THE RELATION BETWEEN STAR FORMATION RATE AND STELLAR MASS FOR GALAXIES AT 3.5 ⩽z⩽ 6.5 IN CANDELS

Abstract

Distant star-forming galaxies show a correlation between their star formation rates (SFR) and stellar masses, and this has deep implications for galaxy formation. Here, we present a study on the evolution of the slope and scatter of the SFR-stellar mass relation for galaxies at 3.5 ≤ z ≤ 6.5 using multiwavelength photometry in GOODS-S from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and Spitzer Extended Deep Survey. We describe an updated, Bayesian spectral-energy distribution fitting method that incorporates effects of nebular line emission, star formation histories that are constant or rising with time, and different dust attenuation prescriptions (starburst and Small Magellanic Cloud). From z=6.5 to z=3.5 star-forming galaxies in CANDELS follow a nearly unevolving correlation between stellar mass and SFR that follows SFR ∼ M a with a= 0.54 ± 0.16 at z ∼ 6 and 0.70 ± 0.21 at z ∼ 4. This evolution requires a star formation history that increases with decreasing redshift (on average, the SFRs of individual galaxies rise with time). The observed scatter in the SFR-stellar mass relation is tight, σ(log SFR/M yr −1 ) < 0.3 − 0.4 dex, for galaxies with log M /M > 9 dex. Assuming that the SFR is tied to the net gas inflow rate (SFR ∼Ṁ gas ), then the scatter in the gas inflow rate is also smaller than 0.3−0.4 dex for star-forming galaxies in these stellar mass and redshift ranges, at least when averaged over the timescale of star formation. We further show that the implied star formation history of objects selected on the basis of their co-moving number densities is consistent with the evolution in the SFR-stellar mass relation.

On the universality of luminosity–metallicity and mass–metallicity relations for compact star-forming galaxies at redshifts 0 < z < 3

“…Lyα emitting galaxies with redshifts 1.9 < z < 3.6 by Hagen et al (2014) and star-forming galaxies with redshifts z ∼ 3.4 by Troncoso et al (2014) are shown by dark-grey stars and asterisks, respectively. The relations for galaxies with z ∼ 4 by Bouwens et al (2012) and for galaxies with z ∼ 5 -6 by Salmon et al (2015) are indicated by thick solid red and yellow lines, respectively. The galaxy candidates with z ∼ 9 -11 by Coe et al (2013) and Oesch et al (2014) are shown by large open dark-grey triangles.…”

SPECTROSCOPIC STUDY OF STAR-FORMING GALAXIES IN FILAMENTS AND THE FIELD ATz∼ 0.5: EVIDENCE FOR ENVIRONMENTAL DEPENDENCE OF ELECTRON DENSITY

“…Many studies have shown a relatively tight correlation (typical dispersion of ∼0.2 dex) between SFR and stellar mass (main sequence of star-forming galaxies), or equivalently between sSFR and stellar mass out to z∼6 (Brinchmann et al 2004;Daddi et al 2007;Elbaz et al 2007;Noeske et al 2007;Salim et al 2007;Karim et al 2011;Reddy et al 2012;Whitaker et al 2012;Sobral et al 2014;Salmon et al 2015;Shivaei et al 2015a). Since we found that EW [O II] and sSFR [O II] are related, we expect to see a relation between EW [O II] and stellar mass.…”

SPITZER ULTRA FAINT SURVEY PROGRAM (SURFS UP). II. IRAC-DETECTED LYMAN-BREAK GALAXIES AT 6 ≲ z ≲ 10 BEHIND STRONG-LENSING CLUSTERS

“…In order to calculate the expected line fluxes for a given BC03 galaxy template, we calculate the integrated Lyman continuum flux (before dust attenuation) and use the relation from Leitherer & Heckman (1995) to calculate the expected fluxes from hydrogen recombination lines (mainly Hα, Hβ, Paβ, and Brγ) while assuming the Lyman continuum escape fraction to be zero. Non-zero Lyman continuum escape fraction will reduce the strength of optical nebular emission lines (see Inoue 2011 andSalmon et al 2015). We then use the tabulated line ratios between Hβ and the metal lines from Anders & Alvensleben (2003) to calculate the metal line fluxes for a metallicity of 0.2Z e .…”