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Title: The era of star formation in galaxy clusters

We analyze the star formation properties of 16 infrared-selected, spectroscopically confirmed galaxy clusters at 1 < z < 1.5 from the Spitzer/IRAC Shallow Cluster Survey (ISCS). We present new spectroscopic confirmation for six of these high-redshift clusters, five of which are at z > 1.35. Using infrared luminosities measured with deep Spitzer/Multiband Imaging Photometer for Spitzer observations at 24 μm, along with robust optical + IRAC photometric redshifts and spectral-energy-distribution-fitted stellar masses, we present the dust-obscured star-forming fractions, star formation rates, and specific star formation rates in these clusters as functions of redshift and projected clustercentric radius. We find that z ∼ 1.4 represents a transition redshift for the ISCS sample, with clear evidence of an unquenched era of cluster star formation at earlier times. Beyond this redshift, the fraction of star-forming cluster members increases monotonically toward the cluster centers. Indeed, the specific star formation rate in the cores of these distant clusters is consistent with field values at similar redshifts, indicating that at z > 1.4 environment-dependent quenching had not yet been established in ISCS clusters. By combining these observations with complementary studies showing a rapid increase in the active galactic nucleus (AGN) fraction, a stochastic star formation history,more » and a major merging episode at the same epoch in this cluster sample, we suggest that the starburst activity is likely merger-driven and that the subsequent quenching is due to feedback from merger-fueled AGNs. The totality of the evidence suggests we are witnessing the final quenching period that brings an end to the era of star formation in galaxy clusters and initiates the era of passive evolution.« less
Authors:
 [1] ;  [2] ; ; ;  [3] ;  [4] ; ;  [5] ; ;  [6] ; ; ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] ;  [14]
  1. Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States)
  2. University of California, Davis, CA 95616 (United States)
  3. Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)
  4. Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)
  5. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  6. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
  7. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
  8. School of Physics, Monash University, Clayton, Victoria 3800 (Australia)
  9. Spitzer Science Center, MC 220-6, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
  10. National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)
  11. INAF—Osservatorio di Roma, Via Frascati 33, I-00040 Monteporzio (Italy)
  12. Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85121 (United States)
  13. Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
  14. Department of Physics and Astronomy, Siena College, 515 Loudon Road, Loudonville, NY 12211 (United States)
Publication Date:
OSTI Identifier:
22348415
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; 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; DISTANCE; DUSTS; ENERGY SPECTRA; EVOLUTION; FEEDBACK; GALAXIES; GALAXY CLUSTERS; LUMINOSITY; MASS; NUCLEI; PHOTOMETERS; RED SHIFT; STAR CLUSTERS; STARS; STOCHASTIC PROCESSES