Galaxy And Mass Assembly (GAMA): the galaxy stellar mass function to z = 0.1 from the r-band selected equatorial regions

Abstract

We derive the low redshift galaxy stellar mass function (GSMF), inclusive of dust corrections, for the equatorial Galaxy And Mass Assembly (GAMA) dataset covering 180 deg 2 . We construct the mass function using a density-corrected maximum volume method, using masses corrected for the impact of optically thick and thin dust. We explore the galactic bivariate brightness plane (M − µ), demonstrating that surface brightness effects do not systematically bias our mass function measurement above 10 7.5 M . The galaxy distribution in the M −µ-plane appears well bounded, indicating that no substantial population of massive but diffuse or highly compact galaxies are systematically missed due to the GAMA selection criteria. The GSMF is fit with a double Schechter function, with M = 10 10.78±0.01±0.20 M , φ 1 = (2.93 ± 0.40) × 10 −3 h 3 70 Mpc −3 , α 1 = −0.62 ± 0.03 ± 0.15, φ 2 = (0.63 ± 0.10) × 10 −3 h 3 70 Mpc −3 , and α 2 = −1.50±0.01±0.15. We find the equivalent faint end slope as previously estimated using the GAMA-I sample, although we find a higher value of M . Using the full GAMA-II sample, we are able to fit the mass function to masses as low as 10 7.5 M , and assess limits to 10 6.5 M . Combining GAMA-II with data from G10-COSMOS we are able to comment qualitatively on the shape of the GSMF down to masses as low as 10 6 M . Beyond the well known upturn seen in the GSMF at 10 9.5 the distribution appears to maintain a single power-law slope from 10 9 to 10 6.5 . We calculate the stellar mass density parameter given our best-estimate GSMF, finding Ω = 1.66 +0.24 −0.23 ± 0.97h −1 70 × 10 −3 , inclusive of random and systematic uncertainties.

Small-Scale Challenges to the ΛCDM Paradigm

“…The dotted line is shifted to the left by the cosmic baryon fraction for each halo M vir → f b M vir . This is compared to the observed stellar mass function of galaxies from Bernardi et al (2013, magenta stars) and Wright et al (2017;cyan squares). The shaded bands demonstrate a range of faint-end slopes αg = −1.62 to −1.32.…”

Automated Mining of the ALMA Archive in the COSMOS Field (A3COSMOS). II. Cold Molecular Gas Evolution out to Redshift 6

“…In recent years, deep HST, Spitzer and ground-based near-IR observations in deep fields have pushed the accurate measurements of the star-forming galaxies' SMFs out to z ∼ 4 − 5 (e.g., Marchesini et al 2009;Peng et al 2010;Baldry et al 2012;Santini et al 2012;Moustakas et al 2013;Muzzin et al 2013;Ilbert et al 2013;Grazian et al 2015;Song et al 2016;Davidzon et al 2017;Wright et al 2017Wright et al , 2018. Similarly, deep Herschel far-infrared/sub-mm and ground-based sub-mm surveys pushed the accurate measurements of cosmic SFR density (CSFRD) out to z ∼ 3 − 4 as well (e.g., Madau & Dickinson 2014;Liu et al 2018;and references therein).…”

Self-consistent Bulge/Disk/Halo Galaxy Dynamical Modeling Using Integral Field Kinematics

“…Additional model complexity (especially dust reddening and stellar population gradients) is necessary to fully reproduce galaxy colors, and full spectral modeling would be ideal. However, it is worth noting that systematic differences in the inferred stellar masses of GAMA galaxies (including the SAMI sample) can be as large as 0.2 dex depending largely on the treatment of star formation histories and dust (Wright et al 2017), even neglecting possible variations in the initial mass function. There are also significant differences among stellar population models, stellar spectral libraries, and isochrones, which preclude making accurate estimates of stellar mass-to-light ratios even given a star formation history, and it is unclear how one might estimate the magnitude of such effects for a given galaxy.…”