Galaxy And Mass Assembly (GAMA): Gas Fuelling of Spiral Galaxies in the Local Universe II. -- Direct Measurement of the Dependencies on Redshift and Host Halo Mass of Stellar Mass Growth in Central Disk Galaxies

M. W. Grootes; A. Dvornik; R. J. Laureijs; R. J. Tuffs; C. C. Popescu; A. S. G. Robotham; J. Liske; M. J. I. Brown; B. W. Holwerda; L. Wang

doi:10.1093/mnras/sty688

paper

Galaxy And Mass Assembly (GAMA): Gas Fuelling of Spiral Galaxies in the Local Universe II. -- Direct Measurement of the Dependencies on Redshift and Host Halo Mass of Stellar Mass Growth in Central Disk Galaxies

arXiv:1803.04962 · doi:10.1093/mnras/sty688

Abstract

We present a detailed analysis of the specific star formation rate -- stellar mass ( $sSFR - M_{*}$ ) of $z \leq 0.13$ disk central galaxies using a morphologically selected mass-complete sample ( $M_{*} \geq 1 0^{9.5} M_{⊙}$ ). Considering samples of grouped and ungrouped galaxies, we find the $sSFR - M_{*}$ relations of disk-dominated central galaxies to have no detectable dependence on host dark-matter halo (DMH) mass, even where weak-lensing measurements indicate a difference in halo mass of a factor $≳ 5$ . We further detect a gradual evolution of the $sSFR - M_{*}$ relation of non-grouped (field) central disk galaxies with redshift, even over a $Δ z \approx 0.04$ ( $\approx 5 \cdot 1 0^{8} yr$ ) interval, while the scatter remains constant. This evolution is consistent with extrapolation of the "main-sequence-of-star-forming-galaxies" from previous literature that uses larger redshift baselines and coarser sampling. Taken together, our results present new constraints on the paradigm under which the SFR of galaxies is determined by a self-regulated balance between gas inflows and outflows, and consumption of gas by star-formation in disks, with the inflow being determined by the product of the cosmological accretion rate and a fuelling-efficiency -- $M ˙_{b, halo} ζ$ . In particular, maintaining the paradigm requires $M ˙_{b, halo} ζ$ to be independent of the mass $M_{halo}$ of the host DMH. Furthermore, it requires the fuelling-efficiency $ζ$ to have a strong redshift dependence ( $\propto (1 + z)^{2.7}$ for $M_{*} = 1 0^{10.3} M_{⊙}$ over $z = 0 - 0.13$ ), even though no morphological transformation to spheroids can be invoked to explain this in our disk-dominated sample. The physical mechanisms capable of giving rise to such dependencies of $ζ$ on $M_{halo}$ and $z$ for disks are unclear.

arXiv comment23 pages, 6 figures, 3 tables. Accepted for publication in MNRAS

Galaxy And Mass Assembly (GAMA): Gas Fuelling of Spiral Galaxies in the Local Universe II. -- Direct Measurement of the Dependencies on Redshift and Host Halo Mass of Stellar Mass Growth in Central Disk Galaxies

Abstract

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