431 citations · 1.3k across the 42 of their papers we have counts for
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Integral and Rxte/Asm Observations on Igr J17098-3628
Yu-Peng Chen, Shu Zhang, Nick Schurch +5
To probe further the possible nature of the unidentified source IGR J17098-3628, we have carried out a detailed analysis of its long-term time variability as monitored by RXTE/ASM,…
High energy properties of PKS 1830-211
Shu Zhang, Yu-peng Chen, Werner Collmar +4
We report on an analysis of X- and -ray observations of PKS 1830-211, based on the long-term campaigns carried out by \emph{INTEGRAL} and COMPTEL. The \emph{INTEGRAL} data curre…
INTEGRAL/XMM views on the MeV source GRO J1411-64
Diego F. Torres, Shu Zhang, Olaf Reimer +9
The COMPTEL unidentified source GRO J 1411-64 was observed by INTEGRAL and XMM-Newton in 2005. The Circinus Galaxy is the only source detected within the 4 location error of GRO…
INTEGRAL and XMM-Newton observations towards the unidentified MeV source GRO J1411-64
Diego F. Torres, Shu Zhang, Olaf Reimer +9
The COMPTEL unidentified source GRO J1411-64 was observed by INTEGRAL, and its central part, also by XMM-Newton. The data analysis shows no hint for new detections at hard X-rays.…
INTEGRAL survey of the Cassiopeia region in hard X rays
P. R. den Hartog, W. Hermsen, L. Kuiper +3
We report on the results of a deep 1.6 Ms INTEGRAL observation of the Cassiopeia region performed from December 2003 to February 2004. Eleven sources were detected with the imager…
INTEGRAL and RXTE Observations of Centaurus A
Richard E. Rothschild, Joern Wilms, John Tomsick +6
INTEGRAL and RXTE performed three simultaneous observations of the nearby radio galaxy Cen A in 2003 March, 2004 January, and 2004 February with the goals of investigating the geom…
COMPTEL Observations of the Gamma-ray Blazars 3C~454.3 and CTA 102 During the CGRO Mission
S. Zhang, W. Collmar, V. Schonfelder
We have investigated the MeV behaviour of the \gray blazars 3C~454.3 and CTA 102 by analyzing all COMPTEL observations of this sky region during the complete CGRO mission. Both sou…
Multifrequency Observations of the Gamma-Ray Blazar 3C 279 in Low-State during Integral AO-1
W. Collmar, M. Böttcher, V. Burwitz +19
We report first results of a multifrequency campaign from radio to hard X-ray energies of the prominent gamma-ray blazar 3C 279 during the first year of the INTEGRAL mission. The v…
Spectral constraints on unidentified EGRET gamma-ray sources from COMPTEL MeV observations
S. Zhang, W. Collmar, W. Hermsen +1
We investigated the MeV properties of 173 unidentified or only tentatively identified EGRET sources listed in the third EGRET catalogue, by analyzing the simultaneously collected C…
BeppoSAX Observations of Centaurus A: the Hard Continuum and the Iron Line Feature
P. Grandi, M. Fiocchi, C. G. Perola +7
The radio galaxy Centaurus A was observed by the BeppoSAX satellite five times from 1997 to 2000. From July 6 1999 to August 17 1999, the source was also simultaneously pointed by…
An Unidentified Variable Gamma-Ray Source near the Galactic Plane Detected by COMPTEL
S. Zhang, W. Collmar, V. Schonfelder
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…
COMPTEL Observations of the Gamma-Ray Blazar PKS 1622-297
S. Zhang, W. Collmar, K. Bennett +7
We report results of observations and analyses on the gamma-ray blazar PKS 1622-297, with emphasis on the COMPTEL data (0.75 - 30 MeV) collected between April 1991 and November 199…
The Soft Gamma-Ray Spectral Variability of Cygnus X-1
M. L. McConnell, A. A. Zdziarski, K. Bennett +11
We have used observations of Cygnus X-1 from the Compton Gamma-Ray Observatory (CGRO) and BeppoSAX to study the variation in the MeV gamma-ray emission between the hard and soft sp…
COMPTEL Observations of the Blazars 3C 454.3 and CTA 102
S. Zhang, W. Collmar, V. Schoenfelder +5
We have analyzed the two blazars of 3C 454.3 and CTA 102 using all available COMPTEL data from 1991 to 1999. In the 10-30 MeV band, emission from the general direction of the sourc…
Gamma-Ray Spectral Variability of Cygnus X-1
M. L. McConnell, K. Bennett, H. Bloemen +11
We have used observations from CGRO to study the variation in the MeV emission of Cygnus X-1 between its low and high X-ray states. These data provide a measurement of the spectral…
AGN: The High-Energy Status before INTEGRAL
W. Collmar
Much progress in the knowledge of the high-energy emission (>50 keV) from Active Galactic Nuclei has been made during the last decade, predominately by the experiments aboard the C…
COMPTEL Observations of the Blazar PKS 1622-297 during a Gamma-Ray High State in 1995
S. Zhang, W. Collmar, V. Schonfelder +6
PKS 1622-297 was detected as a source of gamma-rays by the EGRET experiment at energies above 100 MeV during a gamma-ray outburst June and July 1995. We analyzed the COMPTEL data (…
56Co gamma-rays from SN1998bu: COMPTEL upper limits
S. Plueschke, R. Georgii, R. Diehl +7
The type Ia supernova SN1998bu in M96 was observed by COMPTEL for a total of 88 days starting 17 days after the first detection of the supernova. The accumulated effective observat…
Multifrequency Observations of the Virgo Blazars 3C 273 and 3C 279 in CGRO Cycle 8
W. Collmar, S. Benlloch, J. E. Grove +15
We report first observational results of multifrequency campaigns on the prominent Virgo blazars 3C 273 and 3C 279 which were carried out in January and February 1999. Both blazars…
The first COMPTEL Source Catalogue
V. Schoenfelder, the COMPTEL Collaboration
The imaging Compton telescope COMPTEL aboard NASA's Compton Gamma-Ray Observatory has opened the MeV gamma-ray band as a new window to astronomy. COMPTEL provided the first complet…
The Spectral Variability of Cygnus X-1 at MeV Energies
M. L. McConnell, K. Bennett, H. Bloemen +8
In previous work, we have used data from the first three years of the CGRO mission to assemble a broad-band -ray spectrum of the galactic black hole candidate Cygnus X-1. Contem…
A large high-energy gamma-ray flare from the blazar 3C 273
W. Collmar, O. Reimer, K. Bennett +8
The Compton Gamma-Ray Observatory (CGRO) experiments EGRET and COMPTEL observed the Virgo sky region continuously for 7 weeks between December 10, 1996 and January 28, 1997. The pr…
A High Sensitivity Measurement of the MeV Gamma-Ray Spectrum of Cygnus X-1
M. L. McConnell, J. M. Ryan, W. Collmar +9
The Compton Gamma-Ray Observatory (CGRO) has observed the Cygnus region on several occasions since its launch in 1991. The data collected by the COMPTEL experiment on CGRO represen…
COMPTEL Time-Averaged All-Sky Point Source Analysis
W. Collmar, V. Schoenfelder, A. W. Strong +5
We use all COMPTEL data from the beginning of the CGRO mission (April '91) up to the end of CGRO Cycle 6 (November '97) to carry out all-sky point source analyses in the four stand…