ﻻ يوجد ملخص باللغة العربية
Results are reported for analysis of the extensive Rosat observation of the dipping low mass X-ray binary XB 1916-053. Dipping is 100% deep showing that the emission regions are completely covered by the absorber. A good fit to the non-dip spectrum is obtained using a model consisting of a blackbody with kT_BB = 1.95 +0.74 -0.34 keV and a power law with photon index 2.32 +/- 0.04. These components are identified with emission from the neutron star, and Comptonized emission from an extended accretion disk corona (ADC). Dip spectra are well-fitted by rapid absorption of the blackbody, and progressive covering of the extended component, as the absorber moves across the source, with a covering fraction that increases smoothly from zero to ~1.0. Progressive covering shows that the Comptonized emission region is extended, consistent with it originating in the accretion disk corona. The strong unabsorbed component in the dip spectra is well-modelled as the uncovered part of the Comptonized emission at all stages of dipping. There is no detectable change in the low energy cut-off of the spectrum in dipping which supports the identification of the unabsorbed part of the spectrum with the uncovered part of the ADC emission. The absorbed part of the ADC emission is rapidly removed from the 0.1 - 2.0 keV band of the PSPC, which therefore selects only the uncovered part of the emission, and so the spectral evolution in dipping as viewed by the PSPC depends only on the covering fraction, determined by the geometric overlap between the source and absorber.
Context: XB 1916-053 is a low mass X-ray binary system (LMXB) hosting a neutron star (NS) and showing periodic dips. The spectrum of the persistent emission was modeled with a blackbody component having a temperature between 1.31 and 1.67 keV and wit
We report on the long term monitoring of X-ray dips from the ultracompact low-mass X-ray binary (LMXB) XB 1916-053. Roughly one-month interval observations were carried out with the Rossi X-ray Timing Explorer (RXTE) during 1996, during which the sou
We report the discovery of narrow Fe XXV and Fe XXVI K alpha X-ray absorption lines at 6.65 and 6.95 keV in the persistent emission of the dipping low-mass X-ray binary (LMXB) XB 1916-053 during an XMM-Newton observation performed in September 2002.
The dipping source XB 1916-053 is a compact binary system with an orbital period of 50 min harboring a neutron star. Using ten new {it Chandra} observations and one {it Swift/XRT} observation, we are able to extend the baseline of the orbital ephemer
The very small accretion disks in ultra-compact X-ray binaries (UCXBs) are special laboratories in which to study disk accretion and outflows. We report on three sets of new (250 ks total) and archival (50 ks) Chandra/HETG observations of the dipping