منابع مشابه
X-ray Lines From Gamma-ray Bursts
X-ray lines have been recently detected in the afterglows of a few gamma-ray bursts. We derive constraints on the physical conditions in the line-emitting gas, using as an example the multiple Kα lines detected by Reeves et al. (2002) in GRB 011211. We argue that models previously discussed in the literature require either a very extreme geometry or too much mass in the line-emitting region. We...
متن کاملSatellite absorption lines and the temperature dependence of x-ray absorption features in high-temperature plasmas.
In absorption spectroscopy, absorption features impressed on the spectrum of a continuum background source are interpreted in terms of conditions in an absorbing foreground medium. If the opacity per ion for a particular transition beginning from some initial state is known, then the areal density (i.e., the path integral of the density along the path of the continuum propagation) of ions in th...
متن کاملPhotospheres, Comptonization and X-ray Lines in Gamma Ray Bursts
Steep X-ray spectral slopes, X-ray excesses and preferred spectral energy breaks in the 01-0.3 MeV range are discussed as the possible consequences of the photospheric component of the GRB relativistic outflow, and of pair breakdown in internal shocks leading to comptonization on semirelativistic electrons or MHD waves. We also discuss the X-ray and UV spectra of GRB afterglows occuring in a de...
متن کاملX-ray lines, progenitor and beaming of Gamma-Ray Bursts
X-ray emission features have been detected in at least five GRB afterglows. Their detection and properties are of great importance in our understanding of the nature of the GRB progenitor. Moreover, they provide us with an uncollimated source of photons, allowing us to put firm constraints on the total energy produced in GRBs, and therefore on their degree of collimation. I will review the radi...
متن کاملBroad P Cygni X - ray Lines from Circinus X -
Chandra High Energy Transmission Grating Spectrometer (HETGS) observations of the extremely luminous and violent X-ray binary Cir X-1 reveal many X-ray emission lines showing broad P Cygni profiles. These are from H-like and He-like ions of Ne, Mg, Si, S, Ar, and Fe. The lines originate in a high-velocity (up to 2000 km s) outflow, which may be an accretion disk wind. Cir X-1 has a radio jet, a...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1984
ISSN: 0252-9211
DOI: 10.1017/s0252921100085249