2011A&A...525L...2C


Query : 2011A&A...525L...2C

2011A&A...525L...2C - Astronomy and Astrophysics, volume 525, L2-2 (2011/1-1)

Discovery of X-ray flaring activity in the Arches cluster.

CAPELLI R., WARWICK R.S., CAPPELLUTI N., GILLESSEN S., PREDEHL P., PORQUET D. and CZESLA S.

Abstract (from CDS):

We present a study of the Arches cluster based on XMM-Newton observations performed over the past 8 years. Unexpectedly, we find that the X-ray emission associated with the cluster experienced a marked brightening in March/April 2007. We investigate the origin of both the X-ray continuum emission emanating from the star cluster and the flare. To study the time variability of the total X-ray flux, we stacked the PN and MOS data of observations performed within a time interval of a few days leading to the detection of the flaring episode. We then constructed two spectral datasets, one corresponding to the flare interval (March/April 2007) and another to the normal quiescent state of the source. The X-ray light curve of the Arches cluster shows, with high significance (8.6σ), a 70% increase in the X-ray emission in the March/April 2007 timeframe followed by a decline over the following year to the pre-flare level; the short-term duration of the flare is constrained to be longer than four days. The temperature and the line-of-sight column density inferred from the flare spectrum do not differ from those measured in the normal activity state of the cluster, suggesting that the flux enhancement is thermal in origin. We attribute the X-ray variability to in situ stellar activity: early-type stars may be responsible for the flare via wind collisions, whereas late-type stars may contribute by means of magnetic reconnection. These two possibilities are discussed.

Abstract Copyright:

Journal keyword(s): stars: flare - galaxy: center - X-rays: stars

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 * eta Car Em* 10 45 03.545808 -59 41 03.95124 6.37 7.03 6.48 6.123 4.41 LBV 2458 0
2 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14643 0
3 GCIRS 16 Cl* 17 45 40.0 -29 00 28           ~ 367 0
4 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4449 3
5 [YLW2002] A1 X 17 45 50 -28 49.3           ~ 10 0
6 WR 102ae WR* 17 45 50.28 -28 49 11.4           WN9h 36 0
7 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 747 0
8 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 530 0
9 NAME Galactic Ridge ? ~ ~           ~ 503 1
10 [YLW2002] A3 X ~ ~           ~ 10 0

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