Abstract
Galactic outflows are believed to play a critical role in the evolution of galaxies by regulating their mass build-up and star formation1. Theoretical models assume bipolar shapes for the outflows that extend well into the circumgalactic medium (CGM), up to tens of kiloparsecs (kpc) perpendicular to the galaxies. They have been directly observed in the local Universe in several individual galaxies, for example, around the Milky Way and M82 (refs. 2,3). At higher redshifts, cosmological simulations of galaxy formation predict an increase in the frequency and efficiency of galactic outflows owing to the increasing star-formation activity4. Galactic outflows are usually of low gas density and low surface brightness and therefore difficult to observe in emission towards high redshifts. Here we present an ultra-deep Multi-Unit Spectroscopic Explorer (MUSE) image of the mean Mg II emission surrounding a sample of galaxies at z ≈ 1 that strongly suggests the presence of outflowing gas on physical scales of more than 10 kpc. We find a strong dependence of the detected signal on the inclination of the central galaxy, with edge-on galaxies clearly showing enhanced Mg II emission along the minor axis, whereas face-on galaxies show much weaker and more isotropic emission. We interpret these findings as supporting the idea that outflows typically have a bipolar cone geometry perpendicular to the galactic disk. We demonstrate that this CGM-scale outflow is prevalent among galaxies with stellar mass M* ≳ 109.5M⊙.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
Data availability
This work is mainly based on data release 2 (DR2) of the MUSE Hubble Ultra Deep Field surveys. The reduced MUSE datacubes are available in ref. 22.
References
Tumlinson, J., Peeples, M. S. & Werk, J. K. The circumgalactic medium. Annu. Rev. Astron. Astrophys. 55, 389–432 (2017).
Predehl, P. et al. Detection of large-scale X-ray bubbles in the Milky Way halo. Nature 588, 227–231 (2020).
Bland, J. & Tully, B. Large-scale bipolar wind in M82. Nature 334, 43–45 (1988).
Muratov, A. L. et al. Gusty, gaseous flows of FIRE: galactic winds in cosmological simulations with explicit stellar feedback. Mon. Not. R. Astron. Soc. 454, 2691–2713 (2015).
Bacon, R. et al. The MUSE second-generation VLT instrument. Proc. SPIE 7735, 773508 (2010).
Morrissey, P. et al. The Keck Cosmic Web Imager integral field spectrograph. Astrophys. J. 864, 93 (2018).
Wisotzki, L. et al. Extended Lyman α haloes around individual high-redshift galaxies revealed by MUSE. Astron. Astrophys. 587, A98 (2016).
Wisotzki, L. et al. Nearly all the sky is covered by Lyman-α emission around high-redshift galaxies. Nature 562, 229–232 (2018).
Leclercq, F. et al. The MUSE Hubble Ultra Deep Field Survey. VIII. Extended Lyman-α haloes around high-z star-forming galaxies. Astron. Astrophys. 608, A8 (2017).
Cai, Z. et al. Evolution of the cool gas in the circumgalactic medium of massive halos: a Keck Cosmic Web Imager survey of Lyα emission around QSOs at z ≈ 2. Astrophys. J. Suppl. Ser. 245, 23 (2019).
Kusakabe, H. et al. The MUSE eXtremely Deep Field: individual detections of Lyα haloes around rest-frame UV-selected galaxies at z ≃ 2.9–4.4. Astron. Astrophys. 660, A44 (2022).
Bacon, R. et al. The MUSE Extremely Deep Field: the cosmic web in emission at high redshift. Astron. Astrophys. 647, A107 (2021).
Guo, Y. et al. Metal enrichment in the circumgalactic medium and Lyα halos around quasars at z ~ 3. Astrophys. J. 898, 26 (2020).
Johnson, S. D. et al. Directly tracing cool filamentary accretion over >100 kpc into the interstellar medium of a quasar host at z = 1. Astrophys. J. Lett. 940, L40 (2022).
Herenz, E. C. et al. A ~15 kpc outflow cone piercing through the halo of the blue compact metal-poor galaxy SBS0335–052E. Astron. Astrophys. 670, A121 (2023).
Kacprzak, G. G., Cooke, J., Churchill, C. W., Ryan-Weber, E. V. & Nielsen, N. M. The smooth Mg II gas distribution through the interstellar/extra-planar/halo interface. Astrophys. J. Lett. 777, L11 (2013).
Rubin, K. H. R. et al. Low-ionization line emission from a starburst galaxy: a new probe of a galactic-scale outflow. Astrophys. J. 728, 55 (2011).
Martin, C. L. et al. Scattered emission from z ~ 1 galactic outflows. Astrophys. J. 770, 41 (2013).
Burchett, J. N. et al. Circumgalactic Mg II emission from an isotropic starburst galaxy outflow mapped by KCWI. Astrophys. J. 909, 151 (2021).
Zabl, J. et al. MusE GAs FLOw and Wind (MEGAFLOW) VIII. Discovery of a MgII emission halo probed by a quasar sightline. Mon. Not. R. Astron. Soc. 507, 4294–4315 (2021).
