New Physics and the Black Hole Mass Gap
The LIGO/Virgo collaboration is making astonishing discoveries at a fantastic pace, including a heavy binary black hole merger with component masses in the “black hole mass gap,” which cannot be explained by standard stellar structure theory. In this talk, I will discuss how new light particles that couple to the Standard Model can act as an additional source of energy loss in the cores of population-III stars, dramatically altering their evolution and potentially explaining mass-gap objects. I will also demonstrate how population catalogs can help distinguish different scenarios for the origin of these objects.
How Galaxies Form Stars
The circumgalactic medium (CGM) is host to large reservoirs of gas around galaxies, providing the fuel for galactic star formation. As gas flows from the intergalactic medium (IGM) and on into the CGM, we should be able to detect it as cold gas accretion. Much of this cold gas is too diffuse for easy detection, however if a telescope stares far enough and long enough, we should be able to see it. I will be focusing on recent results from our program to map the CGM of 18 nearby galaxies in neutral hydrogen (HI) with the Green Bank Telescope. For this program we obtained deep observations with high HI column density sensitivity, and focused on the diffuse HI detected outside the disks of each galaxy, as this is the reservoir of gas expected to fuel star formation in the disk.