منابع مشابه
Iron line afterglows : general constraints
The discovery of a powerful and transient iron line feature in the X–ray afterglow spectra of γ–ray bursts would be a major breakthrough for understanding the nature of their progenitors, strongly suggesting the presence of a large, iron rich, mass in the vicinity of the burst event. Model–independent limits to the size and the mass of the the iron line emitting region are derived and discussed...
متن کاملIron line afterglows: how to produce them
We discuss how a powerful iron line emission can be produced if ∼ 1− 5 iron rich solar masses are concentrated in the close vicinity of the burst. Recombination, thermal and fluorescent reflection are discussed. We find that recombination suffers the high Compton temperature of the plasma while the other two scenarios are not mutually exclusive and could account for the claimed iron line detect...
متن کاملIron line emission in X–ray afterglows
Recent observations of X–ray afterglows reveal the presence of a redshifted Kα iron line in emission in four bursts. In GRB 991216, the line was detected by the low energy grating of Chandra, which showed the line to be broad, with a full width of ∼15,000 km s. These observations indicate the presence of a > 1 M⊙ of iron rich material in the close vicinity of the burst, most likely a supernova ...
متن کاملIron line signatures in X-ray afterglows of GRB by BeppoSAX
We report the possible detection (99.3% of statistical significance) of redshifted Fe iron line emission in the X-ray afterglow of Gamma-ray burst GRB970508 observed by BeppoSAX. Its energy is consistent with the redshift of the putative host galaxy determined from optical spectroscopy. In contrast to the fairly clean environment expected in the merging of two neutron stars, the observed line p...
متن کاملOrphan GRB radio afterglows: Candidates and constraints on beaming
The number of orphan radio afterglows associated with γ-ray bursts (GRBs) that should be detected by a flux limited radio survey, is calculated. It is shown that for jetted GRBs this number is smaller for smaller jet opening angle θ, contrary to naive expectation. For a beaming factor f b ≡ (θ/2) ≃ 500, roughly the value inferred by Frail et al. (2001) from analysis of afterglow light curves, w...
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ژورنال
عنوان ژورنال: Astronomy and Astrophysics Supplement Series
سال: 1999
ISSN: 0365-0138,1286-4846
DOI: 10.1051/aas:1999346