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A GALEX and NDWFS Investigation of Star Forming Galaxies at z=1 and 2: 

A GALEX and NDWFS Investigation of Star Forming Galaxies at z=1 and 2 Charles G. Hoopes, Timothy M. Heckman (JHU) Buell T. Jannuzi, Arjun Dey, Michael J. I. Brown, Alison Ford (NOAO) and Davis Schiminovich (Columbia) June 2, 2004

The Galaxy Evolution Explorer (GALEX): 

The Galaxy Evolution Explorer (GALEX) Launched April 28, 2003 Imaging in two UV bands FUV: λ=1516Å, Δλ=268Å NUV: λ=2267Å, Δλ=732Å Spatial resolution ~5' FOV ~1.2 deg2 Slitless Spectroscopy 1350-2800Å Spectral resolution R=80-300 Conducting several surveys of varying depth and area, as well as pointed observations

Mapping the History of Star Formation in the Universe: 

Mapping the History of Star Formation in the Universe SF history of universe mapped out to zandgt;5 Relatively little known about zandlt;3 Different techniques used for different redshift intervals (From Giavalisco 2002 and Barger et al 2000)

Lyman Break Galaxies at z>3: U-band dropouts: 

Lyman Break Galaxies at zandgt;3: U-band dropouts

Lyman Break Galaxies at z>3: U-band dropouts: 

Lyman Break Galaxies at zandgt;3: U-band dropouts

GALEX Observations of Bootes Region: 

GALEX Observations of Bootes Region Deep Imaging Survey 80 deg2, including the 9 deg2 Bootes region of the NDWFS. Limiting magnitude AB=25 1 deg2 observed in 2003 (the '00' field - 43 ksec) 2 more deg2 coming this week Ultra-Deep Imaging Survey 4 deg2, including the '00' field in Bootes Limiting magnitude AB=26 200 ksec planned (100 in 2004) Deep Spectroscopic Survey 2 deg2, including the '00' field Limiting magnitude AB=22.5-24 Supplemented NDWFS data with deep U observations (AB=26) in the '00' field

z=1: FUV Dropouts: 

z=1: FUV Dropouts SExtractor (Bertin andamp; Arnouts 1996) dual band catalog in NUV/FUV matched with U-band Spatial resolution difference (~5' for GALEX, andlt;1' for U-band) creates identification problems Compare colors to model colors of redshifted starburst spectra (following Steidel et al.)

z=2: NUV Dropouts: 

z=2: NUV Dropouts SExtractor single-band catalogs matched in Bw, U, NUV Spatial resolution problems remains Compare colors to model colors of redshifted starburst spectra (following Steidel et al.)

UV Luminosity: 

UV Luminosity Luminosities calculated from filter redward of Lyman break Fainter z=2 galaxies selected against, but bright z=1 galaxies would be detected Indicates that most luminous galaxies at z=2 have faded by z=1 L* at z=0 from Treyer et al. 2004 in GALEX edition of APJL L* for LBGs from Giavalisco 2002

Star Formation and Extinction: 

Star Formation and Extinction We may be seeing the transition in star formation rates from LBGs to present-day starbursts (see also Arnouts et al. 2004 in GALEX edition of ApJL) Mean extinction implied by UV slope is E(B-V)~0.1 for z=1 E(B-V)~0.2 for z=2 (but there is a degeneracy between redshift and UV slope, and only sensitive to E(B-V)andlt;0.4)

Future Work: 

Future Work Improved matching techniques, photo-z Further GALEX observations Spitzer observations of this region are planned Spectroscopic follow up

Summary: 

Summary GALEX-NDWFS collaboration will shed light on galaxy evolution at z=1-2 Large amount of GALEX data in the Bootes region is coming Initial results show the vigorous star formation of Lyman Break Galaxies fading from z=2 to z=1