1. HETDEX PILOT SURVEY FOR LYMAN ALPHA EMITTERS AT 2<z<4 Guillermo A. Blanc The University of Texas at Austin COLABORATORS: Joshua Adams, Karl Gebhardt, Gary Hill, Niv Drory, Phillip MacQueen, Ralf Koehler, Lei Hao, Jeremy Murphy, and the HETDEX Collaboration.

2. HETDEX Hobby-Eberly Telescope Dark Energy eXperiment Measure w(z)=p DE (z)/ρ DE (z) at 2<z<4 using Baryonic Acoustic Oscillations (BAO) Power spectrum of the spatial distribution of 1,000,000 LAEs over a volume of 9 Gpc 3

3. HETDEX How do you find 1,000,000 LAEs? You use a VIRUS Visible Integral-field Replicable Unit Spectrograph 150 replicable IFU = 40 arcmin 2 FOV, 37000 fibers (D=1.5”)

4. VIRUS-P VIRUS Prototype IFU 1.7’x1.7’ FOV at HJST 2.7m 1/3 filling factor Largest FOV of any existent IFU 4.2’’ diameter fibers on sky 3500-5800Å wavelength range R=1000 @ 5000Å

5. The VIRUS-P Pilot Survey 99 arcmin 2 surveyed so far on COSMOS, GOODS-N and MUNICS-S2 fields 6 position dither pattern ensures good field coverage 5σ flux limit of ~6x10 -17 erg/s/cm 2 for a point-source emitting and unresolved line

6. DETECTION OF EMISSION LINES GROW DETECTION UNTIL S/N STOPS INCREASING POSITION GIVEN BY FIRST MOMENT OF LIGHT DISTRIBUTION

7. We have analyze 12 pointings (35 arcmin 2 ) of data in the COSMOS field. 99 unique emission line sources detected. –45 LAEs –35 [OII]λ3727 Emitters –5 [OIII]λ5007 Emitters –3 Hβ Emitters –1 AGN –10 ambiguous classifications PRELIMINARY ANALYSIS

8. LAEs and low-z Galaxies

9. CONCLUSIONS 45 to 55 LAE sample over 35 arcmin 2 to a median flux limit of ~6 ergs/s/cm 2. ~300 LAEs expected over the whole pilot survey area. VIRUS-P IFU samples 50 times more volume per arcmin 2 than narrow-band survey. Number of sources agrees with predictions from previous measurements of the Lyα LF of galaxies. Science: Evolution of the Lyα LF Large scale clustering and bias Physical properties of LAEs (SED fitting) Candidates for NIR Hα spectroscopy VIRUS will be the largest IFU in the world and will be commissioned by the end of 2010. HETDEX will detect ~1,000,000 LAEs in 100 nights. HETDEX will measure w at z~3 with ~1% accuracy and measure evolution if DE≠Λ and w(z) evolves more than a 1%. www.hetdex.org