Selecting and modelling remnant AGNs with limited spectral coverage
Quantifying the energetics and lifetimes of remnant radio-loud active galactic nuclei (AGNs) is much more challenging than for active sources due to the added complexity of accurately determining the time since the central black hole switched off. Independent spectral modelling of remnant lobes enab...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Language: | English |
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OXFORD UNIV PRESS
2022
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| Subjects: | |
| Online Access: | http://purl.org/au-research/grants/arc/FT190100231 http://hdl.handle.net/20.500.11937/91781 |
| _version_ | 1848765590558212096 |
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| author | Quici, B. Turner, Ross Seymour, Nick Hurley-Walker, Natasha Shabala, S.S. Ishwara-Chandra, C.H. |
| author_facet | Quici, B. Turner, Ross Seymour, Nick Hurley-Walker, Natasha Shabala, S.S. Ishwara-Chandra, C.H. |
| author_sort | Quici, B. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Quantifying the energetics and lifetimes of remnant radio-loud active galactic nuclei (AGNs) is much more challenging than for active sources due to the added complexity of accurately determining the time since the central black hole switched off. Independent spectral modelling of remnant lobes enables the derivation of the remnant ratio, Rrem (i.e. 'off-time/source age'); however, the requirement of high-frequency (≳5 GHz) coverage makes the application of this technique over large-area radio surveys difficult. In this work, we propose a new method, which relies on the observed brightness of backflow of Fanaroff-Riley type II lobes, combined with the Radio AGN in Semi-Analytic Environments (RAiSE) code, to measure the duration of the remnant phase. Sensitive radio observations of the remnant radio galaxy J2253-34 are obtained to provide a robust comparison of this technique with the canonical spectral analysis and modelling methods. We find that the remnant lifetimes modelled by each method are consistent; spectral modelling yields Rrem = 0.23 ± 0.02, compared to Rrem = 0.26 ± 0.02 from our new method. We examine the viability of applying our proposed technique to low-frequency radio surveys using mock radio source populations, and examine whether the technique is sensitive to any intrinsic properties of radio AGNs. Our results show that the technique can be used to robustly classify active and remnant populations, with the most confident predictions for the remnant ratio, and thus off-time, in the longest lived radio sources (>50 Myr) and those at higher redshifts (z > 0.1). |
| first_indexed | 2025-11-14T11:37:40Z |
| format | Journal Article |
| id | curtin-20.500.11937-91781 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:37:40Z |
| publishDate | 2022 |
| publisher | OXFORD UNIV PRESS |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-917812023-05-16T02:53:33Z Selecting and modelling remnant AGNs with limited spectral coverage Quici, B. Turner, Ross Seymour, Nick Hurley-Walker, Natasha Shabala, S.S. Ishwara-Chandra, C.H. Science & Technology Physical Sciences Astronomy & Astrophysics galaxies: active galaxies: jets radio continuum: galaxies ACTIVE GALACTIC NUCLEI II RADIO GALAXIES DUTY-CYCLE EVOLUTION CLUSTERS LOFAR MASS MORPHOLOGY ENERGETICS SCIENCE astro-ph.GA astro-ph.GA Quantifying the energetics and lifetimes of remnant radio-loud active galactic nuclei (AGNs) is much more challenging than for active sources due to the added complexity of accurately determining the time since the central black hole switched off. Independent spectral modelling of remnant lobes enables the derivation of the remnant ratio, Rrem (i.e. 'off-time/source age'); however, the requirement of high-frequency (≳5 GHz) coverage makes the application of this technique over large-area radio surveys difficult. In this work, we propose a new method, which relies on the observed brightness of backflow of Fanaroff-Riley type II lobes, combined with the Radio AGN in Semi-Analytic Environments (RAiSE) code, to measure the duration of the remnant phase. Sensitive radio observations of the remnant radio galaxy J2253-34 are obtained to provide a robust comparison of this technique with the canonical spectral analysis and modelling methods. We find that the remnant lifetimes modelled by each method are consistent; spectral modelling yields Rrem = 0.23 ± 0.02, compared to Rrem = 0.26 ± 0.02 from our new method. We examine the viability of applying our proposed technique to low-frequency radio surveys using mock radio source populations, and examine whether the technique is sensitive to any intrinsic properties of radio AGNs. Our results show that the technique can be used to robustly classify active and remnant populations, with the most confident predictions for the remnant ratio, and thus off-time, in the longest lived radio sources (>50 Myr) and those at higher redshifts (z > 0.1). 2022 Journal Article http://hdl.handle.net/20.500.11937/91781 10.1093/mnras/stac1328 English http://purl.org/au-research/grants/arc/FT190100231 OXFORD UNIV PRESS fulltext |
| spellingShingle | Science & Technology Physical Sciences Astronomy & Astrophysics galaxies: active galaxies: jets radio continuum: galaxies ACTIVE GALACTIC NUCLEI II RADIO GALAXIES DUTY-CYCLE EVOLUTION CLUSTERS LOFAR MASS MORPHOLOGY ENERGETICS SCIENCE astro-ph.GA astro-ph.GA Quici, B. Turner, Ross Seymour, Nick Hurley-Walker, Natasha Shabala, S.S. Ishwara-Chandra, C.H. Selecting and modelling remnant AGNs with limited spectral coverage |
| title | Selecting and modelling remnant AGNs with limited spectral coverage |
| title_full | Selecting and modelling remnant AGNs with limited spectral coverage |
| title_fullStr | Selecting and modelling remnant AGNs with limited spectral coverage |
| title_full_unstemmed | Selecting and modelling remnant AGNs with limited spectral coverage |
| title_short | Selecting and modelling remnant AGNs with limited spectral coverage |
| title_sort | selecting and modelling remnant agns with limited spectral coverage |
| topic | Science & Technology Physical Sciences Astronomy & Astrophysics galaxies: active galaxies: jets radio continuum: galaxies ACTIVE GALACTIC NUCLEI II RADIO GALAXIES DUTY-CYCLE EVOLUTION CLUSTERS LOFAR MASS MORPHOLOGY ENERGETICS SCIENCE astro-ph.GA astro-ph.GA |
| url | http://purl.org/au-research/grants/arc/FT190100231 http://hdl.handle.net/20.500.11937/91781 |