THE WiggleZ DARK ENERGY SURVEY: GALAXY EVOLUTION AT 0.25 {<=} z {<=} 0.75 USING THE SECOND RED-SEQUENCE CLUSTER SURVEY
- Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia)
- Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)
- Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710 (Australia)
- Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)
- Department of Physics, University of Queensland, Brisbane, QLD 4072 (Australia)
- Department of Physics, Math, and Astronomy, California Institute of Technology, MC 405-47, 1200, East California Boulevard, Pasadena, CA 91125 (United States)
- Astrophysics and Gravitation Group, Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada)
- Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)
- Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China)
- CSIRO Astronomy and Space Sciences, Australia Telescope National Facility, Epping, NSW 1710 (Australia)
- Observatories of the Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
- School of Physics, Monash University, Clayton, VIC 3800 (Australia)
We study the evolution of galaxy populations around the spectroscopic WiggleZ sample of star-forming galaxies at 0.25 {<=} z {<=} 0.75 using the photometric catalog from the Second Red-Sequence Cluster Survey (RCS2). We probe the optical photometric properties of the net excess neighbor galaxies. The key concept is that the marker galaxies and their neighbors are located at the same redshift, providing a sample of galaxies representing a complete census of galaxies in the neighborhood of star-forming galaxies. The results are compared with those using the RCS WiggleZ Spare-Fibre (RCS-WSF) sample as markers, representing galaxies in cluster environments at 0.25 {<=} z {<=} 0.45. By analyzing the stacked color-color properties of the WiggleZ neighbor galaxies, we find that their optical colors are not a strong function of indicators of star-forming activities such as EW([O II]) or Galaxy Evolution Explorer (GALEX) near-UV luminosity of the markers. The galaxies around the WiggleZ markers exhibit a bimodal distribution on the color-magnitude diagram, with most of them located in the blue cloud. The optical galaxy luminosity functions (GLFs) of the blue neighbor galaxies have a faint-end slope {alpha} of {approx} - 1.3, similar to that for galaxies in cluster environments drawn from the RCS-WSF sample. The faint-end slope of the GLF for the red neighbors, however, is {approx} - 0.4, significantly shallower than the {approx} - 0.7 found for those in cluster environments. This suggests that the buildup of the faint end of the red sequence in cluster environments is in a significantly more advanced stage than that in the star-forming and lower galaxy density WiggleZ neighborhoods. We find that the red galaxy fraction (f{sub red}) around the star-forming WiggleZ galaxies has similar values from z {approx} 0.3 to z {approx} 0.6 with f{sub red} {approx} 0.28, but drops to f{sub red} {approx} 0.20 at z {approx}> 0.7. This change of f{sub red} with redshift suggests that there is either a higher rate of star-forming galaxies entering the luminosity-limited sample at z {approx}> 0.7, or a decrease in the quenching rate of star formation at that redshift. Comparing to that in a dense cluster environment, the f{sub red} of the WiggleZ neighbors is both considerably smaller and has a more moderate change with redshift, pointing to the stronger and more prevalent environmental influences on galaxy evolution in high-density regions.
- OSTI ID:
- 22016268
- Journal Information:
- Astrophysical Journal, Vol. 747, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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