Tidal interaction vs. ram pressure stripping effects as seen in X-rays

Abstract

Context. Cluster and group spiral galaxies are very often affected by their environment. The hot intracluster/intragroup medium (ICM/IGM) and a high galaxy density can lead to perturbations of the galactic interstellar medium (ISM) due to ram pressure and/or tidal interaction effects. In radio polarimetry observations, both phenomena may manifest similar features. X-ray data can help to determine the real origin of the perturbation. Aims. We analyse the distribution and physical properties of the hot gas in the Virgo cluster spiral galaxies NGC 4254 and NGC 4569, which indicate that the cluster environment has had a significant influence on their properties. By performing both spatial and spectral analyses of X-ray data, we try to distinguish between two major phenomena: tidal and ram pressure interactions. We compare our findings with the case of NGC 2276, in which a shock was reported, by analysing XMM-Newton X-ray data for this galaxy. Methods. We use archival XMM-Newton observations of NGC 4254, NGC 4569, and NGC 2276. Maps of the soft diffuse emission in the energy band 0.2−1 keV are obtained. For the three galaxies, especially at the position of magnetic field enhancements we perform a spectral analysis to derive gas temperatures and thus to look for shock signatures. A shock is a signature of ram pressure resulting from supersonic velocities; weak tidal interactions are not expected to influence the temperature of the ionized gas. Results. In NGC 4254, we do not observe any temperature increase at the position of the bright polarized radio ridge. This suggests that the feature is formed by tidal interactions, and not by ram pressure stripping. NGC 4569 shows a higher temperature at the position of the polarized features, which may be indicative of ram-pressure effects. For NGC 2276, we do not find clear indications of a shock. Although ram-pressure effects seem to be visible, the main driver of the observed distortions is most likely tidal interaction. Conclusions. Determining gas temperatures via sensitive X-ray observations at the position of polarized radio ridges seems to be a good method for distinguishing between ram pressure and tidal interaction effects acting upon a galaxy.

On the origin of the intracluster light in massive galaxy clusters

“…The study of the ICL is potentially significant in the context of resolving classic debates about the drivers of galaxy evolution in dense environments. Potentially important processes include galaxy-galaxy tidal interactions and mergers, particularly in in-falling groups and subclusters (Zabludoff et al (1996); Zabludoff & Mulchaey (1998), now called "pre-processing"), encounters with the cluster potential, galaxy harassment, and ram pressure stripping (e.g., Park & Hwang (2009) ;Smith et al (2010); Weżgowiec et al (2012)). If the ICL is dominated by stars stripped from galaxies, it offers something unique: a signature of the history of galaxy tidal interactions.…”

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

“…Therefore, an evolutionary scenario for some S0s in which these processes combine with minor mergers is quite probable. In fact, gas stripping and tidal interactions and mergers are known to be taking place at the same time in many galaxies as they infall into the center of a cluster (Sofue 1994;Weżgowiec et al 2012;Vollmer et al 2013). Consequently, the dispersion of the S0s in the δǫ e,intr diagram is compatible with an evolution induced by minor mergers.…”

Bursting Bubbles: Clustered Supernova Feedback in Local and High-redshift Galaxies

“…Nearly all of the nearby galaxies (and the Solar Circle) fall into the parameter space of the PS case, with the exception of the central regions ( 1 kpc) of NGCs 253 and 4321, which fall into the PBO case ("Powered Break-out"). None of NGCs 3627, 4254 or 5194 (nor the Solar circle) have significantly detected SN-driven outflows (Calzetti et al 2005;Weżgowiec et al 2012;Law et al 2018). However, there is evidence of an outflow originating from the circumnuclear region of NGC 4321 (Castillo-Morales et al 2007).…”

“…Insets at right: These simulations are in good agreement with our model, hosting dramatic break-outs in PBO case parameter space and churning, stalled bubbles in PS case parameter space (images are of projected gas density for the simulations fromFielding et al 2018, adapted from their paper).M , and Ω ≈ 35 Gyr −1 ) are taken fromMcKee et al (2015).Nearly all of the nearby galaxies (and the Solar Circle) fall into the parameter space of the PS case, with the exception of the central regions ( 1 kpc) of NGCs 253 and 4321, which fall into the PBO case ("Powered Break-out"). None of NGCs 3627, 4254 or 5194 (nor the Solar circle) have significantly detected SN-driven outflows(Calzetti et al 2005;Weżgowiec et al 2012;Law et al 2018). However, there is evidence of an outflow originating from the circumnuclear region of NGC 4321(Castillo-Morales et al 2007).…”