J/ApJ/886/48 Radio & opt/NIR counterparts of S2COSMOS submm galaxies (An+, 2019)
Multi-wavelength properties of radio- and machine-learning-identified
counterparts to submillimeter sources in S2COSMOS.
An F.X., Simpson J.M., Smail I., Swinbank A.M., Ma C., Liu D., Lang P.,
Schinnerer E., Karim A., Magnelli B., Leslie S., Bertoldi F., Chen C.-C.,
Geach J.E., Matsuda Y., Stach S.M., Wardlow J.L., Gullberg B., Ivison R.J.,
Ao Y., Coogan R.T., Thomson A.P., Chapman S.C., Wang R., Wang W.-H.,
Yang Y., Asquith R., Bourne N., Coppin K., Hine N.K., Ho L.C., Hwang H.S.,
Kato Y., Lacaille K., Lewis A.J.R., Oteo I., Scholtz J., Sawicki M.,
Smith D.
<Astrophys. J., 886, 48-48 (2019)>
=2019ApJ...886...48A 2019ApJ...886...48A (SIMBAD/NED BibCode)
ADC_Keywords: Millimetric/submm sources; Galaxies, radio; Cross identifications;
Infrared sources; Redshifts
Keywords: Observational astronomy; Starburst galaxies; High-redshift galaxies
Galaxy formation; Galaxy evolution; Submillimeter astronomy
Clustering
Abstract:
We identify multi-wavelength counterparts to 1147 submillimeter
sources from the S2COSMOS SCUBA-2 survey of the COSMOS field by
employing a recently developed radio+machine-learning method trained
on a large sample of Atacama Large Millimeter/submillimeter Array
(ALMA)-identified submillimeter galaxies (SMGs), including 260 SMGs
identified in the AS2COSMOS pilot survey. In total, we identify 1222
optical/near-infrared (NIR)/radio counterparts to the 897 S2COSMOS
submillimeter sources with S850>1.6mJy, yielding an overall
identification rate of (78±9)%. We find that (22±5)% of S2COSMOS
sources have multiple identified counterparts. We estimate that
roughly 27% of these multiple counterparts within the same SCUBA-2
error circles very likely arise from physically associated galaxies
rather than line-of-sight projections by chance. The photometric
redshift of our radio+machine-learning-identified SMGs ranges from
z=0.2 to 5.7 and peaks at z=2.3±0.1. The AGN fraction of our sample
is (19±4)%, which is consistent with that of ALMA SMGs in the
literature. Comparing with radio/NIR-detected field galaxy population
in the COSMOS field, our radio+machine-learning-identified
counterparts of SMGs have the highest star formation rates and stellar
masses. These characteristics suggest that our identified counterparts
of S2COSMOS sources are a representative sample of SMGs at z≲3. We
employ our machine-learning technique to the whole COSMOS field and
identified 6877 potential SMGs, most of which are expected to have
submillimeter emission fainter than the confusion limit of our
S2COSMOS surveys (S850um≲1.5mJy). We study the clustering
properties of SMGs based on this statistically large sample, finding
that they reside in high-mass dark matter halos
((1.2±0.3)x1013h-1M☉), which suggests that SMGs may be the
progenitors of massive ellipticals we see in the local universe.
Description:
The 850um SCUBA-2 COSMOS survey (S2COSMOS) was carried out with the
East Asian Observatory's James Clerk Maxwell Telescope (JCMT) between
2016 January and 2017 June. The full details of observations, data
reduction, and catalog are described in Simpson+ (2019, J/ApJ/880/43).
We have completed an ALMA Cycle 4 pilot study of the brightest 160
single-dish submillimeter sources from S2COSMOS
(Project ID: 2016.1.00463.S). The ALMA follow-up observations were
taken in Band 7 (870um) in 2018 April and May. See Section 2.2.1.
We use additional ALMA archival data in the COSMOS field to construct
our training set.
The COSMOS field is one of the largest extragalactic fields with a
rich ancillary data set.
The radio data we use in this work are from the VLA-COSMOS 3GHz Large
Project (Smolcic+ 2017, J/A+A/602/A1), which were taken with the Karl
G. Jansky Very Large Array (VLA) at 3GHz.
The COSMOS2015 catalog (Laigle+ 2016, J/ApJS/224/24) from the
UltraVISTA-DR2 surveys are used to identify optical/NIR counterparts
for both ALMA submillimeter galaxies and S2COSMOS submillimeter
sources and are then used to construct a training set and a test
sample for the machine-learning analyses.
