Stellar mass functions of galaxies, discs and spheroids at z similar to 0.1

作者：Thanjavur Karun^*; Simard Luc; Bluck Asa F L^*; Mendel Trevor

来源：Monthly Notices of the Royal Astronomical Society, 2016, 459(1): 44-69.

DOI：10.1093/mnras/stw495

• miscellaneous
• astronomical data bases: miscellaneous
• galaxies: fundamental parameters
• galaxies: luminosity function, mass function
• galaxies: statistics
• galaxies: stellar content

We present the stellarmass functions (SMFs) and mass densities of galaxies, and their spheroid and disc components in the local (z similar to 0.1) Universe over the range 8.9 <= log(M/M-circle dot) <= 12 from spheroid+ disc decompositions and corresponding stellar masses of a sample of over 600 000 galaxies in the Sloan Digital Sky Survey Data Release Seven spectroscopic sample. The galaxy SMF is well represented by a single Schechter M* = 11.116 +/- 0.011, alpha = -1.145 +/- 0.008), though with a hint of a steeper faint end slope. The corresponding stellar mass densities are (2.670 +/- 0.110), (1.687 +/- 0.063) and (0.910 +/- 0.029) x 10(8) M-circle dot Mpc(-3) for galaxies, spheroids and discs, respectively. We identify a crossover stellar mass of log(M/M-circle dot) = 10.3 +/- 0.030 at which the spheroid and disc SMFs are equal. Relative contributions of four distinct spheroid/disc dominated sub-populations to the overall galaxy SMF are also presented. The mean disc-to-spheroid stellar mass ratio shows a five-fold disc dominance at the low-mass end, decreasing monotonically with a corresponding increase in the spheroidal fraction till the two are equal at a galaxy stellar mass, log(M/M-circle dot) = 10.479 +/- 0.013; the dominance of spheroids then grows with increasing stellar mass. The relative numbers of composite disc and spheroid-dominated galaxies show peaks in their distributions, perhaps indicative of a preferred galaxy mass. Our characterization of the low-redshift galaxy population provides stringent constraints for numerical simulations to reproduce.

• 出版日期2016-6-11