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We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early Re- lease Science (ERS) observations in the Great Observatories Origins Deep Survey (GOODS) South eld. The new WFC3 ERS data provide calibrated, drizzled mosaics in the mid-UV lters F225W, F275W, and F336W, as well as in the near-IR lters F098W (Ys), F125W (J), and F160W (H) in 1{2 HST orbits per lter. Together with the existing HST Advanced Camera for Surveys (ACS) GOODS-South mosaics in the BVi'z' lters, these panchromatic 10-band ERS data cover 40{50 square arcmin from from 0.2-1.7 m in wavelength at 00:007{ 000 :15 FWHM resolution and 000 :090 multidrizzled pixels to depths of AB<  26.0{27.0 mag (5-sigma) for point sources, and AB<  25.5{26.5 mag for compact galaxies. In this paper, we describe: a) the scienti c rationale, and the data taking plus reduction procedures of the panchromatic 10-band ERS mosaics; b) the procedure of generating object catalogs across the 10 di erent ERS lters, and the speci c star-galaxy separation techniques used; and c) the reliability and completeness of the object catalogs from the WFC3 ERS mosaics. The excellent 00:007{00:015 FWHM resolution of HST/WFC3 and ACS makes star- galaxy separation rather straightforward over a factor of 10 in wavelength to AB<  25{26 mag from the UV to the near-IR, respectively. Our main scienti c results are: 1) We present the resulting Galactic star counts and galaxy counts in 10 di erent lters. From the ERS data, these could be accurately determined from AB'19 mag to AB<  26 from the mid-UV to the near-IR, respectively. 2) Both the Galactic stars counts and the galaxy counts show mild but signi cant trends of decreasing count slopes from the mid{UV to the near-IR over a factor of 10 in wavelength. 3) We combine the 10-band ERS counts with the panchromatic GAMA counts at the bright end (10<  AB<  20 mag), and with the ultradeep BVizYJH HUDF counts and other avail- able HST UV counts at the faint end (24<  AB<  30 mag). The galaxy counts are now well measured over the entire magnitude range 10<  AB<  30 mag from 0.2{2 m in wavelength. 4)We t simple galaxy evolution models to these panchromatic galaxy counts over this entire ux range, using the best available 10-band local galaxy luminosity functions (LFs) from the GAMA survey, as well as simple prescriptions of luminosity and/or density evolution. While these models can explain each of the 10-band counts from 10<  AB<  30 mag well, no single one of these simple models can explain the counts over this entire ux range in all 10 lters simultaneously. 5) The 10-band panchromatic ERS data base is very rich in structural information at all rest-frame wavelengths where young or older stars shine during the peak epoch in the cosmic star-formation rate (z'1{2), and constitutes a unique new HST data base for the community to explore in the future.