Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2009-04-27
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
12 pages, 10 figures, in press on Astronomy and Astrophysics. Minor text revisions to match published version. Reference added
Scientific paper
The colour and metallicity gradients observed in spiral galaxies suggest that the mass-to-light ratio (M*/L) of the stellar disc is a function of radius. This is indeed predicted by chemo-photometric models of galactic discs. We investigate the distribution of luminous and dark matter in spiral galaxies, taking into account the radial dependence of the stellar M*/L - which is usually assumed to be constant in studies of the mass structure. From the chemo-photometric models of Portinari et al. (2004) and in agreement with the observed radial profiles of galaxy colours, we derive the typical average M*/L profile of the stellar discs of spiral galaxies. We compute the corresponding Variable Mass-to-Light (VML) stellar surface density profile and then the VML disc contribution to the circular velocity. We use the latter, combined with a well studied dark matter velocity profile, to mass model the co-added rotation curves of Persic et al. (1996). (See http://www.facebook.com/home.php#!/group.php?gid=310260450630 to retrieve extra information on the kinematics of galaxies) By investigating rotation curves in the framework of VML stellar discs, we confirm, to a first approximation, the scenario obtained with the constant M*/L assumption: a dark matter halo with a shallow core, an inner baryon-dominated region and a larger proportion of Dark Matter in smaller objects. However, the resulting size of the the dark halo core and of the inner baryon dominance region are somewhat smaller. The stronger role that VML discs have in the innermost regions is important to constrain the galaxy mass structure in both Lambda Cold Dark Matter and MOND scenarios.
Portinari Laura
Salucci Paolo
No associations
LandOfFree
The structure of spiral galaxies: radial profiles in stellar Mass-to-Light ratio and the Dark Matter distribution does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The structure of spiral galaxies: radial profiles in stellar Mass-to-Light ratio and the Dark Matter distribution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The structure of spiral galaxies: radial profiles in stellar Mass-to-Light ratio and the Dark Matter distribution will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-322369