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Title: Constraining the low-mass Slope of the star formation sequence at 0.5 < z < 2.5

We constrain the slope of the star formation rate (SFR; log Ψ) to stellar mass (log M {sub *}) relation down to log (M {sub *}/M {sub ☉}) = 8.4 (log (M {sub *}/M {sub ☉}) = 9.2) at z = 0.5 (z = 2.5) with a mass-complete sample of 39,106 star-forming galaxies selected from the 3D-HST photometric catalogs, using deep photometry in the CANDELS fields. For the first time, we find that the slope is dependent on stellar mass, such that it is steeper at low masses (log Ψ∝log M {sub *}) than at high masses (log Ψ∝(0.3-0.6)log M {sub *}). These steeper low-mass slopes are found for three different star formation indicators: the combination of the ultraviolet (UV) and infrared (IR), calibrated from a stacking analysis of Spitzer/MIPS 24 μm imaging; β-corrected UV SFRs; and Hα SFRs. The normalization of the sequence evolves differently in distinct mass regimes as well: for galaxies less massive than log (M {sub *}/M {sub ☉}) < 10 the specific SFR (Ψ/M {sub *}) is observed to be roughly self-similar with Ψ/M {sub *}∝(1 + z){sup 1.9}, whereas more massive galaxies show a stronger evolution with Ψ/M {sub *}∝(1 + z){sup 2.2-3.5} formore » log (M {sub *}/M {sub ☉}) = 10.2-11.2. The fact that we find a steep slope of the star formation sequence for the lower mass galaxies will help reconcile theoretical galaxy formation models with the observations.« less
Authors:
; ;  [1] ; ; ;  [2] ; ; ; ;  [3] ;  [4] ;  [5]
  1. Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)
  2. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
  3. Department of Astronomy, Yale University, New Haven, CT 06520 (United States)
  4. South African Astronomical Observatory, P.O. Box 9, Observatory, Cape Town 7935 (South Africa)
  5. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
Publication Date:
OSTI Identifier:
22370257
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; 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; EVOLUTION; GALAXIES; MASS; PHOTOMETRY; RED SHIFT; STAR EVOLUTION; ULTRAVIOLET RADIATION