Lim, Chen-Fatt and Chen, Chian-Chou and Smail, Ian and Wang, Wei-Hao and Tee, Wei-Leong and Lin, Yen-Ting and Scott, Douglas and Toba, Yoshiki and Chang, Yu-Yen and Ao, YiPing and Babul, Arif and Bunker, Andy and Chapman, Scott C. and Clements, David L. and Conselice, Christopher J. and Gao, Yu and Greve, Thomas R. and Ho, Luis C. and Hong, Sungwook E. and Hwang, Ho Seong and Koprowski, Maciej and Michałowski, Michał J. and Shim, Hyunjin and Shu, Xinwen and Simpson, James M. (2020) 'SCUBA-2 ultra deep imaging EAO survey (STUDIES). IV. spatial clustering and halo masses of submillimeter galaxies.', Astrophysical journal., 895 (2). p. 895.
We analyze an extremely deep 450 μm image (1σ = 0.56 mJy beam−1 ) of a ;300 arcmin2 area in the CANDELS/ COSMOS field as part of the Sub-millimeter Common User Bolometric Array-2 Ultra Deep Imaging EAO Survey. We select a robust (signal-to-noise ratio 4) and flux-limited ( 4 mJy) sample of 164 submillimeter galaxies (SMGs) at 450 μm that have K-band counterparts in the COSMOS2015 catalog identified from radio or midinfrared imaging. Utilizing this SMG sample and the 4705 K-band-selected non-SMGs that reside within the noise level 1 mJy beam−1 region of the 450 μm image as a training set, we develop a machine-learning classifier using K-band magnitude and color–color pairs based on the 13-band photometry available in this field. We apply the trained machine-learning classifier to the wider COSMOS field (1.6 deg2 ) using the same COSMOS2015 catalog and identify a sample of 6182 SMG candidates with similar colors. The number density, radio and/or mid-infrared detection rates, redshift and stellar-mass distributions, and the stacked 450 μm fluxes of these SMG candidates, from the S2COSMOS observations of the wide field, agree with the measurements made in the much smaller CANDELS field, supporting the effectiveness of the classifier. Using this SMG candidate sample, we measure the two-point autocorrelation functions from z = 3 down to z = 0.5. We find that the SMG candidates reside in halos with masses of ;(2.0 ± 0.5) × 1013 h−1 M☉ across this redshift range. We do not find evidence of downsizing that has been suggested by other recent observational studies.
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|Publisher Web site:||https://doi.org/10.3847/1538-4357/ab8eaf|
|Publisher statement:||© 2020. The American Astronomical Society. All rights reserved.|
|Date accepted:||28 April 2020|
|Date deposited:||24 June 2020|
|Date of first online publication:||02 June 2020|
|Date first made open access:||24 June 2020|
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