25 research outputs found
The dynamical state of Abell 2399: a bullet-like cluster
While there are many ways to identify substructures in galaxy clusters using
different wavelengths, each technique has its own caveat. In this paper, we
conduct a detailed substructure search and dynamical state characterisation of
Abell 2399, a galaxy cluster in the local Universe (), by
performing a multi-wavelength analysis and testing the results through
hydro-dynamical simulations. In particular, we apply a Gaussian Mixture Model
to the spectroscopic data from SDSS, WINGS, and Omega WINGS Surveys to identify
substructures. We further use public \textit{XMM-Newton} data to investigate
the intracluster medium (ICM) thermal properties, creating temperature,
metallicity, entropy, and pressure maps. Finally, we run hydro-dynamical
simulations to constrain the merger stage of this system. The ICM is very
asymmetrical and has regions of temperature and pressure enhancement that
evidence a recent merging process. The optical substructure analysis retrieves
the two main X-ray concentrations. The temperature, entropy, and pressure are
smaller in the secondary clump than in the main clump. On the other hand, its
metallicity is considerably higher. This result can be explained by the
scenario found by the hydro-dynamical simulations where the secondary clump
passed very near to the centre of the main cluster possibly causing the
galaxies of that region to release more metals through the increase of
ram-pressure stripping.16Comment: 16 pages, 11 figures. Accepted in MNRA
The effect of cluster dynamical state on ram-pressure stripping
Theoretical and observational studies have suggested that ram-pressure stripping by the intracluster medium can be enhanced during cluster interactions, boosting the formation of the "jellyfish" galaxies. In this work, we study the incidence of galaxies undergoing ram-pressure stripping in 52 clusters of different dynamical states. We use optical data from the WINGS/OmegaWINGS surveys and archival X-ray data to characterise the dynamical state of our cluster sample, applying eight different proxies. We then compute the number of ram-pressure stripping candidates relative to the infalling population of blue late-type galaxies within a fixed circular aperture in each cluster. We find no clear correlation between the fractions of ram-pressure stripping candidates and the different cluster dynamical state proxies considered. These fractions also show no apparent correlation with cluster mass. To construct a dynamical state classification closer to a merging "sequence", we perform a visual classification of the dynamical states of the clusters, combining information available in optical, X-ray, and radio wavelengths. We find a mild increase in the RPS fraction in interacting clusters with respect to all other classes (including post-mergers). This mild enhancement could hint at a short-lived enhanced ram-pressure stripping in ongoing cluster mergers. However, our results are not statistically significant due to the low galaxy numbers. We note this is the first homogeneous attempt to quantify the effect of cluster dynamical state on ram-pressure stripping using a large cluster sample, but even larger (especially wider) multi-wavelength surveys are needed to confirm the results
The effect of cluster dynamical state on ram-pressure stripping
Theoretical and observational studies have suggested that ram-pressure stripping by the intracluster medium can be enhanced during cluster interactions, boosting the formation of the "jellyfish" galaxies. In this work, we study the incidence of galaxies undergoing ram-pressure stripping in 52 clusters of different dynamical states. We use optical data from the WINGS/OmegaWINGS surveys and archival X-ray data to characterise the dynamical state of our cluster sample, applying eight different proxies. We then compute the number of ram-pressure stripping candidates relative to the infalling population of blue late-type galaxies within a fixed circular aperture in each cluster. We find no clear correlation between the fractions of ram-pressure stripping candidates and the different cluster dynamical state proxies considered. These fractions also show no apparent correlation with cluster mass. To construct a dynamical state classification closer to a merging "sequence", we perform a visual classification of the dynamical states of the clusters, combining information available in optical, X-ray, and radio wavelengths. We find a mild increase in the RPS fraction in interacting clusters with respect to all other classes (including post-mergers). This mild enhancement could hint at a short-lived enhanced ram-pressure stripping in ongoing cluster mergers. However, our results are not statistically significant due to the low galaxy numbers. We note this is the first homogeneous attempt to quantify the effect of cluster dynamical state on ram-pressure stripping using a large cluster sample, but even larger (especially wider) multi-wavelength surveys are needed to confirm the results