. This is an important step, particularly because there can be systematic effects that can produce significant modulation in the azimuthal angle distribution even for completely unpolarized photons. These effects are even more prominent in cases where the GRB is dim.
• 5.  
  If the statistical tests suggest that the GRB is truly polarized, we estimate the polarization fraction (PF) by normalizing the fitted modulation factor with μ₁₀₀, which is the modulation factor for 100% polarized photons, obtained by simulating the GRB that is simulated in Geant4 with the AstroSat mass model. If the GRB is found to be unpolarized, we estimate the upper polarizatio limit (see Chattopadhyay et al. 2017).

Figure 11 shows the light curve of GRB 171010A in Compton events in 100–300 keV. The burst is clearly seen in Compton events. We used a total of 747 s of background before and after the burst for the final background estimation. After background subtraction, the number of Compton events during the prompt emission is found to be ∼2000. Figure 12 shows the modulation curve in the 100–300 keV band following background subtraction and geometry correction, as discussed in the last section. We do not see any clear sinusoidal modulation in the azimuthal angle distribution. Figure 13 shows the corresponding contour plot for GRB 171010A. Both PF and PA are poorly constrained, signifying that the burst is either unpolarized or that the PF is below the sensitivity level of CZTI.

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In order to verify this, we measure the Bayes factor for the sinusoidal (for polarized photons) and constant model (unpolarized photons) using the thermodynamic integration method in the MCMC parameter space (for details, we refer to Chattopadhyay et al. 2017). This yields a value lower than 2, which is assumed to be the threshold value of the Bayes factor for claiming a polarization detection. We therefore estimate the upper polarization limit for GRB 171010A, which is done in two steps. The first step involves estimating the polarization detection threshold (P_thr) by limiting the probability of false detections (to 0.05 for ∼2σ or 0.01 for ∼3σ). The false polarization detection probability is estimated by simulating GRB 171010A for the observed number of Compton and background events with 100% unpolarized photons. The second step involves measuring the detection probability of polarization such that the detection probability of a certain level of polarization (P_upper) is greater than the polarization detection threshold (P_thr), which is ≥0.5 (see Chattopadhyay et al. 2017 for more details). The 2σ upper limit (5% false-detection probability) for GRB 171010A is found to be ∼42%. It is to be noted that in the sample of bursts we used for the polarization analysis in Chattopadhyay et al. (2017), GRB 160821A was found to possess the maximum number of Compton events (∼2500). The next-brightest burst was GRB 160623A with ∼1400 Compton events. We estimated ∼50% polarization at <3σ detection significance for GRB 160821A. In comparison, GRB 171010A is found to have ∼2000 Compton events. The GRB is detected at an off-axis angle of 55°. We expect CZTI to have significant polarmetric sensitivity at these off-axis angles. Therefore, polarization for this GRB should be detected at a significant detection level provided the GRB is at least ∼50% polarized. This is consistent with our estimate of a 2σ upper polarization limit of ∼42%.

This is an interesting result becaise the spectral analysis suggests that the time-integrated peak energy for all the models is lower than 200 keV, which falls within the energy range of the polarization analysis. In order to see the variation of polarization below and above the peak energy, we therefore estimate the polarization in two different energy ranges: 100–200 and 200–300 keV (see Figure 14). There is no clear modulation at the lower energies, whereas we see a sinusoidal variation in the modulation curve in 200–300 keV, which is beyond the peak energy of the GRB. However, it is to be noted that the Bayes factors for the two energy ranges are lower than 2, signifying that there is no firm detection of polarization. The modulation at higher energies is therefore just an indication of polarization, which is still an interesting result.

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One main difference between GRB 160821A (or GRB 160802A and GRB 160910A; Chattopadhyay et al. 2017) and GRB 171010A is that the latter lasts longer and has multiple pulses. We also see significant variation in peak energy with time (see Figure 4). These pulses might exhibit different polarization signatures resulting in a net zero or in low polarization when integrated in time. We therefore divided the whole burst into three different time intervals of 0–20, 20–28, and 28–70 s, where "0" is the onset of the burst. Because we have already seen an indication of a polarization signature in 200–300 keV, we further divided the signals into 100–200 and 200–300 keV. Figure 15 shows the variation in PF (middle panel) and PA (bottom panel) in three time intervals for 100–200 keV (left) and 200–300 keV (right). The errors in PA in the first two intervals in the two energy ranges are quite large, with no significant modulation in azimuthal angle distribution; this is consistent with being unpolarized. This is independently verified with the estimate of low values of the Bayes factor. The third interval, on the other hand, shows a high PF with a very clear sinusoidal modulation in the azimuthal angle distribution in 200–300 keV (see Figure 16). The PA is also constrained within 13° uncertainty. The Bayes factor for this interval in 200–300 keV is found to be ∼2, with a false polarization detection probability by chance <1%, clearly signifying that the GRB is polarized in the later part of the emission at higher energies.

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We presented the spectral, timing, and polarization analysis of GRB 171010A, which has an observed fluence >10⁻⁴ erg cm⁻². We found that the spectrum integrated over the duration of the burst is peculiar because it shows a low-energy break and can be modeled by either a BB or another power law. Some GRBs have shown the presence of such a component, which was modeled by a BB with peaks ranging up to 40 keV (Guiriec et al. 2011). In a comprehensive joint analysis of X-rays and higher energies in the prompt emission, a break was found in the XRT-energy window (Zheng et al. 2012; Oganesyan et al. 2018, 2017) and also in the GBM energy range (Ravasio et al. 2018). To study the detailed evolution of the spectral parameters, we sliced the spectrum into multiple time bins and found that Band E_p shows a bimodal distribution. Inclusion of a low-energy component (modeled as a BB or a separate power law) shows that the distribution of the peak energy remains >100 keV and also falls in a concentrated region of between 100 and 200 keV. The mean value of the break energy in the power law with two breaks, model (E₂), is ∼140 keV. The power-law index above the break is softer than the index α obtained from the Band function. The mean value of −α₂ is −1.45, and we are tempted to identify it with the synchrotron fast-cooling process. E₂ can therefore be identified with the minimum energy injected to the electrons, and the corresponding frequency is ν_m. On the other hand, −α₁ is 0.3, harder than the value of the spectral index −2/3 that is allowed below the cooling frequency ν_c of the synchrotron radiation. However, the absorption frequency, which can be near the GBM lower energy window, has an expected index of +1, thus it is possible that the cooling frequency falls very near to the absorption frequency. In this case, E₁ can be either identified as ν_c or ν_a because the ratio ν_c/ν_a or ν_a/ν_c will be closer to 1. Now, relating to the fast-cooling scenario, −α₃ can be set equal to −p/2 − 1 to obtain the index of the power-law distribution of electron energies. We derived p ≃ 3.2, and for the distribution shown by −α₃, the allowed values of p fall in the range 2–4. The component at the low-energy end can also be interpreted as being of photospheric origin, generated in a region that is optically thick to the radiation, and radiation escaping at a radius where it becomes transparent. We also tested the synchrotron model because bkn2pow gives a possibility that a synchrotron model in the marginally fast-cooling regime might work in principle. The direct fitting of the prompt emission spectra by the synchrotron model was performed in number of studies (Tavani 1996; Lloyd & Petrosian 2000; Burgess et al. 2014a; Zhang et al. 2016, 2018; Burgess et al. 2018) that give the preference to the slow- or moderataly fast-cooling radiation regimes. In our analysis, the synchrotron model returns a low ratio between γ_m and γ_c and the range of pgstat/dof that is similar to other models, and it has same number of parameters as the Band function. Our results show that the spectral data can also be well described by a Comptonization (grbcomp) model.

From the afterglows observed in LAT (<100 MeV) and XRT (0.3–10 keV), we concluded that the afterglows are produced in an external shock propagating into the ambient medium. By assuming the ambient medium to be homogeneous, we estimated the initial Lorentz factor of the ejecta. However, the Lorentz factor thus obtained is for the merged ejecta. The sub-MeV emission possibly arises from multiple internal shocks, and a stratification in the Lorentz factor cannot be ruled out. From the observed break in the XRT light curve, we obtained the jet opening angle. GRB 171010A consists of a jet with an initial beaming angle much narrower than the jet opening angle.

The burst shows high polarization, but significant variation in the PF and PA can be seen with energy and time. These variations in PA can arise as a result of an ordered magnetic field or random magnetic fields produced in shocks, and when within the beaming angle, the net magnetic field can be oriented in any direction independent of the other shells. For a high polarization, the coherence length of the magnetic field (θ_B) should be larger than or comparable to the beaming angle 1/Γ, i.e., θ_B ≳ 1/Γ. In case of a jet dominated by Poynting flux, a pulse is produced in each ICMART event. The peak energy and polarization decreases in each ICMART event. The polarization degree and angle can vary (Zhang & Yan 2011; Deng et al. 2016). The spectrum can be a hybrid of the BB and Band function. We have observed a low-energy feature and the spectrum deviating from the Band function, which was also modeled by a BB. This can be contribution from a photosphere (Gao & Zhang 2015). The lower polarization at energies below 200 keV can be due to multiple events superimposing and decreasing the net polarization degree. The change in PA with energy also supports this argument. Therefore, the spectrum and polarization measurents are consistent with the ICMART model.

In the Comptonization model, multiple Compton scatterings are assumed, producing higher energy photons in the jet. The photons below the peak energy in the grbcomp model are produced by the Comptonization of the seed BB photons during the subrelativistic phase. This component is therefore expected to be unpolarized. The high-energy photons above the peak energy are mostly generated by further inverse Compton scattering off the nonthermal relativistic electrons of the relativistic outflow. This can give a polarization up to 100% when the emission is observed at an angle 1/Γ with the beaming axis and unpolarized when viewed on-axis (Rybicki & Lightman 1979). As for the polarization, the highest value is expected for emission in the jet because in this case, a photon originating in the Compton cloud illuminates the jet (or outflow) and undergoes a single up-scattering. Single-scattering off jet electrons can result in a degree of polarization of up to 100%. A change in the PF and angle is only possible if the jet is fragmented, and we are observing it at different viewing angles. The measured high polarization below the peak is in contradiction with the predictions of this model.

The photospheric component found in the spectra suggests that the overall spectral shape may also be explained by the subphotospheric dissipation model (Vurm & Beloborodov 2016). The polarization expected in the subphotospheric dissipation model is low and tends to decrease at higher energies because the higher energy photons are produced deep within the photosphere and are reprocessed through multiple Compton scatterings before they finally leave the system at the photosphere (Lundman et al. 2016). The observed increase in polarization with energy is in contradiction with the predictions of this model.

Another interpretation independent of the synchrotron or inverse Compton origin is that the emission comes from fragmented fireballs moving with different velocity vectors (Lazzati & Begelman 2009). The fragments moving into the direction of the observer will have the least polarization. If the intrinsic brightness of all the fragments is the same, then this would also be the brightest fragment. The fragments making a larger angle with the line of sight, on the other hand, will have higher polarization and lower intensity. The PA can sweep randomly between different pulses in this setting. Another prediction of this geometry is that PF and PA should not change within a single pulse. In the time-integrated analysis, we also find a change in polarization with energy. One possible explanation for this is that given the variability seen in the low-energy light curve (100–200 keV), the contribution in this energy range could be from more fragments than that in the high-energy light curve (200–300 keV). The averaging effect thus results in a relatively lower PF (the maximum PF up to 100% can be achieved for the fragments viewed at 1/Γ, where Γ is the Lorentz factor of a fragment) and a different position angle at lower energies in comparison to those in the high-energy band. The change in polarization with time can be explained by temporally separated internal shocks that are produced in the different fragments. Therefore, the change in polarization from high to low seen in the 100–200 keV energy can be explained by considering that the first pulse is produced off-axis and the other brighter pulses are produced near the axis (line of sight). In the high-energy part, an increase in polarization with time is observed, and the PA is also found to be anticorrelated with the low-energy counterpart. This suggests that the high-energy emission receives an increased contribution with time from energetic off-axis fragments.

