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Constraining the location of rapid gamma-ray flares in the flat spectrum radio quasar 3C 273.
- Source :
-
Astronomy & Astrophysics / Astronomie et Astrophysique . Sep2013, Vol. 557 Issue 1, p1-11. 11p. - Publication Year :
- 2013
-
Abstract
- We present a γ-ray photon flux and spectral variability study of the flat-spectrum radio quasar 3C 273 over a rapid flaring activity period between September 2009 to April 2010. Five major flares were observed in the source during this period. The most rapid flare observed in the source has a flux doubling time of 1.1 hr. The rapid γ-ray flares allow us to constrain the location and size of the γ-ray emission region in the source. The γ-opacity constrains the Doppler factor δγ ⩾ 10 for the highest energy (15 GeV) photon observed by the Fermi-Large Area Telescope (LAT). Causality arguments constrain the size of the emission region to 1.6 × 1015 cm. The γ-ray spectra measured over this period show clear deviations from a simple power law with a break in the 1-2 GeV energy range. We discuss possible explanations for the origin of the γ-ray spectral breaks. Our study suggests that the γ-ray emission region in 3C 273 is located within the broad line region (<1.6 pc). The spectral behavior and temporal characteristics of the individual flares indicate the presence of multiple shock scenarios at the base of the jet. [ABSTRACT FROM AUTHOR]
- Subjects :
- *PHOTON flux
*SPECTRUM analysis
*SOLAR flares
*DOPPLER effect
*GAMMA rays
Subjects
Details
- Language :
- English
- ISSN :
- 00046361
- Volume :
- 557
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Astronomy & Astrophysics / Astronomie et Astrophysique
- Publication Type :
- Academic Journal
- Accession number :
- 90587921
- Full Text :
- https://doi.org/10.1051/0004-6361/201321440