Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-10-12
Astronomy and Astrophysics
Astrophysics
4 pages, including figures. To appear in IAP Conference "Galaxy Dynamics: from the Early Universe to the Present"
Scientific paper
We present first results of a program to study the dynamics of undisturbed bulgeless, low surface density disk galaxies in order to probe the underlying structure of dark matter halos. High resolution H-alpha rotation curves are combined with optical and infrared imaging to place strong limits on the halo profiles. We find noticable variation in the shapes of the rotation curves, in contrast to previous claims. The implied density profiles are still significantly more shallow than profiles derived from most N-body simulations; unlike previous HI observations, beam-smearing cannot significantly affect this result. Based upon stellar mass profiles derived from K' band observations, we derive the angular momentum distribution of the stellar disk and find it to be broader than that of a uniformly rotating solid-body sphere, but remarkably consistent from galaxy-to-galaxy. Finally, based upon K' band surface brightness profiles, we find that low surface density disks must be significantly sub-maximal. Furthermore, maximal disk fits based upon Modified Newtonian Dynamics (MOND) have maximum mass-to-light ratios which are too small to be consistent with stellar population models; without the ability to significantly adjust inclination angles or infrared mass-to-light ratios, this sample presents great difficulties for MOND.
Bernstein Rebecca A.
Dalcanton Julianne J.
No associations
LandOfFree
Galaxy Dynamics from Edge-On Late-type Galaxies 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 Galaxy Dynamics from Edge-On Late-type Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Galaxy Dynamics from Edge-On Late-type Galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-446181