Observing the onset of the accretion wake in Vela X-1

Abstract

High-Mass X-ray Binaries (HMXBs) offer a unique opportunity for the investigation of accretion onto compact objects and of wind structure in massive stars. A key source for such studies is the bright neutron star HMXB Vela X-1 whose convenient physical and orbital parameters facilitate the analysis and in particular enable studies of the wind structure in HMXBs. Here, we analyse simultaneous XMM-Newton and NuSTAR observations at ${\varphi }_{\mathrm{orb}}\approx$ 0.36-0.52 and perform time-resolved spectral analysis down to the pulse period of the neutron star, based on our previous NuSTAR-only results. For the first time, we are able to trace the onset of the wakes in a broad 0.5-78 keV range with a high-time resolution of $\sim$283 s and compare to theoretical predictions. We observe a clear rise of the absorption column density of the stellar wind $N_{\mathrm{H},1}$ starting at orbital phase $\sim$0.44, corresponding to the wake structure entering our line of sight towards the neutron star, together with local extrema throughout the observation possibly associated with clumps or other structures in the wind. Periods of high absorption reveal the presence of multiple fluorescent emission lines of highly ionised species, mainly in the soft X-ray band between 0.5 and 4 keV, indicating photoionisation of the wind.

18 pages, 18 figures

References in corpus (19)

• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• The ephemeris, orbital decay, and masses of 10 eclipsing HMXBs
• X-ray Spectral Study of the Photoionized Stellar Wind in Vela~X-1
• Towards a unified view of inhomogeneous stellar winds in isolated supergiant stars and supergiant high mass X-ray binaries
• High variability in Vela X-1: giant flares and off states
• The clumpy absorber in the high-mass X-ray binary Vela X-1
• Revisiting the archetypical wind accretor Vela X-1 in depth -- A case study of a well-known X-ray binary and the limits of our knowledge
• Origin of the X-ray off-states in Vela X-1
• Neutron star masses from hydrodynamical effects in obscured sgHMXBs
• Laboratory Measurements of the K-shell transition energies in L-shell ions of Si and S
• Chandra X-ray spectroscopy of the focused wind in the Cygnus X-1 system III. Dipping in the low/hard state
• Testing Rate Dependent corrections on timing mode EPIC-pn spectra of the accreting Neutron Star GX 13+1
• NuSTAR low energy effective area correction due to thermal blanket tear
• High-resolution X-ray spectroscopy of the stellar wind in Vela X-1 during a flare
• Continuum, cyclotron line, and absorption variability in the high-mass X-ray binary Vela X-1
• Looking through the photoionisation wake: Vela X-1 at ${\phi }_{\mathrm{orb}}\approx 0.75$ with Chandra/HETG
• Color-color diagrams as tools for assessment of the variable absorption in high mass X-ray binaries
• The X-ray spectral-timing contribution of the stellar wind in the hard state of Cyg X-1

Cited by in corpus (7)

• An in-depth analysis of the variable cyclotron lines in GX 301$-$2
• Disk reflection and energetics from the accreting millisecond pulsar SRGA J144459.2-604207
• Variable structures in the stellar wind of the HMXB Vela X-1
• First look at Vela X-1 with XRISM: A simultaneous campaign with XMM-Newton and NuSTAR
• SAS in ESA Datalabs: A New Platform for XMM-Newton Analysis
• Pulse profile variations in the accreting X-ray pulsar Vela X-1
• Resolving SLX 1744-299 and SLX 1744-300 in the hard X-ray band: implications for their ultracompact nature