0000000000347480
AUTHOR
B. Agrinier
Search for Pulsed Gamma Ray Emission above 50 MeV from NP 0532
OBSERVATIONS of the pulsar NP 0532 in the gamma ray region have yielded evidence of pulsed gamma ray emission for energies up to 10 MeV (refs. 1, 2 and Kurfess, to be published). Above this energy, upper limits between 10 MeV and 150 MeV (refs. 3, 4) and above 50 MeV (ref. 5) are indicated. A result above 70 MeV with phase error of 3 ms with respect to optical signal has been given by a counter experiment6.
Possible pulsed gamma ray emission above 50 MeV from the Crab pulsar.
A SEARCH for pulsed gamma ray emission from NP 0532 has been carried out with a balloon-borne experiment using a spark chamber as the central detector. This pulsar, situated in the Crab Nebula, is already known to pulsate in the radio, optical and X-ray range1–5.
The FIGARO II experiment: a general outline of the mission and the principal scientific results
The FIGARO II (French Italian Gamma-Ray Observatory) experiment has been launched successfully three times: in July 1986 from Milo (Trapani), in November 1988 from Charleville (Australia) and in July 1990 again from Milo. In the first flight the observational program was limited to the Crab pulsar PSR0531+21 only because of a telemetry failure: the high sensitivity of FIGARO II allowed an accurate study of the pulse shape as well as a phase-resolved spectroscopy. It was also possible to evaluate the dispersion measure of the Crab pulsar at the flight date from the time delay between gamma-ray and radio pulses. The major results of the second flight were a stringent upper limit to the low-en…