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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. HETDEX.
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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.
HETDEX • Hobby-Eberly Telescope Dark Energy eXperiment • Measure w(z)=pDE(z)/ρDE(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 Gpc3
HETDEX • How do you find 1,000,000 LAEs? You use a VIRUS Visible Integral-field Replicable Unit Spectrograph 150 replicable IFU = 40 arcmin2 FOV, 37000 fibers (D=1.5”)
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
The VIRUS-P Pilot Survey • 99 arcmin2 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/cm2 for a point-source emitting and unresolved line
DETECTION OF EMISSION LINES • GROW DETECTION UNTIL S/N STOPS INCREASING • POSITION GIVEN BY FIRST MOMENT OF LIGHT DISTRIBUTION
PRELIMINARY ANALYSIS • We have analyze 12 pointings (35 arcmin2) 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
CONCLUSIONS • 45 to 55 LAE sample over 35 arcmin2 to a median flux limit of ~6 ergs/s/cm2. ~300 LAEs expected over the whole pilot survey area. • VIRUS-P IFU samples 50 times more volume per arcmin2 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