Abstract Details

Name: mousumi das
Affiliation: Indian Institute of Astrophysics
Conference ID: ASI2020_568
Title : The Dynamical Mass Distribution in Galaxy Disks and its Implications for Outer Disk Star Formation
Authors and Co-Authors : M.Das
Abstract Type : Invited
Abstract Category : Extragalactic Astronomy
Abstract : We present a study of the gas and stellar mass distribution in galaxy disks and examine how it traces the disk dynamical mass. We use the neutral hydrogen (HI) velocity dispersion in nearly face-on galaxies to estimate the disk dynamical masses and compare them with their baryonic masses in the outer disks. We find that for the large galaxies the disk dynamical masses in the outer disks are one to two times larger than the baryonic masses whereas for the gas rich dwarfs it is several times larger. Our results indicate that there must be dark matter associated with the outer disks of HI rich galaxies and especially in gas rich dwarf galaxies. This dark matter provides the vertical support for the HI gas disks in regions where there is no apparent stellar disk. This dark matter may be in the form of the inner part of the extended, oblate halo that surrounds the disks in these galaxies or it may have accumulated in the disks through minor mergers. We discuss the implications of our results for understanding the distribution of dark matter in galaxies and how it affects star formation in the outer regions of their disks.