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dc.contributor.author | Kleiner, D.![]() |
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dc.contributor.author | Serra, P.![]() |
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dc.contributor.author | Maccagni, F.M.![]() |
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dc.contributor.author | Venhola, A.![]() |
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dc.contributor.author | Morokuma-Matsui, K.![]() |
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dc.contributor.author | Peletier, R.![]() |
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dc.contributor.author | Iodice, E.![]() |
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dc.contributor.author | Raj, M.A.![]() |
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dc.contributor.author | De Blok, W.J.G.![]() |
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dc.contributor.author | Comrie, A.![]() |
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dc.contributor.author | Józsa, G.I.G.![]() |
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dc.contributor.author | Kamphuis, P.![]() |
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dc.contributor.author | Loni, A.![]() |
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dc.contributor.author | Loubser, S.I.![]() |
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dc.contributor.author | Molnar, D. Cs.![]() |
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dc.contributor.author | Passmoor, S.S.![]() |
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dc.contributor.author | Ramatsoku, M.![]() |
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dc.contributor.author | Sivitilli, A.![]() |
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dc.contributor.author | Smirnov, O.![]() |
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dc.contributor.author | Thorat, Kshitij![]() |
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dc.contributor.author | Vitello, F.![]() |
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dc.date.accessioned | 2021-08-27T06:45:48Z | |
dc.date.available | 2021-08-27T06:45:48Z | |
dc.date.issued | 2021-04 | |
dc.description.abstract | We present MeerKAT neutral hydrogen (H i) observations of the Fornax A group, which is likely falling into the Fornax cluster for the first time. Our H i image is sensitive to 1.4 × 1019 atoms cm−2 over 44.1 km s−1 , where we detect H i in 10 galaxies and a total of (1.12 ± 0.02) × 109 M of H i in the intra-group medium (IGM). We search for signs of pre-processing in the 12 group galaxies with confirmed optical redshifts that reside within the sensitivity limit of our H i image. There are 9 galaxies that show evidence of pre-processing and we classify each galaxy into their respective pre-processing category, according to their H i morphology and gas (atomic and molecular) scaling relations. Galaxies that have not yet experienced pre-processing have extended H i discs and a high H i content with a H2-to-H i ratio that is an order of magnitude lower than the median for their stellar mass. Galaxies that are currently being pre-processed display H i tails, truncated H i discs with typical gas fractions, and H2-to-H i ratios. Galaxies in the advanced stages of pre-processing are the most H i deficient. If there is any H i, they have lost their outer H i disc and efficiently converted their H i to H2, resulting in H2-to-H i ratios that are an order of magnitude higher than the median for their stellar mass. The central, massive galaxy in our group (NGC 1316) underwent a 10:1 merger ∼ 2 Gyr ago and ejected 6.6 – 11.2 × 108 M of H i, which we detect as clouds and streams in the IGM, some of which form coherent structures up to ∼ 220 kpc in length. We also detect giant (∼ 100 kpc) ionised hydrogen (Hα) filaments in the IGM, likely from cool gas being removed (and subsequently ionised) from an in-falling satellite. The Hα filaments are situated within the hot halo of NGC 1316 and there are localised regions that contain H i. We speculate that the Hα and multiphase gas is supported by magnetic pressure (possibly assisted by the NGC 1316 AGN), such that the hot gas can condense and form H i that survives in the hot halo for cosmological timescales. | en_ZA |
dc.description.department | Physics | en_ZA |
dc.description.librarian | pm2021 | en_ZA |
dc.description.uri | https://www.aanda.org | en_ZA |
dc.identifier.citation | Kleiner D., Serra, P. & Maccagni, F.M. 2021, 'A MeerKAT view of pre-processing in the Fornax A group', Astronomy and Astrophysics, vol. 648, art. a32, pp. 1-17. | en_ZA |
dc.identifier.issn | 0004-6361 (print) | |
dc.identifier.issn | 1432-0746 (online) | |
dc.identifier.other | 10.1051/0004-6361/202039898 | |
dc.identifier.uri | http://hdl.handle.net/2263/81527 | |
dc.language.iso | en | en_ZA |
dc.publisher | EDP Sciences | en_ZA |
dc.rights | © ESO 2021 | en_ZA |
dc.subject | Galaxies: groups: general | en_ZA |
dc.subject | Galaxies: groups: individual | en_ZA |
dc.subject | Fornax A | en_ZA |
dc.subject | Galaxies: evolution | en_ZA |
dc.subject | Galaxies: interactions | en_ZA |
dc.subject | Galaxies: ISM | en_ZA |
dc.subject | Radio lines: galaxies | en_ZA |
dc.title | A MeerKAT view of pre-processing in the Fornax A group | en_ZA |
dc.type | Preprint Article | en_ZA |