The Dependence of Star Formation Activity on Stellar Mass Surface Density and Sersic Index in zCOSMOS Galaxies at 0.5<z<0.9 Compared with SDSS Galaxies at 0.04<z<0.08 - Astrophysics > Astrophysics of GalaxiesReport as inadecuate




The Dependence of Star Formation Activity on Stellar Mass Surface Density and Sersic Index in zCOSMOS Galaxies at 0.5<z<0.9 Compared with SDSS Galaxies at 0.04<z<0.08 - Astrophysics > Astrophysics of Galaxies - Download this document for free, or read online. Document in PDF available to download.

Abstract: One of the key unanswered questions in the study of galaxy evolution is whatphysical processes inside galaxies drive the changes in the SFRs in individualgalaxies that, taken together, produce the large decline in the globalstar-formation rate density SFRD to redshifts since z~2. Many studies of theSFR at intermediate redshifts have been made as a function of the integratedstellar mass of galaxies but these did not use information on the internalstructural properties of the galaxies. In this paper we present a comparativestudy of the dependence of SFRs on the average surface mass densities SigmaMof galaxies of different morphological types up to z~1 using the zCOSMOS andSDSS surveys. The main findings about the evolution of these relatively massivegalaxies are: 1 There is evidence that, for both SDSS ans zCOSMOS galaxies,the mean specific SFR within a given population either disk-dominated orbulge-dominated is independent of SigmaM; 2 The observed SSFR - SigmaMstep-function relation is due, at all investigated redshifts, to the changingmix of disk-dominated and bulge-dominated galaxies as surface density increasesand the strong difference in the average SSFR between disks and bulges. We alsofind a modest differential evolution in the size-mass relations of disk andspheroid galaxies; 3 The shape of the median SSFR - SigmaM relation issimilar, but with median SSFR values that are about 5-6 times higher in zCOSMOSgalaxies than for SDSS, across the whole range of SigmaM, and in both spheroidand disk galaxies. This increase matches that of the global SFRD of theUniverse as a whole, emphasizing that galaxies of all types are contributing,proportionally, to the global increase in SFRD in the Universe back to theseredshifts abridged.



Author: C. Maier, S. J. Lilly, G. Zamorani, M. Scodeggio, F. Lamareille, T. Contini, M. T. Sargent, C. Scarlata, P. Oesch, C. M. Carollo,

Source: https://arxiv.org/



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