In the fragmented fireball scenario, the jet should be fragmented into small-scale parts (θ_fragment < θ_beam). The Lorentz factor Γ₀ was calculated from the LAT high-energy afterglows that were produced in the external shocks. If the internal shocks were produced before saturation in the Lorentz factor was achieved, then we can have a lower value of the Lorentz factor when the internal shocks occur. This will allow a little room to increase θ_beam. If the internal shocks are produced at small radii, then the velocity vector within the θ_beam for a radially expanding ejecta will also have more divergence in their direction.

We conclude that the polarization results when used with spectral and temporal information are highly constraining. Although we cannot decisively select a single model, we find that models with a decrease in polarization with energy are either less probable or contributions from multiple underlying shocks in different energy ranges are needed to explain the apparent modulation with energy. The Comptonization model has low polarization at low energies, which contradicts our observations. However, independent of emission mechanisms, a geometric model consisting of multiple fragments can explain the data, but demands fragmentation at small angular scale, well within θ_beam.

This research has made use of data obtained through the HEASARC Online Service, provided by the NASA-GSFC, in support of NASA High Energy Astrophysics Programs. This publication also uses the data from the AstroSat mission of the Indian Space Research Organisation (ISRO), archived at the Indian Space Science Data Centre (ISSDC). The CZT-Imager is built by a consortium of institutes across India, including the Tata Institute of Fundamental Research, Mumbai, the Vikram Sarabhai Space Centre, Thiruvananthapuram, the ISRO Satellite Centre, Bengaluru, the Inter University Centre for Astronomy and Astrophysics, Pune, the Physical Research Laboratory, Ahmedabad, and the Space Application Centre, Ahmedabad: contributions from the vast technical teams from all these institutes are gratefully acknowledged. The polarimetric computations were performed on the HPC resources at the Physical Research Laboratory (PRL). We thank Lev Titarchuk for discussions on the grbcomp model.

The results of the time-resolved analysis using various models of the prompt emission are presented in Table 5.

Table 5.  Time-resolved Spectral Fitting for Different Models

Band	(t1, t2)	α	β	Ep (keV)	KB	pgstat/dof
Sr. No.
1	−1, 7	$-{1.2}_{-0.1}^{+0.1}$	$-{9.3}_{-\infty }^{+19.4}$	${141}_{-19}^{+16}$	${0.016}_{-0.003}^{+0.004}$	420/339
2	7, 9	$-{1.10}_{-0.05}^{+0.05}$	$-{8.8}_{-\infty }^{+18.8}$	${222}_{-23}^{+28}$	${0.029}_{-0.005}^{+0.004}$	284/339
3	9, 10	$-{1.08}_{-0.07}^{+0.1}$	$-{7.7}_{-\infty }^{+17.7}$	${274}_{-74}^{+111}$	${0.054}_{-0.009}^{+0.011}$	212/339
4	10, 12	$-{1.0}_{-0.1}^{+0.1}$	$-{2.2}_{-0.5}^{+0.2}$	${303}_{-51}^{+107}$	${0.081}_{-0.011}^{+0.011}$	310/339
5	12, 14	$-{0.90}_{-0.06}^{+0.07}$	$-{2.3}_{-0.3}^{+0.2}$	${362}_{-52}^{+72}$	${0.10}_{-0.01}^{+0.01}$	311/339
6	14, 17	$-{0.90}_{-0.06}^{+0.07}$	$-{2.15}_{-0.17}^{+0.10}$	${329}_{-50}^{+63}$	${0.09}_{-0.01}^{+0.01}$	400/339
7	17, 18	$-{0.8}_{-0.1}^{+0.1}$	$-{2.4}_{-0.4}^{+0.2}$	${206}_{-31}^{+43}$	${0.18}_{-0.03}^{+0.04}$	290/339
8	18, 19	$-{0.8}_{-0.1}^{+0.1}$	$-{2.40}_{-0.25}^{+0.17}$	${217}_{-23}^{+27}$	${0.23}_{-0.03}^{+0.03}$	210/339
9	19, 20	$-{0.82}_{-0.07}^{+0.07}$	$-{2.5}_{-0.3}^{+0.2}$	${241}_{-27}^{+31}$	${0.26}_{-0.03}^{+0.03}$	341/339
10	20, 24	$-{0.80}_{-0.03}^{+0.03}$	$-{2.50}_{-0.01}^{+0.08}$	${230}_{-10}^{+11}$	${0.33}_{-0.01}^{+0.02}$	620/339
11	24, 26	$-{1.00}_{-0.06}^{+0.06}$	$-{2.6}_{-0.2}^{+0.2}$	${130}_{-9}^{+10}$	${0.30}_{-0.30}^{+0.04}$	443/339
12	26, 29	$-{1.10}_{-0.03}^{+0.04}$	$-{2.8}_{-0.4}^{+0.2}$	${196}_{-13}^{+14}$	${0.22}_{-0.01}^{+0.01}$	519/339
13	29, 30	$-{1.00}_{-0.06}^{+0.07}$	$-{2.8}_{-1.6}^{+0.3}$	${255}_{-30}^{+40}$	${0.22}_{-0.02}^{+0.03}$	314/339
14	30, 31	$-{1.00}_{-0.04}^{+0.04}$	$-{9.4}_{9.4}^{+19.4}$	${316}_{-26}^{+28}$	${0.24}_{-0.01}^{+0.02}$	293/339
15	31, 32	$-{0.83}_{-0.05}^{+0.05}$	$-{2.5}_{-0.3}^{+0.2}$	${284}_{-26}^{+32}$	${0.35}_{-0.03}^{+0.03}$	418/339
16	32, 34	$-{0.82}_{-0.03}^{+0.03}$	$-{2.5}_{-0.1}^{+0.1}$	${273}_{-15}^{+17}$	${0.43}_{-0.02}^{+0.02}$	506/339
17	34, 35	$-{0.80}_{-0.05}^{+0.05}$	$-{2.5}_{-0.2}^{+0.1}$	${264}_{-20}^{+23}$	${0.47}_{-0.03}^{+0.04}$	314/339
18	35, 36	$-{0.90}_{-0.05}^{+0.05}$	$-{2.7}_{-0.5}^{+0.2}$	${250}_{-21}^{+24}$	${0.40}_{-0.03}^{+0.03}$	320/339
19	36, 38	$-{0.80}_{-0.04}^{+0.04}$	$-{2.6}_{-0.1}^{+0.1}$	${134}_{-6}^{+7}$	${0.49}_{-0.04}^{+0.04}$	480/339
20	38, 39	$-{1.0}_{-0.1}^{+0.1}$	$-{2.7}_{-0.4}^{+0.2}$	${101}_{-9}^{+10}$	${0.35}_{-0.05}^{+0.07}$	357/339
21	39, 41	$-{0.3}_{-0.3}^{+0.3}$	$-{2.80}_{-0.06}^{+0.05}$	${42}_{-4}^{+5}$	${2.59}_{-1.21}^{+3.07}$	494/339
22	41, 44	$-{1.25}_{-0.04}^{+0.04}$	$-{3}_{-0.7}^{+0.3}$	${110}_{-6}^{+7}$	${0.23}_{-0.02}^{+0.02}$	612/339
23	44, 45	$-{1.1}_{-0.1}^{+0.1}$	$-{3}_{-\infty }^{+0.4}$	${131}_{-16}^{+14}$	${0.27}_{-0.04}^{+0.05}$	288/339
24	45, 46	$-{1.05}_{-0.05}^{+0.05}$	$-{2.8}_{-1.1}^{+0.3}$	${191}_{-14}^{+18}$	${0.32}_{-0.03}^{+0.03}$	366/339
25	46, 47	$-{1.0}_{-0.1}^{+0.1}$	$-{2.5}_{-0.5}^{+0.2}$	${103}_{-12}^{+15}$	${0.33}_{-0.06}^{+0.09}$	356/339
26	47, 48	$-{1.20}_{-0.07}^{+0.07}$	$-{9.4}_{-\infty }^{+19}$	${98}_{-6}^{+7}$	${0.21}_{-0.03}^{+0.03}$	328/339
27	48, 50	$-{1.2}_{-0.1}^{+0.2}$	$-{2.8}_{-1.2}^{+0.4}$	${65}_{-10}^{+7}$	${0.17}_{-0.04}^{+0.10}$	341/339
28	50, 51	$-{1.1}_{-0.1}^{+0.1}$	$-{2.9}_{-1.1}^{+0.4}$	${93}_{-11}^{+11}$	${0.21}_{-0.04}^{+0.06}$	291/339
29	51, 53	$-{1.1}_{-0.1}^{+0.1}$	$-{2.8}_{-0.3}^{+0.2}$	${99}_{-7}^{+8}$	${0.28}_{-0.03}^{+0.04}$	397/339
30	53, 55	$-{1.10}_{-0.04}^{+0.05}$	$-{3.3}_{-\infty }^{+0.6}$	${208}_{-19}^{+17}$	${0.21}_{-0.01}^{+0.02}$	434/339
31	55, 56	$-{1.00}_{-0.04}^{+0.05}$	$-{4.1}_{-\infty }^{+1.2}$	${248}_{-21}^{+22}$	${0.25}_{-0.02}^{+0.02}$	329/339
32	56, 57	$-{1.05}_{-0.04}^{+0.04}$	$-{9}_{-\infty }^{+19}$	${268}_{-20}^{+23}$	${0.29}_{-0.02}^{+0.02}$	339/339
33	57, 58	$-{1.01}_{-0.04}^{+0.04}$	$-{9}_{-\infty }^{+19}$	${252}_{-18}^{+19}$	${0.36}_{-0.02}^{+0.02}$	378/339
34	58, 59	$-{1.00}_{-0.04}^{+0.05}$	$-{2.9}_{-1.0}^{+0.3}$	${245}_{-21}^{+25}$	${0.37}_{-0.01}^{+0.03}$	390/339
35	59, 60	$-{1.05}_{-0.05}^{+0.05}$	$-{2.9}_{-1.1}^{+0.3}$	${233}_{-23}^{+26}$	${0.31}_{-0.02}^{+0.03}$	383/339
36	60, 61	$-{1.00}_{-0.06}^{+0.06}$	$-{2.6}_{-0.6}^{+0.2}$	${212}_{-22}^{+28}$	${0.37}_{-0.03}^{+0.04}$	369/339
37	61, 63	$-{1.00}_{-0.05}^{+0.05}$	$-{2.5}_{-0.2}^{+0.2}$	${165}_{-12}^{+13}$	${0.27}_{-0.02}^{+0.03}$	421/339
38	63, 64	$-{1.0}_{-0.1}^{+0.1}$	$-{2.7}_{-0.6}^{+0.3}$	${141}_{-16}^{+17}$	${0.25}_{-0.04}^{+0.05}$	305/339
39	64, 65	$-{1.0}_{-0.1}^{+0.1}$	$-{2.8}_{-\infty }^{+0.3}$	${154}_{-16}^{+24}$	${0.29}_{-0.04}^{+0.04}$	316/339
40	65, 67	$-{1.00}_{-0.04}^{+0.04}$	$-{2.8}_{-0.3}^{+0.2}$	${165}_{-10}^{+11}$	${0.39}_{-0.03}^{+0.03}$	551/339
41	67, 68	$-{1.04}_{-0.06}^{+0.06}$	$-{3}_{-1}^{+0.3}$	${137}_{-11}^{+12}$	${0.39}_{-0.04}^{+0.05}$	415/339
42	68, 69	$-{1.03}_{-0.05}^{+0.05}$	$-{3}_{-0.7}^{+0.3}$	${153}_{-12}^{+12}$	${0.49}_{-0.04}^{+0.05}$	382/339
43	69, 70	$-{1.0}_{-0.1}^{+0.2}$	$-{2.30}_{-0.15}^{+0.13}$	${87}_{-16}^{+13}$	${0.43}_{-0.09}^{+0.23}$	389/339
44	70, 71	$-{1.08}_{-0.06}^{+0.06}$	$-{2.80}_{-0.64}^{+0.25}$	${140}_{-12}^{+15}$	${0.34}_{-0.04}^{+0.04}$	379/339
45	71, 72	$-{1.00}_{-0.02}^{+0.04}$	$-{9}_{-\infty }^{+19}$	${158}_{-4}^{+8}$	${0.46}_{-0.03}^{+0.03}$	363/339
46	72, 73	$-{1.02}_{-0.08}^{+0.09}$	$-{2.8}_{-0.4}^{+0.3}$	${93}_{-8}^{+8}$	${0.39}_{-0.06}^{+0.08}$	316/339
47	73, 74	$-{0.9}_{-0.2}^{+0.8}$	$-{2.4}_{-0.2}^{+0.2}$	${56}_{-19}^{+12}$	${0.45}_{-0.18}^{+1.79}$	315/339
48	74, 76	$-{1.10}_{-0.06}^{+0.07}$	$-{2.8}_{-0.3}^{+0.2}$	${89}_{-6}^{+6}$	${0.331}_{-0.04}^{+0.05}$	506/339
49	76, 77	$-{1.1}_{-0.1}^{+0.1}$	$-{2.9}_{-0.7}^{+0.4}$	${84}_{-8}^{+9}$	${0.27}_{-0.05}^{+0.07}$	313/339
50	77, 78	$-{0.3}_{-0.9}^{+0.5}$	$-{2.1}_{-0.8}^{+0.1}$	${47}_{-8}^{+57}$	${1.68}_{-1.68}^{+3.71}$	318/339
51	78, 82	$-{1.2}_{-0.1}^{+0.1}$	$-{2.6}_{-0.2}^{+0.2}$	${75}_{-7}^{+6}$	${0.15}_{-0.02}^{+0.03}$	500/339
52	82, 84	$-{1.1}_{-0.1}^{+0.1}$	$-{2.4}_{-0.2}^{+0.2}$	${139}_{-14}^{+15}$	${0.20}_{-0.02}^{+0.03}$	441/339
53	84, 85	$-{1.1}_{-0.1}^{+0.2}$	$-{2.70}_{-\infty }^{+0.35}$	${109}_{-17}^{+28}$	${0.11}_{-0.03}^{+0.04}$	252/339
54	85, 90	$-{1.2}_{-0.1}^{+0.2}$	$-{2.6}_{-0.1}^{+0.3}$	${76}_{-14}^{+7}$	${0.13}_{-0.02}^{+0.08}$	560/339
55	90, 101	$-{1.2}_{-0.1}^{+0.1}$	$-{2.4}_{-0.3}^{+0.2}$	${83}_{-10}^{+9}$	${0.06}_{-0.01}^{+0.02}$	529/339
56	101, 113	$-{1.30}_{-0.07}^{+0.08}$	$-{3.0}_{-1.0}^{+0.4}$	${86}_{-8}^{+8}$	${0.04}_{-0.01}^{+0.01}$	506/339
57	113, 136	$-{1.3}_{-0.1}^{+0.1}$	$-{3}_{-0.8}^{+0.5}$	${66}_{-6}^{+4}$	${0.036}_{-0.004}^{+0.008}$	676/339
58	136, 137	$-{1.3}_{-0.1}^{+0.1}$	$-{9}_{-\infty }^{+19}$	${83}_{-10}^{+13}$	${0.08}_{-0.02}^{+0.03}$	266/339
59	137, 150	$-{1.3}_{-0.1}^{+0.1}$	$-{3}_{-\infty }^{+0.4}$	${66}_{-5}^{+5}$	${0.04}_{-0.01}^{+0.01}$	491/339
60	150, 171	$-{1.1}_{-0.3}^{+1.4}$	$-{2.3}_{-0.2}^{+0.2}$	${33}_{-12}^{+8}$	${0.04}_{-0.02}^{+0.26}$	382/339

