A tomographic study of V691 CrA (X1822−371)

Peris, Charith; Vrtilek, S. D.

doi:10.1111/j.1365-2966.2012.22039.x

Cited by 3 publications

(6 citation statements)

References 28 publications

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“…The presence of matter in the outer region of the disc or in a region surrounding the entire system was also proposed by Harlaftis et al (1997) and Cowley et al (2003), observing that the Hα line is formed in a region not strongly eclipsed and that the Hα velocity variation is very small. These results were confirmed recently by Peris & Dil Vrtilek (2012).…”

Section: Presence Of Neutral Matter Around the Binary Systemsupporting

confidence: 81%

X-ray spectroscopy of the ADC source X1822-371 withChandraandXMM-Newton

Iaria

Salvo

D’Aí

et al. 2012

A&A

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Context. The eclipsing low-mass X-ray binary X1822-371 is the prototype of the accretion disc corona (ADC) sources. Its inclination angle ( 82.5 • ) is high enough that flux from the neutron star is blocked by the edge-on accretion disc. Because the neutron star's direct emission is hidden, its ADC emission is visible. The physical properties of the ADC in X1822-371 have been widely studied, but are still debated in literature. In light of the recent literature and of the results reported in this work we show that the ADC is optically thin. Aims. We analyse two Chandra observations and one XMM-Newton observation to study the discrete features in this source and their variation as a function of the orbital phase, deriving constraints on the temperature, density, and location of the plasma responsible for emission lines. Methods. The HETGS and XMM/Epic-pn observed X1822-371 for 140 and 50 ks, respectively. We extracted an averaged spectrum and five spectra from five selected orbital-phase intervals that are 0.04-0.25, 0.25-0.50, 0.50-0.75, 0.75-0.95, and, finally, 0.95-1.04; the orbital phase zero corresponds to the eclipse time. All spectra cover the energy band between 0.35 and 12 keV. Results. We confirm the presence of local neutral matter that partially covers the X-ray emitting region; the equivalent hydrogen column is 5 × 10 22 cm −2 and the covered fraction is about 60-65%. We identify several emission lines of He-like and H-like ions, and a prominent fluorescence iron line associated with a blending of Fe i-Fe xv resonant transitions. The transitions of He-like ions show that the intercombination dominates over the forbidden and resonance lines. The line fluxes are the highest during the orbital phases between 0.04 and 0.75. Conclusions. We discuss the presence of an extended, optically thin corona with optical depth of about 0.01 that scatters the X-ray photons from the innermost region into the line of sight. The photoionised plasma producing the O viii, Ne ix, Ne x, Mg xi, Mg xii, Si xiii, and Si xiv lines is placed in the bulge at the outer radius of the disc distant from the central source of 6 × 10 10 cm. The O vii and the fluorescence iron line are probably produced in the photoionised surface of the disc at inner radii. Finally, we suggest that the observed local neutral matter is the matter transferred by the companion star that was expelled from the system by the X-ray radiation pressure, which in turn originated in the accretion process onto the neutron star.

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Section: Presence Of Neutral Matter Around the Binary Systemsupporting

confidence: 81%

X-ray spectroscopy of the ADC source X1822-371 withChandraandXMM-Newton

Iaria

Salvo

D’Aí

et al. 2012

A&A

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“…Tomograms of systems both similar to V801 Ara (e.g. X1822-371 Harlaftis et al (1997); Peris & Vrtilek (2012)), and other systems in quiescence containing both neutron stars (e.g. Cen X-4, D'Avanzo et al ( 2005)) and black holes (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…A0620, Neilsen, Steeghs, & Vrtilek (2008)) are also consistent with an asymmetric disk. Peris & Vrtilek (2012) suggested that the combination of a disk offset from the predicted position of the neutron star and the asymmetric structure could be the indication of an eccentric disk. An eccentric disk implies disk precession.…”

