5,644 research outputs found
Optical counterparts of cosmological GRBs due to heating of ISM in the parent galaxy
We investigated influence of cosmological GRB on the surrounding interstellar
medium. It was shown that \gamma-radiation from the burst heats interstellar
gas to the temperatures > 10^4 K up to the distance \sim 10 pc. For high
density ISM optical and UV radiation of the heated gas can be observed on the
Eath several years as a GRB`s counterpartComment: 2 pages, 1 figure; presented at the Rome Conference on Gamma Ray
Bursts in the Afterglow Ag
Time delay between the optical and X-ray outbursts in the high mass X-ray transient A0535+26/HDE245770
The optical behaviour of the Be star in the high mass X-ray transient
A0535+26/HDE245770 shows that at the periastron typically there is an
enhancement in the luminosity of order 0.02 to few tenths mag, and the X-ray
outburst happens about 8 days after the periastron. We construct a quantitative
model of this event, basing on the a nonstationary accretion disk behavior,
connected with a high ellipticity of the orbital motion. The ephemeris used in
this paper -- JD = JD(2,444,944) n(111.0 0.4)
days are derived from the orbital period of the system P days, determined by Priedhorsky & Terrell (1983), and from the optical
flare of December 5, 1981 (Giovannelli et al., 1985) (here after 811205-E; E
stands for the Event occurred at that date) that triggered the subsequent X-ray
outburst of December 13, 1981 (Nagase et al., 1982) (here after 811213-E). We
explain the observed time delay between the peaks of the optical and X-ray
outbursts in this system by the time of radial motion of the matter in the
accretion disk, after an increase of the mass flux in the vicinity of a
periastral point in the binary. This time is determined by the turbulent
viscosity, with the parameter . The increase of the mass flux
is a sort of flush that reaches the external part of the accretion disk around
the neutron star, producing an enhancement in the optical luminosity. The
consequent X-ray flare happens when the matter reaches the hot central parts of
the accretion disk, and the neutron star surface.Comment: 30 pages, 15 figures, with correction in abstrac
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