An Unidentified Variable Gamma-Ray Source near the Galactic Plane Detected by COMPTEL

Abstract

We report the detection of an unidentified gamma-ray source near the Galactic plane by the COMPTEL experiment aboard the Compton Gamma-Ray Observatory. The source is detected at a significance level of ~ 7.2 sigma in the energy range 1-3 MeV and at ~ 4.6 sigma in the lower 0.75-1 MeV band in the time period March to July 1995. At energies above 3 MeV are only marginal hints or upper limits obtained. The MeV spectrum has a soft shape. Strong flux variability is found within one year at energies below 3 MeV. Possible counterparts of galactic and extragalactic nature are discussed.

7 pages including 5 figures, accepted for publication in A&A

References in corpus (11)

• A jet model for the broadband spectrum of XTE J1118+480: Synchrotron emission from radio to X-rays in the Low/Hard spectral state
• The first COMPTEL Source Catalogue
• A High Sensitivity Measurement of the MeV Gamma-Ray Spectrum of Cygnus X-1
• A variability analysis of low-latitude unidentified gamma-ray sources
• Precessing microblazars and unidentified gamma-ray sources
• A Chandra Study of the Circinus Galaxy Point-Source Population
• Variable gamma-ray emission from the Be/X-ray transient A0535+26?
• X-ray imaging of the Seyfert 2 galaxy Circinus with Chandra
• On the time variability of gamma-ray sources: A numerical analysis of variability indices
• Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
• COMPTEL Time-Averaged All-Sky Point Source Analysis

Cited by in corpus (6)

• Spectral constraints on unidentified EGRET gamma-ray sources from COMPTEL MeV observations
• A microquasar model applied to unidentified gamma-ray sources
• Detection of positron in-flight annihilation from the Galaxy
• Gamma-Ray Emission From Be/X-Ray Binaries
• INTEGRAL and XMM-Newton observations towards the unidentified MeV source GRO J1411-64
• INTEGRAL/XMM views on the MeV source GRO J1411-64