Universität zu Köln

Mossoux, Enmanuelle and Eckart, Andreas ORCID: 0000-0001-6049-3132 (2018). The X-ray footprint of the circumnuclear disc. Mon. Not. Roy. Astron. Soc., 474 (3). S. 3787 - 3808. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

We studied the central regions of the Galactic Centre to determine if the circumnuclear disc (CND) acts as an absorber or a barrier for the central X-rays diffuse emission. After reprocessing 4.6 Ms of Chandra observations, we were able to detect, for the first time, a depression in the X-ray luminosity of the diffuse emission whose size and location correspond to those of the CND. We extracted the X-ray spectra for various regions inside the CND footprint as well as for the region where the footprint is observed and for a region located outside the footprint. We simultaneously fitted these spectra as an optically thin plasma whose absorption by the interstellar medium (ISM) and by the local plasma were fitted independently using the Markov chain Monte Carlo method. The hydrogen column density of the ISM is 7.5 x 10(22) cm(-2). The X-ray diffuse emission inside the CND footprint is formed by a 2T plasma of 1 and 4 keV with slightly super-solar abundances except for the iron and carbon that are sub-solar. The plasma from the CND, in turn, is better described by a 1T model with abundances and local hydrogen column density that are very different from those of the innermost regions. The large iron abundance in this region confirms that the CND is dominated by the shock-heated ejecta of the Sgr A East supernova remnant. We deduced that the CND rather acts as a barrier for the Galactic Centre plasma and that the plasma located outside the CND may correspond to the collimated outflow possibly created by Sgr A* or the interaction between the wind of massive stars and the mini-spiral material.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Mossoux, Enmanuelle UNSPECIFIED UNSPECIFIED UNSPECIFIED Eckart, Andreas UNSPECIFIED orcid.org/0000-0001-6049-3132 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-195348
DOI:	10.1093/mnras/stx3026
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	474
Number:	3
Page Range:	S. 3787 - 3808
Date:	2018
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics I
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SAGITTARIUS-A-EAST; SUPERMASSIVE BLACK-HOLE; NUCLEAR STAR CLUSTER; GALACTIC-CENTER; SGR-A; INFRARED EXTINCTION; INTERSTELLAR-MEDIUM; CROSS-SECTIONS; CENTRAL PARSEC; MILKY-WAY Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/19534