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Articles 181 - 209 of 209
Full-Text Articles in Astrophysics and Astronomy
Neutron And Gamma‐Ray Measurements Of The Solar Flare Of 1991 June 9, James M. Ryan, D J. Forrest, J Lockwood, M Loomis, Mark L. Mcconnell, D Morris, W Webber, K Bennett, L O. Hanlon, C Winkler, H Debrunner, G Rank, V Schonfelder, B Swanenburg
Neutron And Gamma‐Ray Measurements Of The Solar Flare Of 1991 June 9, James M. Ryan, D J. Forrest, J Lockwood, M Loomis, Mark L. Mcconnell, D Morris, W Webber, K Bennett, L O. Hanlon, C Winkler, H Debrunner, G Rank, V Schonfelder, B Swanenburg
Space Science Center
The COMPTEL Imaging Compton Telescope on‐board the Compton Gamma Ray Observatory measured significant neutron and γ‐ray fluxes from the solar flare of 9 June 1991. The γ‐ray flux had an integrated intensity (≳1 MeV) of ∼30 cm−2, extending in time from 0136 UT to 0143 UT, while the time of energetic neutron emission extended approximately 10 minutes longer, indicating either extended proton acceleration to high energies or trapping and precipitation of energetic protons. The production of neutrons without accompanying γ‐rays in the proper proportion indicates a significant hardening of the precipitating proton spectrum through either the trapping or …
Simultaneous Observations Of The Continuum Emission Of The Quasar 3c 273 From Radio To Γ‐Ray Energies, G G. Lichti, C Von Montigny, T Balonek, T Courvoisier, N Johnson, Mark L. Mcconnell, W Paciesas, E I. Robson, A Sadun, C Schalinski, H Steppe, A G. Smith, R Staubert, B Swanenburg, M Turner, M Ulrich, O R. Williams
Simultaneous Observations Of The Continuum Emission Of The Quasar 3c 273 From Radio To Γ‐Ray Energies, G G. Lichti, C Von Montigny, T Balonek, T Courvoisier, N Johnson, Mark L. Mcconnell, W Paciesas, E I. Robson, A Sadun, C Schalinski, H Steppe, A G. Smith, R Staubert, B Swanenburg, M Turner, M Ulrich, O R. Williams
Space Science Center
From June 15–28, 1991 the Compton Gamma‐Ray Observatory (CGRO) observed the radio‐loud quasar 3C 273. All four CGRO instruments detected radiation from this quasar in their relevant energy range (from 20 keV to 5 GeV). Simultaneous and quasi‐simultaneous observations by instruments sensitive at other wavelengths have also been obtained. The data from all these observations, spanning the frequency range from ∼109 Hz–∼102 6 Hz, were collected and analyzed. Details of the observations and an overall energy‐density spectrum are presented. This spectrum shows two maxima of nearly equal strength. One is in the UV, while the other one is …
Comptel Observations Of The Quasar Pks 0528+134, W Collmar, R Diehl, G G. Lichti, V Schonfelder, H Steinle, A W. Strong, H Bloemen, W Hermsen, Mark L. Mcconnell, James M. Ryan, G Stacy, K Bennett, O R. Williams, C Winkler
Comptel Observations Of The Quasar Pks 0528+134, W Collmar, R Diehl, G G. Lichti, V Schonfelder, H Steinle, A W. Strong, H Bloemen, W Hermsen, Mark L. Mcconnell, James M. Ryan, G Stacy, K Bennett, O R. Williams, C Winkler
Space Science Center
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 …
Mev Emission From The Black‐Hole Candidate Gro J0422+32 Measured With Comptel, R Vandijk, H Bloemen, W Hermsen, W Collmar, R Diehl, J Greiner, G G. Lichti, V Schonfelder, A W. Strong, K Bennett, L O. Hanlon, C Winkler, Mark L. Mcconnell, James M. Ryan
Mev Emission From The Black‐Hole Candidate Gro J0422+32 Measured With Comptel, R Vandijk, H Bloemen, W Hermsen, W Collmar, R Diehl, J Greiner, G G. Lichti, V Schonfelder, A W. Strong, K Bennett, L O. Hanlon, C Winkler, Mark L. Mcconnell, James M. Ryan
Space Science Center
