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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-1667
DTSTART:20091027T203000Z
DTEND:20091027T220000Z
DTSTAMP:20260501T042940Z
LAST-MODIFIED:20091021T131522Z
LOCATION:3425 Sterling Hall
SUMMARY:The Dark Lives of Galaxies: Investigating Their Seedy Baryonic
  Underbellies with Ultraviolet Spectroscopy\, Astronomy Colloquium\, T
 odd Tripp\, University of MA- Amhearst
DESCRIPTION:t has long been recognized that stars and planets and such
  account<br>
\nfor a tiny fraction of the ordinary matter in the unive
 rse\, and astronomers have been intensively searching for the missing 
 baryons for more than a decade\, with some palpable (but frustratingly
  slow) progress.  It is likely that the missing baryons are hiding out
  in very low-density plasmas in galaxy halos and the intergalactic med
 ium.<br><br>
\n<br>
\nIt is difficult to detect emission from those sh
 ady plasmas\;  ultraviolet and X-ray absorption spectroscopy will prov
 ide the main tools for surveillance of most of the baryons for the for
 eseeable future.  UV spectroscopy provides a particularly potent combi
 nation of high spectral resolution (R = 20\,000 to >>>100\,000)\, rich
  diagnostics of physical conditions\, access to a large number of meta
 ls\, and many bright background continuum sources.  Detection of the m
 issing baryons is a consistency check of CDM cosmology and how large-s
 cale structures grow\, but it is also much more.  Galaxy-halo-IGM inte
 ractions via inflows and outflows must play a major role in galaxy evo
 lution\, but again the baryons in the flows are dark\, and the flow ph
 ysics are poorly understood due to missing observational constraints\,
  e.g.\, of cooling gas at T > 100\,000 K.<br>
\n<br>
\nWith the recent
  deployment of the UV Cosmic Origins Spectrograph on HST\, we are on t
 he verge of a major observational bust of the dark baryons.  Using dat
 a from UV spectrographs on HST and FUSE\, this talk will demonstrate t
 he power of the technique and anticipate upcoming breakthroughs.  Exam
 ples will include insights on galaxy transformation via ram-pressure s
 tripping (or something) and gas consumption\, dusty and multiphase gal
 actic fountains\, and a new signature of galactic flows.  Within 5 yea
 rs\, COS will provide strong statistical constraints on the quantity a
 nd physical state of baryons in halos and the IGM.
URL:https://www.physics.wisc.edu/events/?id=1667
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