H-ATLAS/GAMA: Quantifying the Morphological Evolution of the Galaxy Population Using Cosmic Calorimetry
Abstract
Using results from the Herschel Astrophysical Terrahertz Large-Area Survey and the Galaxy and Mass Assembly project, we show that, for galaxy masses above approximately 1.0e8 solar masses, 51% of the stellar mass-density in the local Universe is in early-type galaxies (ETGs: Sersic n > 2.5) while 89% of the rate of production of stellar mass-density is occurring in late-type galaxies (LTGs: Sersic n < 2.5). From this zero-redshift benchmark, we have used a calorimetric technique to quantify the importance of the morphological transformation of galaxies over the history of the Universe. The extragalactic background radiation contains all the energy generated by nuclear fusion in stars since the Big Bang. By resolving this background radiation into individual galaxies using the deepest far-infrared survey with the Herschel Space Observatory and a deep near-infrared/optical survey with the Hubble Space Telescope (HST), and using measurements of the Sersic index of these galaxies derived from the HST images, we estimate that approximately 83% of the stellar mass-density formed over the history of the Universe occurred in LTGs. The difference between this and the fraction of the stellar mass-density that is in LTGs today implies there must have been a major transformation of LTGs into ETGs after the formation of most of the stars.
Keywords
Cite
@article{arxiv.1506.05466,
title = {H-ATLAS/GAMA: Quantifying the Morphological Evolution of the Galaxy Population Using Cosmic Calorimetry},
author = {Stephen Eales and Andrew Fullard and Matthew Allen and M. W. L. Smith and Ivan Baldry and Nathan Bourne and C. J. R. Clark and Simon Driver and Loretta Dunne and Simon Dye and Alister W. Graham and Edo Ibar and Andrew Hopkins and Rob Ivison and Lee S. Kelvin and Steve Maddox and Claudia Maraston and Aaron S. G. Robotham and Dan Smith and Edward N. Taylor and Elisabetta Valiante and Paul van der Werf and Maarten Baes and Sarah Brough and David Clements and Asantha Cooray and Haley Gomez and Jon Loveday and Steven Phillipps and Douglas Scott and Steve Serjeant},
journal= {arXiv preprint arXiv:1506.05466},
year = {2015}
}
Comments
Accepted for publication in MNRAS