On Aug. 5, 1992 BATSE discovered the bright X‐ray transient GRO J0422+32, also known as Nova Per 1992. The COMPTEL instrument (0.75–30 MeV) aboard CGRO observed this black‐hole candidate twice. During the first observation, which started when the X‐ray flux was at its maximum, GRO J0422+32 was detected up to 2 MeV. The fluxes in the 0.75–1 and 1–2 MeV range were signficantly higher than expected based on an extrapolation of the contemporaneous OSSE data. The COMPTEL spectral points can be interpreted as evidence for a Wien‐type spectral component with temperature k T≊300 keV. During the second observation, 3 …
Spectral Properties Of Gamma‐Ray Bursts Observed By Comptel, L O. Hanlon, K Bennett, O R. Williams, C Winkler, W Collmar, R Diehl, J Greiner, V Schonfelder, H Steinle, A W. Strong, M Varendorff, R Vandijk, J W. Den Herder, W Hermsen, L Kuiper, A Connors, R M. Kippen, Mark L. Mcconnell, James M. Ryan
Spectral Properties Of Gamma‐Ray Bursts Observed By Comptel, L O. Hanlon, K Bennett, O R. Williams, C Winkler, W Collmar, R Diehl, J Greiner, V Schonfelder, H Steinle, A W. Strong, M Varendorff, R Vandijk, J W. Den Herder, W Hermsen, L Kuiper, A Connors, R M. Kippen, Mark L. Mcconnell, James M. Ryan
Space Science Center
During the first year of operation, the COMPTEL instrument on board the Compton Gamma Ray Observatory detected 22 γ‐ray bursts within its field of view. Spectra and time histories for the strongest 7 of these bursts have been obtained from both the main instrument (0.75–30 MeV) and the burst modules (0.1–10 MeV). The deconvolved photon spectra for the majority of bursts are fit by a single power law model with spectral index between −1.6 and −2.8. One strong burst, GRB 910814, exhibited significant curvature and could not be fit by a single power law model. A broken power law model …
Recent Results From Comptel Observations Of Cygnus X‐1, Mark L. Mcconnell, D J. Forrest, James M. Ryan, W Collmar, V Schonfelder, H Steinle, A W. Strong, R Vandijk, W Hermsen, K Bennett, R Much
Recent Results From Comptel Observations Of Cygnus X‐1, Mark L. Mcconnell, D J. Forrest, James M. Ryan, W Collmar, V Schonfelder, H Steinle, A W. Strong, R Vandijk, W Hermsen, K Bennett, R Much
Space Science Center
The COMPTEL experiment on the Compton Gamma‐Ray Observatory (CGRO) has now observed Cyg X‐1 on four separate occasions during phase 1 and phase 2 of its orbital mission (April, 1991 to August, 1993). Here we report on the results of the latest analysis of these data, which provide a spectrum extending to energies greater than 2 MeV. A spectral analysis of these data, in the context of a classical Comptonization model, indicates an electron temperature much higher than previous hard X‐ray measurements would suggest (200 keV vs 60–80 keV). This implies either some limitations in the standard Comptonization model and/or …
Instrument Description And Performance Of The Imaging Gamma-Ray Telescope Comptel Aboard The Compton Gamma-Ray Observatory, V. Schonfelder, H. Aarts, K Bennett, H Deboer, J. Clear, W Collmar, A Connors, A. Deerenberg, R Diehl, A. Von Dordrecht, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, G. Simpson, M. Snelling, G Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, C De Vries, C Winkler
Instrument Description And Performance Of The Imaging Gamma-Ray Telescope Comptel Aboard The Compton Gamma-Ray Observatory, V. Schonfelder, H. Aarts, K Bennett, H Deboer, J. Clear, W Collmar, A Connors, A. Deerenberg, R Diehl, A. Von Dordrecht, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, G. Simpson, M. Snelling, G Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, C De Vries, C Winkler
Space Science Center
The COMPTEL instrument aboard the COMPTEL Gamma-Ray Observatory and its performance capabilities are described. Calibration data are used to determine the angular and energy response, and the effective detection area. The imaging properties of COMPTEL are demonstrated, and the sensitivity of Comptel to celestial gamma-ray sources are estimated from flight data.
