Related papers: Modeling X-ray Bursting Neutron Star Atmospheres
The spectral properties of X--ray radiation produced in a static atmosphere around a neutron star accreting at very low rates are investigated. Previous results by Alme \& Wilson (1973) are extended to the range $10^{-7}\leq L/L_{Edd}\leq…
Magnetar outbursts are among the most noteworthy manifestations of magnetism in neutron stars. They are episodes in which the X-ray luminosity of a strongly magnetised neutron star swiftly rises by several orders of magnitude to then decay…
Soft X-ray emission from neutron stars affords powerful diagnostic tools for uncovering their surface and interior properties, as well as their geometric configurations. In the atmospheres of neutron stars, the presence of magnetic fields…
We investigate the effects of dynamical Comptonization on the emergent radiation spectrum produced by near critical accretion onto a neutron star. The flow dynamics and the transfer of radiation are self--consistently solved in the case of…
We present a model for the gamma-ray emission of pulsars in terms of curvature radiation by highly relativistic particles. It is shown that the injection of power-law primary particles from an outer gap and subsequent cooling by curvature…
Powerful Type I X-ray burst with strong radial expansion was observed from the low mass X-ray binary 4U 1820-30 with Rossi X-ray Timing Explorer on May 2, 1997. We investigate closely the flux profile during the burst expansion stage.…
In this paper, we discuss the influence of the gravitational darkening effect on the emergent spectrum of a fast-rotating, flattened neutron star. Model atmosphere codes always calculate spectra of emergent intensities and fluxes emitted…
Interstellar extinction includes both absorption and scattering of photons from interstellar gas and dust grains, and it has the effect of altering a source's spectrum and its total observed intensity. However, while multiple absorption…
We develop a simple, time-dependent Comptonization model to probe the origins of spectral variability in accreting neutron star systems. In the model, soft ``seed photons'' are injected into a corona of hot electrons, where they are Compton…
A number of Anomalous X-ray Pulsars (AXPs) have recently been detected in the optical/IR wavelengths. We use their inferred brightness to place general constraints on any model for this emission within the magnetar framework. We find that…
We model the thermal states of both isolated neutron stars and accreting neutron stars in X-ray transients in quiescence and confront them with observations. We use an equation of state and superfluid baryon gaps, which are consistently…
We describe our recent progress in modeling supernova-fallback disks and neutron star (NS) atmospheres. We present a first detailed spectrum synthesis calculation of a SN-fallback disk composed of iron. We assume a thin disk with a radial…
Superbursts are very energetic Type I X-ray bursts discovered in recent years by long term monitoring of X-ray bursters, and believed to be due to unstable ignition of carbon in the deep ocean of the neutron star. In this Letter, we follow…
A decade of X-ray stellar observations with Chandra and XMM-Newton has led to significant advances in our understanding of the physical processes at work in hot (magnetized) plasmas in stars and their immediate environment, providing new…
We describe in detail the implementation of a simplified approach to radiative transfer in general relativity by means of the well-known neutrino leakage scheme (NLS). In particular, we carry out an extensive investigation of the properties…
Using a Hartree-Fock formalism, we estimate energy levels and photon cross sections for atomic iron in magnetic fields B ~ 10^13 G. Computing ionization equilibrium and normal mode opacities with these data, we construct LTE neutron star…
We continue to investigate two-dimensional laterally propagating flames in type I X-ray bursts using fully compressible hydrodynamics simulations. In the current study we relax previous approximations where we artificially boosted the…
Millisecond period brightness oscillations during the intensity rise of thermonuclear X-ray bursts are likely caused by an azimuthally asymmetric, expanding burning region on the stellar surface. The time evolution of the oscillation…
The hot component of the circum-galactic medium (CGM) around star forming galaxies is detected as diffuse X-ray emission. The X-ray spectra from the CGM depend on the temperature and metallicity of the emitting plasma, providing important…
We describe sophisticated new Bayesian analysis methods that make it possible to estimate quickly the masses and radii of rapidly rotating, oblate neutron stars by fitting oblate-star waveform models to energy-resolved observations of the…