Stephan's Quintet with XMM-Newton

¹ INAF-Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy e-mail: ginevra@brera.mi.astro.it
² University of Alabama, Tuscaloosa, AL 35487, USA
³ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85740 Garching, Germany
⁴ Institut für Astronomie, Universität Wien, Türkenschanzstr. 17, 1180 Wien, Austria

Received: 21 February 2005
Accepted: 27 June 2005

Abstract

The prototype compact group known as Stephan's Quintet (SQ) was observed with XMM-Newton in order to complement the excellent resolution of Chandra with high sensitivity to extended emission. SQ is a dynamic environment whose main effect, at both X-ray and optical wavelengths, appears to be ISM stripping. This is manifested by: 1) secular evolution of morphological types towards earlier types and 2) growth of diffuse emission. Virtually all cold, warm, and hot gas in SQ is found outside of the member galaxies. XMM-Newton offers the opportunity to study the hot gas with unprecedented sensitivity. We find two main components: 1) extended high surface brightness emission from shocked gas associated with an ongoing collision and 2) even more extended and unrelaxed diffuse emission that follows the stripped stellar envelope of the group.