Search For Gamma‐Ray Emission From Agn With Comptel, W Collmar, R Diehl, G G. Lichti, V Schonfelder, H Steinle, A W. Strong, H Bloemen, J W. Den Herder, W Hermsen, B Swanenburg, C De Vries, Mark L. Mcconnell, James M. Ryan, G Stacy, K Bennett, O R. Williams, C Winkler
Search For Gamma‐Ray Emission From Agn With Comptel, W Collmar, R Diehl, G G. Lichti, V Schonfelder, H Steinle, A W. Strong, H Bloemen, J W. Den Herder, W Hermsen, B Swanenburg, C De Vries, Mark L. Mcconnell, James M. Ryan, G Stacy, K Bennett, O R. Williams, C Winkler
Space Science Center
The COMPTEL data (∼0.7–30 MeV) were searched for emission from AGN. Four sources have been detected so far: the quasars 3C 273, 3C 279, PKS 0528+134, and the radio galaxy Centaurus A. 3C 273 and 3C 279 were detected in CGRO observation period 3 with quite different spectral shapes. There is also evidence for 3C 273 at a weak flux level in observation period 11. The quasar PKS 0528+134 was detected above 3 MeV as part of a search for AGN already observed by EGRET. Cen A was seen up to 3 MeV by combining data from different observation periods.
Comptel Observations Of Gamma-Ray Bursts - Imaging And Localization, A Connors, H Aarts, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, R Diehl, R Van Dijk, L O. Hanlon, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, A. Klumper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, O R. Williams, C Winkler
Comptel Observations Of Gamma-Ray Bursts - Imaging And Localization, A Connors, H Aarts, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, R Diehl, R Van Dijk, L O. Hanlon, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, A. Klumper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, O R. Williams, C Winkler
Space Science Center
The COMPTEL experiment on GRO images 0.7-30 MeV celestial gamma-radiation that falls within its 1 steradian field of view. During the first eleven months of orbit, preliminary lozalizations from BATSE triggers indicated that about 1 in 6 cosmic events could have fallen within COMPTEL's field of view. WE present COMPTEL positions for four of the brighter of these gamma-ray bursts.
Gamma‐Ray Burst Studies By Comptel During Its First Year Of Operation, C Winkler, K Bennett, L O. Hanlon, O R. Williams, W Collmar, R Diehl, V Schonfelder, H Steinle, M Varendorff, J W. Den Herder, W Hermsen, L Kuiper, B Swanenburg, C De Vries, A Connors, D J. Forrest, R M. Kippen, Mark L. Mcconnell, James M. Ryan
Gamma‐Ray Burst Studies By Comptel During Its First Year Of Operation, C Winkler, K Bennett, L O. Hanlon, O R. Williams, W Collmar, R Diehl, V Schonfelder, H Steinle, M Varendorff, J W. Den Herder, W Hermsen, L Kuiper, B Swanenburg, C De Vries, A Connors, D J. Forrest, R M. Kippen, Mark L. Mcconnell, James M. Ryan
Space Science Center
During the first year of Compton GRO operations, more than 20 cosmic gamma‐ray burst‐detected by the BATSE instrument ‐ occurred inside the 1 sr field of view of the imaging gamma‐ray telescope COMPTEL. Using COMPTEL’s primary mode of operation (the telescope mode) direct images (with ∼1° GRB location accuracy) and event spectra (0.7 MeV – 30 MeV) with spectral resolution better than 10% FWHM have been obtained. In its secondary mode of burst operations, COMPTEL has recorded time resolved spectra (0.1 MeV – 10 MeV) from its large NaI detectors. This paper summarises the results on cosmic GRB sources obtained …
Initial Results From Comptel—An Overview, V Schonfelder, W Collmar, R Diehl, G G. Lichti, H Steinle, A W. Strong, M Varendorff, H Bloemen, H Deboer, R Vandijk, J W. Den Herder, W Hermsen, L Kuiper, B Swanenburg, C De Vries, A Connors, D J. Forrest, Mark L. Mcconnell, D Morris, James M. Ryan, G Stacy, K Bennett, C Winkler, B G. Taylor
