The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources
We report an ASKAP search for associated H i 21-cm absorption against bright radio sources from the Molonglo Reference Catalogue (MRC) 1-Jy sample. The search uses pilot survey data from the ASKAP First Large Absorption Survey in H i (FLASH) covering the redshift range 0.42 < z < 1.00. From a...
| Main Authors: | , , , , , , , , , , , , , , , , , , |
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| Format: | Journal Article |
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2024
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| Online Access: | http://purl.org/au-research/grants/arc/CE170100013 http://hdl.handle.net/20.500.11937/94770 |
| _version_ | 1848765918993186816 |
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| author | Aditya, J.N.H.S. Yoon, H. Allison, J.R. An, T. Chhetri, Rajan Curran, S.J. Darling, J. Emig, K.L. Glowacki, Marcin Kerrison, E. Koribalski, B.S. Mahony, E.K. Moss, V.A. Morgan, John Sadler, E.M. Soria, R. Su, R. Weng, S. Whiting, M. |
| author_facet | Aditya, J.N.H.S. Yoon, H. Allison, J.R. An, T. Chhetri, Rajan Curran, S.J. Darling, J. Emig, K.L. Glowacki, Marcin Kerrison, E. Koribalski, B.S. Mahony, E.K. Moss, V.A. Morgan, John Sadler, E.M. Soria, R. Su, R. Weng, S. Whiting, M. |
| author_sort | Aditya, J.N.H.S. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We report an ASKAP search for associated H i 21-cm absorption against bright radio sources from the Molonglo Reference Catalogue (MRC) 1-Jy sample. The search uses pilot survey data from the ASKAP First Large Absorption Survey in H i (FLASH) covering the redshift range 0.42 < z < 1.00. From a sample of 62 MRC 1-Jy radio galaxies and quasars, we report three new detections of associated H i 21-cm absorption, yielding an overall detection fraction of. The detected systems comprise two radio galaxies (MRC 2216-281 at z = 0.657 and MRC 0531-237 at z = 0.851) and one quasar (MRC 2156-245 at z = 0.862). The MRC 0531-237 absorption system is the strongest found to date, with a velocity integrated optical depth of. All three objects with detected H i 21-cm absorption are peaked-spectrum or compact steep-spectrum (CSS) radio sources. Two of them show strong interplanetary scintillation at 162 MHz, implying that the radio continuum source is smaller than 1 arcsec in size even at low frequencies. Among the class of peaked-spectrum and compact steep-spectrum radio sources, the H i detection fraction is. All three detections have a high 1.4 GHz radio luminosity, with MRC 0531-237 and MRC 2216-281 having the highest values in the sample,. The preponderance of extended radio sources in our sample could partially explain the overall low detection fraction, while the effects of a redshift evolution in gas properties and AGN UV luminosity on the neutral gas absorption still need to be investigated. |
| first_indexed | 2025-11-14T11:42:53Z |
| format | Journal Article |
| id | curtin-20.500.11937-94770 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T11:42:53Z |
| publishDate | 2024 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-947702024-05-09T06:24:36Z The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources Aditya, J.N.H.S. Yoon, H. Allison, J.R. An, T. Chhetri, Rajan Curran, S.J. Darling, J. Emig, K.L. Glowacki, Marcin Kerrison, E. Koribalski, B.S. Mahony, E.K. Moss, V.A. Morgan, John Sadler, E.M. Soria, R. Su, R. Weng, S. Whiting, M. We report an ASKAP search for associated H i 21-cm absorption against bright radio sources from the Molonglo Reference Catalogue (MRC) 1-Jy sample. The search uses pilot survey data from the ASKAP First Large Absorption Survey in H i (FLASH) covering the redshift range 0.42 < z < 1.00. From a sample of 62 MRC 1-Jy radio galaxies and quasars, we report three new detections of associated H i 21-cm absorption, yielding an overall detection fraction of. The detected systems comprise two radio galaxies (MRC 2216-281 at z = 0.657 and MRC 0531-237 at z = 0.851) and one quasar (MRC 2156-245 at z = 0.862). The MRC 0531-237 absorption system is the strongest found to date, with a velocity integrated optical depth of. All three objects with detected H i 21-cm absorption are peaked-spectrum or compact steep-spectrum (CSS) radio sources. Two of them show strong interplanetary scintillation at 162 MHz, implying that the radio continuum source is smaller than 1 arcsec in size even at low frequencies. Among the class of peaked-spectrum and compact steep-spectrum radio sources, the H i detection fraction is. All three detections have a high 1.4 GHz radio luminosity, with MRC 0531-237 and MRC 2216-281 having the highest values in the sample,. The preponderance of extended radio sources in our sample could partially explain the overall low detection fraction, while the effects of a redshift evolution in gas properties and AGN UV luminosity on the neutral gas absorption still need to be investigated. 2024 Journal Article http://hdl.handle.net/20.500.11937/94770 10.1093/mnras/stad3722 http://purl.org/au-research/grants/arc/CE170100013 http://purl.org/au-research/grants/arc/DP210102103 http://creativecommons.org/licenses/by/4.0/ fulltext |
| spellingShingle | Aditya, J.N.H.S. Yoon, H. Allison, J.R. An, T. Chhetri, Rajan Curran, S.J. Darling, J. Emig, K.L. Glowacki, Marcin Kerrison, E. Koribalski, B.S. Mahony, E.K. Moss, V.A. Morgan, John Sadler, E.M. Soria, R. Su, R. Weng, S. Whiting, M. The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources |
| title | The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources |
| title_full | The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources |
| title_fullStr | The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources |
| title_full_unstemmed | The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources |
| title_short | The FLASH pilot survey: An H i absorption search against MRC 1-Jy radio sources |
| title_sort | flash pilot survey: an h i absorption search against mrc 1-jy radio sources |
| url | http://purl.org/au-research/grants/arc/CE170100013 http://purl.org/au-research/grants/arc/CE170100013 http://hdl.handle.net/20.500.11937/94770 |