THE ASSEMBLY OF MILKY-WAY-LIKE GALAXIES SINCE z {approx} 2.5
- Department of Astronomy, Yale University, New Haven, CT 06511 (United States)
- Leiden Observatory, Leiden University, Leiden (Netherlands)
- European Southern Observatory, Alonson de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile)
- Astrophysics Science Division, Goddard Space Center, Greenbelt, MD 20771 (United States)
- Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States)
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States)
- Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany)
- Department of Astronomy, University of California, Berkeley, CA 94720 (United States)
- Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)
- Max Planck Institute for Astronomy (MPIA), Koenigstuhl 17, D-69117 Heidelberg (Germany)
Galaxies with the mass of the Milky Way dominate the stellar mass density of the universe but it is uncertain how and when they were assembled. Here we study progenitors of these galaxies out to z = 2.5, using data from the 3D-HST and CANDELS Treasury surveys. We find that galaxies with present-day stellar masses of log (M) Almost-Equal-To 10.7 built {approx}90% of their stellar mass since z = 2.5, with most of the star formation occurring before z = 1. In marked contrast to the assembly history of massive elliptical galaxies, mass growth is not limited to large radii: the mass in the central 2 kpc of the galaxies increased by a factor of 3.2{sup +0.8}{sub -0.7} between z = 2.5 and z = 1. We therefore rule out simple models in which bulges were fully assembled at high redshift and disks gradually formed around them. Instead, bulges (and black holes) likely formed in lockstep with disks, through bar instabilities, migration, or other processes. We find that after z = 1 the growth in the central regions gradually stopped and the disk continued to be built up, consistent with recent studies of the gas distributions in z {approx} 1 galaxies and the properties of many spiral galaxies today.
- OSTI ID:
- 22118687
- Journal Information:
- Astrophysical Journal Letters, Vol. 771, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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