Initial Results From Comptel—An Overview, V Schonfelder, W Collmar, R Diehl, G G. Lichti, H Steinle, A W. Strong, M Varendorff, H Bloemen, H Deboer, R Vandijk, J W. Den Herder, W Hermsen, L Kuiper, B Swanenburg, C De Vries, A Connors, D J. Forrest, Mark L. Mcconnell, D Morris, James M. Ryan, G Stacy, K Bennett, C Winkler, B G. Taylor
Space Science Center
COMPTEL is presently completing the first full sky survey in MeV gamma‐ray astronomy (0.7 to 30 MeV). An overview of initial results from the survey is given: among these are the observations of the Crab and Vela pulsars with unprecedented accuracy, the observation of the black hole candidates Cyg X‐1 and Nova Persei 1992, an analysis of the diffuse Galactic continuum emission from the Galactic center region, the broad scale distribution of the 1.8 MeV line from radioactive 2 6Al, upper limits on gamma‐ray line emission from SN 1991T, observations of the three quasars 3C273, 3C279 and PKS 0528+134 …
Comptel Observations Of Gamma-Ray Bursts - Time Profiles And Spectra, W Collmar, K Bennett, H Bloemen, H Deboer, M Busetta, A Connors, R Diehl, J Greiner, L O. Hanlon, J W. Den Herder, W Hermsen, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, O R. Williams, C Winkler
Comptel Observations Of Gamma-Ray Bursts - Time Profiles And Spectra, W Collmar, K Bennett, H Bloemen, H Deboer, M Busetta, A Connors, R Diehl, J Greiner, L O. Hanlon, J W. Den Herder, W Hermsen, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, O R. Williams, C Winkler
Space Science Center
The COMPTEL experiment aboard CGRO is designed to image celestial gamma-radiation in the energy range from 0.7-30 MeV, and also to accumulate time-resolved NaI detector spectra (0.1-10 MeV) upon receipt of a BATSE burst trigger signal. During the early phases of the GRO mission several bursts have been observed. In this paper we present time profiles and first results from spectral analysis for GRB 910425, GRB 910601, and GRB 910814.
The Design Of A Gamma‐Ray Burst Polarimeter, Mark L. Mcconnell, D J. Forrest, K Levenson, W T. Vestrand
The Design Of A Gamma‐Ray Burst Polarimeter, Mark L. Mcconnell, D J. Forrest, K Levenson, W T. Vestrand
Space Science Center
The study of the polarization properties of the gamma‐ray bursts is the one remaining unexplored avenue of research which may help to answer some of the fundamental problems regarding the nature of these mysterious objects. We have designed an instrument to measure linear polarization in cosmic gamma‐ray bursts at energies ≳50 keV. Here we describe the design of this instrument, which we call the Gamma‐ray Burst Polarimeter Experiment (GRAPE).
Comptel Observations Of The Inner Galaxy, H Bloemen, H Deboer, R Van Dijk, J W. Den Herder, W Hermsen, L Kuiper, B Swanenburg, C De Vries, W Collmar, R Diehl, G G. Lichti, V Schonfelder, H Steinle, A W. Strong, Mark L. Mcconnell, A Connors, D Morris, G Stacy, K Bennett
Comptel Observations Of The Inner Galaxy, H Bloemen, H Deboer, R Van Dijk, J W. Den Herder, W Hermsen, L Kuiper, B Swanenburg, C De Vries, W Collmar, R Diehl, G G. Lichti, V Schonfelder, H Steinle, A W. Strong, Mark L. Mcconnell, A Connors, D Morris, G Stacy, K Bennett
Space Science Center
This paper presents a first global study of COMPTEL observations of the inner Galaxy in the energy range 0.75–10 MeV. Preliminary findings demonstrate COMPTEL’s capabilities for mapping the observed gamma radiation and disentangling the contributions from point sources and diffuse emission.
