2019 HotSci at STScI
Space Telescope Science Institute (STScI)
3700 San Martin Drive
Baltimore, MD 21218
2:45 PM - 4:00 PM
Featuring Patrick Ogle on A Break in the Tully-Fisher Relation and Cosmic Mass Limit for Spiral Galaxies and Annalisa Calamida on Omega Cen.
All talks are held on Wednesdays in the STScI John N. Bahcall Auditorium at 3:00 p.m. preceded by refreshments at 2:45 p.m.
Name: Patrick Ogle
Title: A Break in the Tully-Fisher Relation and Cosmic Mass Limit for Spiral Galaxies
Abstract: Super spiral galaxies are the most massive, giant spiral galaxies in the local universe, at redshift z<0.3. I measured H-alpha rotation curves for 16 super spiral galaxies with SALT and found unprecedented rotation velocities up to 570 km/s, indicating very massive dark matter halos. Super spirals break from the baryonic Tully-Fisher relation established for less massive galaxies, with baryonic masses that are much smaller than what that relation predicts. They appear to obey a stellar mass limit of 6E11 Msun, set by the critical mass for shocks at the virial radius of their dark matter halos. Once they hit that limit, they can no longer efficiently accrete cold gas. The existence of a cosmic mass limit for galaxies also has important implications for the formation and evolution of giant elliptical galaxies at the centers of massive galaxy clusters, and puts the final nail in the coffin of the Modified Newtonian Gravity (MOND) theory.
Name: Annalisa Calamida
Title: Omega Cen