ﻻ يوجد ملخص باللغة العربية
We present an analysis of the first observation of the iconic High Mass X-ray Binary so with the chandra High Energy Transmission Gratings during an X-ray eclipse. The goal of the observation was to study the structure/physical conditions in the clumpy stellar wind through high resolution spectroscopy. We find that: a) emission line brightness from K shell transitions, corresponding to near neutral species, directly correlates with continuum illumination. However, these lines do not greatly diminish during eclipse. This is readily explained if fluorescence K$alpha$ emission comes from the bulk of the wind. b) The highly ionised Fexxv and Fexxvi Ly$alpha$ diminish during eclipse. Thus, they must be produced in the vicinity of the compact object where $log xi >3$. c) to describe the emission line spectrum, the sum of two self consistent photo ionisation models with low ionisation ($log xisim -1$) and high ionisation ($log xisim 2.4$) is required. From their emission measures, the clump-to-interclump density ratio can be estimated to be $n_c/n_isim 300$. To fit the complex He-like ion{Si}{xiii}{} profile, the plasma requires a broadening with $v_{rm bulk}sim 840$ km s$^{-1}$. Reproducing the observed $rapprox f$ line fluxes requires the addition of a third collisionally ionised plasma. d) Emission lines widths appear unresolved at the textsc{hetg} gratings resolution with exception of Silicon. There is no clear radial segregation between (quasi)neutral and ionised species, consistent with cold wind clumps interspersed in a hot rarefied interclump medium.
We present results of a monitoring campaign of the high-mass X-ray binary system 4U 1700-37/HD 153919, carried out with XMM-Newton in February 2001. The system was observed at four orbital phase intervals, covering 37% of one 3.41-day orbit. The ligh
We present the results of a detailed non-LTE analysis of the UV and optical spectrum of the O6.5Iaf+ star HD153919 - the mass donor in the high-mass X-ray binary 4U1700-37. Given the eclipsing nature of the system these results allow us to determine
Based on its Hipparcos proper motion, we propose that the high-mass X-ray binary HD153919/4U1700-37 originates in the OB association Sco OB1. At a distance of 1.9 kpc the space velocity of 4U1700-37 with respect to Sco OB1 is 75 km/s. This runaway ve
We present a $sim$130 ks observation of the prototypical wind-accreting, high-mass X-ray binary Vela X-1 collected with XMM-Newton at orbital phases between 0.12 and 0.28. A strong flare took place during the observation that allows us to investigate
Since the launch of Chandra and XMM-Newton, high-resolution X-ray spectra of cosmic sources of all kinds have become available. These spectra have resulted in major scientific breakthroughs. However, due to the techniques used, in general high-qualit