Most Submillimeter Galaxies are Major Mergers

Creators: Engel, H.; Tacconi, L. J.; Davies, R. I.; Neri, R.; Smail, I.; Chapman, S. C.; Genzel, R.; Cox, P.; Greve, T. R.; Ivison, R. J.; Blain, A.; Bertoldi, F.; Omont, A.

Abstract

We analyze subarcsecond resolution interferometric CO line data for 12 submillimeter-luminous (S_(850 μm) ≥ 5 mJy) galaxies with redshifts between 1 and 3, presenting new data for 4 of them. Morphologically and kinematically, most of the 12 systems appear to be major mergers. Five of them are well-resolved binary systems, and seven are compact or poorly resolved. Of the four binary systems for which mass measurements for both separate components can be made, all have mass ratios of 1:3 or closer. Furthermore, comparison of the ratio of compact to binary systems with that observed in local ULIRGs indicates that at least a significant fraction of the compact submillimeter-luminous galaxies (SMGs) must also be late-stage mergers. In addition, the dynamical and gas masses we derive are most consistent with the lower end of the range of stellar masses published for these systems, favoring cosmological models in which SMGs result from mergers. These results all point to the same conclusion that most of the bright SMGs with L_(IR) ≳ 5 × 10^(12) L_☉ are likely major mergers.

Additional Information

© 2010 American Astronomical Society. Received 2010 April 12; accepted 2010 September 10; published 2010 November 1. We would like to thank the anonymous referee for a thoughtful and thorough reading of the manuscript, which helped to improve and clarify the paper. H.E. would like to thank Desika Narayanan for a helpful discussion of his simulations and the merger evolution of S850μm versus LIR. We thank the staff of the IRAM observatory for their support of this program. The Dark Cosmology Centre is funded by DNRF. T.R.G. acknowledges support from IDA. I.R.S. acknowledges support from STFC.

Attached Files

Published - Engel2010p12061Astrophys_J.pdf

Files

Engel2010p12061Astrophys_J.pdf

Files (1.1 MB)

Name	Size	Download all
Engel2010p12061Astrophys_J.pdf md5:4299ca21a7e22bacd7ac1e472b9d0a9e	1.1 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes