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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-1961
DTSTART:20101013T170000Z
DTEND:20101013T180000Z
DTSTAMP:20260506T161039Z
LAST-MODIFIED:20101005T142328Z
LOCATION:4421 Sterling Hall
SUMMARY:The Hobby-Eberly Telescope Dark Energy Experiment\, Special We
 dnesday Astronomy Talk\, Gary Hill\, University of  Texas
DESCRIPTION:The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX)
  aims to make a direct detection of dark energy at z~3\, in the case t
 hat it is a cosmological constant. HETDEX uses baryonic acoustic oscil
 lations and the shape of the Lyman-alpha emitting (LAE) galaxy power s
 pectrum to constrain H(z) and Da(z) to percent levels. As a result\, t
 he experiment will place tight constraints on possible dark energy evo
 lution\, complementing studies of the phenomenon at low redshift. HETD
 EX will also provide the most accurate constraint on the curvature of 
 the Universe.<br><br>
\n<br><br>
\nHETDEX will outfit the 10 m HET wit
 h a new wide field and an array of at least 150 integral-field spectro
 graphs to survey a 400 sq. degree area in the north galactic cap. Each
  fiber-coupled unit spectrograph will cover 350-550 nm\, simultaneousl
 y at 6 A resolution\, providing ~36\,000 spectra per exposure. This in
 strument\, called VIRUS\, will open up surveys of the emission-line un
 iverse for the first time\, and in particular will be used to detect ~
 0.8 million LAE galaxies with 1.9 &lt\; z &lt\; 3.5 and more than a mi
 llion [OII] emitting galaxies with z &lt\; 0.5. The 3-D map of LAE gal
 axies in 9 cubic Gpc volume will be used to constrain the expansion hi
 story at this early epoch.<br><br>
\n<br><br>
\nThe prototype of the V
 IRUS unit spectrograph (VIRUS-P) is a powerful instrument in its own r
 ight. Used on the McDonald 2.7 m Smith reflector\, it covers the large
 st area of any integral field spectrograph\, and has coverage down to 
 340 nm. It is currently in use for a pilot survey to better measure th
 e properties of LAE galaxies in support of HETDEX\, among other invest
 igations where it is uniquely powerful.<br><br>
\n<br><br>
\nI will de
 scribe the motivations for HETDEX and preliminary results from the Pil
 ot Survey and look forward to completion of VIRUS on the upgraded HET 
 as a unique facility in Astronomy <br><br>
\n
URL:https://www.physics.wisc.edu/events/?id=1961
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