Leclercq, F. et al. The MUSE eXtremely deep field: first panoramic view of an Mg II emitting intragroup medium. Astron. Astrophys. 663, A11 (2022).
Bacon, R. et al. The MUSE Hubble Ultra Deep Field surveys: data release II. Astron. Astrophys. 670, A4 (2023).
Kornei, K. A. et al. The properties and prevalence of galactic outflows at z ~ 1 in the Extended Groth Strip. Astrophys. J. 758, 135 (2012).
Feltre, A. et al. The MUSE Hubble Ultra Deep Field Survey. XII. Mg II emission and absorption in star-forming galaxies. Astron. Astrophys. 617, A62 (2018).
Bouché, N. et al. Physical properties of galactic winds using background quasars. Mon. Not. R. Astron. Soc. 426, 801–815 (2012).
Zabl, J. et al. MusE GAs FLOw and Wind (MEGAFLOW) II. A study of gas accretion around z ≈ 1 star-forming galaxies with background quasars. Mon. Not. R. Astron. Soc. 485, 1961–1980 (2019).
Martin, C. L., Ho, S. H., Kacprzak, G. G. & Churchill, C. W. Kinematics of circumgalactic gas: feeding galaxies and feedback. Astrophys. J. 878, 84 (2019).
Schroetter, I. et al. MusE GAs FLOw and Wind (MEGAFLOW) – III. Galactic wind properties using background quasars. Mon. Not. R. Astron. Soc. 490, 4368–4381 (2019).
Muratov, A. L. et al. Metal flows of the circumgalactic medium, and the metal budget in galactic haloes. Mon. Not. R. Astron. Soc. 468, 4170–4188 (2017).
Péroux, C. et al. Predictions for the angular dependence of gas mass flow rate and metallicity in the circumgalactic medium. Mon. Not. R. Astron. Soc. 499, 2462–2473 (2020).
Claeyssens, A. et al. Spectral variations of Lyman α emission within strongly lensed sources observed with MUSE. Mon. Not. R. Astron. Soc. 489, 5022–5029 (2019).
Leclercq, F. et al. The MUSE Hubble Ultra Deep Field Survey. XIII. Spatially resolved spectral properties of Lyman α haloes around star-forming galaxies at z > 3. Astron. Astrophys. 635, A82 (2020).
Erb, D. K. et al. The circumgalactic medium of extreme emission line galaxies at z~2: resolved spectroscopy and radiative transfer modeling of spatially extended Lyα emission in the KBSS-KCWI survey. Astrophys. J. 953, 118 (2023).
Bacon, R. et al. The MUSE Hubble Ultra Deep Field Survey. I. Survey description, data reduction, and source detection. Astron. Astrophys. 608, A1 (2017).
Bouché, N. F. et al. The MUSE Hubble Ultra Deep Field Survey. XVI. The angular momentum of low-mass star-forming galaxies: A cautionary tale and insights from TNG50. Astron. Astrophys. 654, A49 (2021).
Rubin, K. H. R. et al. Evidence for ubiquitous collimated galactic-scale outflows along the star-forming sequence at z ~ 0.5. Astrophys. J. 794, 156 (2014).
Walter, F., Weiss, A. & Scoville, N. Molecular gas in M82: resolving the outflow and streamers. Astrophys. J. 580, L21 (2002).
Chisholm, J., Prochaska, J. X., Schaerer, D., Gazagnes, S. & Henry, A. Optically thin spatially resolved Mg II emission maps the escape of ionizing photons. Mon. Not. R. Astron. Soc. 498, 2554–2574 (2020).
Katz, H. et al. Mg II in the JWST era: a probe of Lyman continuum escape?. Mon. Not. R. Astron. Soc. 515, 4265–4286 (2022).
Bordoloi, R. et al. The radial and azimuthal profiles of Mg II absorption around 0.5 < z < 0.9 zCOSMOS galaxies of different colors, masses, and environments. Astrophys. J. 743, 10 (2011).
Kacprzak, G. G., Churchill, C. W. & Nielsen, N. M. Tracing outflows and accretion: a bimodal azimuthal dependence of Mg II absorption. Astrophys. J. Lett. 760, L7 (2012).
Bordoloi, R., Lilly, S. J., Kacprzak, G. G. & Churchill, C. W. Modeling the distribution of Mg II absorbers around galaxies using background galaxies and quasars. Astrophys. J. 784, 108 (2014).
Lan, T.-W. & Mo, H. The circumgalactic medium of eBOSS emission line galaxies: signatures of galactic outflows in gas distribution and kinematics. Astrophys. J. 866, 36 (2018).
Lundgren, B. F. et al. The geometry of cold, metal-enriched gas around galaxies at z ~ 1.2. Astrophys. J. 913, 50 (2021).
Chen, Y.-M. et al. Absorption-line probes of the prevalence and properties of outflows in present-day star-forming galaxies. Astrophys. J. 140, 445 (2010).
Bordoloi, R. et al. The dependence of galactic outflows on the properties and orientation of zCOSMOS galaxies at z ~ 1. Astrophys. J. 794, 130 (2014).
