FIRST RESULTS FROM THE 3D-HST SURVEY: THE STRIKING DIVERSITY OF MASSIVE GALAXIES AT z > 1
- Department of Astronomy, Yale University, New Haven, CT 06520 (United States)
- European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile)
- Leiden Observatory, Leiden University, Leiden (Netherlands)
- Max Planck Institute for Astronomy (MPIA), Koenigstuhl 17, 69117, Heidelberg (Germany)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
- Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)
- Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany)
- Astronomy Department, University of California, Santa Cruz, CA 95064 (United States)
We present first results from the 3D-HST program, a near-IR spectroscopic survey performed with the Wide Field Camera 3 (WFC3) on the HST. We have used 3D-HST spectra to measure redshifts and H{alpha} equivalent widths (EW{sub H{alpha}}) for a complete, stellar mass-limited sample of 34 galaxies at 1 < z < 1.5 with M{sub star} > 10{sup 11} M{sub Sun} in the COSMOS, GOODS, and AEGIS fields. We find that a substantial fraction of massive galaxies at this epoch are forming stars at a high rate: the fraction of galaxies with EW{sub H{alpha}} >10 A is 59%, compared to 10% among Sloan Digital Sky Survey galaxies of similar masses at z = 0.1. Galaxies with weak H{alpha} emission show absorption lines typical of 2-4 Gyr old stellar populations. The structural parameters of the galaxies, derived from the associated WFC3 F140W imaging data, correlate with the presence of H{alpha}; quiescent galaxies are compact with high Sersic index and high inferred velocity dispersion, whereas star-forming galaxies are typically large two-armed spiral galaxies, with low Sersic index. Some of these star-forming galaxies might be progenitors of the most massive S0 and Sa galaxies. Our results challenge the idea that galaxies at fixed mass form a homogeneous population with small scatter in their properties. Instead, we find that massive galaxies form a highly diverse population at z > 1, in marked contrast to the local universe.
- OSTI ID:
- 22047300
- Journal Information:
- Astrophysical Journal Letters, Vol. 743, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
HST/WFC3 CONFIRMATION OF THE INSIDE-OUT GROWTH OF MASSIVE GALAXIES AT 0 < z < 2 AND IDENTIFICATION OF THEIR STAR-FORMING PROGENITORS AT z {approx} 3
AN HST/WFC3-IR MORPHOLOGICAL SURVEY OF GALAXIES AT z = 1.5-3.6. I. SURVEY DESCRIPTION AND MORPHOLOGICAL PROPERTIES OF STAR-FORMING GALAXIES