SizeLuminosity Scaling Relations of Local and Distant Starforming Regions
Abstract
We investigate starforming scaling relations using Bayesian inference on a comprehensive data sample of low (z < 0.1) and highredshift (1 < z < 5) starforming regions. This full data set spans a wide range of host galaxy stellar mass (M _{*} ∼ 10^{6}10^{11} {M}_{⊙ }) and clump star formation rates (SFR ∼ 10^{5} 10^{2} {M}_{⊙ } yr^{1}). We fit the powerlaw relationship between the size ({r}_{{{H}}α }) and luminosity ({L}_{{{H}}α }) of the starforming clumps using the Bayesian statistical modeling tool Stan, which makes use of Markov Chain Monte Carlo (MCMC) sampling techniques. Trends in the scaling relationship are explored for the full sample and subsets based on redshift and selection effects between samples. In our investigation, we find neither evidence of redshift evolution of the sizeluminosity scaling relationship nor a difference in slope between lensed and unlensed data. There is evidence of a break in the scaling relationship between high and low SFR surface density ({{{Σ }}}_{SFR}}) clumps. The sizeluminosity powerlaw fit results are {L}_{{{H}}α } ∼ {r}_{{{H}}α } ^{2.8} and {L}_{{{H}}α } ∼ {r}_{{{H}}α } ^{1.7} for low and high {{{Σ }}}_{SFR}} clumps, respectively. We present a model where starforming clumps form at locations of gravitational instability and produce an ionized region represented by the Strömgren radius. A radius smaller than the scale height of the disk results in a scaling relationship of L ∝ r ^{3} (high {{{Σ }}}_{SFR}} clumps), and a scaling of L ∝ r ^{2} (low {{{Σ }}}_{SFR}} clumps) if the radius is larger than the disk scale height.
 Publication:

The Astrophysical Journal
 Pub Date:
 December 2018
 DOI:
 10.3847/15384357/aaeb8f
 arXiv:
 arXiv:1810.10494
 Bibcode:
 2018ApJ...869...11C
 Keywords:

 galaxies: highredshift;
 galaxies: star formation;
 galaxies: structure;
 methods: data analysis;
 methods: statistical;
 techniques: imaging spectroscopy;
 Astrophysics  Astrophysics of Galaxies
 EPrint:
 33 pages, 16 figures, 8 tables. Accepted for publication in The Astrophysical Journal