High-Energy Astrophysics American and Soviet Perspectives/Proceedings from the U.S.-U.S.S.R. Workshop on High-Energy Astrophysics (1991) / Chapter Skim
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X-RAY RADIATION FROM SUPERNOVA 1987A. THE RESULTS OF THE KVANT MODULE IN 1987-89
X-RAY RADIATION FROM SUPERNOVA 1987A. THE RESULTS OF THE KVANT MODULE IN 1987-89
Pages 368-384
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From page 368... ...
INI8oDucrIoN The Roentgen international X-ray observatory on the Kvant module of the Mir space station has been operating successfully since the beginning of June 1987. Four telescopes mounted onboard the Kvant module cover a wide energy range: Coded Mask Imaging Spectrometer 1TM (2-30 keV)
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From page 369... ...
Note here especially the pO=t corresponding to observations on June 16, 1987, when the hard X-ray 6= in the 45-105 keV spectral channel was detected at four standard deviation levels (it was first noticed by Englhauser et al.
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From page 370... ...
. The errors correspond to one standard deviation, the upper limits - to three standard deviations (in the last graph the HEXE upper limits are shown by tnangles)
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From page 371... ...
Three sigma upper limit on the flux observed in May-June 1989 is presented. the traces of a shock wave generated due to collision between the expanding envelope of the supernova and a stellar wind emitted by the presupernova on a red giant stage of the evolution.
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From page 372... ...
The results of Monte-Carlo simulations carried out for the envelope model accepted in the present paper are shown by solid lines.
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From page 373... ...
The 56Co distribution (mass-fraction) consistent with the observed light curve is shown in Figure 4 by crosses (the vertical line of a cross corresponds to an error at one standard deviation level)
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From page 374... ...
And about 40% is mixed over all the envelope volume. Note that the data of only mro hard energy bands 45-200 keV were used dunog the cobalt distribution reconstruction.
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From page 375... ...
For the whole period from September 1988 to June 1989 the Roentgen observatory has not detected a statistically significant enhancement of X-ray luminosity in the 45-105 keV energy band over the model predictions in which the whole observed flux is connected with the 56Co decay. The upper limits at three standard deviation levels for the ratio of 57 Co/56 Co relative abundance in the supernova envelope to the Earth's 57Fe/s6Fe relative abundance were equal to Z4 in September 1988, 3.3 in December 1988, and 1.8 in June 1989 at the accepted assumptions.
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From page 376... ...
The data obtained in May-June 1989 also provides a possibility to set up an upper limit on a fraction of the 22Na and 44Ti radioactive photons in the X-ray 45-105 keV flux from SN1987A in 830 days after the explosion. The corresponding upper limits at three standard deviation levels on mass of 22Na and 44Ti contained in the envelope at the moment of explosion are 1.3 10-3M~ and 9 10-3M~.
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From page 377... ...
Comparing these values with the HEXE upper limits for 57Co, 22Na, and 44Ti abundances, M57 < 2.8 10-3M~ and M44 < 9 10-3M~, M22 < 1.3 10-3 Me, we come to the conclusion that the assumption about the radioactive nature of excess has failed in the case of 57Co and is unlikely ~ the case of 44Ti and 22Na. TTM/COMIS UPPER LIMITS ON THE FLUX FROM SN1987A The 11M/COMIS instrument on board the Kvant module is a coded mask-imaging spectrometer, sensitive in 2-30 keV energy, and with 7 .5 x 7°.5 FWHM field of view.
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From page 378... ...
obtained By 1=I instrument during the observations of November 1988 - June 1989. The labels mark signifi~tl~r detected LMC sources as well as the position of SN1987A.
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From page 379... ...
. The upper limit in the whole 2-27 keV energy band is equal to 0.6 mCrab for Crab-like spectrum.
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From page 380... ...
All the HEXE upper limits for the September 1988 to June 1989 time span are below the TIM 3~ upper limits for the 16-17 keV band for any power law extrapolation of detected HEXE nux towards lower energies with photon spectral index ~ > - 4.5. The change in shape of the SN1987A spectrum, according to the HEXE data, in September 1988 undoubtedly shows that any flux at energies lower than 40 keV has an origin unrelated to the radioactive decay of both 56Co and 57Co.
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From page 381... ...
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From page 382... ...
Note in conclusion that the supernova light curie in 45-105 keV energy band did not show a single sharp statistically confident burst similar to the burst observed by the Ginga satellite in January 1988 in the softer energy band. In hard X-rays the light curie was smooth as it was expected for the light curve of the source connected with radioactive decay.
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From page 383... ...
1990) coincides with the presented power law approximation within the limits of experimental data errors.
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From page 384... ...
1988. Soviet Astron.
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