SUZAKU Observation of a New Merging Group of Galaxies at a Filamentary Junction

TL;DR

This paper reports the discovery of a new merging galaxy group at a filament junction, observed with Suzaku, showing complex X-ray morphology and a hot spot indicative of a major merger process, providing insights into galaxy group evolution.

Contribution

First detailed Suzaku observation of a merging galaxy group at a filament junction, revealing complex X-ray features and hot spots linked to dynamic merging activity.

Findings

Identification of a new galaxy group Suzaku J1552+2739 at z ~ 0.08

Detection of multiple X-ray peaks and a hot spot in the group

Spectroscopic temperature measurements indicating active merging

Abstract

We report on a new merging group of galaxies, Suzaku J1552+2739 at z ~ 0.08 revealed by a SUZAKU observation. The group was found by observing a junction of galaxy filaments optically identified in the Sloan Digital Sky Survey spectroscopic data. Suzaku J1552+2739 exhibits an irregular morphology and presents several peaks in its X-ray image. A bright elliptical galaxy, observable in the central peak, allows the localization of the group at z = 0.083. We found a significant hot spot visible in the X-ray hardness map, close to the second peak. The spectroscopic temperature is T = 1.6+0.4-0.1 keV within R500 = 0.6 Mpc and T = 3 - 5 keV in the hot spot. We interpret those results as Suzaku J1552+2739 being located in the center of a major merging process. The observation of a galaxy group showing multiple X-ray peaks and a hot spot at the same time is rare and we believe in particular that the study of Suzaku J1552+2739 potentially presents a significant interest to better understand the dynamical and thermal evolution of the intragroup and intracluster medium, as well as its relation with surrounding environment.