Major mergers are not significant drivers of star formation or morphological transformation around the epoch of peak cosmic star formation
Lofthouse, E. K.
Conselice, C. J.
We investigate the contribution of major mergers (mass ratios > 1 : 5) to stellar mass growth and morphological transformations around the epoch of peak cosmic star formation (z ∼ 2). We visually classify a complete sample of massive (M > 1010M) galaxies at this epoch, drawn from the CANDELS survey, into late-type galaxies, major mergers, spheroids and disturbed spheroids which show morphological disturbances. Given recent simulation work, which indicates that recent (<0.3-0.4 Gyr) major-merger remnants exhibit clear tidal features in such images, we use the fraction of disturbed spheroids to probe the role of major mergers in driving morphological transformations. The percentage of blue spheroids (i.e. with ongoing star formation) that show morphological disturbances is only 21 ± 4 per cent, indicating that major mergers are not the dominant mechanism for spheroid creation at z ∼ 2 - other processes, such as minor mergers or cold accretion are likely to be the main drivers of this process. We also use the rest-frame U-band luminosity as a proxy for star formation to show that only a small fraction of the star formation budget (∼3 per cent) is triggered by major mergers. Taken together, our results show that major mergers are not significant drivers of galaxy evolution at z ∼ 2.
Published inMonthly Notices of the Royal Astronomical Society
RelationsSchool of Physics, Astronomy and Mathematics
MetadataShow full item record
Showing items related by title, author, creator and subject.
The H alpha galaxy survey. I. The galaxy sample, H alpha narrow-band observations and star formation parameters for 334 galaxies James, P.A.; Shane, N.S.; Beckman, J.E.; Cardwell, A.; Collins, C.A.; Etherton, J.; de Jong, R.S.; Fathi, K.; Knapen, J.; Peletier, R.F.; Percival, S.M.; Pollacco, D.L.; Seigar, M.S.; Stedman, S. (2004)We discuss the selection and observations of a large sample of nearby galaxies, which we are using to quantify the star formation activity in the local Universe. The sample consists of 334 galaxies across all Hubble types ...
Banfield, J. K.; Andernach, H.; Kapinska, A. D.; Rudnick, L.; Hardcastle, M. J.; Cotter, G.; Vaughan, S.; Jones, T. W.; Heywood, I.; Wing, J. D.; Wong, O. I.; Matorny, T.; Terentev, I. A.; Lopez-Sanchez, A. R.; Norris, R. P.; Seymour, N.; Shabala, S. S.; Willett, K. W. (2016-08-11)We have discovered a previously unreported poor cluster of galaxies (RGZ-CL J0823.2+0333) through an unusual giant wide-angle tail radio galaxy found in the Radio Galaxy Zoo project. We obtained a spectroscopic redshift ...
Wong, O.I.; Schawinski, K.; Kaviraj, S.; Lintott, C.; Darg, D.; Masters, K.L.; Nichol, R.C.; Thomas, D.; Keel, W.C.; Bamford, S.P.; Andreescu, D.; Murray, P.; Raddick, M.J.; Szalay, A.; Vandenberg, J. (2012-02-01)We present a study of local post-starburst galaxies (PSGs) using the photometric and spectroscopic observations from the Sloan Digital Sky Survey and the results from the Galaxy Zoo project. We find that the majority of ...