Discovery of a high confidence soft lag from an X-ray flare of Markarian 421
Abstract
We present the X-ray variability properties of the X-ray and TeV bright blazar Mrk 421 with a ∼60 ks long XMM-Newton observation performed on November 9-10, 2005. The source experienced a pronounced flare, of which the inter-band time lags were determined with a very high confidence level. The soft (0.6-0.8 keV) X-ray variations lagged the hard (4-10 keV) ones by 1.09{-0.12/+0.11} ks, and the soft lag increases with increasing difference in the photon energy. The energy-dependent soft lags can be well fitted with the difference of the energy-dependent cooling timescales of the relativistic electron distribution responsible for the observed X-ray emission, which constrains the magnetic field strength and Doppler factor of the emitting region to be Bδ 1/3∼1.78 Gauss.
- Publication:
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Science China Physics, Mechanics, and Astronomy
- Pub Date:
- January 2010
- DOI:
- 10.1007/s11433-010-0017-1
- arXiv:
- arXiv:1003.5033
- Bibcode:
- 2010SCPMA..53S.224Z
- Keywords:
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- BL Lacertae objects: individual: Mrk 421;
- galaxies: active;
- radiation mechanisms: non-thermal;
- X-rays: galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Published in Science China-Physics, Mechanics &