Quasars Probing Quasars: Understanding the Physics of Massive Galaxy Formation
Joe Hennawi (UC Berkeley) - Apr 21, 2008 at 12:10 pm
One of the most important in galaxy formation is understanding the physics
which governs the observed bimodality in the galaxy population. Lower mass
galaxies are gas rich and form a "blue cloud" in the color magnitude
diagram, whereas more massive "red-and-dead" galaxies are gas poor and
inhabit the red sequence. As a result, all galaxy formation models include
some variant of feedback which acts to "quench" star formation in massive
systems. Observing the formation epoch of red and dead galaxies will shed
light on the physics behind this quenching. The strong clustering of
luminous quasars at z ~ 2-3 indicates that they are indeed the progenitors
of galaxies on the red sequence today. I will introduce a novel technique
whereby a foreground quasar can be studied in absorption against a
background quasar, resolving scales as small as 30kpc. This experiment
reveals a rich absorption spectrum which contains a wealth of information
about the physical conditions of gas in massive proto-galaxies. I will
review absorption line modeling techniques and discuss the implications of
these new observations for galaxy formation and feedback scenarios.
The seminar will be held in 544 Campbell Hall.
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