Nowak, M. A., Neilsen, J., Markoff, S. B., Baganoff, F. K., Porquet, D., Grosso, N., Levin, Y., Houck, J., Eckart, A., Falcke, H., Ji, L., Miller, J. M. and Wang, Q. D. (2012). CHANDRA/HETGS OBSERVATIONS OF THE BRIGHTEST FLARE SEEN FROM Sgr A*. Astrophys. J., 759 (2). BRISTOL: IOP PUBLISHING LTD. ISSN 1538-4357
Full text not available from this repository.Abstract
Starting in 2012, we began an unprecedented observational program focused on the supermassive black hole in the center of our Galaxy, Sgr A*, utilizing the High Energy Transmission Grating Spectrometer (HETGS) instrument on the Chandra X-Ray Observatory. These observations will allow us to measure the quiescent X-ray spectra of Sgr A* for the first time at both high spatial and spectral resolution. The X-ray emission of Sgr A*, however, is known to flare roughly daily by factors of a few to ten times over quiescent emission levels, with rarer flares extending to factors of greater than 100 times quiescence. Here we report an observation performed on 2012 February 9 wherein we detected what are the highest peak flux and fluence flare ever observed from Sgr A*. The flare, which lasted for 5.6 ks and had a decidedly asymmetric profile with a faster decline than rise, achieved a mean absorbed 2-8 keV flux of (8.5 +/- 0.9) x 10(-12) erg cm(-2) s(-1). The peak flux was 2.5 times higher, and the total 2-10 keV emission of the event was approximately 10(39) erg. Only one other flare of comparable magnitude, but shorter duration, has been observed in Sgr A* by XMM-Newton in 2002 October. We perform spectral fits of this Chandra-observed flare and compare our results to the two brightest flares ever observed with XMM-Newton. We find good agreement among the fitted spectral slopes (Gamma similar to 2) and X-ray absorbing columns (N-H similar to 15 x 10(22) cm(-2)) for all three of these events, resolving prior differences (which are most likely due to the combined effects of pileup and spectral modeling) among Chandra and XMM-Newton observations of Sgr A* flares. We also discuss fits to the quiescent spectra of Sgr A*.
| Item Type: | Journal Article | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Creators: |
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| URN: | urn:nbn:de:hbz:38-479018 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DOI: | 10.1088/0004-637X/759/2/95 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Journal or Publication Title: | Astrophys. J. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Volume: | 759 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Number: | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Date: | 2012 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Publisher: | IOP PUBLISHING LTD | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Place of Publication: | BRISTOL | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ISSN: | 1538-4357 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Language: | English | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Faculty: | Unspecified | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Divisions: | Unspecified | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Subjects: | no entry | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| URI: | http://kups.ub.uni-koeln.de/id/eprint/47901 |
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