Section: Discussionmentioning

confidence: 99%

Phase-resolved spectroscopy of the low-mass X-ray binary V801 Ara

Brauer

Vrtilek

Peris

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present phase-resolved optical spectra of the low mass X-ray binary system V801 Ara. The spectra, obtained in 2014 with IMACS on the Magellan/Baade telescope at Las Campanas Observatory, cover the full binary orbit of 3.8 hours. They contain strong emission features allowing us to map the emission of Hα, Hβ, He II λ4686, and the Bowen blend at λ4640. The radial velocity curves of the Bowen blend shows significantly stronger modulation at the orbital period than Hα as expected for the former originating on the secondary with the latter consistent with emission dominated by the disk. Our tomograms of Hα and Hβ are the most detailed studies of these lines for V801 to date and they clearly detect the accretion disk. The Hβ emission extends to higher velocities than Hα, suggesting emission from closer to the neutron star and differentiating temperature variance in the accretion disk for the first time. The center of the accretion disk appears offset from the center-of-mass of the neutron star as has been seen in several other X-ray binaries. This is often interpreted to imply disk eccentricity. Our tomograms do not show strong evidence for a hot spot at the point where the accretion stream hits the disk. This could imply a reduced accretion rate or could be due to the spot being drowned out by bright accretion flow around it. There is enhanced emission further along the disk, however, which implies gas stream interaction downstream of the hot spot.

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“…We detect a similar bright spot, but find that it is offset from the secondary at ∆V ∼ 200 km s −1 larger Vy owing to the updated dynamical model. H α emission, identified as originating from the secondary, has been observed in other black hole and neutron star systems (e.g., Marsh et al 1994;Shahbaz et al 1999;Torres et al 2002;González Hernández & Casares 2010;Peris & Vrtilek 2012), some compatible with the Roche lobe of the secondary and some slightly offset. Although it has been commonly attributed to chromospheric activity or X-ray heating of the secondary, an unequivocal interpretation has not yet been established.…”

Section: Detection Of the Secondary Starmentioning

confidence: 99%

“…This interaction typically occurs in a small region also known as the "hotspot" and is observed in these systems both as a peak in the orbital light curve at phase ∼ 0.8 − 0.9 (where phase 0.0 is defined as the superior conjunction of the compact object) and as a bright spot at the same phase in tomograms (e.g., Krzeminski 1965;Wood et al 1986, Neilsen, Steeghs & Vrtilek 2008, Calvelo et al 2009Peris & Vrtilek 2012). Lubow & Shu (1976) were the first to suggest that some of the gaseous matter falling from the donor star onto the disc via the stream does not stop at the hotspot but flows over and under the disc.…”

Section: Introductionmentioning

confidence: 99%

Tomography of X-ray Nova Muscae 1991: evidence for ongoing mass transfer and stream–disc overflow★

Peris

Vrtilek

Steiner

et al. 2015

Monthly Notices of the Royal Astronomical Society

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We present a spectroscopic analysis of the black hole binary Nova Muscae 1991 in quiescence using data obtained in 2009 with MagE on the Magellan Clay telescope and in 2010 with IMACS on the Magellan Baade telescope at the Las Campanas Observatory. Emission from the disc is observed in H α, H β and Ca II (λ8662). A prominent hotspot is observed in the Doppler maps of all three emission lines. The existence of this spot establishes ongoing mass transfer from the donor star in 2009-2010 and, given its absence in the 1993-1995 observations, demonstrates the presence of a variable hotspot in the system. We find the radial distance to the hotspot from the black hole to be consistent with the circularization radius. Our tomograms are suggestive of stream-disc overflow in the system. We also detect possible Ca II (λ8662) absorption from the donor star.

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A tomographic study of V691 CrA (X1822−371)

Cited by 3 publications

References 28 publications

X-ray spectroscopy of the ADC source X1822-371 withChandraandXMM-Newton

X-ray spectroscopy of the ADC source X1822-371 withChandraandXMM-Newton

Phase-resolved spectroscopy of the low-mass X-ray binary V801 Ara

Tomography of X-ray Nova Muscae 1991: evidence for ongoing mass transfer and stream–disc overflow★

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