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First minute-scale ...
First minute-scale variability in Fermi -LAT blazar observations during the giant outburst of 3C279 in 2015 June
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Hayashida, M. (författare)
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Madejski, G. (författare)
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Blandford, R. (författare)
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Asano, K. (författare)
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- Larsson, Stefan (författare)
- KTH,Fysik,Oskar Klein Centre for Cosmoparticle Physics
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Nalewajko, K. (författare)
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Sikora, M. (författare)
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(creator_code:org_t)
- American Institute of Physics Inc. 2017
- 2017
- Engelska.
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Ingår i: AIP Conference Proceedings. - : American Institute of Physics Inc.. - 0094-243X. - 9780735414563
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
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- The Flat Spectrum Radio Quasar 3C 279 underwent several outbursts in the past, having flared with a peak γ-ray flux above 100 MeV (FE>100 MeV) exceeding 10-5 ph cm-2 s-1, in 2013 December, 2014 April, and 2015 June. The 2013 December outburst showed an unusually hard power-law γ-ray spectrum (index∼1.7), and an asymmetric light curve profile with few-hour time scale variability. This could be successfully explained using our second order Fermi acceleration model. The outburst in 2015 June was even more powerful, with FE>100 MeV ∼ 4×10-5 ph cm-2 s-1, the historically highest even when the EGRET era is included. For the first time, significant flux variability at sub-orbital timescales was found in blazar observations by Fermi-LAT, with flux doubling times of less than 5 minutes. In the standard external-Compton scenario with conical jet geometry, the minute-scale variability requires a very high bulk jet Lorentz factor (> 50) and extremely low magnetization even at the jet base (∼ 100RS). However, such a high bulk jet Lorentz factor and low magnetization at the jet base pose challenges to standard models of electromagnetically driven jets. Alternately, we consider a synchrotron origin scenario for the GeV γ-ray outburst, which would work in a magnetically dominated jet. In this contribution, we present observational results of the outbursts in detail and discuss current problems on relativistic jets inferred from γ-ray observations.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Publikations- och innehållstyp
- ref (ämneskategori)
- kon (ämneskategori)
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