Differences in the structural properties and star formation rates of field and cluster galaxies at Z ∼ 1

Rebecca J. Allen, Glenn G. Kacprzak, Karl Glazebrook, Kim Vy H Tran, Lee R. Spitler, Caroline M S Straatman, Michael Cowley, Themiya Nanayakkara

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    16 Citations (Scopus)


    We investigate the dependence of galaxy sizes and star formation rates (SFRs) on their environment using a mass-limited sample of quiescent and star-forming galaxies with log(MM) ≥ 9.5 at selected from the NEWFIRM medium-band Survey (NMBS). Using the Galaxy Environment Evolution Collaboration 2 spectroscopic cluster catalog and the accurate photometric redshifts from the NMBS, we select quiescent and star-forming cluster (σ = 490 km s-1) galaxies within two virial radius, Rvir, intervals of 2 > R vir > 0.5 and R vir < 0.5. Galaxies residing outside of the 2 R vir of both the cluster centers and the additional candidate over-densities are defined as our field sample. Galaxy structural parameters are measured from the COSMOS legacy Hubble Space Telescope/ACS F814W image. The sizes and Sérsic indices of quiescent field and cluster galaxies have the same distribution regardless of R vir. However, cluster star-forming galaxies within 0.5 R vir have lower mass-normalized average sizes by 16 ± 7%, and a higher fraction of Sérsic indices with , than field star-forming galaxies. The average SFRs of star-forming cluster galaxies show a trend of decreasing SFR with clustocentric radius. The mass-normalized average SFR of cluster star-forming galaxies is a factor of 2-2.5(7-9σ) lower than that of star-forming galaxies in the field. While we find no significant dependence on environment for quiescent galaxies, the properties of star-forming galaxies are affected, which could be the result of environment acting on their gas content.

    Original languageEnglish
    Article number60
    Pages (from-to)1-12
    Number of pages12
    JournalAstrophysical Journal
    Issue number1
    Publication statusPublished - 20 Jul 2016


    • galaxies: clusters: general
    • galaxies: evolution
    • galaxies: star formation
    • galaxies: structure


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