SUZAKU OBSERVATION OF A NEW MERGING GROUP OF GALAXIES AT A FILAMENTARY JUNCTION

We report on a new merging group of galaxies, Suzaku J1552+2739, at z similar to 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 R-500 = 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 is potentially of significant interest for better understanding the dynamical and thermal evolution of the intragroup and intracluster medium, as well as its relation with the surrounding environment.