1. A Massive Galaxy in Its Core Formation Phase Three Billion Years After the Big Bang
- Author
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Nelson, Erica, van Dokkum, Pieter, Franx, Marijn, Brammer, Gabriel, Momcheva, Ivelina, Schreiber, Natascha M. Forster, da Cunha, Elisabete, Tacconi, Linda, Bezanson, Rachel, Kirkpatrick, Allison, Leja, Joel, Rix, Hans-Walter, Skelton, Rosalind, van der Wel, Arjen, Whitaker, Katherine, and Wuyts, Stijn
- Subjects
Astrophysics - Abstract
Most massive galaxies are thought to have formed their dense stellar cores at early cosmic epochs. However, cores in their formation phase have not yet been observed. Previous studies have found galaxies with high gas velocity dispersions or small apparent sizes but so far no objects have been identified with both the stellar structure and the gas dynamics of a forming core. Here we present a candidate core in formation 11 billion years ago, at z = 2.3. GOODS-N-774 has a stellar mass of 1.0 × 10 (exp 11) solar mass, a half-light radius of 1.0 kpc, and a star formation rate of 90 (sup +45 / sub −20) solar mass/yr. The star forming gas has a velocity dispersion 317 plus or minus 30 km/s, amongst the highest ever measured. It is similar to the stellar velocity dispersions of the putative descendants of GOODS-N-774, compact quiescent galaxies at z is approximately equal to 2 (exp 8-11) and giant elliptical galaxies in the nearby Universe. Galaxies such as GOODS-N-774 appear to be rare; however, from the star formation rate and size of the galaxy we infer that many star forming cores may be heavily obscured, and could be missed in optical and near-infrared surveys.
- Published
- 2014