See Section 2.3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 102 1222 Radio+machine-learning identified counterparts
to S2COSMOS sources
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See also:
II/298 : AKARI/FIS All-Sky Survey Point Source Catalogues (ISAS/JAXA, 2010)
J/MNRAS/238/1171 : Optical/IR obs. of Radio Galaxies and QSOs (Dunlop+, 1989)
J/ApJ/622/772 : Redshift survey of submillimeter galaxies (Chapman+, 2005)
J/MNRAS/372/1621 : SCUBA Half-Degree Extragalactic Survey. II (Coppin+, 2006)
J/ApJS/172/29 : XMM-Newton survey in COSMOS field. I. (Hasinger+, 2007)
J/MNRAS/380/199 : SCUBA Half-Degree Extragalactic Survey. III (Ivison+, 2007)
J/ApJ/707/1201 : LABOCA ECDFS Submillimeter Survey (LESS) (Weiss+, 2009)
J/ApJ/716/348 : The XMM-Newton survey of the COSMOS field (Brusa+, 2010)
J/ApJS/188/384 : The VLA-COSMOS survey. IV. (Schinnerer+, 2010)
J/MNRAS/411/373 : Catalog of AKARI Deep Field South (Clements+, 2011)
J/A+A/532/A90 : PACS Evolutionary Probe (PEP-DR1) catalogs (Lutz+, 2011)
J/MNRAS/415/3831 : AzTEC/ASTE source catalogue (Aretxaga+, 2011)
J/MNRAS/426/1845 : AzTEC survey of the SHADES fields. II. (Michalowski+, 2012)
J/ApJ/768/91 : ALMA observations of LESS submm galaxies (Hodge+, 2013)
J/A+A/556/A55 : Multi-color phot. of star-forming galaxies (Ilbert+, 2013)
J/ApJ/777/18 : Stellar mass functions of galaxies to z=4 (Muzzin+, 2013)
J/ApJ/788/125 : ALMA survey of ECDFS submillimeter galaxies (Simpson+, 2014)
J/MNRAS/442/577 : Selected ALESS submm gal. radio properties (Thomson+, 2014)
J/ApJ/817/34 : C-COSMOS Legacy multiwavelength cat. (Marchesi+, 2016)
J/ApJS/222/1 : Faint ALMA 1.2mm sources down to ∼0.02mJy (Fujimoto+, 2016)
J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)
J/ApJ/820/82 : S2CLS: multiwavelength counterparts to SMGs (Chen+, 2016)
J/ApJS/224/24 : The COSMOS2015 catalog (Laigle+, 2016)
J/MNRAS/465/1789 : SCUBA-2 Cosmology Legacy Survey (Geach+, 2017)
J/ApJ/837/139 : SUPER GOODS. I. Ultradeep SCUBA-2 survey (Cowie+, 2017)
J/ApJ/839/58 : ALMA submm galaxies multi-wavelength data (Simpson+, 2017)
J/ApJ/840/78 : Redshift survey of ALMA SMGs in ECDFS (Danielson+, 2017)
J/A+A/602/A1 : VLA-COSMOS 3 GHz Large Project (Smolcic+, 2017)
J/A+A/602/A2 : VLA-COSMOS 3 GHz Large Project. II. (Smolcic+, 2017)
J/ApJ/853/172 : "Super-deblended" dust emission in galaxies. I. (Liu+, 2018)
J/ApJ/880/43 : S2COSMOS: SCUBA-2 submm sources in COSMOS (Simpson+, 2019)
J/ApJS/244/40 : A3COSMOS. I. ALMA continuum photometry catalogs (Liu+, 2019)
http://sites.google.com/view/a3cosmos : A3COSMOS home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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3- 10 A8 --- --- [S2COS850]
11 A1 --- --- [.]
12- 15 I04 --- S2COS850 Short ID of S2COSMOS source
from Simpson+ 2009, J/ApJ/880/43
17- 27 F11.6 deg RAdeg [149.3/150.9] Right ascension
of S2COSMOS source (J2000)
29- 38 F10.6 deg DEdeg [1.5/3] Declination of S2COSMOS source (J2000)
40- 50 F11.6 deg RANdeg ?=-99 RA of the NIR counterpart (J2000)
52- 61 F10.6 deg DENdeg ?=-99 DEC of the NIR counterpart (J2000)
63- 65 I3 --- Cl-XGB ? Classification by machine-learning (1)
67- 77 F11.6 deg RARdeg ?=-99 RA of the radio counterpart (J2000)
79- 88 F10.6 deg DERdeg ?=-99 DEC of the radio counterpart (J2000)
90- 92 I3 --- Cl-Rad Classification by radio identification (2)
94-102 F9.2 --- zphot [0/5.6]?=-99 Photometric redshift
from COSMOS2015 catalog
(Laigle+, 2016, J/ApJS/224/24)
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Note (1): Flag as follows:
1 = XGBoost (Chen & Guestrin 2016, arXiv:1603.02754) classified
submillimeter galaxies (SMGs; 658 occurrences);
0 = classified non-SMGs (157 occurrences);
-99 = not qualified for machine-learning classification.
Note (2): Code as follows:
1 = radio identified SMGs (932 occurrences);
-99 = does not have radio detection;
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Apr-2021