Comptel Gamma Ray And Neutron Measurements Of Solar Flares, James M. Ryan, D J. Forrest, J Lockwood, M Loomis, Mark L. Mcconnell, D Morris, W Webber, G Rank, V Schonfelder, B Swanenburg, K Bennett, L O. Hanlon, C Winkler, H Debrunner
Comptel Gamma Ray And Neutron Measurements Of Solar Flares, James M. Ryan, D J. Forrest, J Lockwood, M Loomis, Mark L. Mcconnell, D Morris, W Webber, G Rank, V Schonfelder, B Swanenburg, K Bennett, L O. Hanlon, C Winkler, H Debrunner
Space Science Center
COMPTEL on the Compton Gamma Ray Observatory has measured the flux of x‐rays and neutrons from several solar flares. These data have also been used to image the Sun in both forms of radiation. Unusually intense flares occurred during June 1991 yielding data sets that offer some new insight into of how energetic protons and electrons are accelerated and behave in the solar environment. We summarize here some of the essential features in the solar flare data as obtained by COMPTEL during June 1991.
Comptel Observations Of Cygnus X‐1, Mark L. Mcconnell, A Connors, D J. Forrest, James M. Ryan, W Collmar, R Diehl, V Schonfelder, H Steinle, A W. Strong, H Bloemen, R Van Dijk, W Hermsen, L Kuiper, B Swanenburg, C Winkler
Comptel Observations Of Cygnus X‐1, Mark L. Mcconnell, A Connors, D J. Forrest, James M. Ryan, W Collmar, R Diehl, V Schonfelder, H Steinle, A W. Strong, H Bloemen, R Van Dijk, W Hermsen, L Kuiper, B Swanenburg, C Winkler
Space Science Center
We report on the latest results from an analysis of data on Cygnus X‐1 as collected by the COMPTEL experiment on the Compton Gamma‐Ray Observatory (CGRO). COMPTEL detected the source around 1 MeV during two separate one‐week observations in 1991. The measured flux levels indicate variability on a time scale of weeks. The results also indicate flux levels which are well below the levels reported by some investigators for an excess of emission in the energy range ≥1 MeV.
An Overview Of First Results From Comptel, V. Schonfelder, H Aarts, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, C Winkler
An Overview Of First Results From Comptel, V. Schonfelder, H Aarts, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, C Winkler
Space Science Center
COMPTEL is the first imaging telescope to explore the MeV gamma-ray range (0.7 to 30 MeV). At present, it is performing a complete sky survey. Targets of special interest in the COMPTEL energy range are radio pulsars, X-ray binaries, novae, supernovae, supernova remnants, mulecular clouds, the interstellar medium within the Milky Way, active galactic nuclei, and the diffuse cosmic background radiation. The data from the first half year of the mission have demonstrated that COMPTEL performs as expected. The Crab is clearly seen at its proper position in the first images of the anticenter region of the galaxy. The Crab …
Comptel Detections Of The Quasars 3c 273 And 3c 279, W Hermsen, H Aarts, K Bennett, H Bloemen, H Deboer, W Collmar, A Connors, R Diehl, R Vandijk, J W. Den Herder, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, James M. Ryan, V. Schonfelder, G. Simpson, H Steinle, A W. Strong, B Swanenburg, C De Vries, W Webber, O R. Williams, C Winkler
Comptel Detections Of The Quasars 3c 273 And 3c 279, W Hermsen, H Aarts, K Bennett, H Bloemen, H Deboer, W Collmar, A Connors, R Diehl, R Vandijk, J W. Den Herder, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, James M. Ryan, V. Schonfelder, G. Simpson, H Steinle, A W. Strong, B Swanenburg, C De Vries, W Webber, O R. Williams, C Winkler
Physics & Astronomy
