A Lack of Evidence for Global Ram-pressure Induced Star Formation in the Merging Cluster Abell 3266

TL;DR

This study investigates whether ram-pressure stripping in the merging cluster Abell 3266 triggers star formation, finding no clear correlation and suggesting that starburst phases are brief and not solely driven by ram pressure.

Contribution

The paper provides evidence that ram-pressure induced star formation is not the dominant process in Abell 3266, highlighting the transient nature of starburst phases during cluster mergers.

Findings

Post-starburst galaxies are more frequent in Abell 3266 than in the Coma cluster.

Starburst and post-starburst galaxies are found in both low and high ram pressure environments.

Starburst phases are likely very brief, explaining the lack of correlation with ram pressure.

Abstract

We have selected Abell 3266 to search for ram-pressure induced star formation as a global property of a merging cluster. Abell 3266 (z = 0.0594) is a high mass cluster that features a high velocity dispersion, an infalling subcluster near to the line of sight, and a strong shock front. These phenomena should all contribute to making Abell 3266 an optimum cluster to see the global effects of RPS induced star formation. Using archival X-ray observations and published optical data, we cross-correlate optical spectral properties ([OII, H$\beta$]), indicative of starburst and post starburst, respectively with ram-pressure, $\rho$v$^{2}$, calculated from the X-ray and optical data. We find that post-starburst galaxies, classified as E+A, occur at a higher frequency in this merging cluster than in the Coma cluster and at a comparable rate to intermediate redshift clusters. This is consistent with increased star formation due to the merger. However, both starburst and post-starburst galaxies are equally likely to be in a low or high ram pressure environment. From this result we infer that the duration of the starburst phase must be very brief so that: (1) at any time only a small fraction of the galaxies in a high ram pressure environment show this effect, and (2) most post-starburst galaxies are in an environment of low ram pressure due too their continued orbital motion in the cluster.