ICTS:31416

Exploring the dark matter distribution of nearby galaxies using HI velocity dispersion

APA

(2025). Exploring the dark matter distribution of nearby galaxies using HI velocity dispersion. SciVideos. https://youtu.be/sZ4Va5H9YYo

MLA

Exploring the dark matter distribution of nearby galaxies using HI velocity dispersion. SciVideos, Apr. 08, 2025, https://youtu.be/sZ4Va5H9YYo

BibTex

          @misc{ scivideos_ICTS:31416,
            doi = {},
            url = {https://youtu.be/sZ4Va5H9YYo},
            author = {},
            keywords = {},
            language = {en},
            title = {Exploring the dark matter distribution of nearby galaxies using HI velocity dispersion},
            publisher = {},
            year = {2025},
            month = {apr},
            note = {ICTS:31416 see, \url{https://scivideos.org/index.php/icts-tifr/31416}}
          }
          
Mousumi Das
Talk numberICTS:31416

Abstract

Dark matter plays a major role in the equilibrium of galaxy disks, especially the outer disks of galaxies where the stellar disk surface density declines. The hydrostatic equilibrium of the HI disk in these regions can be used to probe the dark matter distribution within the disk. In this presentation we show that the disk dark matter in nearly face-on galaxies can be probed with sensitive HI velocity dispersion observations. Alternatively, the HI disk thickness in edge-on galaxies can be used to estimate the disk dark matter. We show that both methods have assumptions and advantages/disadvantages. Assuming a form of the halo potential, we show that the disk dark matter can be used to probe the halo shape. We apply our methods to nearby galaxies and show that smaller dwarf galaxies appear to be more dark matter dominated and their halo shapes appear to be oblate, whereas massive galaxies have more spherical halos. We also discuss how HI velocity dispersion can explore the dark matter distribution of very close, low luminosity satellites such as Leo-T. The halo shape can affect galaxy disk properties, such as the stellar velocity dispersion and disk surface density, which in turn affects bar formation, gas kinematics and star formation in galaxy disks, all of which are important for galaxy evolution. Our study thus demonstrates the importance of SKA HI surveys to probe the dark matter distribution in galaxies. We discuss how the SKA sensitivity will allow us to probe HI and dark matter at much larger distances compared to present studies.