Quenching or Bursting: The Role of Stellar Mass, Environment, and Specific Star Formation Rate to z ~ 1

Abstract

sing a novel approach, we study the quenching and bursting of galaxies as a function of stellar mass (M *), local environment (Σ), and specific star formation rate (sSFR) using a large spectroscopic sample of ~123,000 GALEX/SDSS and ~420 GALEX/COSMOS/LEGA-C galaxies to z ~ 1. We show that out to z ~ 1 and at fixed sSFR and local density, on average, less massive galaxies are quenching, whereas more massive systems are bursting, with a quenching/bursting transition at log(M_*/M_⊙) ~ 10.5-11 and likely a short quenching/bursting timescale (≾300 Myr). We find that much of the bursting of star formation happens in massive (log(M_*/M_⊙) ≳ 11), high-sSFR galaxies (log(sSFR/Gyr^(−1)) ≳ −2), particularly those in the field (log(Σ/Mpc−2) ≾0 and, among group galaxies, satellites more than centrals). Most of the quenching of star formation happens in low-mass (log(M_*/M_⊙) ≾ 9), low-sSFR galaxies (log(sSFR/Gyr−1) ≾ −2), in particular those located in dense environments (log(Σ/Mpc^(−2)) ≳1), indicating the combined effects of M * and Σ in the quenching/bursting of galaxies since z ~ 1. However, we find that stellar mass has stronger effects than environment on the recent quenching/bursting of galaxies to z ~ 1. At any given M_*, sSFR, and environment, centrals are quenchier (quenching faster) than satellites in an average sense. We also find evidence for the strength of mass and environmental quenching being stronger at higher redshift. Our preliminary results have potential implications for the physics of quenching/bursting in galaxies across cosmic time.

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