MeerKAT Observations of Herschel Protocluster Candidates
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| author | Ding, Y. Clements, D. L. Leeuw, L. L. Heywood, I. Dannerbauer, H. Parmar, A. Legodi, P. Ivison, R. J. Blake, R. Gutiérrez, C. M. Carnero, A. Sutherland, W. |
| author_facet | Ding, Y. Clements, D. L. Leeuw, L. L. Heywood, I. Dannerbauer, H. Parmar, A. Legodi, P. Ivison, R. J. Blake, R. Gutiérrez, C. M. Carnero, A. Sutherland, W. |
| contents | High-redshift protoclusters consisting of dusty starbursts are thought to play an important role in galaxy evolution. Their dusty nature makes them bright in the FIR/submm but difficult to find in optical/NIR surveys. Radio observations are an excellent way to study these dusty starbursts, as dust is transparent in the radio and there is a tight correlation between the FIR and radio emission of a galaxy. Here, we present MeerKAT 1.28 GHz radio imaging of 3 Herschel candidate protoclusters, with a synthesised beam size of ~$7.5'' \times 6.6''$ and a central thermal noise down to $4.35~μ$Jy/beam. Our source counts are consistent with other radio counts with no evidence of overdensities. Around 95% of the Herschel sources have 1.28 GHz IDs. Using the Herschel 250 micron primary beam size as the searching radius, we find 54.2% Herschel sources have multiple 1.28 GHz IDs. Our average FIR-radio correlation coefficient $q_{250μm}$ is $2.33\pm 0.26$. Adding $q_{250μm}$ as a new constraint, the probability of finding chance-aligned sources is reduced by a factor of ~6, but with the risk of discarding true identifications of radio-loud/quiet sources. With accurate MeerKAT positions, we cross-match our Herschel sources to optical/NIR data followed by photometric redshift estimations. By removing $z<1$ sources, the density contrasts of two of the candidate protoclusters increase, suggestive of them being real protoclusters at $z>1$. There is also potentially a $0.9<z<1.2$ overdensity associated with one candidate protocluster. In summary, photometric redshifts from radio-optical cross-identifications have provided some tentative evidence of overdensities aligning with two of the candidate protoclusters. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2410_08843 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | MeerKAT Observations of Herschel Protocluster Candidates Ding, Y. Clements, D. L. Leeuw, L. L. Heywood, I. Dannerbauer, H. Parmar, A. Legodi, P. Ivison, R. J. Blake, R. Gutiérrez, C. M. Carnero, A. Sutherland, W. Astrophysics of Galaxies High-redshift protoclusters consisting of dusty starbursts are thought to play an important role in galaxy evolution. Their dusty nature makes them bright in the FIR/submm but difficult to find in optical/NIR surveys. Radio observations are an excellent way to study these dusty starbursts, as dust is transparent in the radio and there is a tight correlation between the FIR and radio emission of a galaxy. Here, we present MeerKAT 1.28 GHz radio imaging of 3 Herschel candidate protoclusters, with a synthesised beam size of ~$7.5'' \times 6.6''$ and a central thermal noise down to $4.35~μ$Jy/beam. Our source counts are consistent with other radio counts with no evidence of overdensities. Around 95% of the Herschel sources have 1.28 GHz IDs. Using the Herschel 250 micron primary beam size as the searching radius, we find 54.2% Herschel sources have multiple 1.28 GHz IDs. Our average FIR-radio correlation coefficient $q_{250μm}$ is $2.33\pm 0.26$. Adding $q_{250μm}$ as a new constraint, the probability of finding chance-aligned sources is reduced by a factor of ~6, but with the risk of discarding true identifications of radio-loud/quiet sources. With accurate MeerKAT positions, we cross-match our Herschel sources to optical/NIR data followed by photometric redshift estimations. By removing $z<1$ sources, the density contrasts of two of the candidate protoclusters increase, suggestive of them being real protoclusters at $z>1$. There is also potentially a $0.9<z<1.2$ overdensity associated with one candidate protocluster. In summary, photometric redshifts from radio-optical cross-identifications have provided some tentative evidence of overdensities aligning with two of the candidate protoclusters. |
| title | MeerKAT Observations of Herschel Protocluster Candidates |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2410.08843 |