A panchromatic catalog of early-type galaxies at intermediate redshift in the Hubble Space Telescope wide field camera 3 early release science field

Abstract

In the first of a series of forthcoming publications, we present a panchromatic catalog of 102 visually selected early-type galaxies (ETGs) from observations in the Early Release Science (ERS) program with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) of the Great Observatories Origins Deep Survey-South (GOODS-S) field. Our ETGs span a large redshift range, 0.35 ≲z ≲1.5, with each redshift spectroscopically confirmed by previous published surveys of the ERS field. We combine our measured WFC3 ERS and Advanced Camera for Surveys (ACS) GOODS-S photometry to gain continuous sensitivity from the rest-frame far-UV to near-IR emission for each ETG. The superior spatial resolution of the HST over this panchromatic baseline allows us to classify the ETGs by their small-scale internal structures, as well as their local environment. By fitting stellar population spectral templates to the broadband photometry of the ETGs, we determine that the average masses of the ETGs are comparable to the characteristic stellar mass of massive galaxies, 1011 < M *[M ]<1012. By transforming the observed photometry into the Galaxy Evolution Explorer FUV and NUV, Johnson V, and Sloan Digital Sky Survey g′ and r′ bandpasses we identify a noteworthy diversity in the rest-frame UV-optical colors and find the mean rest-frame (FUV-V) = 3.5 and (NUV-V) = 3.3, with 1σ standard deviations ≃1.0. The blue rest-frame UV-optical colors observed for most of the ETGs are evidence for star formation during the preceding gigayear, but no systems exhibit UV-optical photometry consistent with major recent (≲50Myr) starbursts. Future publications which address the diversity of stellar populations likely to be present in these ETGs, and the potential mechanisms by which recent star formation episodes are activated, are discussed. © 2012. The American Astronomical Society. All rights reserved.