SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). V. Confusion-limited Submillimeter Galaxy Number Counts at 450 μm and Data Release for the COSMOS Field

Abstract We present confusion-limited SCUBA-2 450 μ m observations in the COSMOS-CANDELS region as part of the James Clerk Maxwell Telescope Large Program SCUBA-2 Ultra Deep Imaging EAO Survey. Our maps at 450 and 850 μ m cover an area of 450 arcmin 2 . We achieved instrumental noise levels of σ 450 = 0.59 mJy beam −1 and σ 850 = 0.09 mJy beam −1 in the deepest area of each map. The corresponding confusion noise levels are estimated to be 0.65 and 0.36 mJy beam −1 . Above the 4 σ (3.5 σ ) threshold, we detected 360 (479) sources at 450 μ m and 237 (314) sources at 850 μ m. We derive the deepest blank-field number counts at 450 μ m, covering the flux-density range of 2–43 mJy. These are in agreement with other SCUBA-2 blank-field and lensing-cluster observations but are lower than various model counts. We compare the counts with those in other fields and find that the field-to-field variance observed at 450 μ m at the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>R</mml:mi> <mml:mo>=</mml:mo> <mml:mn>6</mml:mn> <mml:mo accent="false">′</mml:mo> </mml:math> scale is consistent with Poisson noise, so there is no evidence of strong 2D clustering at this scale. Additionally, we derive the integrated surface brightness at 450 μ m down to 2.1 mJy to be <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>57.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>6.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>1.0</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> Jy deg −2 , contributing to 41% ± 4% of the 450 μ m extragalactic background light (EBL) measured by Cosmic Background Explorer and Planck. Our results suggest that the 450 μ m EBL may be fully resolved at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>0.08</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.08</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.09</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> mJy, which extremely deep lensing-cluster observations and next-generation submillimeter instruments with large aperture sizes may be able to achieve.

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Publication Details

Journal
The Astrophysical Journal
Published
2024-08-01
DOI
https://doi.org/10.3847/1538-4357/ad53c1
Citations
4
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
1.33

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article

SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). V. Confusion-limited Submillimeter Galaxy Number Counts at 450 μm and Data Release for the COSMOS Field

Xianzhong Zheng, D. Scott, Zhen-Kai Gao, S. Urquhart et al.
4 citations
The Astrophysical Journal
Galaxies: Formation, Evolution, Phenomena
1.33
article

SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). V. Confusion-limited Submillimeter Galaxy Number Counts at 450 μm and Data Release for the COSMOS Field

Xianzhong Zheng, D. Scott, Zhen-Kai Gao, S. Urquhart, Wei-Hao Wang, Yiping Ao, Chian-Chou Chen, J. S. Dunlop, Yoshiki Toba, Ian Smail, Tadayuki Kodama, Chen-Fatt Lim, Yun-Hsin Hsu, Ho Seong Hwang, S. C. Chapman, Luis C. Ho, S. Serjeant, M. P. Koprowski, D. L. Clements, Chorng‐Yuan Hwang, Hyunjin Shim, Siou-Yu 修瑜 Chang 張
article en
4 citations

Abstract

Abstract We present confusion-limited SCUBA-2 450 μ m observations in the COSMOS-CANDELS region as part of the James Clerk Maxwell Telescope Large Program SCUBA-2 Ultra Deep Imaging EAO Survey. Our maps at 450 and 850 μ m cover an area of 450 arcmin 2 . We achieved instrumental noise levels of σ 450 = 0.59 mJy beam −1 and σ 850 = 0.09 mJy beam −1 in the deepest area of each map. The corresponding confusion noise levels are estimated to be 0.65 and 0.36 mJy beam −1 . Above the 4 σ (3.5 σ ) threshold, we detected 360 (479) sources at 450 μ m and 237 (314) sources at 850 μ m. We derive the deepest blank-field number counts at 450 μ m, covering the flux-density range of 2–43 mJy. These are in agreement with other SCUBA-2 blank-field and lensing-cluster observations but are lower than various model counts. We compare the counts with those in other fields and find that the field-to-field variance observed at 450 μ m at the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>R</mml:mi> <mml:mo>=</mml:mo> <mml:mn>6</mml:mn> <mml:mo accent="false">′</mml:mo> </mml:math> scale is consistent with Poisson noise, so there is no evidence of strong 2D clustering at this scale. Additionally, we derive the integrated surface brightness at 450 μ m down to 2.1 mJy to be <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>57.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>6.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>1.0</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> Jy deg −2 , contributing to 41% ± 4% of the 450 μ m extragalactic background light (EBL) measured by Cosmic Background Explorer and Planck. Our results suggest that the 450 μ m EBL may be fully resolved at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>0.08</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.08</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.09</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> mJy, which extremely deep lensing-cluster observations and next-generation submillimeter instruments with large aperture sizes may be able to achieve.

The Astrophysical JournalVol. 971(1)
University of Science and Technology of China (CN), Dalhousie University (CA), Institute of Astronomy and Astrophysics, Academia Sinica (TW), Seoul National University (KR), University of British Columbia (CA), Durham University (GB), Chinese Academy of Sciences (CN), Tohoku University (JP), Peking University (CN), The Open University (GB), National Central University (TW), Purple Mountain Observatory (CN), Nicolaus Copernicus University (PL), Kyungpook National University (KR), Royal Observatory (GB), Kavli Institute for Theoretical Sciences (CN), National Astronomical Observatory of Japan (JP), Ehime University (JP), Imperial College London (GB), University of Edinburgh (GB)
National Science Foundation, National Astronomical Research Institute of Thailand, National Research Foundation, National Natural Science Foundation of China, Academia Sinica, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Korea Astronomy and Space Science Institute, National Research Foundation of Korea, National Astronomical Observatory of Japan, Ministry of Science and ICT, South Korea, National Science and Technology Council, Science and Technology Facilities Council
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Openalex Percentile: Top 20%
Galaxies: Formation, Evolution, Phenomena
1.33
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