skip to main content

Title: Galaxy stellar mass functions from ZFOURGE/CANDELS: An excess of low-mass galaxies since z = 2 and the rapid buildup of quiescent galaxies

Using observations from the FourStar Galaxy Evolution Survey (ZFOURGE), we obtain the deepest measurements to date of the galaxy stellar mass function (SMF) at 0.2 < z < 3. ZFOURGE provides well-constrained photometric redshifts made possible through deep medium-bandwidth imaging at 1-2 μm. We combine this with Hubble Space Telescope imaging from the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey, allowing for the efficient selection of both blue and red galaxies down to stellar masses of ∼10{sup 9.5} M {sub ☉} at z ∼ 2.5. The total surveyed area is 316 arcmin{sup 2} distributed over three independent fields. We supplement these data with the wider and shallower NEWFIRM Medium-Band Survey to provide stronger constraints at high masses. Several studies at z ≤ 1.5 have revealed a steepening of the slope at the low-mass end of the SMF, leading to an upturn at masses <10{sup 10} M {sub ☉} that is not well described by a standard single-Schechter function. We find evidence that this feature extends to at least z ∼ 2 and that it can be found in both the star-forming and quiescent populations individually. The characteristic mass (M*) and slope at the lowest masses (α) of a double-Schechter functionmore » fit to the SMF stay roughly constant at Log(M/M {sub ☉}) ∼ 10.65 and ∼ – 1.5, respectively. The SMF of star-forming galaxies has evolved primarily in normalization, while the change in shape is relatively minor. Our data allow us, for the first time, to observe a rapid buildup at the low-mass end of the quiescent SMF. Since z = 2.5, the total stellar mass density of quiescent galaxies (down to 10{sup 9} M {sub ☉}) has increased by a factor of ∼12, whereas the mass density of star-forming galaxies only increases by a factor of ∼2.2.« less
Authors:
; ; ; ; ; ;  [1] ; ; ; ; ;  [2] ; ;  [3] ; ; ;  [4] ;  [5] ;  [6]
  1. George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)
  2. Carnegie Observatories, Pasadena, CA 91101 (United States)
  3. Sterrewacht Leiden, Leiden University, NL-2300 RA Leiden (Netherlands)
  4. Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia)
  5. European Southern Observatory, Alonso de Córdova 3107, Casilla 19001, Vitacura, Santiago (Chile)
  6. Department of Astronomy, Yale University, New Haven, CT 06520 (United States)
Publication Date:
OSTI Identifier:
22351591
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; GALACTIC EVOLUTION; GALAXIES; LIMITING VALUES; LUMINOSITY; MASS; NEAR INFRARED RADIATION; RED SHIFT; SPACE; STARS; TELESCOPES