TY - JOUR
T1 - Chandra/HETGS observations of the brightest flare seen from SgrA*
AU - Nowak, M. A.
AU - Neilsen, J.
AU - Markoff, S. B.
AU - Baganoff, F. K.
AU - Porquet, D.
AU - Grosso, N.
AU - Levin, Y.
AU - Houck, J.
AU - Eckart, A.
AU - Falcke, H.
AU - Ji, L.
AU - Miller, J. M.
AU - Wang, Q. D.
PY - 2012/11/10
Y1 - 2012/11/10
N2 - Starting in 2012, we began an unprecedented observational program focused on the supermassive black hole in the center of our Galaxy, SgrA*, 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 SgrA* for the first time at both high spatial and spectral resolution. The X-ray emission of SgrA*, 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 100times 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 SgrA*. The flare, which lasted for 5.6ks and had a decidedly asymmetric profile with a faster decline than rise, achieved a mean absorbed 2-8keV flux of (8.5 ± 0.9) × 10-12 erg cm-2 s-1. The peak flux was 2.5times higher, and the total 2-10keV emission of the event was approximately 1039erg. Only one other flare of comparable magnitude, but shorter duration, has been observed in SgrA* 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 (Γ ∼ 2) and X-ray absorbing columns (N H ∼ 15 × 1022cm -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 SgrA* flares. We also discuss fits to the quiescent spectra of SgrA*.
AB - Starting in 2012, we began an unprecedented observational program focused on the supermassive black hole in the center of our Galaxy, SgrA*, 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 SgrA* for the first time at both high spatial and spectral resolution. The X-ray emission of SgrA*, 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 100times 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 SgrA*. The flare, which lasted for 5.6ks and had a decidedly asymmetric profile with a faster decline than rise, achieved a mean absorbed 2-8keV flux of (8.5 ± 0.9) × 10-12 erg cm-2 s-1. The peak flux was 2.5times higher, and the total 2-10keV emission of the event was approximately 1039erg. Only one other flare of comparable magnitude, but shorter duration, has been observed in SgrA* 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 (Γ ∼ 2) and X-ray absorbing columns (N H ∼ 15 × 1022cm -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 SgrA* flares. We also discuss fits to the quiescent spectra of SgrA*.
KW - accretion, accretion disks
KW - black hole physics
KW - radiation mechanisms: non-thermal
UR - https://www.scopus.com/pages/publications/84868146111
U2 - 10.1088/0004-637X/759/2/95
DO - 10.1088/0004-637X/759/2/95
M3 - Article
AN - SCOPUS:84868146111
SN - 0004-637X
VL - 759
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 95
ER -