Date:
Tue, 12/04/202212:30-13:30
Title: The Dark-Matter Halo of the Milky Way and Dark-Matter Deficient Cores in Other Galaxies
Abstract: I will address two topics concerning the dynamics of dark-matter halos.
The Milky Way (MW) galaxy is one of the most important laboratories for studying galaxy formation and cosmology. The mass distribution in the MW outskirts (>100 kpc) was historically poorly constrained due to inadequate observations and model uncertainties. Using Gaia kinematics of nearby dwarf galaxies and new dynamical modeling techniques, we obtained the current best mass estimates for the MW halo. Beyond the conventional virial radius, we measured for the first time the outermost edge of the MW in terms of the “depletion" radius, which separates the growing halo from the draining environment.
While dark matter (DM) only simulations predict steep "cuspy” inner density profiles for DM halos, observations indicate shallower "cores" in a fraction of dwarf galaxies and high-z massive galaxies, raising doubts about the standard paradigm of cosmology. Here we propose an analytic model for the response of DM halos to central gas ejection by supernovae or AGN as a mechanism for generating DM-deficient cores within the standard paradigm. We test this model and three other variants using idealized N-body simulations. The current model is physically justified and provides more accurate predictions.
Zoom link :
https://huji.zoom.us/j/83072998638?pwd=S1U0NDcvbFZZVmx1VGQyUDRZU2NpUT09
Meeting ID: 830 7299 8638
Passcode: w31c0m3
Abstract: I will address two topics concerning the dynamics of dark-matter halos.
The Milky Way (MW) galaxy is one of the most important laboratories for studying galaxy formation and cosmology. The mass distribution in the MW outskirts (>100 kpc) was historically poorly constrained due to inadequate observations and model uncertainties. Using Gaia kinematics of nearby dwarf galaxies and new dynamical modeling techniques, we obtained the current best mass estimates for the MW halo. Beyond the conventional virial radius, we measured for the first time the outermost edge of the MW in terms of the “depletion" radius, which separates the growing halo from the draining environment.
While dark matter (DM) only simulations predict steep "cuspy” inner density profiles for DM halos, observations indicate shallower "cores" in a fraction of dwarf galaxies and high-z massive galaxies, raising doubts about the standard paradigm of cosmology. Here we propose an analytic model for the response of DM halos to central gas ejection by supernovae or AGN as a mechanism for generating DM-deficient cores within the standard paradigm. We test this model and three other variants using idealized N-body simulations. The current model is physically justified and provides more accurate predictions.
Zoom link :
https://huji.zoom.us/j/83072998638?pwd=S1U0NDcvbFZZVmx1VGQyUDRZU2NpUT09
Meeting ID: 830 7299 8638
Passcode: w31c0m3