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ALMACAL VII: First Interferometric Number Counts at 650 μm

Klitsch, A.; Zwaan, M.A.; Smail, I.; Péroux, C.; Biggs, A.D.; Chen, C-C.; Ivison, R.J.; Popping, G.; Lagos, C.; Béthermin, M.; Swinbank, A.M.; Hamanowicz, A.; Dutta, R.

ALMACAL VII: First Interferometric Number Counts at 650 μm Thumbnail


A. Klitsch

M.A. Zwaan

C. Péroux

A.D. Biggs

C-C. Chen

R.J. Ivison

G. Popping

C. Lagos

M. Béthermin

A. Hamanowicz

R. Dutta


Measurements of the cosmic far-infrared background (CIB) indicate that emission from many extragalactic phenomena, including star formation and black hole accretion, in the Universe can be obscured by dust. Resolving the CIB to study the population of galaxies in which this activity takes place is a major goal of submillimetre astronomy. Here, we present interferometric 650휇m submillimetre number counts. Using the Band 8 data from the ALMACAL survey, we have analysed 81 ALMA calibrator fields together covering a total area of 5.5 arcmin2 . The typical central rms in these fields is ∼ 100휇Jy beam−1 with the deepest maps reaching 휎 = 47휇Jy beam−1 at sub-arcsec resolution. Multi-wavelength coverage from ALMACAL allows us to exclude contamination from jets associated with the calibrators. However, residual contamination by jets and lensing remain a possibility. Using a signal-to-noise threshold of 4.5휎, we find 21 dusty, star-forming galaxies with 650휇m flux densities of ≥ 0.7mJy. At the detection limit we resolve ' 100 per cent of the CIB at 650휇m, a significant improvement compared to low resolution studies at similar wavelength. We have therefore identified all the sources contributing to the EBL at 650 microns and predict that the contribution from objects with flux 0.7


Klitsch, A., Zwaan, M., Smail, I., Péroux, C., Biggs, A., Chen, C., …Dutta, R. (2020). ALMACAL VII: First Interferometric Number Counts at 650 μm. Monthly Notices of the Royal Astronomical Society, 495(2), 2332-2341.

Journal Article Type Article
Acceptance Date May 1, 2020
Online Publication Date May 12, 2020
Publication Date Jun 30, 2020
Deposit Date May 13, 2020
Publicly Available Date May 13, 2020
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 495
Issue 2
Pages 2332-2341


Accepted Journal Article (1.5 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2020 The Author(s) . Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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