Southern Galaxies. V. Isophotometry of the Large Barred Spiral NGC 4945.
Abstract
[sophotes and photometric parameters are derived for the large SB(s)d spiral NGC 4945 from a unt Stromlo 304nch reflector plate. The total apparent photographic magnitude mr = 9.85 (with visional zero point) and maximum dimensions 24' X 6' (at the threshold it = 27.3 mag/sec2 = 0.95 pc2) correspond to Mr = -19.15 and Dm = 26.5 kpc, if m - M = 29.0 and A = 3.8 Mpc. The A 1.1 mag is uncertain at the low latitude bIl = +13?5 of this object. The major axis p.a. 0 = 420; the mean axis ratio of the outer regions q = (b/a) = 0.193 corresponds to an ination i = 820, if qo = 0.13. The equivalent radius is r0* = 2 13 = 2.34 kpc, the effective surface ;htness it = 22.80 mag = 58 0/pc2, and the mean luminosity gradient in the roughiy exential outer regions G(a) = -0.13 = -0.12 . The continuum radio emission is discussed; apparent radio index is m - = 0.0; the index corrected for both galactic and internal absorption - mp = +1.3, which is about average for Sc-Sd galaxies.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1964
- DOI:
- 10.1086/147824
- Bibcode:
- 1964ApJ...139..899D