THE BROAD-BAND ENERGY-DISTRIBUTION OF THE MISALIGNED GAMMA-RAY BLAZARPKS-0521-365

Citation
E. Pian et al., THE BROAD-BAND ENERGY-DISTRIBUTION OF THE MISALIGNED GAMMA-RAY BLAZARPKS-0521-365, The Astrophysical journal, 459(1), 1996, pp. 169-174
Citations number
54
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
459
Issue
1
Year of publication
1996
Part
1
Pages
169 - 174
Database
ISI
SICI code
0004-637X(1996)459:1<169:TBEOTM>2.0.ZU;2-4
Abstract
Simultaneous UV and X-ray observations of the blazar PKS 0521-365 are combined with radio, IR, optical, and gamma-ray data taken at differen t epochs to study the overall emission from 10(9) to 10(23) Hz. The fl ux distribution declines from the IR to the UV range (alpha(opt-UV) = 1.4 +/- 0.1), but hardens at higher frequencies. The remarkably flat X -ray spectrum (energy index alpha(X) = 0.68 +/- 0.12 in the range 0.2- 7 keV) suggests a significant contribution by the inverse Compton proc ess in this band. This is supported by the detection of the source in gamma-rays by the EGRET experiment. The full radio-to-gamma-ray energy distribution is discussed. Various arguments suggest that the jet is not closely aligned with the line of sight (theta similar to 30 degree s), implying that the observed radiation is weakly boosted. This allow s a direct estimate of the importance of different sources of photons available for upscattering. We conclude that in this source the synchr otron photons are likely to be the seeds for the inverse Compton proce ss.