The COMPTEL experiment aboard the Compton Gamma Ray Observatory, sensitive in the energy range from about 0.7 to 30 MeV, observed the high-latitude region containing 3C 273 and 3C 279 during a 2-week period in June, 1991. A search for sources using a maximum likelihood analysis revealed two statistically significant point-like excesses, the positions of which are consistent with those of 3C 273 and 3C 279. These sources are the first QSOs detected at MeV energies. In the COMPTEL energy domain their spectra appear to be greatly different. A comparison with earlier and simultaneous measurements in neighboring energy ranges indicates …
Comptel Observations Of The Crab And Vela Pulsars, K Bennett, H Aarts, H Bloemen, R Buccheri, M Busetta, W Collmar, A Connors, A Carramiñana, R Diehl, H Deboer, J W. Den Herder, W Hermsen, L Kuiper, J Lockwood, G G. Lichti, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, C Winkler
Comptel Observations Of The Crab And Vela Pulsars, K Bennett, H Aarts, H Bloemen, R Buccheri, M Busetta, W Collmar, A Connors, A Carramiñana, R Diehl, H Deboer, J W. Den Herder, W Hermsen, L Kuiper, J Lockwood, G G. Lichti, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, W Webber, C Winkler
Physics & Astronomy
The COMPTEL gamma-ray telescope, sensitive in the range 0.7-30 MeV, has viewed the Crab and Vela Pulsars. The light curves observed from both objects have been derived in several energy bands. Features of these light curves and some spectral details are discussed.
First Results From Comptel Measurement Of The Al-26 1.8 Mev Gamma-Ray Line From The Galactic Center Region, R Diehl, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, A Connors, J W. Den Herder, C. Devries, W Hermsen, J Knodlseder, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, M Varendorff, P. Von Ballmoos, W Webber, C Winkler
First Results From Comptel Measurement Of The Al-26 1.8 Mev Gamma-Ray Line From The Galactic Center Region, R Diehl, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, A Connors, J W. Den Herder, C. Devries, W Hermsen, J Knodlseder, L Kuiper, G G. Lichti, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, M Varendorff, P. Von Ballmoos, W Webber, C Winkler
Physics & Astronomy
The COMPTEL instrument on GRO is designed to image celestial gamma radiation in the approximately 0.7-30 MeV region of nuclear lines. Within a large field of view of about 1 sr its angular resolution of about 1 deg enables mapping of extended emission and location of (strong) point sources to an accuracy of better than 0.5 deg. The Galactic center region was observed by COMPTEL for a 2-week period in July 1991. Here we report the detection of the line at 1.8 MeV attributed to Al-26, addressing in particular the extent of the emission and the 1.8 MeV line flux.
The Crab And Galactic Anticentre Region Observed By Comptel, A W. Strong, K Bennett, H Bloemen, H Deboer, R Buccheri, M Busetta, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, L Kuiper, J Lockwood, G G. Lichti, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, B Swanenburg, M Varendorff, C Winkler, C De Vries
The Crab And Galactic Anticentre Region Observed By Comptel, A W. Strong, K Bennett, H Bloemen, H Deboer, R Buccheri, M Busetta, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, L Kuiper, J Lockwood, G G. Lichti, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, B Swanenburg, M Varendorff, C Winkler, C De Vries
Physics & Astronomy
The Galactic anticenter region including the Crab nebula has been observed with the COMPTEL gamma-ray telescope on the Gamma Ray Observatory. A map of the region in the 1-30 MeV energy range is presented. The total spectrum of the Crab is derived as well as that of the pulsed and unpulsed components. Upper limits on the pulsar Geminga are also presented.
