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Swift/XRT observations of a huge flare from 3C 454.3

ATEL # 2329; T. Sakamoto (CRESTT/GSFC/UMBC), F. D'Ammando (INAF/IASF-Roma), N. Gehrels (GSFC), Y.Y. Kovalev (ASC Lebedev and MPIfR), K. Sokolovsky (MPIfR)
on 4 Dec 2009; 19:42 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Filippo D'Ammando (

Subjects: X-ray, AGN
Referred to by ATEL #: 2333

Based on the recent high activity of the blazar 3C 454.3 in both gamma-ray and optical (ATel #2322; ATel #2325; ATel #2326; ATel #2328), we have initiated the intense ToO monitoring observations by Swift starting from Dec 1.

According to our quick-look analysis of the Swift/XRT data, we found that the X-ray flux is reaching to the same level of the giant X-ray flare on May 2005 (Giommi et al. 2005). We fit the spectrum of the Swift/XRT data in the 0.3-10 keV energy band with an absorbed power law model with a column density n_H = 1.34e21 cm^-2, which is the value found by previous Chandra observation (Villata et al. 2006). Our preliminary spectral analysis is shown below.

   Date (start/stop)      Exposure Ph.Index    F(2-10 keV)                          [ks]                 [erg/cm2/s]   ---------------------- -------- ----------- -----------   2009-12-01 16:38-16:56 1.0      1.58+/-0.05 1.14e-10   2009-12-02 00:30-00:50 1.2      1.56+/-0.05 1.32e-10   2009-12-03 15:25-15:40 1.0      1.60+/-0.06 1.22e-10   2009-12-04 00:43-02:43 2.7      1.52+/-0.03 1.58e-10   

The Swift ToO monitoring program of 3C 454.3 will continue at least until Dec 14 with a typical exposure of 1 ksec every day. Further observations at all wavelengths are encouraged.

We would like to thank the Swift Team for making these observations possible, in particular the duty scientists and science planners

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R. E. Rutledge , Editor
ATEL Mirror v1.0 Updates