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Bhat, P. N.

Publications and source records attributed to Bhat, P. N..

38 records · Page 3

Observations on TeV gamma rays from Geminga and PSR 0950+08

The Geminga (2 CG 195+04) which exhibits a periodicity with a period of 59 to 60 s in its emission of X-rays, GeV gamma rays and TeV gamma rays was studied. During the winter of 1984 to 1985, this object was observed to see if it emits TeV gamma rays with a periodicity approx 60 s. The observations were carried out at two different sites separated by 11 Km with the Ooty Atmospheric Cerenkov Array split into two parts. Data were collected during clear moonless nights for a total duration of 15.3 hours spread over 2 months. Since the first time derivative of period is believed to be large and uncertain. The total data are subdivided into segments of duration not more than 3 days each to steer clear of the effects of P in the phase analysis. If TeV gamma ray signals are seen in each of these segments, it is possible to derive P from observed data.

Bhat, P. N.↗

Search for TeV gamma rays from extragalactic sources and the Galactic Center

The Ooty atmospheric Cerenkov array was used in 1982-83 to see if the galactic center and the extra-galactic sources 3C 273, Centaurus A emit gamma rays at TeV energies. The ON/OFF method was used wherein the source was tracked for 16 minutes and immediately afterwards, a background region in the same zenith angle range was tracked for the next 16 minutes. Data were taken for approx 15 hours (55 scans) on 3C273, approx 7 hours (26 scans) on Cen A and 5 hours (19 scans) on galactic center. A preliminary analysis involving direct comparison of total rates on and off the source shows no significant excess from any of these orbits. Results of detailed analysis using different energy thresholds are presented.

Bhat, P. N.↗