New observational constraints on theories of galaxy accretion and feedback

by Jonathan Stern

at Astrophysics and Cosmology Seminar

Wed, 05 Apr 2017, 11:15
Seminar Room 207, Building 54

Abstract

I will present two novel observational tests of astrophysical theories that are central to our understanding of galaxy evolution The first test concerns quasar driven galactic scale outflows which are often invoked by cosmological simulations to regulate star formation in massive galaxies Several physical mechanisms have been proposed for the acceleration of these outflows such as the ram pressure of shock heated nuclear winds and radiation pressure on dust grains I will demonstrate that the nature of the acceleration mechanism can be constrained using emission lines that originate from HII regions surrounding quasars I will then present new constraints derived from observations with Gemini Chandra HST and SDSS The second test concerns the physical properties of the circumgalactic medium CGM which regulate the accretion rate onto the galaxy I will present a new technique to constrain the CGM thermal properties and chemical abundance based on the signatures imprinted by the CGM on the spectra and photometry of background sources I will demonstrate that recent HST COS and SDSS observations suggest that the CGM is highly metal enriched and that its thermal state is strongly coupled to the galaxy star formation rate This result provides a challenge for cosmological hydro simulations

Created on 02-04-2017 by Bar Lev, Yevgeny (ybarlev)
Updaded on 02-04-2017 by Bar Lev, Yevgeny (ybarlev)