Constraints on the star formation histories of galaxies from z~1 to z~0

Abstract

We present a new method to estimate the average star formation rate per unit stellar mass (SSFR) of a stacked population of galaxies. We combine the spectra of 600-1000 galaxies with similar stellar masses and parameterise the star formation history of this stacked population using a set of exponentially declining functions. The strength of the Hydrogen Balmer absorption line series in the rest-frame wavelength range 3750-4150Åis used to constrain the SSFR by comparing with a library of models generated using the BC03 stellar population code. Our method, based on a principal component analysis (PCA), can be applied in a consistent way to spectra drawn from local galaxy surveys and from surveys at $z\sim 1$, and is only weakly influenced by attenuation due to dust. We apply our method to galaxy samples drawn from SDSS and DEEP2 to study mass-dependent growth of galaxies from $z\sim 1$ to $z\sim 0$. We find that, (1) high mass galaxies have lower SSFRs than low mass galaxies; (2) the average SSFR has decreased from $z=1$ to $z=0$ by a factor of $\sim 3-4$, independent of galaxy mass. Additionally, at $z\sim 1$ our average SSFRs are a factor of $2-2.5$ lower than those derived from multi-wavelength photometry using similar datasets. We then compute the average time (in units of the Hubble time, $t_{\mathrm{H}}(z)$) needed by galaxies of a given mass to form their stars at their current rate. At both $z=0$ and at $z=1$, this timescale decreases strongly with stellar mass from values close to unity for galaxies with masses $\sim 10^{10}{M}_{\odot }$, to more than ten for galaxies more massive than $10^{11}{M}_{\odot }$. Our results are in good agreement with models in which AGN feedback is more efficient at preventing gas from cooling and forming stars in high mass galaxies.

14 pages, 11 figures, accepted by MNRAS

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Cited by in corpus (9)

• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• The Main Sequence of star-forming galaxies across cosmic times
• The Evolving Interstellar Medium of Star-Forming Galaxies, as traced by $\text{Stardust}$
• The starburst-AGN connection: the role of young stellar populations in fueling supermassive black holes
• The Evolution of Star Formation Activity in Cluster Galaxies Over $0.15<z<1.5$
• A Uniform History for Galaxy Evolution
• A study of the HI gas fractions of galaxies at z ~ 1
• A Comparative Study of Star Forming Dwarf Galaxies using the UVIT
• Effect of the environment on star formation activity and stellar mass for star-forming galaxies in the COSMOS field