In:
The Astrophysical Journal, American Astronomical Society, Vol. 691, No. 1 ( 2009-01-20), p. L13-L19
Abstract:
We present optical, X-ray, high-energy (⪅30 GeV) and very high energy (⪆100 GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high-energy γ-ray signal was detected by AGILE with between June 9 and 15, with F ( E 〉 100 MeV) = 42 +14 −12 × 10 −8 photons cm −2 s −1 . This flaring state is brighter than the average flux observed by EGRET by a factor of ∼3, but still consistent with the highest EGRET flux. In hard X-rays (20–60 keV) SuperAGILE resolved a five-day flare (June 9–15) peaking at ∼55 mCrab. SuperAGILE, RXTE /ASM and Swift /BAT data show a correlated flaring structure between soft and hard X-rays. Hints of the same flaring behavior are also detected in the simultaneous optical data provided by the GASP-WEBT. A Swift /XRT observation near the flaring maximum revealed the highest 2–10 keV flux ever observed from this source, of 2.6 × 10 −9 erg cm −2 s −1 (i.e. 〉 100 mCrab). A peak synchrotron energy of ∼3 keV was derived, higher than typical values of ∼0.5–1 keV. VHE observations with MAGIC and VERITAS between June 6 and 8 showed the flux peaking in a bright state, well correlated with the X-rays. This extraordinary set of simultaneous data, covering a 12-decade spectral range, allowed for a deep analysis of the spectral energy distribution as well as of correlated light curves. The γ-ray flare can be interpreted within the framework of the synchrotron self-Compton model in terms of a rapid acceleration of leptons in the jet.
Type of Medium:
Online Resource
ISSN:
0004-637X
,
1538-4357
DOI:
10.1088/0004-637X/691/1/L13
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2009
detail.hit.zdb_id:
2207648-7
detail.hit.zdb_id:
1473835-1
SSG:
16,12
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