2002A&A...396..793B


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.26CET01:33:56

2002A&A...396..793B - Astronomy and Astrophysics, volume 396, 793-799 (2002/12-4)

Flux and spectral variations in the Circinus Galaxy.

BIANCHI S., MATT G., FIORE F., FABIAN A.C., IWASAWA K. and NICASTRO F.

Abstract (from CDS):

We report on a dramatic flux (∼50% increase in the LECS and MECS band) and spectral variation between two BeppoSAX observations of the Circinus Galaxy performed almost three years apart. Through the analysis of all Chandra observations available in the archive, including a new DDT observation on May 2001, we show that a high flux state of an extremely variable Ultra Luminous X-ray source (CG X-1: Bauer et al., 2001AJ....122..182B), which is within the adopted BeppoSAX source extraction region of 2', is the most likely explanation for most of the observed variation. However, the presence of a high flux 6.7 keV line and the spectral variation of the PDS in the new BeppoSAX data could be partly due to intrinsic variation of the nucleus. Comparing the longest Chandra observation and the BeppoSAX one, we find that the long-term flux variability of CG X-1 is not accompanied by a significant spectral variability. We also re-analysed the Chandra HEG nuclear spectra and report on the presence of a Compton shoulder with a flux of about 20% the line core, in agreement with theoretical expectations for Compton-thick matter.

Abstract Copyright:

Journal keyword(s): galaxies: individual: Circinus - galaxies: Seyfert - X-rays: galaxies - X-rays: individuals: CG X-1 - X-rays: individuals: CG X-2

Simbad objects: 4

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Number of rows : 4

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME Circinus Galaxy Sy2 14 13 09.906 -65 20 20.47   10.89 9.84 10.6 10.0 ~ 1032 2
2 SN 1996cr SN* 14 13 10.05 -65 20 44.8     19.5     SNIIn: 69 1
3 [SGT2004] J141312.24-652014.0 CV* 14 13 12.24 -65 20 14.0           ~ 18 0
4 Granat 1915+105 HXB 19 15 11.55576 +10 56 44.9052           ~ 2333 0

    Equat.    Gal    SGal    Ecl

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2021.01.26-01:33:56

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