Comptel Observations Of The 1.809 Mev Gamma-Ray Line From Galactic 26al, R Diehl, C. Dupraz, K Bennett, H Bloemen, H Deboer, W Hermsen, G G. Lichti, Mark L. Mcconnell, D Morris, James M. Ryan, V. Schonfelder, H Steinle, A W. Strong, B Swanenburg, M Varendorff, C Winkler
Comptel Observations Of The 1.809 Mev Gamma-Ray Line From Galactic 26al, R Diehl, C. Dupraz, K Bennett, H Bloemen, H Deboer, W Hermsen, G G. Lichti, Mark L. Mcconnell, D Morris, James M. Ryan, V. Schonfelder, H Steinle, A W. Strong, B Swanenburg, M Varendorff, C Winkler
Physics & Astronomy
No abstract provided.
Preliminary Results From Comptel On A Search For Gamma-Ray Line Emission From Sn 1991t, G G. Lichti, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, A Connors, R Diehl, R Van Dijk, J W. Den Herder, W Hermsen, L Kuiper, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, M Varendorff, C De Vries, C Winkler
Preliminary Results From Comptel On A Search For Gamma-Ray Line Emission From Sn 1991t, G G. Lichti, K Bennett, H Bloemen, H Deboer, M Busetta, W Collmar, A Connors, R Diehl, R Van Dijk, J W. Den Herder, W Hermsen, L Kuiper, J Lockwood, John R. Macri, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V. Schonfelder, G. Simpson, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, M Varendorff, C De Vries, C Winkler
Physics & Astronomy
The COMPTEL experiment aboard the Compton Gamma-Ray Observatory is designed to image celestial gamma-radiation in the energy range from 0.7-30 MeV. With a field of view of 1 sr it is capable of locating strong point sources with an accuracy of better than 0.5 deg. From June 15 to 28, 1991 and a second time from October 3 to 17, 1991 the region containing the supernova SN 1991T was observed by COMPTEL. Here preliminary results from these observations are presented, with special attention to a search for gamma-ray line emission from the supernova.
The Gamma-Ray Burst Of 3 May 1991 Observed By Comptel On Board Gro, C Winkler, K Bennett, H Bloemen, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, G G. Lichti, J Lockwood, Mark L. Mcconnell, D Morris, James M. Ryan, V. Schonfelder, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries
The Gamma-Ray Burst Of 3 May 1991 Observed By Comptel On Board Gro, C Winkler, K Bennett, H Bloemen, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, G G. Lichti, J Lockwood, Mark L. Mcconnell, D Morris, James M. Ryan, V. Schonfelder, J G. Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries
Physics & Astronomy
The Compton Gamma-Ray Observatory was launched on April 5, 1991, carrying the imaging Compton telescope COMPTEL. Since its activation on April 25, 1991, COMPTEL has observed several gamma-ray bursts in its 1-sr field of view. The strongest of these bursts was observed on May 3, 1991. Event data over 0.8 MeV to 30 MeV as well as time resolved spectra over 0.1 MeV to 10 MeV have been recorded. For the first time, a direct single-telescope MeV image of a cosmic gamma-ray burst has been produced. The burst is located at (l,b) = (171.8 deg, 6.4 deg) with a statistical …
Gamma-Ray Emission From Cygnus-X-1 - Emission Mechanisms And Implications For The Standard Model, A Owens, Mark L. Mcconnell
Gamma-Ray Emission From Cygnus-X-1 - Emission Mechanisms And Implications For The Standard Model, A Owens, Mark L. Mcconnell
Physics & Astronomy
No abstract provided.
Comptel Images Locations Of Gamma‐Ray Bursts, M Varendorff, K Bennett, H Deboer, M Busetta, H Bloemen, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, G G. Lichti, J Lockwood, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V Schonfelder, G Stacy, H Steinle, A W. Strong, B Swanenburg, C De Vries, C Winkler
Comptel Images Locations Of Gamma‐Ray Bursts, M Varendorff, K Bennett, H Deboer, M Busetta, H Bloemen, W Collmar, A Connors, R Diehl, J W. Den Herder, W Hermsen, R M. Kippen, L Kuiper, G G. Lichti, J Lockwood, Mark L. Mcconnell, D Morris, R Much, James M. Ryan, V Schonfelder, G Stacy, H Steinle, A W. Strong, B Swanenburg, C De Vries, C Winkler
Space Science Center
The γ‐ray telescope COMPTEL onboard GRO has so far located 6 gamma‐ray bursts which occurred in its ∼1 sr field of view. The positions of the sources were derived by the maximum‐entropy method. Systematic and statistical uncertainties for the four strongest bursts are approximately 1° to 2° and can be reduced in future analysis.
