Abstract
We present the multiwavelength counterparts of 850-μm selected submillimetre sources over a 2-deg2 field centred on the North Ecliptic Pole. In order to overcome the large beam size (15 arcsec) of the 850-μm
images, deep optical to near-infrared (NIR) photometric data and
arcsecond-resolution 20-cm images are used to identify counterparts of
submillimetre sources. Among 647 sources, we identify 514 reliable
counterparts for 449 sources (69 per cent in number), based either on
probabilities of chance associations calculated from positional offsets
or offsets combined with the optical-to-NIR colours. In the radio
imaging, the fraction of 850-μm
sources having multiple counterparts is 7 per cent. The photometric
redshift, infrared luminosity, stellar mass, star formation rate (SFR),
and the active galactic nucleus (AGN) contribution to the total infrared
luminosity of the identified counterparts are investigated through
spectral energy distribution fitting. The SMGs are infrared-luminous
galaxies at an average 〈z〉 = 2.5 with log10(LIR/L⊙) = 11.5–13.5, with a mean stellar mass of log10(Mstar/M⊙) = 10.90 and SFR of log10(SFR/M⊙yr−1)=2.34.
The submillimetre galaxies (SMGs) show twice as large SFR as galaxies
on the star-forming main sequence, and about 40 per cent of the SMGs are
classified as objects with bursty star formation. At z ≥ 4,
the contribution of AGN luminosity to total luminosity for most SMGs is
larger than 30 per cent. The FIR-to-radio correlation coefficient of
SMGs is consistent with that of main-sequence galaxies at z ≃ 2.
Original language | English |
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Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 514 |
Issue number | 2 |
Pages (from-to) | 2915-2935 |
ISSN | 0035-8711 |
DOIs | |
Publication status | Published - 2022 |
Keywords
- Galaxies: evolution
- Galaxies: high-redshift
- Galaxies: Starburst
- Submillimetre: galaxies
- Surveys