Broken Power-law	(t1, t2)	α1	E1 (keV)	${\alpha }_{2}$	E2 (keV)	β	Ka	pgstat/dof
Sr. no.
1	−1, 7	[−3.0]	${12.3}_{-1.1}^{+0.2}$	${1.6}_{-0.6}^{+0.6}$	${256}_{-122}^{+47}$	${7}_{-4}^{+\infty }$	${0.0001}_{-0.00004}^{+0.002}$	408/337
2	7, 9	[−3.0]	${12.7}_{-2.0}^{+1.8}$	${1.4}_{-0.1}^{+0.1}$	${142}_{-28}^{+59}$	${2.4}_{-0.3}^{+0.6}$	${0.0002}_{-0.00007}^{+0.0002}$	275/338
3	9, 10	${0.9}_{-0.5}^{+0.7}$	${17}_{-17}^{+\infty }$	${1.3}_{-0.1}^{+0.1}$	${194}_{-51}^{+73}$	${2.5}_{-0.4}^{+0.7}$	${5}_{-5}^{+29}$	215/338
4	10, 12	$-{0.5}_{-\infty }^{+0.5}$	${17.0}_{-1.5}^{+1.2}$	${1.25}_{-0.04}^{+0.05}$	${170}_{-23}^{+41}$	${2.1}_{-0.1}^{+0.1}$	${0.14}_{-0.01}^{+0.02}$	287/338
5	12, 14	${0.2}_{-0.7}^{+0.6}$	${18}_{-4}^{+5}$	${1.20}_{-0.05}^{+0.04}$	${212}_{-27}^{+52}$	${2.2}_{-0.1}^{+0.1}$	${0.9}_{-0.9}^{+2.6}$	315/337
6	14, 17	$-{1}_{-1}^{+1}$	${16}_{-2}^{+3}$	${1.20}_{-0.04}^{+0.05}$	${185}_{-22}^{+50}$	${2.1}_{-0.1}^{+0.1}$	${0.023}_{-0.023}^{+0.296}$	373/337
7	17, 18	$-{0.8}_{0.8}^{+0.8}$	${15}_{-2}^{+2}$	${1.10}_{-0.06}^{+0.07}$	${124}_{-13}^{+23}$	${2.2}_{-0.1}^{+0.1}$	${0.11}_{-0.02}^{+0.03}$	288/338
8	18, 19	${0.4}_{-0.4}^{+0.3}$	${19}_{-19}^{+\infty }$	${1.00}_{-0.06}^{+0.06}$	${138.0}_{-15.4}^{+22.3}$	${2.2}_{-0.1}^{+0.1}$	${2.98}_{-2.98}^{+4.78}$	218/338
9	19, 20	$-{0.2}_{-0.9}^{+0.8}$	${17}_{-4}^{+4}$	${1.10}_{-0.05}^{+0.05}$	${146}_{-12}^{+14}$	${2.3}_{-0.1}^{+0.1}$	${0.67}_{-0.67}^{+4.73}$	337/337
10	20, 24	$-{0.2}_{-0.7}^{+0.4}$	${17}_{-2}^{+2}$	${1.10}_{-0.02}^{+0.02}$	${158}_{-8}^{+8}$	${2.30}_{-0.05}^{+0.05}$	${0.80}_{-0.66}^{+1.43}$	611/337
11	24, 26	$-{0.8}_{-0.8}^{+1.2}$	${15}_{-2}^{+5}$	${1.40}_{-0.04}^{+0.06}$	${118}_{-9}^{+10}$	${2.5}_{-0.1}^{+0.1}$	${0.25}_{-0.25}^{+2.07}$	386/337
12	26, 29	${0.2}_{-0.5}^{+0.3}$	${18}_{-1}^{+2}$	${1.50}_{-0.02}^{+0.02}$	${352}_{-26}^{+24}$	${5.3}_{-0.6}^{+0.8}$	${0.013}_{-0.001}^{+0.001}$	571/337
13	29, 30	$-{1.3}_{-0.8}^{+1.2}$	${15.5}_{-1.5}^{+2.5}$	${1.30}_{-0.04}^{+0.04}$	${205}_{-28}^{+30}$	${2.6}_{-0.2}^{+0.2}$	${0.044}_{-0.044}^{+0.490}$	283/337
14	30, 31	$-{0.1}_{-0.6}^{+0.5}$	${15}_{-15}^{+\infty }$	${1.20}_{-0.03}^{+0.03}$	${177}_{-14}^{+16}$	${2.4}_{-0.1}^{+0.1}$	${1.16}_{-1.16}^{+3.50}$	298/338
15	31, 32	$-{0.6}_{-0.5}^{+0.4}$	${16.7}_{-16.7}^{+\infty }$	${1.10}_{-0.03}^{+0.03}$	${186.0}_{-17.3}^{+20.4}$	${2.3}_{-0.1}^{+0.1}$	${0.35}_{-0.35}^{+0.70}$	408/338
16	32, 34	$-{0.2}_{-0.8}^{+0.4}$	${18.0}_{-2.3}^{+2.7}$	${1.10}_{-0.03}^{+0.03}$	${175.0}_{-11}^{+13}$	${2.30}_{-0.05}^{+0.06}$	${1.09}_{-1.09}^{+2.17}$	485/337
17	34, 35	${0.06}_{-0.60}^{+0.40}$	${19}_{-4}^{+4}$	${1.10}_{-0.04}^{+0.04}$	${174}_{-13}^{+15}$	${2.3}_{-0.1}^{+0.1}$	${2.15}_{-2.15}^{+4.08}$	317/337
18	35, 36	${0.1}_{-0.7}^{+0.4}$	${18}_{-3}^{+3}$	${1.10}_{-0.03}^{+0.04}$	${159}_{-12}^{+14}$	${2.4}_{-0.1}^{+0.1}$	${2.31}_{-2.31}^{+4.52}$	319/337
19	36, 38	$-{0.3}_{-0.6}^{+0.4}$	${17}_{-1.5}^{+1.4}$	${1.30}_{-0.03}^{+0.03}$	${116}_{-6}^{+7}$	${2.50}_{-0.07}^{+0.07}$	${1.10}_{-1.10}^{+1.69}$	386/337
20	38, 39	$-{0.3}_{-1.0}^{+0.5}$	${17}_{-2}^{+2}$	${1.60}_{-0.05}^{+0.05}$	${114}_{-13}^{+16}$	${2.7}_{-0.2}^{+0.2}$	${0.94}_{-0.94}^{+2.66}$	294/337
21	39, 41	${0.3}_{-0.3}^{+0.3}$	${19.0}_{-1.4}^{+1.5}$	${1.80}_{-0.05}^{+0.04}$	${126}_{-22}^{+22}$	${3}_{-0.3}^{+0.3}$	${5.24}_{-3.10}^{+5.23}$	391/337
22	41, 44	$-{0.6}_{-0.3}^{+0.2}$	${15}_{-15}^{+\infty }$	${1.60}_{-0.02}^{+0.02}$	${133}_{-10}^{+11}$	${2.80}_{-0.14}^{+0.14}$	${0.51}_{-0.29}^{+0.44}$	443/338
23	44, 45	$[-2.5]$	${12.3}_{-0.7}^{+0.6}$	${1.40}_{-0.04}^{+0.04}$	${108}_{-11}^{+13}$	${2.5}_{-0.1}^{+0.2}$	${0.005}_{-0.001}^{+0.001}$	271/338
24	45, 46	$[-2.0]$	${14.4}_{-0.6}^{+0.6}$	${1.40}_{-0.03}^{+0.03}$	${169}_{-21}^{+16}$	${2.6}_{-0.2}^{+0.2}$	${0.013}_{-0.001}^{+0.002}$	292/338
25	46, 47	$[-3.0]$	${13.0}_{-0.5}^{+0.5}$	${1.50}_{-0.05}^{+0.04}$	${110}_{-17}^{+12}$	${2.5}_{-0.2}^{+0.2}$	${0.0012}_{-0.0002}^{0.0002}$	313/338
26	47, 48	$[-3.0]$	${13.0}_{-0.6}^{+0.6}$	${1.60}_{-0.05}^{+0.04}$	${121}_{-14}^{+17}$	${3.0}_{-0.3}^{+0.3}$	${0.00128}_{-0.0002}^{+0.0003}$	290/338
27	48, 50	$[-3.0]$	${12.6}_{-0.4}^{+0.4}$	${1.80}_{-0.05}^{+0.04}$	${104}_{-23}^{+13}$	${3.0}_{-0.4}^{+0.4}$	${0.00114}_{-0.0002}^{+0.0002}$	288/338
28	50, 51	$[-3.0]$	${13.3}_{-0.7}^{+0.7}$	${1.60}_{-0.06}^{+0.06}$	${109}_{-17}^{+20}$	${2.8}_{-0.3}^{+0.4}$	${0.00085}_{-0.0002}^{+0.0002}$	255/338
29	51, 53	$-{0.8}_{-1.0}^{+0.8}$	${15.0}_{-1.4}^{+1.6}$	${1.60}_{-0.04}^{+0.04}$	${113}_{-13}^{+15}$	${2.7}_{-0.2}^{+0.2}$	${0.24}_{-0.24}^{+1.53}$	335/337
30	53, 55	$[-3.0]$	${13}_{-0.4}^{+0.4}$	${1.40}_{-0.03}^{+0.03}$	${157}_{-14}^{+17}$	${2.5}_{-0.1}^{+0.1}$	${0.0011}_{-0.0001}^{+0.0002}$	370/338
