During Phase I and Phase II of the CGRO‐mission, the quasar PKS 0528+134 was in the field of view of the COMPTEL instrument during several viewing periods. The quasar was detected by COMPTEL mainly at energies above 10 MeV. Below 10 MeV there is evidence for the source during some CGRO viewing periods, while below 3 MeV no signal is detected. The detections and non‐detections during different viewing periods follow the trend seen by EGRET, thereby indicating a time‐variable MEV‐flux of the quasar. The COMPTEL spectral results together with the simultaneously measured EGRET spectrum, indicate a spectral break in the upper part of the COMPTEL energy range at energies between 10 MeV and 30 MeV.

Publication Date


Journal Title

AIP Conference Proceedings


AIP Publishing

Digital Object Identifier (DOI)


Document Type

Conference Proceeding


© 1994 American Institute of Physics