COMPTEL observation of the flaring quasar PKS0528+134

Citation
S. Zhang et al., COMPTEL observation of the flaring quasar PKS0528+134, ASTRON ASTR, 340(1), 1998, pp. 62-66
Citations number
22
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
00046361 → ACNP
Volume
340
Issue
1
Year of publication
1998
Pages
62 - 66
Database
ISI
SICI code
0004-6361(199812)340:1<62:COOTFQ>2.0.ZU;2-O
Abstract
With a direct demodulation method, we have reanalyzed the data from the COM PTEL observation of PKS0528+134 during the 1993 March flare in gamma-rays. Our results show that during the flare gamma-rays were detected at a level approximately 2.4-3.8 times higher than the observed intensity in two earli er COMPTEL observations VP 0 and VP 1 in the energy range 3 MeV to 30 MeV. The 3-30 MeV, time variability of the flux follows well the trend as observ ed by EGRET at higher energies. No convincing excess can be found around th e position of PKS0528+134 in the energy range 0.75 MeV to 3 MeV, which indi cates a spectral break around 3 MeV. The detections and non-detections in t he four standard COMPTEL energy bands are consistent with the earlier repor ts given by Collmar et al., while the feature that gamma-rays of the quasar still kept on flaring at energies down to 3 MeV is clearly found.