31	55, 56	$-{0.2}_{-0.7}^{+0.6}$	${17}_{-3}^{+3}$	${1.30}_{-0.04}^{+0.04}$	${200}_{-24}^{+31}$	${2.6}_{-0.2}^{+0.2}$	${0.88}_{-0.88}^{+3.29}$	309/337
32	56, 57	$-{1.2}_{-0.9}^{+1.5}$	${14}_{-1}^{+4}$	${1.30}_{-0.03}^{+0.04}$	${177}_{-15}^{+19}$	${2.5}_{-0.1}^{+0.1}$	${0.09}_{-0.09}^{+0.96}$	330/337
33	57, 58	$-{0.6}_{-0.8}^{+1}$	${15.0}_{-2.3}^{+3.1}$	${1.30}_{-0.03}^{+0.03}$	${169}_{-13}^{+15}$	${2.50}_{-0.12}^{+0.14}$	${0.56}_{-0.56}^{+2.12}$	359/337
34	58, 59	$-{0.6}_{-0.5}^{+0.9}$	${15.0}_{-2.3}^{+3.0}$	${1.30}_{-0.03}^{+0.03}$	${168}_{-12}^{+14}$	${2.4}_{-0.1}^{+0.1}$	${0.57}_{-0.57}^{+2.99}$	366/337
35	59, 60	${0.4}_{-0.4}^{+0.3}$	${21.0}_{-2.8}^{+3.4}$	${1.40}_{-0.04}^{+0.04}$	${211}_{-25}^{+36}$	${2.6}_{-0.1}^{+0.2}$	${5.93}_{-4.02}^{+6.67}$	364/337
36	60, 61	${0.2}_{-0.5}^{+0.4}$	${19.0}_{-2.3}^{+3.0}$	${1.40}_{-0.03}^{+0.04}$	${166}_{-13}^{+14}$	${2.4}_{-0.1}^{+0.1}$	${3.40}_{-2.58}^{+5.85}$	330/337
37	61, 63	$[-3]$	${13.0}_{-0.5}^{+0.5}$	${1.30}_{-0.03}^{+0.03}$	${120}_{-9}^{+9}$	${2.3}_{-0.1}^{+0.1}$	${0.0012}_{-0.0002}^{+0.0002}$	375/338
38	63, 64	$-{1.4}_{-\infty }^{+1.4}$	${14}_{-1}^{+1}$	${1.30}_{-0.05}^{+0.05}$	${120}_{-13}^{+15}$	${2.50}_{-0.15}^{+0.16}$	${0.04}_{-0.005}^{+0.007}$	283/338
39	64, 65	${0.40}_{-0.40}^{+0.35}$	${21}_{-3}^{+5}$	${1.50}_{-0.05}^{+0.06}$	${164}_{-26}^{+23}$	${2.7}_{-0.2}^{+0.2}$	${4.51}_{-3.04}^{+7.11}$	289/337
40	65, 67	$-{0.8}_{-1.0}^{+0.7}$	${15.3}_{-1.6}^{+1.9}$	${1.00}_{-0.03}^{+0.03}$	${132}_{-9}^{+10}$	${2.50}_{-0.08}^{+0.08}$	${0.32}_{-0.32}^{+1.68}$	461/337
41	67, 68	$-{0.5}_{-1}^{+0.7}$	${16.0}_{-1.6}^{+2.1}$	${1.40}_{-0.04}^{+0.04}$	${130}_{-14}^{+14}$	${2.6}_{-0.2}^{+0.2}$	${0.81}_{-0.81}^{+3.82}$	366/337
42	68, 69	${0.2}_{-0.6}^{+0.4}$	${18}_{-4}^{+3}$	${1.4}_{-0.1}^{+0.05}$	${146}_{-30}^{+18}$	${2.6}_{-0.3}^{+0.2}$	${5}_{-5}^{+10}$	340/337
43	69, 70	$-{0.07}_{-0.5}^{+0.4}$	${17.0}_{-1.7}^{+1.8}$	${1.60}_{-0.05}^{+0.05}$	${109}_{-16}^{+18}$	${2.4}_{-0.1}^{+0.1}$	${2.15}_{-2.15}^{+4.62}$	334/337
44	70, 71	${0.05}_{-0.50}^{+0.30}$	${18}_{-2}^{+2}$	${1.5}_{-0.04}^{+0.04}$	${154}_{-18}^{+20}$	${2.7}_{-0.2}^{+0.2}$	${2.62}_{-2.624}^{+3.64}$	301/337
45	71, 72	$-{0.2}_{-0.5}^{+0.5}$	${17}_{-1.6}^{+1.8}$	${1.40}_{-0.03}^{+0.03}$	${149}_{-10}^{+12}$	${2.8}_{-0.1}^{+0.2}$	${1.59}_{-1.59}^{+3.97}$	307/337
46	72, 73	${0.3}_{-0.5}^{+0.3}$	${18.2}_{-2.0}^{+2.2}$	${1.60}_{-0.05}^{+0.05}$	${105}_{-9}^{+10}$	${2.70}_{-0.20}^{+0.14}$	${5.57}_{-5.57}^{+8.05}$	275/337
47	73, 74	${0.4}_{-0.9}^{+0.3}$	${18}_{-5}^{+2}$	${1.8}_{-0.2}^{+0.1}$	${110}_{-44}^{+31}$	${2.7}_{-0.4}^{+0.3}$	${5.60}_{-5.60}^{8.12}$	278/337
48	74, 76	$-{0.1}_{-0.8}^{+0.4}$	${16}_{-1.7}^{+1.5}$	${1.6}_{-0.05}^{+0.04}$	${108}_{-15}^{+12}$	${2.7}_{-0.2}^{+0.2}$	${1.86}_{-1.86}^{3.62}$	410/337
49	76, 77	${0.4}_{-0.5}^{+0.4}$	${19}_{-2}^{+3}$	${1.70}_{-0.05}^{+0.06}$	${129}_{-17}^{+15}$	${3.0}_{-0.3}^{+0.4}$	${4.52}_{-4.52}^{+8.12}$	285/337
50	77, 78	$-{1}_{-1}^{+1}$	${15.0}_{-1.6}^{+3.3}$	${1.70}_{-0.06}^{+0.06}$	${136}_{-34}^{+21}$	${3.0}_{-0.3}^{+0.4}$	${0.18}_{-0.18}^{+3.52}$	271/337
51	78, 82	${0.3}_{-0.5}^{+0.3}$	${17.3}_{-1.7}^{+1.5}$	${1.80}_{-0.04}^{+0.04}$	${108}_{-10}^{+12}$	${2.7}_{-0.2}^{+0.2}$	${2.91}_{-2.15}^{+3.58}$	381/337
52	82, 84	$-{1.3}_{-0.9}^{+0.9}$	${15.0}_{-1.1}^{+1.5}$	${1.50}_{-0.04}^{+0.04}$	${128}_{-15}^{+20}$	${2.4}_{-0.1}^{+0.2}$	${0.06}_{-0.06}^{+0.57}$	352/337
53	84, 85	${0.3}_{-0.8}^{+0.6}$	${17.0}_{-5.3}^{+4.4}$	${1.6}_{-0.1}^{+0.1}$	${119}_{-24}^{+23}$	${2.6}_{-0.3}^{+0.4}$	${2.15}_{-2.15}^{+4.85}$	238/337
54	85, 90	$-{0.2}_{-0.8}^{+0.6}$	${16}_{-2}^{+2}$	${1.80}_{-0.05}^{+0.04}$	${118}_{-21}^{+15}$	${2.8}_{-0.2}^{+0.2}$	${0.71}_{-0.71}^{2.27}$	462/337
55	90, 101	$[-2]$	${12.7}_{-0.4}^{+0.4}$	${1.60}_{-0.05}^{+0.03}$	${101}_{-23}^{+13}$	${2.5}_{-0.3}^{+0.2}$	${0.00456}_{-0.00046}^{0.00054}$	470/338
56	101, 113	$[-3]$	${12.8}_{-0.4}^{+0.4}$	${1.70}_{-0.03}^{+0.03}$	${122}_{-12}^{+14}$	${2.9}_{-0.3}^{+0.3}$	${0.00027}_{-0.00003}^{+0.00004}$	403/338
57	113, 136	$[-3.0]$	${12.20}_{-0.30}^{+0.04}$	${1.8}_{-0.06}^{+0.03}$	${97}_{-15}^{+15}$	${2.9}_{-0.3}^{+0.4}$	${0.0003}_{-0.00003}^{+0.000005}$	556/337
58	136, 137	$[-3.0]$	${12.4}_{-1.0}^{+0.9}$	${1.80}_{-0.06}^{+0.07}$	${181}_{-68}^{+51}$	${5.1}_{-2.2}^{+\infty }$	${0.0008}_{-0.0002}^{+0.0003}$	256/338
59	137, 150	$[-3.0]$	${11.6}_{-0.4}^{+0.1}$	${1.70}_{-0.04}^{+0.04}$	${94}_{-10}^{+12}$	${2.9}_{-0.2}^{+0.4}$	${0.0004}_{-0.00006}^{+0.00001}$	449/337
60	150, 171	${0.4}_{-0.8}^{+0.8}$	${14.0}_{-1.5}^{+4}$	${2.0}_{-0.1}^{+0.1}$	${95}_{-62}^{+39}$	${2.9}_{-0.6}^{+0.8}$	${0.93}_{-0.93}^{+5.78}$	372/337

