Gamma Ray Sky Surveys

Symposium - International Astronomical Union ◽

10.1017/s0074180900128220 ◽

1998 ◽

Vol 179 ◽

pp. 69-77

Author(s):

N. Gehrels

Keyword(s):

Gamma Ray ◽

High Energy ◽

Energy Bands ◽

Sky Surveys ◽

X Ray ◽

High Energy Gamma ◽

Limited Energy ◽

Energy Gamma

Prior to the current Compton Gamma Ray Observatory (Compton) mission, no comprehensive all-sky gamma-ray surveys had been performed. There were, however, some surveys performed over limited energy bands and/or over portions of the sky. These include the HEAO-A4 hard X-ray survey and the COS-B and SAS-2 high-energy gamma-ray surveys. The early work forms a basis for understanding and appreciating the Compton results, and so is reviewed in Section 2.

Download Full-text

On the possible gamma-ray source in Cygnus

Symposium - International Astronomical Union ◽

10.1017/s0074180900101391 ◽

1967 ◽

Vol 31 ◽

pp. 469-471

Author(s):

J. G. Duthie ◽

M. P. Savedoff ◽

R. Cobb

Keyword(s):

Gamma Rays ◽

Gamma Ray ◽

Right Ascension

A source of gamma rays has been found at right ascension 20h15m, declination +35°, with an uncertainty of 6° in each coordinate. Its flux is (1·5 ± 0·8) x 10-4photons cm-2sec-1at 100 MeV. Possible identifications are reviewed, but no conclusion is reached. The mechanism producing the radiation is also uncertain.

Download Full-text

Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

International Astronomical Union Colloquium ◽

10.1017/s0252921100026208 ◽

1994 ◽

Vol 144 ◽

pp. 635-639

Author(s):

J. Baláž ◽

A. V. Dmitriev ◽

M. A. Kovalevskaya ◽

K. Kudela ◽

S. N. Kuznetsov ◽

...

Keyword(s):

Solar Flare ◽

Energy Range ◽

Gamma Rays ◽

Pulse Shape ◽

Gamma Ray ◽

Pulse Shape Discrimination ◽

Shape Discrimination ◽

Solar Neutron ◽

Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

Download Full-text

Seti Figure of Merit

International Astronomical Union Colloquium ◽

10.1017/s0252921100015293 ◽

1997 ◽

Vol 161 ◽

pp. 711-717 ◽

Cited By ~ 1

Author(s):

John W. Dreher ◽

D. Kent Cullers

Keyword(s):

Figure Of Merit ◽

Qualitative Difference ◽

Current Generation ◽

Detection Range ◽

Sky Surveys ◽

Independent Observations ◽

Good For

AbstractWe develop a figure of merit for SETI observations which is anexplicitfunction of the EIRP of the transmitters, which allows us to treat sky surveys and targeted searches on the same footing. For each EIRP, we calculate the product of terms measuring the number of stars within detection range, the range of frequencies searched, and the number of independent observations for each star. For a given set of SETI observations, the result is a graph of merit versus transmitter EIRP. We apply this technique to several completed and ongoing SETI programs. The results provide a quantitative confirmation of the expected qualitative difference between sky surveys and targeted searches: the Project Phoenix targeted search is good for finding transmitters in the 109to 1014W range, while the sky surveys do their best at higher powers. Current generation optical SETI is not yet competitive with microwave SETI.

Download Full-text