The nature of 500 micron risers - II. Multiplicities and environments of sub-mm faint dusty star-forming galaxies
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
We present Submillimeter Common User Bolometer Array 2 (SCUBA-2) and Submillimeter Array (SMA) follow-up observations of four candidate high-redshift dusty star-forming galaxies, selected as sources with rising spectral energy distributions in the 250, 350, and 500 μm Herschel SPIRE bands. Previous SMA observations showed no counterparts to these sources, but in our deeper sub-mm observations we detect counterparts to all four 500 μm risers, with three resolving into multiple systems. For these three multiple systems, the SMA 345 GHz (≈870 μm) observations recover 123 ± 73 per cent, 60 ± 15 per cent,
, and 19 ± 4 per cent of the integrated 850 μm flux density from SCUBA-2, indicating that there may be additional sources below our SMA detection limit making up a dense, protocluster core. The fourth 500 μm riser was observed at a lower frequency and so we cannot make a similar comparison. We estimate photometric redshifts based on FIR/sub-mm colours, finding that three fourths likely lie at z ≥ 2. This fits with the interpretation that the 500 μm riser selection criterion selects both intrinsically red, individual galaxies at z > 4, and multiple systems at more moderate redshifts, artificially reddened by the effects of blending. We use the SCUBA-2 850 μm maps to investigate the environments of these 500 μm risers. By constructing cumulative number counts and estimating photometric redshifts for surrounding SCUBA-2 detections, we find that one of our 500 μm risers could plausibly reside in a z ≥ 2 protocluster. We infer that bright 500 μm risers with faint 850 μm flux densities are typically multiple systems at z ≥ 2 that may reside in overdensities of bright sub-mm galaxies.
, and 19 ± 4 per cent of the integrated 850 μm flux density from SCUBA-2, indicating that there may be additional sources below our SMA detection limit making up a dense, protocluster core. The fourth 500 μm riser was observed at a lower frequency and so we cannot make a similar comparison. We estimate photometric redshifts based on FIR/sub-mm colours, finding that three fourths likely lie at z ≥ 2. This fits with the interpretation that the 500 μm riser selection criterion selects both intrinsically red, individual galaxies at z > 4, and multiple systems at more moderate redshifts, artificially reddened by the effects of blending. We use the SCUBA-2 850 μm maps to investigate the environments of these 500 μm risers. By constructing cumulative number counts and estimating photometric redshifts for surrounding SCUBA-2 detections, we find that one of our 500 μm risers could plausibly reside in a z ≥ 2 protocluster. We infer that bright 500 μm risers with faint 850 μm flux densities are typically multiple systems at z ≥ 2 that may reside in overdensities of bright sub-mm galaxies.
Date Issued
2023-02-01
Date Acceptance
2022-11-18
Citation
Monthly Notices of the Royal Astronomical Society, 2023, 519 (1), pp.709-728
ISSN
0035-8711
Publisher
Oxford University Press
Start Page
709
End Page
728
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
519
Issue
1
Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. All rights reserved.
Identifier
10.1093/mnras/stac3486
Subjects
ALMA SURVEY
Astronomy & Astrophysics
COSMOLOGY LEGACY SURVEY
DEEP FIELD-SOUTH
galaxies
galaxies - submillimetre
HERSCHEL
high-redshift - galaxies
MOLECULAR GAS
Physical Sciences
PHYSICAL-PROPERTIES
REDSHIFT DISTRIBUTION
Science & Technology
starburst - infrared
STARBURST GALAXY
SUBMILLIMETER GALAXIES
ULTRALUMINOUS INFRARED GALAXIES
Publication Status
Published
Date Publish Online
2022-11-28