BB+Band	(t1, t2)	α	β	Ep (keV)	KB	kTBB (keV)	KBB	pgstat/dof
Sr. no.
1	−1, 7	$-{0.9}_{-0.3}^{+0.5}$	$-{9.4}_{-\infty }^{+19}$	${153}_{-23}^{+34}$	${0.02}_{-0.01}^{+0.01}$	${6.5}_{-1.6}^{+2.4}$	${0.50}_{-0.34}^{+0.39}$	414/337
2	7, 9	${0.01}_{-0.90}^{+1.80}$	$-{2.4}_{-\infty }^{+0.3}$	${149}_{-34}^{+68}$	${0.08}_{-0.05}^{+0.36}$	${5.5}_{-1.1}^{+1.3}$	${1.36}_{-0.81}^{+0.78}$	276/337
3	9, 10	$-{1.1}_{-0.2}^{+0.2}$	$-{9}_{-\infty }^{+19}$	${299}_{-41}^{+191}$	${0.05}_{-0.01}^{+0.01}$	${13}_{-8}^{+\infty }$	${0.73}_{-0.73}^{+2.00}$	212/337
4	10, 12	$-{0.4}_{-0.4}^{+0.4}$	$-{2.1}_{-0.2}^{+0.1}$	${215}_{-34}^{+81}$	${0.12}_{-0.04}^{+0.06}$	${7.0}_{-1.0}^{+1.5}$	${2.55}_{-1.03}^{+0.78}$	296/337
5	12, 14	$-{0.8}_{-0.3}^{+0.2}$	$-{2.2}_{-\infty }^{+0.1}$	${331}_{-59}^{+383}$	${0.10}_{-0.04}^{+0.02}$	${7.2}_{-3.1}^{+\infty }$	${0.79}_{-0.79}^{+1.05}$	309/337
6	14, 17	$-{0.5}_{-0.2}^{+0.4}$	$-{2.1}_{-0.1}^{+0.1}$	${260}_{-54}^{+66}$	${0.11}_{-0.02}^{+0.05}$	${8.0}_{-1.1}^{+1.5}$	${2.09}_{-0.88}^{+1.06}$	383/337
7	17, 18	$-{0.5}_{-0.2}^{+0.5}$	$-{2.3}_{-0.3}^{+0.2}$	${185}_{-34}^{+51}$	${0.22}_{-0.04}^{+0.17}$	${7}_{-2}^{+7}$	${2.13}_{-1.90}^{+2.20}$	287/337
8	18, 19	$-{0.7}_{-0.4}^{+0.3}$	$-{2.4}_{-\infty }^{+0.2}$	${219}_{-34}^{+219}$	${0.23}_{-0.12}^{+0.08}$	${10}_{-10}^{+\infty }$	${1.20}_{-1.20}^{+2.24}$	209/337
9	19, 20	$-{0.6}_{-0.2}^{+0.5}$	$-{2.4}_{-0.3}^{+0.2}$	${218}_{-41}^{+42}$	${0.31}_{-0.06}^{+0.17}$	${7.0}_{-1.5}^{+3.0}$	${3.16}_{-2.21}^{+2.99}$	335/337
10	20, 24	$-{0.5}_{-0.1}^{+0.1}$	$-{2.4}_{-0.1}^{+0.1}$	${212}_{-12}^{+14}$	${0.39}_{-0.04}^{+0.04}$	${7.3}_{-0.6}^{+0.8}$	${4.26}_{-1.14}^{+1.19}$	579/337
11	24, 26	$-{0.1}_{-0.3}^{+0.4}$	$-{2.5}_{-0.1}^{+0.1}$	${122}_{-9}^{+10}$	${0.63}_{-0.19}^{+0.41}$	${6.0}_{-0.4}^{+0.4}$	${7.79}_{-1.94}^{+2.14}$	390/337
12	26, 29	$-{0.8}_{-0.1}^{+0.1}$	$-{10.0}_{-\infty }^{+0.0}$	${196}_{-7}^{+8}$	${0.25}_{-0.02}^{+0.02}$	${6.0}_{-0.5}^{+0.5}$	${4.55}_{-0.94}^{+0.99}$	458/337
13	29, 30	$-{0.5}_{-0.2}^{+0.1}$	$-{2.6}_{-0.3}^{+0.2}$	${213}_{-21}^{+33}$	${0.30}_{-0.06}^{+0.11}$	${7.0}_{-0.8}^{+0.9}$	${5.63}_{-2.08}^{+2.14}$	293/337
14	30, 31	$-{0.7}_{-0.2}^{+0.2}$	$-{3.0}_{-0.6}^{+0.2}$	${256}_{-31}^{+59}$	${0.29}_{-0.04}^{+0.06}$	${5.7}_{-1.2}^{+1.5}$	${2.74}_{-1.37}^{+2.03}$	289/337
15	31, 32	$-{0.6}_{-0.2}^{+0.2}$	$-{2.4}_{-0.2}^{+0.1}$	${254}_{-30}^{+38}$	${0.40}_{-0.06}^{+0.08}$	${7.4}_{-1.5}^{+2.3}$	${4.14}_{-2.36}^{+2.57}$	409/337
16	32, 34	$-{0.5}_{-0.1}^{+0.1}$	$-{2.4}_{-0.1}^{+0.1}$	${241}_{-18}^{+20}$	${0.52}_{-0.05}^{+0.07}$	${8.0}_{-0.6}^{+0.7}$	${7.67}_{-2.00}^{+2.13}$	460/337
17	34, 35	$-{0.5}_{-0.1}^{+0.2}$	$-{2.4}_{-0.1}^{+0.1}$	${241}_{-26}^{+27}$	${0.54}_{-0.07}^{+0.11}$	${7.7}_{-1.2}^{+1.6}$	${5.62}_{-2.78}^{+3.14}$	302/337
18	35, 36	$-{0.6}_{-0.2}^{+0.3}$	$-{2.6}_{-0.3}^{+0.2}$	${224}_{-30}^{+32}$	${0.46}_{-0.07}^{+0.13}$	${6.7}_{-1.2}^{+1.9}$	${4.25}_{-2.56}^{+3.03}$	313/337
19	36, 38	${0.1}_{-0.3}^{+0.4}$	$-{2.5}_{-0.1}^{+0.1}$	${122}_{-7}^{+8}$	${1.23}_{-0.36}^{+0.70}$	${6.0}_{-0.3}^{+0.3}$	${11.35}_{-2.35}^{+2.50}$	400/337
20	38, 39	${0.3}_{-0.6}^{+1}$	$-{2.7}_{-0.2}^{+0.2}$	${103.0}_{-9.5}^{+10.5}$	${1.21}_{-0.61}^{+3.03}$	${5.9}_{-0.4}^{+0.4}$	${11.89}_{-3.13}^{+3.33}$	305/337
21	39, 41	$-{0.4}_{-0.3}^{+0.5}$	$-{2.8}_{-0.3}^{+0.2}$	${99}_{-9}^{+8}$	${0.50}_{-0.16}^{0.45}$	${6.0}_{-0.3}^{+0.4}$	${11.20}_{-1.93}^{+2.22}$	399/337
22	41, 44	$-{0.4}_{-0.2}^{+0.3}$	$-{2.8}_{-0.2}^{+0.2}$	${116}_{-7}^{+7}$	${0.49}_{-0.11}^{+0.20}$	${5.5}_{-0.2}^{+0.2}$	${10.36}_{-1.48}^{+1.60}$	456/337
23	44, 45	$-{0.5}_{-0.4}^{+0.5}$	$-{2.6}_{-0.3}^{+0.2}$	${116}_{-12}^{+17}$	${0.52}_{-0.19}^{+0.49}$	${5.0}_{-0.6}^{+0.8}$	${6.01}_{-2.89}^{+3.02}$	276/337
24	45, 46	$-{0.4}_{-0.1}^{+0.2}$	$-{2.5}_{-0.2}^{+0.1}$	${167}_{-9}^{+16}$	${0.53}_{-0.10}^{+0.06}$	${6.5}_{-0.5}^{+0.4}$	${10.77}_{-1.48}^{+1.56}$	317/337
25	46, 47	$-{0.2}_{-0.5}^{+0.8}$	$-{2.5}_{-0.3}^{+0.2}$	${107}_{-13}^{+16}$	${0.70}_{-0.31}^{+1.17}$	${6.0}_{-0.5}^{+0.7}$	${9.29}_{-2.90}^{+3.36}$	320/337
26	47, 48	$-{0.3}_{-0.5}^{+0.7}$	$-{3.1}_{-\infty }^{+0.4}$	${108}_{-10}^{+14}$	${0.45}_{-0.19}^{+0.51}$	${5.7}_{-0.5}^{+0.6}$	${8.26}_{-2.73}^{+2.63}$	293/337
27	48, 50	$-{0.3}_{-0.5}^{+1.1}$	$-{2.8}_{-0.6}^{+0.3}$	${81}_{-6}^{+8}$	${0.42}_{-0.21}^{+1.75}$	${4.95}_{-0.34}^{+0.40}$	${5.87}_{-1.80}^{+2.05}$	303/337
28	50, 51	${0.1}_{-0.7}^{+1.3}$	$-{2.8}_{-0.6}^{+0.3}$	${99}_{-12}^{+13}$	${0.67}_{-0.38}^{+2.82}$	${5.5}_{-0.5}^{+0.5}$	${6.90}_{-2.59}^{+2.59}$	268/337
29	51, 53	$-{0.4}_{-0.3}^{+0.3}$	$-{2.7}_{-0.2}^{+0.2}$	${100}_{-7}^{+8}$	${0.58}_{-0.17}^{+0.29}$	${5.0}_{-0.1}^{+\infty }$	${6.53}_{-1.77}^{+1.43}$	354/337
30	53, 55	$-{0.7}_{-0.2}^{+0.2}$	$-{2.7}_{-0.4}^{+0.2}$	${177}_{-17}^{+21}$	${0.29}_{-0.05}^{+0.07}$	${6.0}_{-0.5}^{+0.6}$	${5.09}_{-1.55}^{+1.56}$	402/337
