GASP XXIX-unwinding the arms of spiral galaxies via ram-pressure stripping

Bellhouse, Callum; McGee, Sean L.; Smith, Rory; Poggianti, Bianca M.; Jaffé, Yara L.; Kraljic, Katarina; Franchetto, Andrea; Fritz, Jacopo; Vulcani, Benedetta; Tonnesen, Stephanie; Roediger, Elke; Moretti, Alessia; Gullieuszik, Marco; Shin, Jihye

Abstract

We present the first study of the effect of ram pressure ‘unwinding’ the spiral arms of cluster galaxies. We study 11 ram-pressure stripped galaxies from GASP (GAs Stripping Phenomena in galaxies) in which, in addition to more commonly observed ‘jellyfish’ features, dislodged material also appears to retain the original structure of the spiral arms. Gravitational influence from neighbours is ruled out and we compare the sample with a control group of undisturbed spiral galaxies and simulated stripped galaxies. We first confirm the unwinding nature, finding that the spiral arm pitch angle increases radially in 10 stripped galaxies and also simulated face-on and edge-on stripped galaxies. We find only younger stars in the unwound component, while older stars in the disc remain undisturbed. We compare the morphology and kinematics with simulated ram-pressure stripping galaxies, taking into account the estimated inclination with respect to the intracluster medium (ICM) and find that in edge-on stripping, unwinding can occur due to differential ram pressure caused by the disc rotation, causing stripped material to slow and ‘pile up’. In face-on cases, gas removed from the outer edges falls to higher orbits, appearing to ‘unwind’. The pattern is fairly short-lived (

Citation

Bellhouse, C., McGee, S. L., Smith, R., Poggianti, B. M., Jaffé, Y. L., Kraljic, K., …Shin, J. (2020). GASP XXIX-unwinding the arms of spiral galaxies via ram-pressure stripping. Monthly notices of the Royal Astronomical Society, 500(1), 1285-1312. https://doi.org/10.1093/mnras/staa3298

• Journal Article Type: Article
• Acceptance Date: Oct 16, 2020
• Online Publication Date: Oct 28, 2020
• Publication Date: Nov 18, 2020
• Deposit Date: Dec 18, 2020
• Publicly Available Date: Dec 21, 2020
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 500
• Issue: 1
• Pages: 1285-1312
• DOI: https://doi.org/10.1093/mnras/staa3298
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://hull-repository.worktribe.com/output/3679916
• Publisher URL: https://academic.oup.com/mnras/article-abstract/500/1/1285/5942665?redirectedFrom=fulltext