SC 1327–312 & SC 1329–313: Two galaxy groups in-between a major merging event observed with Beppo–SAX

¹ Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
² Osservatorio Astronomico di Brera, Via Bianchi 46, 23807 Merate (LC), Italy
³ Institute of Astronomy, Madingley Road, CB3 0HA Cambridge, UK
⁴ Istituto di Fisica Cosmica “G. Occhialini”, Via Bassini 15, 20133 Milano, Italy
⁵ Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio Catone, Italy

Corresponding author: S. Bardelli, bardelli@bo.astro.it

Received: 1 August 2001
Accepted: 18 October 2001

Abstract

We present the results of two Beppo-SAX observations of the poor clusters SC 1327–312 and SC 1329–313: these objects are located in a huge structure, formed by three ACO clusters, which is probably the remnant of one of the largest and best studied major mergings known. Given the fact that these poor clusters are in between two interacting ACO clusters, the aim of this work is to study the physics of the intracluster medium and to look for the possible presence of shocks. We derived the gas distribution profiles, the global (i.e. within 0.3  h^-1 Mpc) temperatures and abundances and the temperature profiles and maps for SC 1327–312 and SC 1329–313. Also the presence of soft excess in LECS and hard excess in PDS have been examined. We do not find evidence of regions where the gas is shocked or significantly heated. The image of SC 1327–312 seems rather symmetric, while the gas profile of SC 1329–313 shows disturbed, “comet-like" shaped isophotes, with the tail pointing toward A3562 and a compression toward SC 1327–312. The presence of multiphase gas in SC 1329–313, as claimed by Hanami et al. ([CITE]) based on ASCA data, has been found only at the 2σ confidence level. The lack of heating supports the hypothesis that the merging is at a late stage, after the first core–core encounter, when the main shock front had the time to travel to the external regions of the main clusters.