Comptel Observations Of Cosmic Gamma‐Ray Bursts, C Winkler, K Bennett, H Bloemen, H Deboer, W Collmar, A Connors, R Diehl, L O. Hanlon, J W. Den Herder, W Hermsen, L Kuiper, R M. Kippen, G G. Lichti, J Lockwood, Mark L. Mcconnell, D Morris, James M. Ryan, V Schonfelder, G Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, O R. Williams, M Busetta
Comptel Observations Of Cosmic Gamma‐Ray Bursts, C Winkler, K Bennett, H Bloemen, H Deboer, W Collmar, A Connors, R Diehl, L O. Hanlon, J W. Den Herder, W Hermsen, L Kuiper, R M. Kippen, G G. Lichti, J Lockwood, Mark L. Mcconnell, D Morris, James M. Ryan, V Schonfelder, G Stacy, H Steinle, A W. Strong, B Swanenburg, B G. Taylor, M Varendorff, C De Vries, O R. Williams, M Busetta
Space Science Center
The imaging γ‐ray telescope COMPTEL on board NASA’s Compton Gamma‐Ray Observatory (GRO) has observed many cosmic gamma‐ray bursts during the early mission phase of GRO. COMPTEL records time‐resolved burst spectra over 0.1 MeV to 10 MeV energies, and, for the first time, produces direct single‐telescope gamma‐ray images (0.8–30 MeV) of cosmic gamma‐ray bursts occurring in its 1 sr field of field.
Gamma-Ray Observations Of Cygnus X-1 And Cygnus X-3 Using A Coded-Aperture Telescope, Mark L. Mcconnell, D J. Forrest, A Owens, P. P. Dunphy, W T. Vestrand, E. L. Chupp
Gamma-Ray Observations Of Cygnus X-1 And Cygnus X-3 Using A Coded-Aperture Telescope, Mark L. Mcconnell, D J. Forrest, A Owens, P. P. Dunphy, W T. Vestrand, E. L. Chupp
Physics & Astronomy
A balloon-borne coded-aperture telescope, measuring gamma-ray photons in the 160 keV to 9.3 MeV range, was used to observe the Cygnus region of the sky on October 1 and 2, 1984. In the 2-9.3-MeV band, evidence is found for a hard spectral component with a mean flux level at the top of the atmosphere of 7.4 + or - 2.5 x 10 to the -7th photons/sq cm per s per keV, inconsistent with the predictions of the inverse Compton models normally used to describe the X-ray emission. Both Cyg X-1 and Cyg X-3 could be observed simultaneously with the telescope. …
Gamma-Ray Observations Of The Crab Region Using A Coded-Aperture Telescope, Mark L. Mcconnell, P. P. Dunphy, D J. Forrest, E. L. Chupp, A Owens
Gamma-Ray Observations Of The Crab Region Using A Coded-Aperture Telescope, Mark L. Mcconnell, P. P. Dunphy, D J. Forrest, E. L. Chupp, A Owens
Physics & Astronomy
The region of the Galactic anticenter, including the Crab Nebula, was observed during a balloon flight of the University of New Hampshire Directional Gamma-Ray Telescope employing the coded-aperture imaging technique to image celestial gamma-radiation between 160 keV and 9.3 MeV. The background systematics are treated with a simple and relatively straightforward correction procedure. The results demonstrate that the coded-aperture procedure is a viable approach for imaging not only point sources of radiation, but also extended sources of emission. The results for the Crab's photon spectrum are consistent with a power-law spectrum. Upper limits on the flux levels of line emission …