1998/03/21 by M. S. Seigar, P. A. James, Seigar, M. S. +1
Chemistry · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Spectroscopy and Laser Applications #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9803253
11 pages, 17 figures, to be published in MNRAS
arxiv created 1998/03/21 · openalex publication_date 1998/03/21 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
We present data for a sample of 45 spiral galaxies over a range of Hubble types, imaged in the near-IR J and K bands. Parameters are calculated describing the bulge, disk and bar K-band light distributions, and we look for correlations showing the interrelation between these components. We find that bulge profiles are not well-fitted by the classic de Vaucouleurs profile, and that exponential or R1/2 fits are preferred. Bulge-to-disk ratio correlates only weakly with Hubble type. Many of the galaxies show central reddening of their J-K colours, which we interpret as due to nuclear starbursts or dusty AGN. We define a new method for measuring the strength of bars, which we call Equivalent Angle. We stress that this is better than the traditional bar-interbar contrast, as it is not subject to seeing and resolution effects. Bars are found in 40 of the 45 galaxies, 9 of which had been previously classified as unbarred. Bar strengths are found not to correlate with disk surface brightness or the presence of near neighbours, but a tendency is found for the most strongly barred galaxies to lie within a restricted, intermediate range of bulge-to-disk ratio. Bar light profiles are found to be either flat or exponentially decreasing along their long axes, with profile type not correlating strongly with Hubble type. Bar short axis profiles are significantly asymmetric, with the steeper profile being generally on the leading edge, assuming trailing arms. In the K-band we find bars with higher axial ratios than have been found previously in optical studies.