GASP. XV. A MUSE view of extreme ram-pressure stripping along the line of sight: physical properties of the jellyfish galaxy JO201

Abstract

We present a study of the physical properties of JO201, a unique disk galaxy with extended tails undergoing extreme ram-pressure stripping as it moves through the massive cluster Abell 85 at supersonic speeds mostly along the line of sight. JO201 was observed with MUSE as part of the GASP programme. In a previous paper (GASP II) we studied the stellar and gas kinematics. In this paper we present emission-line ratios, gas-phase metallicities and ages of the stellar populations across the galaxy disk and tails. We find that while the emission at the core of the galaxy is dominated by an active galactic nucleus (AGN), the disk is composed of star-forming knots surrounded by excited diffuse gas. The collection of star-forming knots presents a metallicity gradient steadily decreasing from the centre of the galaxy outwards, and the ages of the stars across the galaxy show that the tails formed 10 9 yr ago. This result is consistent with an estimate of the stripping timescale (∼ 1 Gyr), obtained from a toy orbital model. Overall, our results independently and consistently support a scenario in which a recent or ongoing event of intense ram-pressure stripping acting from the outer disk inwards, causes removal and compression of gas, thus altering the AGN and star-formation activity within and around the galaxy.

A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

“…A lot of observational evidence indicates that this process, which is commonly referred to as ram pressure stripping (Gunn & Gott 1972), dominates the evolution of gas-rich late-type systems in nearby massive clusters (e.g., Boselli & Gavazzi 2006, 2014; this evidence includes the presence of galaxies with long cometary tails in the various gas phases (atomic cold, e.g., Chung et al 2007;ionised, Yagi et al 2010;hot, e.g., Sun et al 2007) without any associated stellar counterpart or the high frequency of spirals with radially truncated gaseous discs (e.g., Cayatte et al 1994;Koopmann & Kenney 2004). While many representative objects undergoing a ram pressure stripping event have been already studied in detail using multi-frequency observations (Kenney et al 2004(Kenney et al , 2014(Kenney et al , 2015Crowl et al 2005;Boselli et al 2016a;Sun et al 2006Sun et al , 2007Sun et al , 2010Merluzzi et al 2013;Abramson & Kenney 2014;Abramson et al 2011Abramson et al , 2016Jáchym et al 2013Jáchym et al , 2014Jáchym et al , 2017Jáchym et al , 2019Fumagalli et al 2014;Fossati et al 2016;Poggianti et al 2019;Bellhouse et al 2019;Deb et al 2020;Moretti et al 2020a) and tuned models and simulations (Vollmer et al 1999(Vollmer et al , 2000(Vollmer et al , 2004a(Vollmer et al ,b, 2006(Vollmer et al , 2008a(Vollmer et al ,b, 2012(Vollmer et al , 2018Roediger & Hensl...…”

A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

“…In some cases, this gas also appears as ionised (hotter) and is detected through its Hα emission (e.g. Boselli et al 2016;Poggianti et al 2017;Fossati et al 2018;Bellhouse et al 2019), or it may get heated to the cluster X-ray temperature (Sun et al 2006). Finally, cold molecular gas, which is usually detected through its CO emission, has been found to follow the stripped HI component (e.g.…”

The role of environment on quenching, star formation and AGN activity

“…Moreover, the combination of MUSE and multiwavelength data has provided strong evidence for the effects of AGN feedback in the jellyfish galaxy JO201 (George et al 2019, see also Bellhouse et al 2017Bellhouse et al , 2019. The central 8kpc region of JO201 is depleted of both molecular gas (as traced by a CO ALMA observation) and of recent and ongoing star formation (as traced by NUV and FUV imaging with UVIT@ASTROSAT) (Fig.…”

“…4). Moreover, jellyfish galaxies follow the mass-metallicity relation of non-stripped cluster galaxies, with metallicities higher than The long extraplanar tails of ionized gas are visible (Bellhouse et al 2017(Bellhouse et al , 2019. Other three panels: a zoom on the disk of (from left to right) NUV emission, ionization source map and CO map (George et al 2019).…”

“…Smith et al 2010;Hester et al 2010), and UV+Halpha studies (e.g. Boselli et al 2018;Abramson et al 2011), but integral-field spectroscopy observations have allowed us to ascertain the presence of star formation in the tails and study its properties in an unprecedented way (Merluzzi et al 2013;Fumagalli et al 2014;Fossati et al 2016;Consolandi et al 2017;Gullieuszik et al 2017;Moretti et al 2018a;Bellhouse et al 2019;George et al 2018). In GASP, the dominant ionization mechanism in the long extraplanar Hα-emitting tails is photoionization by young massive stars (Poggianti et al 2019a).…”