* Astronomy

Title: A cluster pair : A3532 and A3530
Authors: K. Lakhchaura, K. P. Singh, D. J. Saikia, R. W. Hunstead

We present a detailed study of the environments of a close pair of clusters of galaxies, A3532 and A3530. The Chandra X-ray image of A3532 reveals presence of substructures on scales of 20 arcseconds in its core. XMM-Newton maps of the clusters show excess X-ray emission from an overlapping region between them. Spectrally determined projected temperature and entropy maps do not show any signs of mergers, either in the overlapping region or within A3530. A3532, however, shows many signs of the presence of mergers: anisotropic temperature variations seen in the projected thermodynamic maps, a wide angled tailed (WAT) radio source at its center, and several X-ray candidate cavities near the WAT. A small sized cavity appears coincident with the southern tail of the WAT. Low frequency radio observations show an extension of the WAT radio emission towards the northwest, coinciding with a large scale X-ray cavity. The extension seems either a part of the WAT or an unrelated diffuse source from A3532 itself or from the background. A3530 shows a temperature drop and peak in the abundance at its centre and, therefore, seems to host at least a weak cool core. The cool core in A3532 seems to be disrupted by the ongoing mergers. A reanalysis of the redshifts data reinforces the close proximity of the clusters. The excess emission in the overlapping region seems to be a result of the tidal interactions as the two clusters approach each other for the first time.

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