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arXiv · 2111.04501

Observing ram pressure at work in intermediate redshift clusters with MUSE: the case of Abell 2744and Abell 370

A. Moretti·M. Radovich·B. M. Poggianti·B. Vulcani·M. Gullieuszik·A. Werle·C. Bellhouse·C. Bacchini·J. Fritz·G. Soucail·J. Richard·A. Franchetto·N. Tomicic·A. Omizzolo
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Abstract

Ram pressure stripping has been proven to be effective in shaping galaxy properties in dense environments at low redshift. The availability of MUSE observations of a sample of distant (z$\sim 0.3-0.5$) clusters has allowed to search for galaxies subject to this phenomenon at significant lookback times. In this paper we describe how we discovered and characterized 13 ram-pressure stripped galaxies in the central regions of two intermediate redshift (z$\sim$0.3-0.4) clusters, A2744 and A370, using the MUSE spectrograph. Emission line properties as well as stellar features have been analyzed to infer the presence of this gas--only stripping mechanism, that produces spectacular ionized gas tails (H$_{\alpha}$ and even more astonishing [OII](3727,3729) departing from the main galaxy body. The inner regions of these two clusters reveal the predominance of such galaxies among blue star-forming cluster members, suggesting that ram-pressure stripping was even more effective at intermediate redshift than in today's Universe. Interestingly, the resolved [OII]/H$_{\alpha}$ line ratio in the stripped tails is exceptionally high compared to that in the disks of these galaxies, (which is comparable to that in normal low-z galaxies), suggesting lower gas densities and/or an interaction with the hot surrounding ICM.

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A. Moretti, M. Radovich, B. M. Poggianti, B. Vulcani, M. Gullieuszik, A. Werle, C. Bellhouse, C. Bacchini, J. Fritz, G. Soucail, J. Richard, A. Franchetto, N. Tomicic, A. Omizzolo. 2021-11-08. Observing ram pressure at work in intermediate redshift clusters with MUSE: the case of Abell 2744and Abell 370. https://doi.org/10.3847/1538-4357/ac36c7

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