Hard X-ray observations of the LMC field with SIGMA telescope on board "Granat". Upper limits on the flux from SN 1987A.
Abstract
In the course of a hard X-ray (35 - 1300 keV) survey of the Large Magellanic Cloud region by the SIGMA telescope aboard "Granat" none of the sources from Einstein LMC survey (Long, K. et al., 1981) was detected, excluding, perhaps, CAL 87. The sensitivity (3 σ) achieved in the survey corresponds to 6·1037ergs/s in the 40 - 150 keV band (assuming 55 kpc distance). Thus a hard source in the LMC a few times more luminous than the well known galactic black hole candidate Cyg X-1 should be reliably detected by SIGMA. On this basis upper limits on the flux from the stellar remnant SN 1987A, supposed to be a powerful source of hard X-rays, are given. The amount of radioactive nuclides produced during the supernova explosion was restricted to be less than 2.4·10-3Msun of 22Na and less than 2.3·10-2Msun of 44Ti. Upper limits obtained during separate periods indicate that no hard-tail transient (like galactic X-ray Nova GS2023-338 etc., supposed to have intrinsic luminosity ≡1038ergs/sec) was in the bright state in the LMC during the observations.
- Publication:
-
Astronomy Letters
- Pub Date:
- March 1993
- Bibcode:
- 1993AstL...19...69F
- Keywords:
-
- Magellanic Clouds;
- Radiant Flux Density;
- Supernova 1987a;
- X Ray Astronomy;
- Stellar Envelopes;
- Stellar Luminosity;
- Stellar Spectra;
- Astronomy;
- Magellanic Clouds: Hard X Rays;
- Magellanic Clouds: X-Ray Surveys;
- Supernovae: X-Ray Surveys;
- Supernovae: Hard X Rays;
- Supernova 1987A in LMC