31	55, 56	$-{0.7}_{-0.1}^{+0.2}$	$-{4}_{-\infty }^{+1}$	${241}_{-26}^{+23}$	${0.28}_{-0.03}^{+0.05}$	${7}_{-1}^{+1}$	${5.48}_{-1.98}^{+2.13}$	307/337
32	56, 57	$-{0.9}_{-0.1}^{+0.1}$	$-{9}_{-\infty }^{+19}$	${267}_{-20}^{+23}$	${0.305}_{-0.022}^{+0.065}$	${7.5}_{-1.2}^{+1.4}$	${4.87}_{-2.12}^{+2.21}$	325/337
33	57, 58	$-{0.8}_{-0.1}^{+0.2}$	$-{3.1}_{-\infty }^{+0.5}$	${234}_{-25}^{+25}$	${0.41}_{-0.05}^{+0.07}$	${7}_{-1}^{+1}$	${6.84}_{-2.49}^{+2.57}$	356/337
34	58, 59	$-{0.7}_{-0.2}^{+0.2}$	$-{2.6}_{-0.4}^{+0.2}$	${219}_{-23}^{+29}$	${0.44}_{-0.06}^{+0.09}$	${7}_{-1}^{+1}$	${7.37}_{-2.67}^{+2.83}$	367/337
35	59, 60	$-{0.8}_{-0.1}^{+0.2}$	$-{2.8}_{-0.6}^{+0.3}$	${225}_{-26}^{+31}$	${0.34}_{-0.04}^{+0.06}$	${8}_{-1}^{+1}$	${6.39}_{-2.24}^{+2.38}$	359/337
36	60, 61	$-{0.6}_{-0.2}^{+0.3}$	$-{2.5}_{-0.3}^{+0.14}$	${190}_{-20}^{+35}$	${0.48}_{-0.10}^{+0.14}$	${7.0}_{-0.7}^{+1.0}$	${9.53}_{-2.75}^{+3.05}$	330/337
37	61, 63	$-{0.5}_{-0.3}^{+0.4}$	$-{2.40}_{-0.15}^{+0.12}$	${143}_{-15}^{+17}$	${0.46}_{-0.12}^{+0.24}$	${5.7}_{-0.4}^{+0.5}$	${5.83}_{-1.88}^{+2.04}$	389/337
38	63, 64	$-{0.4}_{-0.4}^{+0.6}$	$-{2.5}_{-0.2}^{+0.2}$	${130}_{-18}^{+22}$	${0.41}_{-0.14}^{+0.40}$	${6.0}_{-0.8}^{+1.3}$	${4.68}_{-2.28}^{+2.49}$	293/337
39	64, 65	$-{0.80}_{-0.15}^{+0.40}$	$-{3.4}_{3.4}^{+0.8}$	${182}_{-34}^{+25}$	${0.28}_{-0.05}^{+0.15}$	${8.4}_{-1.5}^{+1.4}$	${7.31}_{-2.24}^{+2.35}$	285/337
40	65, 67	$-{0.3}_{-0.2}^{+0.2}$	$-{2.6}_{-0.1}^{+0.1}$	${146}_{-9}^{+10}$	${0.69}_{-0.13}^{+0.19}$	${6.3}_{-0.2}^{+0.3}$	${10.53}_{-1.98}^{+2.00}$	464/337
41	67, 68	$-{0.4}_{-0.3}^{+0.4}$	$-{2.7}_{-0.3}^{+0.2}$	${132}_{-11}^{+13}$	${0.66}_{-0.17}^{+0.34}$	${6.0}_{-0.5}^{+0.6}$	${10.57}_{-2.93}^{+3.19}$	373/337
42	68, 69	$-{0.6}_{-0.2}^{+0.3}$	$-{2.7}_{-0.4}^{+0.2}$	${147}_{-13}^{+15}$	${0.69}_{-0.14}^{+0.24}$	${6.4}_{-0.5}^{+0.7}$	${11.30}_{-3.00}^{+3.22}$	336/337
43	69, 70	$-{0.15}_{-0.5}^{+1.1}$	$-{2.4}_{-0.2}^{+0.1}$	${97}_{-15}^{+18}$	${0.96}_{-0.51}^{+2.77}$	${6.0}_{-0.4}^{+0.7}$	${11.53}_{-3.46}^{+4.10}$	345/337
44	70, 71	$-{0.5}_{-0.2}^{+0.3}$	$-{2.7}_{-0.3}^{+0.2}$	${141}_{-13}^{+14}$	${0.53}_{-0.12}^{+0.23}$	${6.0}_{-0.5}^{+0.5}$	${11.14}_{-2.53}^{+2.70}$	318/337
45	71, 72	$-{0.5}_{-0.2}^{+0.2}$	$-{3.2}_{-1.0}^{+0.3}$	${153}_{-10}^{+10}$	${0.65}_{-0.11}^{+0.17}$	${6.0}_{-0.5}^{+0.6}$	${10.67}_{-2.84}^{+2.90}$	317/337
46	72, 73	${0.1}_{-0.6}^{+1.1}$	$-{2.7}_{-0.3}^{+0.2}$	${97}_{-8}^{+10}$	${1.25}_{-0.67}^{3.44}$	${6.0}_{-0.4}^{+0.4}$	${11.90}_{-3.81}^{+4.22}$	276/337
47	73, 74	${0.1}_{-0.6}^{+\infty }$	$-{2.6}_{-0.2}^{+0.2}$	${81}_{-9}^{+10}$	${1.04}_{-0.03}^{+0.29}$	${5.2}_{-0.3}^{+0.4}$	${9.73}_{-0.47}^{+1.28}$	275/337
48	74, 76	${0.1}_{-0.4}^{+0.8}$	$-{2.7}_{-0.2}^{+0.2}$	${95}_{-8}^{+7}$	${1.14}_{-0.49}^{+2.26}$	${5.5}_{-0.3}^{+0.3}$	${11.56}_{-2.38}^{+2.80}$	413/337
49	76, 77	$-{0.5}_{-0.4}^{+0.5}$	$-{3}_{-0.7}^{+0.3}$	${98}_{-9}^{+11}$	${0.40}_{-0.15}^{+0.36}$	${6.0}_{-0.6}^{+0.9}$	${6.66}_{-2.30}^{+2.54}$	290/337
50	77, 78	$-{0.5}_{-0.4}^{+0.6}$	$-{2.8}_{-0.6}^{+0.3}$	${111}_{-13}^{+15}$	${0.38}_{-0.14}^{+0.42}$	${6.2}_{-0.5}^{+0.7}$	${9.02}_{-2.52}^{+2.62}$	275/337
51	78, 82	${0.0}_{-0.4}^{+0.7}$	$-{2.7}_{-0.2}^{+0.2}$	${91}_{-6}^{+6}$	${0.49}_{-0.21}^{+0.66}$	${5.0}_{-0.2}^{+0.2}$	${6.57}_{-1.20}^{+1.23}$	386/337
52	82, 84	$-{0.3}_{-0.3}^{+0.5}$	$-{2}_{-0.2}^{+0.1}$	${131}_{-15}^{+15}$	${0.38}_{-0.11}^{0.28}$	${6.0}_{-0.4}^{+0.5}$	${6.61}_{-1.55}^{+1.67}$	380/337
53	84, 85	${0.4}_{-1.0}^{+4.0}$	$-{2.6}_{-0.4}^{+0.3}$	${104}_{-19}^{+17}$	${0.54}_{-0.36}^{+60.34}$	${5.5}_{-0.6}^{+0.8}$	${5.13}_{-2.06}^{+2.04}$	235/337
54	85, 90	$-{0.3}_{-0.4}^{+1}$	$-{2.6}_{-0.2}^{+0.2}$	${91}_{-11}^{+8}$	${0.31}_{-0.12}^{+0.43}$	${5.3}_{-0.3}^{+0.3}$	${4.64}_{-0.97}^{+1.39}$	463/337
55	90, 101	$-{0.2}_{-0.4}^{+4.5}$	$-{2.5}_{-0.2}^{+0.2}$	${88}_{-20}^{+101}$	${0.17}_{-0.08}^{+75.02}$	${5}_{-0.3}^{+0.3}$	${2.02}_{-0.53}^{+1.19}$	477/337
56	101, 113	$-{0.3}_{-0.4}^{+0.5}$	$-{3}_{-0.5}^{+0.3}$	${100}_{-8}^{+10}$	${0.09}_{-0.03}^{+0.08}$	${5}_{-0.3}^{+0.3}$	${1.69}_{-0.36}^{+0.36}$	441/337
57	113, 136	${0.25}_{-0.90}^{-0.25}$	$-{2.6}_{-0.6}^{+0.2}$	${72}_{-11}^{+11}$	${0.27}_{-0.19}^{+40.62}$	${4.5}_{-0.2}^{+0.2}$	${1.65}_{-0.46}^{+0.56}$	610/337
58	136, 137	$-{0.8}_{-0.4}^{+0.6}$	$-{9.3}_{9.3}^{+19}$	${103}_{-15}^{+18}$	${0.11}_{-0.04}^{+0.102}$	${5.0}_{-0.7}^{+0.8}$	${2.85}_{-1.70}^{+1.71}$	257/337
59	137, 150	$-{0.5}_{-0.4}^{+0.7}$	$-{3}_{-0.6}^{+0.3}$	${79}_{-6}^{+6}$	${0.10}_{-0.04}^{+0.15}$	${4.0}_{-0.3}^{+0.3}$	${1.40}_{-0.47}^{+0.49}$	463/337
60	150, 171	$-{1.1}_{-0.4}^{+1.1}$	$-{2.8}_{-\infty }^{+0.5}$	${63}_{-24}^{+16}$	${0.02}_{-0.01}^{+0.36}$	${4}_{-1}^{+1}$	${0.57}_{-0.30}^{+0.84}$	374/337

