Deep radio imaging of the SCUBA 8-mJy survey fields: submillimetre source identifications and redshift distribution

By R. Ivison, T. Greve, I. Smail, J. Dunlop, N. Roche, S. Scott, M. Page, J. Stevens, O. Almaini, A. Blain and 5 more. 2002

308 citations recorded by the source corpus.

The SCUBA 8-mJy survey is the largest submillimetre (submm) extragalactic mapping survey undertaken to date, covering 260arcmin 2 to a 4� detection limit of ≃8mJy at 850µm, centred on the Lockman Hole and ELAIS N2 regions. Here, we present the results of new 1.4-GHz imaging of these fields, of the depth and resolution necessary to reliably identify radio counterparts for 18 of 30 submm sources, with possible detections of a further 25 per cent. Armed with this greatly improved positional information, we present and analyse new optical, near-infrared (IR) and XMM-Newton X-ray imaging to identify optical/IR host galaxies to half of the submm-selected sources in those fields. As many as 15 per cent of the submm sources detected at 1.4GHz are resolved by the 1.4 ′′ beam and a further 25 per cent have more than one radio counterpart, suggesting that radio and submm emission arise from extended starbursts and that interactions are common. We note that less than a quarter of the submm-selected sample would have been recovered by targeting optically faint radio sources, underlining the selective nature of such surveys. At least 60 per cent of the radio-confirmed optical/IR host galaxies appear to be morphologically distorted; many are composite systems — red galaxies with relatively blue companions; just over one half are found to be very red (I −K > 3.3) or extremely red (I −K > 4); contrary to popular belief, most are sufficiently bright to be tackled with spectrographson 8-m telescopes. We find one submm source which is associated with the steep-spectrum lobe of a radio galaxy, at least two more with flatter radio spectra typical of radio-loud active galactic nuclei (AGN), one of them variable. The latter is amongst four sources (≡15 per cent of the full sample) with X-ray emission consistent with obscured AGN, though the AGN would need to be Compton thick to power the observed far-IR luminosity. We exploit our well-matched radio and submm data to estimate the median redshift of the S850µm ∼8mJy submm galaxy population. If the radio/far-IR correlation holds at high redshift, and our sample is unbiased, we derive a conservative limit of ≥2.0, or ≥2.4 using spectral templates more representative of known submm galaxies.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/17ba5ea2463e2e48ea4162049c5c3c7f8ee48c2f

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In Astronomy and Astrophysics

1. L. Hernquist
2. P. Hopkins
3. D. M. Alexander
4. D. Narayanan
5. R. Dav'e
6. R. Somerville
7. Thomas J. Cox
8. C. Conroy

