EUV and X-ray observations of Abell 2199: a three-phase intracluster medium with a massive warm component

Citation
R. Lieu et al., EUV and X-ray observations of Abell 2199: a three-phase intracluster medium with a massive warm component, ASTRON ASTR, 364(2), 2000, pp. 497-500
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
0004-6361 → ACNP
Volume
364
Issue
2
Year of publication
2000
Pages
497 - 500
Database
ISI
SICI code
0004-6361(200012)364:2<497:EAXOOA>2.0.ZU;2-J
Abstract
Various independent ways of constraining key cosmological parameters yielde d a consensus range of values which indicates that at the present epoch the bulk of the universe's baryons is in the form of a warm (similar to 10(6) K) gas - a temperature regime which renders them difficult to detect. The d iscovery of EW and soft X-ray excess emission from clusters of galaxies was originally interpreted as the first direct evidence for the large scale pr esence of such a warm component. We present results from an EWE Deep Survey (DS) observation of the rich cluster Abell 2199 in the Lex/B (69-190 eV) f ilter passband. The soft excess radial trend (SERT), shown by a plot agains t cluster radius r of the percentage EW emission eta observed above the lev el expected from the hot intracluster medium (ICM), behaves as a simple fun ction of r which decreases monotonically towards r = 0; it smoothly turns n egative at r similar to 6 arcmin, inwards of this radius the EUV is absorbe d by cold matter with a line-of-sight column density of greater than or equ al to 2.7 x 10(19) cm(-2). The centre of absorption is offset from that of the emission by similar to 1 arcmin, and the area involved is much larger t han that of the cooling flow. These facts together provide strong evidence for a centrally concentrated but cluster-wide distribution of clumps of col d gas which co-exist with warm,aas of similar spatial properties. Further, the simultaneous modeling of EUV and Xray data requires a warm component ev en within the region of absorption. The phenomenon demonstrates a three pha se ICM, with the warm phase estimated to be similar to 5-10 times more mass ive than the hot.