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We consider the interpretation of a pair of kHz quasiperiodic oscillations (QPOs) in the Fourier spectra of two low-mass x-ray binaries, Sco X-1 and 4U1608-52, hosting an old accreting neutron star.
Observation of X-ray lines from a gamma-ray burst (GRB991216): evidence of moving ejecta from the progenitor.
Two emission features observed in the x-ray spectrum of the afterglow of the gamma-ray burst of 16 December 1999 by the Chandra X-ray Observatory are identified with the Ly(alpha) line and the narrow recombination continuum by hydrogenic ions of iron, providing an unambiguous measurement of the distance of a GRB.
Lense-Thirring Precession and Quasi-periodic Oscillations in Low-Mass X-Ray Binaries
Relativistic dragging of inertial frames around fast-rotating collapsed stars is substantial and can give rise to observable effects. We consider kHz quasi-periodic oscillation (QPO) sources,
The Acceleration of Ultra--High-Energy Cosmic Rays in Gamma-Ray Bursts
UHECRs are roughly isotropic and attain very large energies, $E \gtrsim 3\times 10~{20} \; eV$. Conventional models fail to explain both facts. I show here that acceleration of UHECRs in GRBs
Correlations in the Quasi-periodic Oscillation Frequencies of Low-Mass X-Ray Binaries and the Relativistic Precession Model
A remarkable correlation between the centroid frequencies of quasi-periodic oscillations (or peaked noise components) from low-mass X-ray binaries has been recently discovered by Psaltis, Belloni, &
Discovery of a transient absorption edge in the X-ray spectrum of GRB 990705.
The discovery of a transient equivalent hydrogen column density with an absorption edge at approximately 3.8 kiloelectron volts in the spectrum of the prompt x-ray emission of gamma-ray burst (GRB) 990705 points to the existence of a burst environment enriched by a supernova along the line of sight.
The X-Ray Afterglow of the Gamma-Ray Burst of 1997 May 8:Spectral Variability and Possible Evidence of an Iron Line
We report the possible detection (99.3% of statistical significance) of redshifted iron line emission in the X-ray afterglow of gamma-ray burst GRB 970508 observed by BeppoSAX. Its energy is
The Afterglow of Gamma-Ray Bursts: The Cases of GRB 970228 and GRB 970508
Highly radiative expansion of a relativistic shell is shown to explain all observed features of the afterglows of the two bursts GRB 970228 and GRB 970508. In particular, in the first case the
Are All Gamma-Ray Bursts Like GRB 980425, GRB 030329, and GRB 031203?
We study the probability that three GRBs (980425, 030329, 031203) are found within z = 0.17, given the luminosity functions consistent with the log N-log S relationship for classical cosmological