Related papers: The Ionized Stellar Wind in Vela X-1 During Eclips…
We present results from quantitative modeling and spectral analysis of the high mass X-ray binary Vela X-1 obtained with the Chandra HETGS. The spectra exhibit emission lines from H-like and He-like ions driven by photoionization, as well…
We present a quantitative analysis of the X-ray spectrum of the eclipsing high mass X-ray binary Vela X-1 (4U 0900-40) using archival data from ASCA. The observation covers a time interval centered on eclipse of the X-ray pulsar by the…
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…
The Supergiant X-ray binary Vela X-1 represents one of the best astrophysical sources to investigate the wind environment of a O/B star irradiated by an accreting neutron star. Previous studies and hydrodynamic simulations of the system…
Vela X-1 is the prototype of the class of wind-fed accreting pulsars in high mass X-ray binaries hosting a supergiant donor. We have analyzed in a systematic way ten years of INTEGRAL data of Vela X-1 (22-50 keV) and we found that when…
We investigate the spectral and temporal behavior of the high mass X-ray binary Vela X-1 during a phase of high activity, with special focus on the observed giant flares and off states. INTEGRAL observed Vela X-1 in a long almost…
The stellar wind around the compact object in luminous wind-accreting high mass X-ray binaries is expected to be strongly ionized with the X-rays coming from the compact object. The stellar wind of hot stars is mostly driven by light…
High resolution spectral studies were undertaken at orbital phases 0, 0.25 and 0.5 on the high-mass X-ray binary (HMXB) Vela X-1 using archival Chandra data. We present (a) the first detailed analysis of the multiple strong narrow emission…
The Vela region has been observed for 1.7 Ms in November 2005 by the INTEGRAL satellite. We present preliminary spectral and temporal results of Vela X-1, an eclipsing neutron star hosted in a wind-accreting high-mass X-ray binary system.…
Vela X-1 is one of the most archetypal wind-fed X-ray pulsars (XRPs), and the emergence of its orthogonal polarization states reveals distinctive polarimetric properties. Using data from Imaging X-ray Polarimetry Explorer (IXPE)…
Vela X-1 is the archetypical eclipsing high-mass X-ray binary, composed of a neutron star (NS) accreting the B-star wind. It was observed by nearly all X-ray observatories, often multiple times, featuring a rich spectrum of variable…
We present a detailed study of the high mass X-ray binary Vela X-1, using observations performed by Insight-HXMT in 2019 and 2020, concentrating on timing analysis and spectral studies including pulse phase-resolved spectroscopy. The…
Vela X-1 is among the best studied and most luminous accreting X-ray pulsars. The supergiant optical companion produces a strong radiatively-driven stellar wind, which is accreted onto the neutron star producing highly variable X-ray…
The wind-accreting X-ray binary pulsar and cyclotron line source Vela X-1 has been observed extensively during INTEGRAL Core Program observations of the Vela region in June-July and November-December 2003. In the latter set of observations…
We present an in-depth analysis of the spectral and temporal behavior of a long almost uninterrupted INTEGRAL observation of Vela X-1 in Nov/Dec 2003. In addition to an already high activity level, Vela X-1 exhibited several very intense…
We investigate the structure of the wind in the neutron star X-ray binary system Vela X-1 by analyzing its flaring behavior. Vela X-1 shows constant flaring, with some flares reaching fluxes of more than 3.0 Crab between 20-60 keV for…
Vela X-1 is the archetype of high-mass X-ray binaries, composed of a neutron star and a massive B supergiant. The supergiant is a source of a strong radiatively-driven stellar wind. The neutron star sweeps up this wind, and creates a huge…
Context. Vela X-1 is among the earliest discovered high-mass X-ray binary (HMXB) pulsars. In such systems, the companion's stellar wind is strongly affected by ionisation from X-rays emitted by the compact object. A smooth, isotropic…
The radiation from accreting X-ray pulsars was expected to be highly polarized, with some estimates for the polarization degree of up to 80%. However, phase-resolved and energy-resolved polarimetry of X-ray pulsars is required in order to…
We report on a Chandra line spectrum observation of the O supergiant, Zeta Orionis (O9.7 Ib). A 73.4 ks HETGS observation shows a wide range of ionization stages and line strengths over the wavelength range of 5 to 26 A. The observed…