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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-4660
DTSTART:20171012T203000Z
DTEND:20171012T220000Z
DTSTAMP:20260414T193510Z
LAST-MODIFIED:20171002T125930Z
LOCATION:4421 Sterling Hall\, Coffee and Cookies 3:30 PM. Talk begins 
 at 3:45 PM
SUMMARY:Observing gas in the circumgalactic medium and the Cosmic Web\
 , Astronomy Colloquium\, Bart Wakker\, UW Madison Astronomy Dept
DESCRIPTION:Using HST spectra of AGN we study the gas inside and outsi
 de galaxy halos. We find that galaxies have extended (300 kpc radius) 
 halos\, which blend into the general intergalactic medium. We study pr
 operties of the gas as function of location in the galaxy halos. We al
 so have constructed the first 3-D view of a 30x6 Mpc filament at cz~35
 00 km/s\, This filamentis defined using a new catalogue of nearby gala
 xies\, which is mostly complete down to a luminosity of about 0.05 L* 
 and includes homogenized diameters and luminosities. The baryonic mass
  of the filament galaxies is 1.4x10^13 Msun\, while the mass of filame
 nt gas outside galaxy halos is found to be 5.2x10^13 Msun. We find tha
 t simulations overpredict the detection rate of gas in the filament be
 tween 2.1 and 5 Mpc from the axis. The width of the Lya lines correlat
 es with filament impact parameter and four BLAs in our sample all occu
 r within 400 kpc of the filament axis\, indicating increased temperatu
 re and/or turbulence. We further find that the recent Haardt & Madau (
 2012) extragalactic ionizing background predicts a factor 3-5 too few 
 ionizing photons.
URL:https://www.physics.wisc.edu/events/?id=4660
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