0000000000061371
AUTHOR
Enrico Massaro
A Very Large Area Telescope for γ-Ray Astronomy Above 100 MeV Employing Limited Streamer Tubes
A new detector for γ-ray astronomy above 100 MeV is described in which the electron-positron pairs are tracked by means of a set of plane arrays of Limited Streamer Tubes. This technique allows to build up very large area experiments which are specifically useful to study variable or transient sources.
Imaging Performance of FIGARO-IV, A Large Area γ-Ray Telescope Above 100 MeV.
We are developing a new telescope, named FIGARO-IV, for γ-ray astronomy above 100 MeV, in which the electron-positron pairs, produced by photons in lead converters, are tracked in several independent planes of Limited Streamer Tubes (LST). Because of its large sensitive area and good angular resolution, this telescope is well suitable, and competitive with respect to satellite-based detectors as EGRET, to localise discrete γ-ray sources in a relatively short observation time, to detect high-energy γ-ray bursts and to investigate both periodic and random time variability on -ray sources.
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…
On gamma-ray emission from CYG X-2
We discuss the importance of hard X- and gamma-ray emission from thermal X-ray sources to obtain a more realistic picture of these objects.
The complex behaviour of the microquasar GRS 1915+105 in theρclass observed withBeppoSAX
BeppoSAX observed GRS 1915+105 on October 2000 with a long pointing lasting about ten days. During this observation, the source was mainly in the rho class characterized by bursts with a recurrence time of between 40 and 100 s. We identify five segments in the burst structure and accumulate the average spectra of these segments during each satellite orbit. We present a detailed spectral analysis aimed at determining variations that occur during the burst and understanding the physical process that produces them. We compare MECS, HPGSPC, and PDS spectra with several models. Under the assumption that a single model is able to fit all spectra, we find that the combination of a multi-temperatur…
FIGARO IV: Large-area balloon-borne telescope to study rapid time variabilities in the gamma-ray sources at energies above 50 MeV
We present a new γ-ray telescope based on the Limited Streamer Tube technology, used as tracking chambers to detect photons above 100 MeV. This technique allows to obtain very large sensitive areas (16 m2 in our experiment), together with a good angular resolution for payloads embarcable in high-altitude balloon flights. The capability to collect a large signal in a short exposure time makes the telescope particularly suitable and competitive with respect to satellite-based detectors for studying both periodic and random time variabilities on galactic and extragalactic γ-ray sources.