grbcomp	(t1, t2)	${{kT}}_{s}$ (keV)	kTe (keV)	τ	δ	αb	Rph (1010) cm	pgstat/dof
Sr. no.
1	−1, 7	[5.3]	${90}_{-14}^{+4}$	[3.2]	1.50 ± −0.05	${30}_{-24}^{+\infty }$	${8.7}_{-0.3}^{+0.2}$	412/339
2	7, 9	[4.1]	${77}_{-32}^{+20}$	${4.0}_{-0.9}^{+1.5}$	1.80 ± 0.07	${2.6}_{-1.3}^{+\infty }$	${17}_{-1}^{+1}$	281/338
3	9, 10	[4.5]	${78}_{-32}^{+40}$	${4}_{-1}^{+1}$	1.70 ± 0.06	${1.8}_{-0.7}^{+1.6}$	${20}_{-1}^{+1}$	213/338
4	10, 12	${7.7}_{-1.8}^{+1.5}$	${117}_{-62}^{+90}$	${3.0}_{-0.8}^{+2.1}$	1.20 ± 0.03	${1.4}_{-0.3}^{+0.6}$	${10}_{-2}^{+6}$	287/337
5	12, 14	${6.5}_{-2.6}^{+1.7}$	${86}_{-22}^{+30}$	${4}_{-1}^{+1}$	1.60 ± 0.05	${1.3}_{-0.2}^{0.2}$	${14}_{-4}^{+17}$	305/337
6	14, 17	${8.1}_{-1.7}^{+1.5}$	${91}_{-31}^{+45}$	${3.6}_{-0.8}^{+1.5}$	1.50 ± 0.05	${1.2}_{-0.1}^{+0.2}$	${9}_{-2}^{+4}$	371/337
7	17, 18	$[7]$	${57}_{-18}^{+32}$	${5.0}_{-1.4}^{+2.7}$	2.40 ± 0.13	${1.4}_{-0.2}^{+0.4}$	${14.7}_{-0.3}^{+0.3}$	283/338
8	18, 19	$[6]$	${58}_{-12}^{+16}$	${5}_{-1}^{+1}$	2.36 ± 0.12	${1.4}_{-0.2}^{+0.3}$	${21.6}_{-0.4}^{+0.4}$	207/338
9	19, 20	${7.4}_{-2.3}^{+1.7}$	${62}_{-16}^{+19}$	${4.5}_{-1.0}^{+2.0}$	2.20 ± 0.10	${1.5}_{-0.2}^{+0.3}$	${17}_{-4}^{+16}$	329/337
10	20, 24	${7.3}_{-0.8}^{+0.7}$	${63}_{-6}^{+7}$	${4.8}_{-0.4}^{+0.5}$	2.2 ± 0.1	${1.5}_{-0.1}^{+0.1}$	${19}_{-2}^{+4}$	551/337
11	24, 26	${7.6}_{-0.7}^{+0.7}$	${35.5}_{-9.3}^{+11.5}$	${7}_{-2}^{+15}$	3.8 ± 0.3	${1.6}_{-0.2}^{+0.3}$	${17}_{-2}^{+3}$	386/337
12	26, 29	${6.8}_{-0.5}^{+0.5}$	${53.0}_{-7.8}^{+9.8}$	${5.0}_{-0.7}^{+1.0}$	2.6 ± 0.14	${1.70}_{-0.15}^{+0.2}$	${20}_{-2}^{+3}$	462/337
13	29, 30	${7.7}_{-1.2}^{+1.1}$	${69}_{-17}^{+22}$	${4.5}_{-0.9}^{+1.5}$	2.0 ± 0.1	${1.7}_{-0.2}^{+0.4}$	${16}_{-3}^{+6}$	286/337
14	30, 31	${6.3}_{-1.5}^{+1.1}$	${67.2}_{-10.1}^{+13.7}$	${4.9}_{-0.7}^{+0.9}$	2.0 ± 0.1	${1.6}_{-0.2}^{+0.3}$	${23}_{-5}^{+16}$	285/337
15	31, 32	${7.1}_{-1.5}^{+1.3}$	${74.3}_{-12.6}^{+15.3}$	${4.5}_{-0.6}^{+0.8}$	1.83 ± 0.07	${1.5}_{-0.1}^{+0.2}$	${21}_{-4}^{+11}$	397/337
16	32, 34	${8.3}_{-0.9}^{+0.8}$	${71}_{-9}^{+10}$	${4.6}_{-0.5}^{+0.6}$	1.9 ± 0.1	${1.5}_{-0.1}^{+0.1}$	${19}_{-2}^{+4}$	437/337
17	34, 35	${7.6}_{-1.6}^{+1.3}$	${68}_{-11}^{+12}$	${4.8}_{-0.6}^{+1.0}$	2 ± 0.1	${1.5}_{-0.1}^{+0.2}$	${22}_{-4}^{+11}$	291/337
18	35, 36	${7.0}_{-1.5}^{+1.2}$	${64}_{-11}^{+12}$	${5.0}_{-0.7}^{+1.0}$	2 ± 0.1	${1.6}_{-0.2}^{+0.2}$	${24}_{-5}^{+14}$	304/337
19	36, 38	${8.0}_{-0.6}^{+0.5}$	${30.0}_{-5.2}^{+6.4}$	${12.6}_{-5.3}^{+\infty }$	4.5 ± 0.5	${1.6}_{-0.1}^{+0.1}$	${18}_{-8}^{+2}$	395/337
20	38, 39	${7.5}_{-0.5}^{+0.5}$	${28.5}_{-2.5}^{+2.6}$	$[10]$	4.7 ± 0.5	${1.8}_{-0.2}^{+0.2}$	${18}_{-2}^{+2}$	302/338
21	39, 41	${7.0}_{-0.5}^{+0.5}$	${50}_{-20}^{+25}$	${3.8}_{-0.9}^{+2.5}$	2.7 ± 0.2	${2.4}_{-0.6}^{+1.7}$	${20}_{-2}^{+3}$	388/337
22	41, 44	${7.0}_{-0.4}^{+0.4}$	${40}_{-8.4}^{+10}$	${5.8}_{-1.2}^{+2.7}$	3.4 ± 0.3	${2.0}_{-0.3}^{+0.3}$	${21}_{-2}^{+2}$	448/337
23	44, 45	${6.0}_{-1.3}^{+0.9}$	${42}_{-15}^{+18}$	${5.0}_{-1.3}^{+5.1}$	3.2 ± 0.2	${1.8}_{-0.3}^{+0.6}$	${25}_{-5}^{+14}$	271/337
24	45, 46	${7.8}_{-0.8}^{+0.8}$	${54}_{-13}^{+16}$	${5.0}_{-1.1}^{+2.3}$	2.5 ± 0.1	${1.7}_{-0.2}^{+0.4}$	${19}_{-3}^{+4}$	310/337
25	46, 47	${7}_{-1}^{+1}$	${47}_{-23}^{+32}$	${4.4}_{-1.4}^{+11.6}$	2.9 ± 0.2	${1.9}_{-0.4}^{+1.1}$	${20}_{-3}^{+7}$	314/337
26	47, 48	${7}_{-1}^{+1}$	${47}_{-18}^{+25}$	${5.0}_{-1.4}^{+6.2}$	2.9 ± 0.2	${2.8}_{-0.9}^{+\infty }$	${19}_{-3}^{+6}$	290/337
27	48, 50	${6.1}_{-0.8}^{+0.7}$	${33}_{-17}^{+24}$	${5}_{-2}^{+\infty }$	4.1 ± 0.4	${2.2}_{-0.6}^{+2.1}$	${20}_{-3}^{+6}$	302/337
28	50, 51	${7}_{-1}^{+1}$	${27}_{-8}^{+24}$	${11}_{-7}^{+\infty }$	5.1 ± 0.6	${2.0}_{-0.4}^{+1.3}$	${16}_{-2}^{+6}$	267/337
29	51, 53	${6.8}_{-0.7}^{+0.6}$	${43}_{-13}^{+16}$	${4.8}_{-1.1}^{+3}$	3.1 ± 0.2	${2.2}_{-0.4}^{+0.8}$	${20}_{-3}^{+5}$	335/337
30	53, 55	${6.4}_{-0.7}^{+0.6}$	${64}_{-12}^{+14}$	${4.3}_{-0.6}^{+0.9}$	2.1 ± 0.1	${1.9}_{-0.3}^{+0.4}$	${23}_{-3}^{+5}$	387/337
31	55, 56	${7.2}_{-1.5}^{+1.1}$	${85}_{-18}^{+20}$	${3.9}_{-0.5}^{+0.8}$	1.60 ± 0.06	${2.3}_{-0.5}^{+1.2}$	${19}_{-3}^{+8}$	301/337
32	56,57	${6.7}_{-1.3}^{+1.1}$	${83}_{-17}^{+20}$	${3.8}_{-0.5}^{+0.7}$	1.60 ± 0.06	${2.0}_{-0.3}^{+0.6}$	${24}_{-4}^{+11}$	317/337
33	57,58	${6.9}_{-1.3}^{+1.0}$	${78}_{-14}^{+16}$	${4.0}_{-0.5}^{+0.7}$	1.75 ± 0.07	${2.1}_{-0.4}^{+0.6}$	${25}_{-4}^{+11}$	349/337
34	58,59	${7.0}_{-1.1}^{+1.0}$	${72}_{-13}^{+15}$	${4.2}_{-0.6}^{+0.8}$	1.9 ± 0.1	${1.8}_{-0.2}^{+0.3}$	${24}_{-4}^{+9}$	359/337
35	59,60	${6.9}_{-1.2}^{+1.0}$	${86}_{-18}^{+20}$	${3.5}_{-0.5}^{+0.6}$	1.60 ± 0.06	${2.0}_{-0.3}^{+0.5}$	${23}_{-4}^{+101}$	345/337
36	60,61	${7.5}_{-1.2}^{+1.0}$	${81}_{-21}^{+25}$	${3.5}_{-0.6}^{+1.0}$	1.67 ± 0.06	${1.8}_{-0.3}^{+0.5}$	${21}_{-3}^{+7}$	315/337
37	61, 63	${6.7}_{-0.7}^{+0.7}$	${44}_{-10}^{+12}$	${5.6}_{-1.1}^{+2.5}$	3.1 ± 0.2	${1.5}_{-0.2}^{+0.2}$	${21}_{-3}^{+5}$	378/337
38	63, 64	${6.6}_{-1.4}^{+1.1}$	${45}_{-16}^{+20}$	${5}_{-1}^{+5}$	3.0 ± 0.2	${1.7}_{-0.3}^{+0.6}$	${19}_{-4}^{+11}$	288/337
39	64, 65	${7.3}_{-1.8}^{+1.2}$	${82.7}_{-25.2}^{+30}$	${3.3}_{-0.6}^{+1}$	1.60 ± 0.06	${2.5}_{-0.7}^{+2.5}$	${19}_{-4}^{+7}$	277/337
40	65, 67	${7.5}_{-0.6}^{+0.5}$	${47}_{-9}^{+10}$	${5.5}_{-1}^{+1.8}$	2.9 ± 0.2	${1.7}_{-0.2}^{+0.2}$	${21}_{-2}^{+3}$	447/337
41	67, 68	${7.1}_{-0.8}^{+0.7}$	${49}_{-13}^{+16}$	${5}_{-1.1}^{+2.4}$	2.8 ± 0.2	${2.0}_{-0.3}^{+0.6}$	${23}_{-3}^{+6}$	366/337
42	68, 69	${7.0}_{-0.8}^{+0.7}$	${57}_{-14}^{+16}$	${4.3}_{-0.7}^{+1.3}$	2.4 ± 0.1	${2.0}_{-0.3}^{+0.6}$	${26}_{-3}^{+6}$	323/337
43	69, 70	${6.6}_{-1}^{+0.7}$	${75}_{-47}^{+42}$	${2.9}_{-0.7}^{+4.3}$	1.8 ± 0.1	${2.0}_{-0.6}^{+1.3}$	${24}_{-3}^{+8}$	335/337
44	70, 71	${7.4}_{-0.8}^{+0.7}$	${56}_{-16}^{+21}$	${4.2}_{-0.9}^{+2.0}$	2.4 ± 0.1	${2.0}_{-0.3}^{+0.7}$	${21}_{-3}^{+4}$	308/337
45	71, 72	${7.2}_{-0.7}^{+0.7}$	${56}_{-9.5}^{+10}$	${4.8}_{-0.7}^{+1}$	2.4 ± 0.1	${2.4}_{-0.4}^{+0.7}$	${24}_{-3}^{+5}$	306/337
46	72, 73	${7.4}_{-0.9}^{+0.7}$	${26}_{-6.2}^{+18}$	${11.8}_{-7}^{-12}$	5.2 ± 0.6	${1.9}_{-0.2}^{+0.5}$	${20}_{-2}^{+5}$	274/337
47	73, 74	${7.0}_{-0.6}^{+0.5}$	${23.0}_{-3.2}^{+3.3}$	$[10]$	6.0 ± 0.8	${1.7}_{-0.2}^{+0.3}$	${20}_{-2}^{+3}$	275/338
48	74, 76	${7.2}_{-0.5}^{+0.5}$	${25.0}_{-6.4}^{+11.7}$	${12.8}_{-7.2}^{+\infty }$	5.5 ± 0.6	${1.8}_{-0.2}^{+0.2}$	$-{20}_{-2}^{+3}$	406/337
49	76, 77	${6.7}_{-1.3}^{+0.9}$	${45}_{-21}^{+28}$	${4.3}_{-1.25}^{+6.4}$	3.0 ± 0.2	${2.4}_{-0.7}^{+3.7}$	${19}_{-3}^{+10}$	284/337
50	77, 78	${7.2}_{-1}^{+0.9}$	${52}_{-27}^{+34}$	${4.0}_{-1.2}^{+8.4}$	2.6 ± 0.2	${2.3}_{-0.7}^{+4}$	${18}_{-3}^{+5}$	270/337
51	78, 82	$[7]$	${24}_{-5.5}^{+8.2}$	${11}_{-5}^{+\infty }$	5.7 ± 0.7	${2}_{-0.2}^{+0.2}$	${15.3}_{-0.2}^{+0.2}$	384/338
52	82, 84	${7.4}_{-0.7}^{+0.7}$	${38.4}_{-12.3}^{+17.1}$	${6}_{-1.9}^{+8.6}$	3.5 ± 0.3	${1.4}_{-0.2}^{+0.3}$	${16}_{-2}^{+3}$	375/337
53	84, 85	${7}_{-1}^{+1}$	${38}_{-6}^{+6}$	$[6]$	3.6 ± 0.3	${2.0}_{-0.5}^{+0.8}$	${14}_{-2}^{+4}$	237/338
54	85, 90	${6.6}_{-0.5}^{+0.5}$	${32}_{-15}^{+19}$	${5.8}_{-2}^{+\infty }$	4.2 ± 0.4	${2.0}_{-0.3}^{+0.6}$	${15}_{-2}^{+2}$	462/337
55	90, 101	${6.1}_{-0.4}^{+0.4}$	${30}_{-3.4}^{+3.4}$	$[6]$	4.5 ± 0.4	${1.7}_{-0.2}^{+0.3}$	${12}_{-1}^{+2}$	473/338
56	101, 113	${6.5}_{-0.6}^{+0.6}$	${39}_{-15}^{+20}$	${5.0}_{-1.6}^{+8.3}$	3.5 ± 0.3	${2.2}_{-0.5}^{+1.5}$	${9}_{-1}^{+2}$	437/337
57	113, 136	${5.8}_{-0.5}^{+0.5}$	${25}_{-10}^{+17}$	${7.8}_{-3.4}^{+\infty }$	2.0 ± 0.1	${1.9}_{-0.4}^{+1.0}$	${11}_{-1}^{+2}$	603/337
58	136, 137	${5.8}_{-2}^{+1}$	${67}_{-26}^{+26}$	${3.5}_{-0.8}^{+1.9}$	2.0 ± 0.1	${30}_{-27}^{+\infty }$	${17}_{-4}^{+18}$	256/337
59	137, 150	${5.6}_{-0.7}^{+0.6}$	${28}_{-12}^{+16}$	${6.6}_{-2.3}^{+160}$	4.8 ± 0.5	${2.2}_{-0.5}^{+1.4}$	${12}_{-2}^{+4}$	462/337
60	150, 171	${4.5}_{-1.7}^{+0.9}$	${61}_{-50}^{+146}$	${3.0}_{-1.3}^{+2.1}$	2.2 ± 0.1	${3.4}_{-2.0}^{+\infty }$	${13}_{-3}^{+19}$	372/337

