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Title: Steadily increasing star formation rates in galaxies observed at 3 ≲ z ≲ 5 in the CANDELS/GOODS-S field

We investigate the star formation histories (SFHs) of high redshift (3 ≲ z ≲ 5) star-forming galaxies selected based on their rest-frame ultraviolet (UV) colors in the CANDELS/GOODS-S field. By comparing the results from the spectral-energy-distribution-fitting analysis with two different assumptions about the SFHs—i.e., exponentially declining SFHs as well as increasing ones, we conclude that the SFHs of high-redshift star-forming galaxies increase with time rather than exponentially decline. We also examine the correlations between the star formation rates (SFRs) and the stellar masses. When the galaxies are fit with rising SFRs, we find that the trend seen in the data qualitatively matches the expectations from a semi-analytic model of galaxy formation. The mean specific SFR is shown to increase with redshift, also in agreement with the theoretical prediction. From the derived tight correlation between stellar masses and SFRs, we derive the mean SFH of star-forming galaxies in the redshift range of 3 ≤ z ≤ 5, which shows a steep power-law (with power α = 5.85) increase with time. We also investigate the formation timescales and mean stellar population ages of these star-forming galaxies. Our analysis reveals that UV-selected star-forming galaxies have a broad range of the formation redshift. Themore » derived stellar masses and the stellar population ages show positive correlation in a sense that more massive galaxies are on average older, but with significant scatter. This large scatter implies that the galaxies' mass is not the only factor which affects the growth or star formation of high-redshift galaxies.« less
Authors:
 [1] ; ;  [2] ;  [3] ;  [4] ;  [5]
  1. Center for the Exploration of the Origin of the Universe, Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of)
  2. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  3. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)
  4. Astronomy Department, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States)
  5. ESO/Joint ALMA Observatory, 3107 Alonso de Cordova, Santiago (Chile)
Publication Date:
OSTI Identifier:
22351587
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; CORRELATIONS; ENERGY SPECTRA; GALAXIES; GROWTH; MASS; RED SHIFT; STAR EVOLUTION; STARS; STATISTICS; ULTRAVIOLET RADIATION