Journal Article

Spectroscopic characterization of 250-μm-selected hyper-luminous star-forming galaxies

C. M. Casey, S. C. Chapman, Ian Smail, S. Alaghband-Zadeh, M. S. Bothwell and A. M. Swinbank

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 411, issue 4, pages 2739-2749
Published in print March 2011 | ISSN: 0035-8711
Published online March 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.17876.x
Spectroscopic characterization of 250-μm-selected hyper-luminous star-forming galaxies

More Like This

Show all results sharing this subject:

  • Astronomy and Astrophysics

GO

Show Summary Details

Preview

We present near-infrared (near-IR) spectroscopic observations from Very Large Telescope Infrared Spectrometer And Array Camera (ISAAC) of 13 250-μm luminous galaxies in the Chandra Deep Field-South, seven of which have confirmed redshifts which average to 〈z〉= 2.0 ± 0.4. Another two sources of the 13 have tentative z > 1 identifications. Eight of the nine redshifts were identified with Hα detection in H and K bands, three of which are confirmed redshifts from previous spectroscopic surveys. We use their near-IR spectra to measure Hα linewidths and luminosities, which average to 415 ± 20 km s−1 and 3 × 1035 W (implying SFR ∼ 200 M yr−1), both similar to the Hα properties of submillimetre galaxies (SMGs). Just like SMGs, 250-μm-luminous galaxies have large Hα to far-infrared (FIR) extinction factors such that the Hα star formation rates (SFRs) underestimate the FIR SFRs by approximately eight to 80 times. FIR photometric points observed from 24 to 870 μm are used to constrain the spectral energy distributions even though uncertainty caused by FIR confusion in the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) bands is significant. The population has a mean dust temperature of Td= 52 ± 6 K, emissivity β= 1.73 ± 0.13 and FIR luminosity LFIR= 3 × 1013 L. Although selection at 250 μm allows for the detection of much hotter dust-dominated hyper-luminous infrared galaxies (HyLIRGs) than SMG selection (at 850 μm), we do not find any ≳60-K ‘hot-dust’ HyLIRGs. We have shown that near-IR spectroscopy combined with good photometric redshifts is an efficient way to spectroscopically identify and characterize these rare, extreme systems, hundreds of which are being discovered by the newest generation of IR observatories including the Herschel Space Observatory.

Keywords: galaxies: evolution; galaxies: high-redshift; galaxies: starburst; infrared: galaxies

Journal Article.  8168 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.