Synchrotron model	(t1, t2)	γm/γc	Ec (keV)	p	pgstat/dof
Sr. no.
1	−1, 7	${3.6}_{-1.4}^{+0.5}$	${18.2}_{-5.7}^{+3.4}$	>3.04	420/339
2	7, 9	${3.7}_{-2.1}^{+3.5}$	${29.6}_{-12.1}^{+22.0}$	>2.33	286/339
3	9, 10	${3.5}_{-2.1}^{+0.8}$	${41.2}_{-13.2}^{+15.0}$	>2.43	214/339
4	10, 12	${5.0}_{-1.6}^{+1.4}$	${45.2}_{-6.5}^{+8.7}$	>2.98	296/339
5	12, 14	${4.1}_{-1.3}^{+0.7}$	${69.8}_{-8.9}^{+12.4}$	>3.18	302/339
6	14, 17	${4.8}_{-1.8}^{+1.3}$	${60.5}_{-7.4}^{+11.3}$	>2.69	384/339
7	17, 18	${2.6}_{-2.1}^{+0.9}$	${62.4}_{-11.3}^{+125.8}$	>2.86	285/339
8	18, 19	${1.8}_{-0.8}^{+0.8}$	${81.9}_{-19.2}^{+150.7}$	${3.93}_{-0.87}^{+0.89}$	207/339
9	19, 20	${1.9}_{-0.9}^{+0.8}$	${84.8}_{-17.9}^{+146.3}$	>3.41	334/339
10	20, 24	${1.6}_{-0.1}^{+0.1}$	${89.5}_{-10.5}^{+133.7}$	${3.88}_{-0.37}^{+0.54}$	602/339
11	24, 26	${2.3}_{-0.7}^{+0.3}$	${35.4}_{-2.3}^{+7.3}$	>3.28	434/339
12	26, 29	${3.3}_{-0.3}^{+0.1}$	${32.8}_{-2.6}^{+0.9}$	>4.24	558/339
13	29, 30	${3.1}_{-0.7}^{+0.6}$	${51.7}_{-6.9}^{+10.7}$	>3.81	311/339
14	30, 31	${2.3}_{-0.4}^{+0.5}$	${77.6}_{-12.1}^{+11.9}$	>4.13	298/339
15	31, 32	${2.3}_{-0.5}^{+0.4}$	${90.9}_{-6.4}^{+20.5}$	>4.09	406/339
16	32, 34	${1.8}_{-0.1}^{+0.3}$	${99.4}_{-10.4}^{+19.2}$	>3.62	485/339
17	34, 35	${1.5}_{-0.2}^{+0.6}$	${113.7}_{-19.9}^{+200.9}$	>3.37	304/339
18	35, 36	${2.1}_{-0.8}^{+0.2}$	${81.4}_{-5.3}^{+85.8}$	>4.33	314/339
19	36, 38	${1.7}_{-0.7}^{+0.0}$	${62.9}_{-12.6}^{+1.2}$	${3.60}_{-0.27}^{+0.34}$	478/339
20	38, 39	${2.3}_{-0.7}^{+0.5}$	${26.1}_{-4.3}^{+6.0}$	>3.56	347/339
21	39, 41	${2.7}_{-0.6}^{+0.1}$	${15.5}_{-1.4}^{+2.5}$	>3.67	470/339
22	41, 44	${3.5}_{-0.3}^{+0.2}$	${14.9}_{-0.9}^{+1.8}$	>4.55	572/339
23	44, 45	${2.4}_{-0.6}^{+0.1}$	${30.2}_{-3.3}^{+6.5}$	>3.77	285/339
24	45, 46	${2.9}_{-0.4}^{+0.1}$	${37.6}_{-5.2}^{+2.4}$	>3.89	364/339
25	46, 47	${2.8}_{-0.8}^{+0.5}$	${22.9}_{-3.4}^{+4.9}$	>3.41	339/339
26	47, 48	${2.5}_{-0.5}^{+0.1}$	${19.7}_{-3.4}^{+1.4}$	>3.99	321/339
27	48, 50	${2.7}_{-0.8}^{+0.1}$	${13.2}_{-1.7}^{+3.2}$	>3.45	326/339
28	50, 51	${2.0}_{-0.6}^{+0.2}$	${26.3}_{-6.5}^{+6.0}$	>3.58	287/339
29	51, 53	${2.5}_{-0.5}^{+0.1}$	${23.0}_{-1.2}^{+3.9}$	>3.99	378/339
30	53, 55	${3.5}_{-0.5}^{+0.4}$	${30.1}_{-2.8}^{+4.0}$	>4.28	446/339
31	55, 56	${2.6}_{-0.4}^{+0.1}$	${53.3}_{-8.5}^{+6.2}$	>4.04	345/339
32	56, 57	${3.0}_{-0.5}^{+0.5}$	${47.3}_{-5.3}^{+7.3}$	>4.20	351/339
33	57, 58	${2.8}_{-0.5}^{+0.4}$	${50.8}_{-5.4}^{+7.8}$	>4.10	392/339
34	58, 59	${2.8}_{-0.4}^{+0.4}$	${50.7}_{-5.7}^{+6.4}$	>4.05	397/339
35	59, 60	${3.3}_{-0.4}^{+0.6}$	${40.5}_{-4.8}^{+4.8}$	>4.13	374/339
36	60, 61	${3.2}_{-0.5}^{+0.4}$	${40.7}_{-4.1}^{+4.9}$	>4.05	346/339
37	61, 63	${2.9}_{-0.6}^{+0.1}$	${36.0}_{-1.1}^{+4.2}$	>3.66	414/339
38	63, 64	${2.2}_{-1.5}^{+0.3}$	${39.5}_{-6.6}^{+69.8}$	>3.02	302/339
39	64, 65	${2.7}_{-0.6}^{+0.5}$	${34.0}_{-4.7}^{+6.4}$	>3.90	300/339
40	65, 67	${2.5}_{-0.3}^{+0.5}$	${40.0}_{-3.1}^{+1.8}$	>4.39	531/339
41	67, 68	${2.5}_{-0.4}^{+0.1}$	${31.4}_{-4.3}^{+4.0}$	>3.98	406/339
42	68, 69	${2.7}_{-0.4}^{+0.3}$	${33.3}_{-3.4}^{+4.5}$	>4.01	367/339
43	69, 70	${2.9}_{-0.8}^{+0.1}$	${19.5}_{-2.2}^{+4.1}$	>3.42	361/339
44	70, 71	${3.1}_{-0.5}^{+0.4}$	${25.4}_{-3.0}^{+4.0}$	>3.92	358/339
45	71, 72	${2.0}_{-0.3}^{+0.1}$	${44.7}_{-5.6}^{+6.3}$	>4.54	372/339
46	72, 73	${2.2}_{-0.6}^{+0.4}$	${25.0}_{-3.7}^{+5.3}$	>3.77	305/339
47	73, 74	${2.5}_{-0.9}^{+0.7}$	${14.9}_{-3.3}^{+5.8}$	>2.97	303/339
48	74, 76	${2.5}_{-0.4}^{+0.1}$	${20.5}_{-1.6}^{+2.9}$	>3.96	481/339
49	76, 77	${2.3}_{-0.8}^{+0.5}$	${21.4}_{-4.1}^{+6.2}$	>3.40	303/339
50	77, 78	${2.8}_{-0.8}^{+0.1}$	${17.7}_{-2.3}^{+4.2}$	>3.36	300/339
51	78, 82	${2.9}_{-0.7}^{+0.6}$	${13.6}_{-1.7}^{+2.5}$	>3.31	465/339
52	82, 84	${3.2}_{-1.0}^{+1.0}$	${24.0}_{-3.4}^{+4.4}$	>2.68	427/339
53	84, 85	${3.1}_{-1.3}^{+0.4}$	${19.2}_{-3.8}^{+8.2}$	>2.98	250/339
54	85, 90	${2.8}_{-0.6}^{+0.1}$	${15.0}_{-1.3}^{+2.5}$	>3.60	524/339
55	90, 101	${3.2}_{-1.1}^{+0.2}$	${14.2}_{-1.3}^{+3.2}$	>2.95	511/339
56	101, 113	${3.3}_{-0.7}^{+0.2}$	${12.8}_{-1.2}^{+2.3}$	>3.52	485/339
57	113, 136	${2.9}_{-0.6}^{+0.1}$	${11.3}_{-1.7}^{+1.9}$	>3.72	654/339
58	136, 137	${3.0}_{-1.0}^{+1.2}$	${13.0}_{-4.6}^{+1.8}$	>3.39	265/339
59	137, 150	${3.0}_{-0.6}^{+0.8}$	${11.2}_{-1.2}^{+2.4}$	>3.70	485/339
60	150, 171	${2.1}_{-1.7}^{+1.6}$	${7.6}_{-3.3}^{+15.5}$	>2.56	378/339

Note.

^aPhotons keV⁻¹ cm⁻² s⁻¹ at 1 keV.

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