XMM-Newton view of galaxy pairs: activation of quiescent black holes?^*

¹ Dipartimento di Fisica di l'Universita Roma 3, via della Vasca Navale 84, 00146 Roma, Italy e-mail: ejimenez@fis.uniroma3.it
² XMM-Newton Science Operations Center, ESAC, ESA, Apartado 50727, 28080 Madrid, Spain
³ Instituto Nacional de Astrofísica Optica y Electrónica, Luis Enrique Erro No. 1. Tonantzintla, Puebla, C.P. 72840, México
⁴ Osservatorio Astronomico di Roma (INAF), via Frascati 33, 00040 Monteporzio Catone, Italy

Received: 17 November 2006
Accepted: 23 March 2007

Abstract

We report on XMM-Newton  observations of three nearby galaxy pairs, AM0707-273, AM1211-465, and AM2040-674. All six galaxies were previously classified as HII galaxies based on optical and IR spectroscopic analysis. All galaxies were detected with XMM-Newton and each member was isolated and analyzed independently. The X-ray spectra reveal strong evidence of AGN activity in the NE member of AM1211-465 pair. We measured a luminosity of 10⁴² erg/s in the 2–10 keV band and the presence of a neutral FeKα line with a confidence level of 98.8%. The high  value, 2.2 ± 0.210²² cm^-2, would explain the misclassification of the source. Marginal evidence of AGN nature was found in the X-ray spectra of AM1211-465SW and AM0707-273E. The X-ray emission of the three remaining galaxies can be explained by starburst activity.