Herschel and SCUBA-2 imaging and spectroscopy of a bright, lensed submillimetre galaxy at z = 2.3

Ivison, R. J.; Swinbank, A. M.; Swinyard, B.; Smail, I.; Pearson, C. P.; Rigopoulou, D.; Polehampton, E.; Baluteau, J.-P.; Barlow, M. J.; Blain, A. W.; Bock, J.; Clements, D. L.; Coppin, K.; Cooray, A.; Danielson, A.; Dwek, E.; Edge, A. C.; Franceschini, A.; Fulton, T.; Glenn, J.; Griffin, M.; Isaak, K.; Leeks, S.; Lim, T.; Naylor, D.; Oliver, S. J.; Page, M. J.; Pérez-Fournon, I.; Rowan-Robinson, M.; Savini, G.; Scott, D.; Spencer, L.; Valtchanov, I.; Vigroux, L.; Wright, G. S.
Bibliographical reference

Astronomy and Astrophysics, Volume 518, id.L35

Advertised on:
7
2010
Number of authors
35
IAC number of authors
1
Citations
190
Refereed citations
185
Description
We present a detailed analysis of the far-infrared (-IR) properties of the bright, lensed, z = 2.3, submillimetre-selected galaxy (SMG), SMM J2135-0102 (hereafter SMM J2135), using new observations with Herschel, SCUBA-2 and the Very Large Array (VLA). These data allow us to constrain the galaxy's spectral energy distribution (SED) and show that it has an intrinsic rest-frame 8-1000-μm luminosity, Lbol, of (2.3±0.2) × 1012 L&sun; and a likely star-formation rate (SFR) of ~400 M&sun; yr-1. The galaxy sits on the far-IR/radio correlation for far-IR-selected galaxies. At ⪆70 μm, the SED can be described adequately by dust components with dust temperatures, Td ~ 30 and 60 k. Using SPIRE's Fourier- transform spectrometer (FTS) we report a detection of the [C ii] 158 μm cooling line. If the [C ii], CO and far-IR continuum arise in photo-dissociation regions (PDRs), we derive a characteristic gas density, n ~ 103 cm-3, and a far-ultraviolet (-UV) radiation field, G0, 103× stronger than the Milky Way. L[CII]/Lbol is significantly higher than in local ultra-luminous IR galaxies (ULIRGs) but similar to the values found in local star-forming galaxies and starburst nuclei. This is consistent with SMM J2135 being powered by starburst clumps distributed across ~2 kpc, evidence that SMGs are not simply scaled-up ULIRGs. Our results show that SPIRE's FTS has the ability to measure the redshifts of distant, obscured galaxies via the blind detection of atomic cooling lines, but it will not be competitive with ground-based CO-line searches. It will, however, allow detailed study of the integrated properties of high-redshift galaxies, as well as the chemistry of their interstellar medium (ISM), once more suitably bright candidates have been found. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Related projects
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Formation and Evolution of Galaxies: Observations in Infrared and other Wavelengths
This IAC research group carries out several extragalactic projects in different spectral ranges, using space as well as ground-based telescopes, to study the cosmological evolution of galaxies and the origin of nuclear activity in active galaxies. The group is a member of the international consortium which built the SPIRE instrument for the
Ismael
Pérez Fournon