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Preprint typeset using L ATEX style emulateapj v. 14/09/00 AN XMM-NEWTON OBSERVATION OF THE GALAXY GROUP NGC 5044: ABUNDANCE PROFILES, INTRINSIC ABSORPTION, AND IMPLICATIONS.

By David A. Buote, Aaron D. Lewis, Fabrizio Brighenti and William G. Mathews

Abstract

We present a detailed initial analysis of a new XMM observation of the bright nearby galaxy group NGC 5044, which has been previously interpreted as a massive cooling flow. Outside of the central ∼ 1 ′ (10 kpc) region the diffuse X-ray emission is approximately circular. Within a 1 ′ radius the emission displays asymmetries which the archival Chandra image reveals to be holes similar to those seen in other cooling flows. To obtain the spherically averaged three-dimensional properties of the diffuse gas we perform a simultaneous spatial-spectral deprojection analysis of the EPIC MOS CCD data. Assuming a single-phase gas in each spatial bin we find that the 3D temperature profile rises outwards from T ≈ 0.75 keV at the center to T ≈ 1.2 keV at r ≈ 50 kpc and then declines slowly until reaching a value of T ≈ 1.1 keV at r ≈ 100 kpc similar to the profile obtained with ROSAT. Within the central ∼ 30 kpc, where the temperature is changing rapidly, the quality of the deprojected fits is notably superior to their traditional un-deprojected counterparts. Moreover, using a simple gaussian or flat emission measure model within the three inner 1 ′-wide spatial bins we measure in each bin the narrow temperature distribution expected for the single-phase temperature gradient. A standard multiphase cooling flow, which implies a much wider temperature distribution, is a poor fit to the XMM data

Year: 2002
OAI identifier: oai:CiteSeerX.psu:10.1.1.316.8696
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