dc.contributor.author | Swinbank, Mark | en_US |
dc.contributor.author | Smail, Ian | en_US |
dc.contributor.author | Chapman, Scott | en_US |
dc.contributor.author | Blain, Andrew | en_US |
dc.contributor.author | Ivison, Rob | en_US |
dc.contributor.author | Keel, William | en_US |
dc.date.accessioned | 2014-03-12T19:20:59Z | |
dc.date.available | 2014-03-12T19:20:59Z | |
dc.date.issued | 2004-11-20 | en_US |
dc.identifier.citation | Swinbank, Mark, Ian Smail, Scott Chapman, Andrew Blain, et al. 2004. "The Rest-frame Optical Spectra of SCUBA Galaxies." The Astrophysical Journal 616(1): 71-85 | en_US |
dc.identifier.issn | 0004-637X | en_US |
dc.identifier.uri | http://dx.doi.org/10.1086/424896 | en_US |
dc.identifier.uri | http://hdl.handle.net/10222/45442 | |
dc.description.abstract | We present near-infrared spectroscopy and narrow-band imaging at the wavelength of redshifted H-alpha for a sample of 30 high-redshift, far-infrared luminous galaxies. This sample is selected from surveys in the sub-millimeter, millimeter and radio wavebands and has complete redshift coverage with a median redshift of z~2.4. Removing obvious AGN, we find that the predicted H-alpha star formation rates in this diverse population are suppressed (by ~10x) compared to those derived from their far-infrared luminosities. We estimate that AGN are present in at least 40% of the galaxies in our sample. To further investigate this, we construct a composite rest-frame spectrum for both the entire sample and for those galaxies which individually show no signs of nuclear activity. We find [NII]/H-alpha ratios for both composite spectra which suggest that the energy output of the galaxies is star-formation- rather than AGN-dominated. The median H-alpha line width for our sample (removing obvious AGN) is 400+/-70km/s (FWHM), and the typical spatial extent of the H-alpha emission in our narrow-band observations is < 4-8kpc, which indicates a dynamical mass of 1-2 x 10^11 Mo. This estimate is larger than recent estimates of the dynamical masses of UV-selected galaxies at similar redshifts derived in an identical manner. We also compared our H-alpha and far-infrared luminosities with deep Chandra observations of a subset of our survey fields and use these data to further assess their AGN content. We conclude that these high-redshift, far-infrared luminous galaxies represent a population of massive, metal-rich, merging systems with high instantaneous star formation rates, strong dust obscuration and actively-fueled AGN which are likely to be the progenitors of massive local elliptical galaxies. (abridged) | en_US |
dc.title | The Rest-frame Optical Spectra of SCUBA Galaxies | en_US |
dc.title.alternative | The Astrophysical Journal | en_US |
dc.type | article | en_US |
dc.identifier.volume | 616 | en_US |
dc.identifier.issue | 1 | en_US |
dc.identifier.startpage | 71 | en_US |