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High-resolution SMA imaging of bright submillimetre sources from the SCUBA-2 Cosmology Legacy Survey

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posted on 2018-07-25, 14:48 authored by Ryley Hill, Scott C. Chapman, Douglas Scott, Glen Petitpas, Ian Smail, Edward L. Chapin, Mark A. Gurwell, Ryan Perry, Andrew W. Blain, Malcolm N. Bremer, Chian-Chou Chen, James S. Dunlop, Duncan Farrah, Giovanni G. Fazio, James E. Geach, Paul Howson, R. J. Ivison, Kevin Lacaille, Michał J. Michałowski, James M. Simpson, A. M. Swinbank, Paul. van der Werf, David J. Wilner
We have used the Submillimeter Array (SMA) at 860 μm to observe the brightest sources in the Submillimeter Common User Bolometer Array-2 (SCUBA-2) Cosmology Legacy Survey (S2CLS). The goal of this survey is to exploit the large field of the S2CLS along with the resolution and sensitivity of the SMA to construct a large sample of these rare sources and to study their statistical properties. We have targeted 70 of the brightest single-dish SCUBA-2 850  μm sources down to S850 ≈  8 mJy, achieving an average synthesized beam of 2.4 arcsec and an average rms of σ860 =  1.5 mJy beam−1 in our primary beam-corrected maps. We searched our SMA maps for 4σ peaks, corresponding to S860 ≳  6 mJy sources, and detected 62, galaxies, including three pairs. We include in our study 35 archival observations, bringing our sample size to 105 bright single-dish submillimetre sources with interferometric follow-up. We compute the cumulative and differential number counts, finding them to overlap with previous single-dish survey number counts within the uncertainties, although our cumulative number count is systematically lower than the parent S2CLS cumulative number count by 14 ±  6 per cent between 11 and 15 mJy. We estimate the probability that a ≳10 mJy single-dish submillimetre source resolves into two or more galaxies with similar flux densities to be less than 15 per cent. Assuming the remaining 85 per cent of the targets are ultraluminous starburst galaxies between z =  2 and 3, we find a likely volume density of ≳400 M⊙ yr−1 sources to be ∼3+0.7−0.6×10−7  Mpc−3. We show that the descendants of these galaxies could be ≳4 ×  1011 M⊙ local quiescent galaxies, and that about 10 per cent of their total stellar mass would have formed during these short bursts of star formation.


The JCMT is now operated by the East Asian Observatory on behalf of The National Astronomical Observatory of Japan, Academia Sinica Institute of Astronomy and Astrophysics, the Korea Astronomy and Space Science Institute, the National Astronomical Observatories of China, and the Chinese Academy of Sciences (Grant No. XDB09000000), with additional funding support from the Science and Technology Facilities Council of the United Kingdom and participating universities in the United Kingdom and Canada. The SMA is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This work was supported by the Natural Sciences and Research Council of Canada. IRS and AMS acknowledge support from the Science and Technology Facilities Council (ST/P000541/1). IRS also acknowledges the European Research Council Advanced Investigator programme DUSTYGAL 321334 and a Royal Society/Wolfson Merit Award. MJM acknowledges the support of the National Science Centre, Poland through the POLONEZ grant 2015/19/P/ST9/04010. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 665778.



Monthly Notices of the Royal Astronomical Society, 2018, 477 (2), pp. 2029-2054 (26)

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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Monthly Notices of the Royal Astronomical Society


Oxford University Press (OUP), Royal Astronomical Society





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