Low energy gamma ray observations of celestial objects
Low energy gamma ray observations of celestial objects
The MISO telescope is a double Compton gamma ray detector operating in the 0.1 - 20.0 MeV energy range, with an area of 560 cm2 and a field of view of 3.20 x 3.20 F.W.H.M. This telescope was flown on stratospheric balloons from Palestine, Texas (U.S.A.) in May 1977, October 1978 and September 1979. Results from MISO observations of the soft gamma ray emission from the Seyfert galaxies NGC 4151 (1977, 1979) and MCG 8-11-11 (1979), the BL Lac object MrK 501 (1979) and the COS B high energy (EY > 100 MeV) gamma ray sources CG 135+1 (1978) and CG 195+4 (1978) are presented. Both the data on NGC 4151 and MCG 8-11-11 were found to be consistent with power laws having photon spectral indices a ro 1 in the 0.1 MeV 2 EY 2 3.0 MeV energy range. Above this energy, the MISO and SAS 2 measurements required spectral breaks to a S 3. The data on CG 135+1 in the 0.1 MeV 2 EY t 1.0 MeV energy range were found to be compatible with a power law having a photon spectral index a ti 1, that was followed by a steepening at EY S I MeV. Upper limits were obtained on the emission from MrK 501 and CG 195+4. The present instrumental techniques and the observations that have been carried out at low gamma ray energies are reviewed. The need for higher sensitivity and angular resolution telescopes is demonstrated, and an imaging low energy (0.2 - 10.0 MeV) gamma ray detector with an angular resolution of 20 arc minutes F.W.H.M. is described.
University of Southampton
1981
Hayles, Robert Ignatius
(1981)
Low energy gamma ray observations of celestial objects.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The MISO telescope is a double Compton gamma ray detector operating in the 0.1 - 20.0 MeV energy range, with an area of 560 cm2 and a field of view of 3.20 x 3.20 F.W.H.M. This telescope was flown on stratospheric balloons from Palestine, Texas (U.S.A.) in May 1977, October 1978 and September 1979. Results from MISO observations of the soft gamma ray emission from the Seyfert galaxies NGC 4151 (1977, 1979) and MCG 8-11-11 (1979), the BL Lac object MrK 501 (1979) and the COS B high energy (EY > 100 MeV) gamma ray sources CG 135+1 (1978) and CG 195+4 (1978) are presented. Both the data on NGC 4151 and MCG 8-11-11 were found to be consistent with power laws having photon spectral indices a ro 1 in the 0.1 MeV 2 EY 2 3.0 MeV energy range. Above this energy, the MISO and SAS 2 measurements required spectral breaks to a S 3. The data on CG 135+1 in the 0.1 MeV 2 EY t 1.0 MeV energy range were found to be compatible with a power law having a photon spectral index a ti 1, that was followed by a steepening at EY S I MeV. Upper limits were obtained on the emission from MrK 501 and CG 195+4. The present instrumental techniques and the observations that have been carried out at low gamma ray energies are reviewed. The need for higher sensitivity and angular resolution telescopes is demonstrated, and an imaging low energy (0.2 - 10.0 MeV) gamma ray detector with an angular resolution of 20 arc minutes F.W.H.M. is described.
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Published date: 1981
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Local EPrints ID: 459574
URI: http://eprints.soton.ac.uk/id/eprint/459574
PURE UUID: 5203d9c4-ea8c-44c6-acd4-d5edb1082cf3
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Date deposited: 04 Jul 2022 17:14
Last modified: 04 Jul 2022 17:14
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Author:
Robert Ignatius Hayles
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