Shaban, A. et al. A 30 kpc spatially extended clumpy and asymmetric galactic outflow at z ~ 1.7. Astrophys. J. 936, 77 (2022).
Rupke, D. S. N. et al. A 100-kiloparsec wind feeding the circumgalactic medium of a massive compact galaxy. Nature 574, 643–646 (2019).
Sobolev, V. V. Moving Envelopes of Stars (Harvard University Press, 1960) [transl.].
Carr, C., Scarlata, C., Panagia, N. & Henry, A. A Semi-analytical Line Transfer (SALT) Model. II: the effects of a bi-conical geometry. Astrophys. J. 860, 143 (2018).
Zahid, H. J., Kewley, L. J. & Bresolin, F. The mass–metallicity and luminosity–metallicity relations from DEEP2 at z ~ 0.8. Astrophys. J. 730, 137 (2011).
Kennicutt, R. C. Star formation in galaxies along the Hubble sequence. Annu. Rev. Astron. Astrophys. 36, 189–231 (1998).
Mitchell, P. D. & Schaye, J. How gas flows shape the stellar–halo mass relation in the EAGLE simulation. Mon. Not. R. Astron. Soc. 511, 2948–2967 (2022).
Acknowledgements
Y.G. thanks Z. Xu for helpful discussions. Y.G., R.B. and L.W. acknowledge support from the ANR/DFG grant L-INTENSE (ANR-20-CE92-0015, DFG Wi 1369/31-1). L.W. acknowledges support by the European Research Council (ERC) Advanced Grant SPECMAG-CGM (GA101020943). A.V. and H.K. acknowledge support from the Swiss National Foundation grant PP00P2_211023. S.C. gratefully acknowledges support from the ERC under the European Union’s Horizon 2020 Research and Innovation programme grant agreement no. 864361. L.B. acknowledges support by ERC AdG grant 740246 (Cosmic-Gas). J.Brinchmann acknowledges financial support from the Fundação para a Ciência e a Tecnologia (FCT) through research grants UIDB/04434/2020 and UIDP/04434/2020, national funds PTDC/FIS-AST/4862/2020 and work contract 2020.03379.CEECIND. N.F.B. acknowledges support from the ANR grant 3DGasFlows (ANR-17-CE31-0017).
Author information
Authors and Affiliations
Contributions
Y.G. conceived the project. R.B. led the MUSE data acquisition and data reduction. All authors participated in the observation and/or data reduction of the MUSE Hubble Ultra Deep Field surveys. Y.G. performed the sample selection and analysed the data. Y.G., R.B., N.F.B., L.W., J.S., J.Blaizot and S.C. worked on the interpretation of the results. Y.G. wrote the manuscript and produced the figures, with R.B., N.F.B., L.W. and J.Blaizot contributing to their design. All co-authors provided critical feedback on the text and helped shape the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature thanks Anshu Gupta and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
Extended Data Fig. 1 Distribution of the redshifts and stellar masses in the MUSE sample.
The parent sample is shown by grey bars and the edge-on and face-on subsamples are shown in black and red, respectively.
Extended Data Fig. 2 HST images of all the face-on galaxies.
Each thumbnail has the same size as in Fig. 1.
Extended Data Fig. 3 HST images of all the edge-on galaxies.
Each thumbnail has the same size as in Fig. 1. The dashed and dotted lines show the major and minor axes of the galaxies, respectively.
Extended Data Fig. 4 The surface brightness of the Mg II outflow from each edge-on galaxy.
The distributions of surface brightness (a) and S/N (b). The signals are extracted in 1″-diameter apertures above and below the edge-on galaxies, at a distance to the galactic plane of 1″. The distribution of surface-brightness signals skews towards positive values, despite most of the signals being of low S/N. The negative S/N values correspond to the negative signals in the left panel.
Extended Data Fig. 5 The spectra of the extended Mg II emission.
The spectra in each panel are extracted from the grid cell at the corresponding position in Fig. 1. The black and red spectra denote the edge-on and face-on galaxy samples, respectively. In each panel, the coloured shading represents the 1σ error range of the corresponding spectra. The panels for which the peak of the Mg II 2,796 Å line in the black spectra falls below the 2σ threshold are marked with a lighter colour.
Extended Data Fig. 6 The continuum-subtracted spectrum of the ‘ring’ in face-on galaxies.
The red line denotes the spectrum extracted from the ‘ring’ region of the stacked face-on galaxy sample. For comparison, we also show the continuum-subtracted spectrum from the ‘outflow’ region of the edge-on galaxy. The coloured shadings represent the 1σ error range of the corresponding spectra. The two vertical dashed lines indicate the wavelength of Mg II doublets. The horizontal shadow shows the noise level. The EWs of the Mg II 2,796 Å line for the red and black spectra are −21 ± 15 Å and −56 ± 22 Å, respectively.
Supplementary information
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Guo, Y., Bacon, R., Bouché, N.F. et al. Bipolar outflows out to 10 kpc for massive galaxies at redshift z ≈ 1. Nature 624, 53–56 (2023). https://doi.org/10.1038/s41586-023-06718-w
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41586-023-06718-w
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