In Nuclear and High Energy Physics

1. D. M. Alexander
2. R. Ivison
3. I. Smail
4. W. N. Brandt
5. L. Hernquist
6. P. Hopkins
7. S. Chapman
8. A. Blain

Citations in the corpus

• EXTRAGALACTIC MILLIMETER-WAVE SOURCES IN SOUTH POLE TELESCOPE SURVEY DATA: SOURCE COUNTS, CATALOG, AND STATISTICS FOR AN 87 SQUARE-DEGREE FIELD (2009, background): “…SPT observations will be sensitive to a higher-redshift population than the submm surveys (due to the stronger negative K-correction), and there is considerable evidence that the very brightest SMGs are at the highest redshifts (Ivison et al. 2002; Pope et al. 2005; Greve et al. 2008).”
• The X-Ray Spectral Properties of SCUBA Galaxies (2005, background): “Many studies have suggested that star formation accounts for a large fraction of the bolometric output of SMGs (e.g., Frayer et al. 1998, 2004; Ivison et al. 2002, 2004; Alexander et al. 2003b; Almaini et al. 2003; Chapman et al. 2004a; Egami et al. 2004; Swinbank et al. 2004), but none has…”
• An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: high-resolution 870 μm source counts (2012, background): “For example, it has been claimed that the brightest (most luminous) SMGs evolve more strongly than fainter systems and hence are preferentially found at the highest redshifts (e.g., Ivison et al. 2002, 2007; Wall et al. 2008; Marsden et al. 2011; Smolčić et al. 2012).”
• COSBO: The MAMBO 1.2 Millimeter Imaging Survey of the COSMOS Field (2007, background): “The significance of an association is estimated in the common way, by computing the corrected Poisson probability that a radio source is found by chance in a background of randomly distributed radio sources (Downes et al. 1986; see also Ivison et al. 2002, 2005).”
• Interferometric Observations of Powerful CO Emission from Three Submillimeter Galaxies at z = 2.39, 2.51, and 3.35 (2003, methodology): “…program of obtaining spectro- scopic redshifts with the Keck telescope for a number of sources detected with the SCUBA camera at 850µm, to a large extent aided by more precise positions derived from deep 1.4 GHz VLA observations of the same fields (Ivison et al. 2002; Chapman et al. 2003a, 2003b).”
• Spatially Resolved Millimeter Interferometry of SMM J02399–0136: A Very Massive Galaxy at z = 2.8 (2002, background): “Although the latter step is the most uncertain, evidence from the weakness of radio and optical/UV counterparts for submillimeter sources suggests that these additional four sources are more likely to lie at high than at low redshifts (Dannerbauer et al. 2002; Ivison et al. 2002).”
• VERY LARGE ARRAY 1.4 GHz OBSERVATIONS OF THE GOODS-NORTH FIELD: DATA REDUCTION AND ANALYSIS (2010, background): “The rotational offset was about 1′′ at a radial distance of 20′ from the phase center, and is likely the cause of the optical–radio offsets reported regularly over the last decade (e.g. Ivison et al. 2002).”
• Cosmic evolution of submillimeter galaxies and their contribution to stellar mass assembly (2009, background): “Columns 3-7 and 9 have been corrected for incompleteness by a factor of 3.5 (Section 3.2). or SFRIR, the scatter at optical and near-IR wavelengths is significant, showing that SMGs exhibit a wide range of stellar population properties (as also noted by Ivison et al., 2002).”
• An interferometric CO survey of luminous submillimetre galaxies (2005, methodology): “…is wrong, and thereforeth redshift is for the wrong object, appears to be remote given the exc llent correspondence between the radio and submm (e.g. Ivison et al. 2002), and the extremely small likelihood of finding az ∼ 2 galaxy at that position, which is not related to the submm emission.”
• The star formation history of K-selected galaxies (2008, background): “5 (left) translates into a steep rise of L1,400 with redshift.”
• A census of metals and baryons in stars in the local universe (2007, background): “…2006, and references therein), more uncertain is the behaviour at redshift higher than 2, because of the poor understanding of the effect of dust on the SFR derived from UV spectral energy distributions (SEDs) of high-redshift galaxies (Madau et al. 1996; Steidel et al. 1999; Ivison et al. 2002).”
• Evidence for a Population of High-Redshift Submillimeter Galaxies from Interferometric Imaging (2007, background): “%) of the most luminous sources in the AzTEC/COSMOS catalog are radio–dim; as first noted by Ivison et al. (2002), the most luminous SMGs may have a higher average/median redshift.”
• Deep multi-frequency radio imaging in the Lockman Hole using the GMRT and VLA (2009, background): “Radio imaging has played a key role in characterising SMGs (e.g. Ivison et al. 2002) providing a high-resolution proxyfor the rest-frame far-IR emission via the far-IR/radio correlation (Helou et al. 1985; Appleton et al. 2004; Ibar et al. 2008).”
• AN ALMA SURVEY OF SUBMILLIMETER GALAXIES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH: THE REDSHIFT DISTRIBUTION AND EVOLUTION OF SUBMILLIMETER GALAXIES (2013, background): “…(e.g. Ivison et al. 1998, 2000), as deep 1.4 GHz radio imaging with the Very Large Array (VLA) provides the sub-arcsecond resolution required to accurately locate the counterpart to the submm emission (Ivison et al. 2002, 2004, 2007; Bertoldi et al. 2007; Biggs et al. 2011; Lindner et al. 2011).”
• Evidence for Extended, Obscured Starbursts in Submillimeter Galaxies (2004, background): “…of the bright submillimeter population at high redshifts are detected as microjansky radio sources (Smail et al. 2000; Barger et al. 2000; Chapman et al. 2001; Ivison et al. 2002), as expected given their submillimeter luminosities and the local far-IR–radio correlation (Chapman et al. 2004).”
• The Hubble Deep Field North SCUBA Super-map - III. Optical and near-infrared properties of submillimetre galaxies (2005, background): “Because the presence of a radio counterpart is sufficiently rare, it can be partially used to assess the reliability of sources in sub-mm surveys, and as are ult doubt has been cast in the reality of some of the radio-undetected sub-mm sources (Ivison et al. 2002; Greve et al. 2004).”
• The far-infrared/radio correlation as probed by Herschel (2010, methodology): “…flux density ratio has been useful when estimating the redshift or Td of a distant starburst, or when defining samples of AGN (Condon 1992; Carilli & Yun 1999; Ivison et al. 2002; Bell 2003; Chapman et al. 2005; Donley et al. 2005), or probing magnetic field strength (Thompson et al. 2006).”