scholarly journals A Wind-disk Self-irradiation Model for Supercritical Accretion

2019 ◽  
Vol 884 (1) ◽  
pp. L3
Author(s):  
Yuhan Yao ◽  
Hua Feng
Keyword(s):  
Supercritical Accretion

scholarly journals IUE Studies of Luminous X-Ray Binaries

1983 ◽  
Vol 6 ◽  
pp. 648-648
Author(s):  
J.B. Hutchings
Keyword(s):  
Magellanic Clouds ◽  
Thick Shell ◽  
High Luminosity ◽  
Uv Spectrum ◽  
X Ray ◽  
Unique Object ◽  
The Future ◽  
Orbit Inclination ◽  
Supercritical Accretion ◽  
X Ray Binaries

IUE has been used to study 11 high luminosity X-ray binaries, of which 3 are in the Magellanic Clouds. In the supergiant systems, X-ray ionisation bubbles have been found in most cases, leading to a greater understanding of the winds and accretion processes. Further studies of precessing objects such as LMC X-4 with IUE and ST are clearly of considerable interest, relating to X-ray heating and blanketing. Detailed studies of the Cyg X-l ionisation bubble may resolve the long standing puzzle of its orbit inclination and masses. UV continua have furnished valuable information on extinction, temperatures and luminosities, and the presence of non-stellar (i.e. disk) luminosity. Here too, more detailed studies are clearly indicated for the future. A unique object of interest is the LMC transient 0538-66 whose UV spectrum has quasarlike lines and luminosity which varies oppositely to the visible. This may be a case of supercritical accretion generating an optically thick shell (“disk”) about the pulsar.

A radio jet associated with the symbiotic star CH Cygni

1986 ◽  
Vol 64 (4) ◽  
pp. 520-522 ◽  
Author(s):  
E. R. Seaquist ◽  
A. R. Taylor
Keyword(s):  
Electron Density ◽  
White Dwarf ◽  
Transverse Velocity ◽  
Stellar Object ◽  
Symbiotic Star ◽  
Ionized Gas ◽  
Radio Outburst ◽  
Supercritical Accretion ◽  
End To End ◽  
Red Giant

We present observations that show that the symbiotic star CH Cygni recently underwent a strong radio outburst that produced a radio-emitting thermal jet. The jet is two-sided and is expanding lengthwise at an observed rate (end to end) of 1 arcsec/year, corresponding to a transverse velocity of 1100 km∙s−1 in each direction. The electron density on January 22, 1985 exceeded 2 × 106 cm−3, and the mass of the (ionized) gas exceeded [Formula: see text]. The emergence of the jet coincided with a decline in the visual luminosity of [Formula: see text].The data are consistent with a jet produced by supercritical accretion in a binary containing a red giant and a [Formula: see text] white dwarf. The discovery of a jet in such a system provides confirming evidence of the role played by accretion in determining the optical and radio properties of this system. It is also the first expanding jet found to be associated with an evolved stellar object.

scholarly journals TWO-DIMENSIONAL NUMERICAL SIMULATIONS OF SUPERCRITICAL ACCRETION FLOWS REVISITED

2013 ◽  
Vol 780 (1) ◽  
pp. 79 ◽  
Author(s):  
Xiao-Hong Yang ◽  
Feng Yuan ◽  
Ken Ohsuga ◽  
De-Fu Bu
Keyword(s):  
Numerical Simulations ◽  
Two Dimensional ◽  
Accretion Flows ◽  
Supercritical Accretion

scholarly journals Constraining Soft and Hard X-Ray Irradiation in Ultraluminous X-Ray Sources

2021 ◽  
Vol 922 (2) ◽  
pp. 91
Author(s):  
Yanli Qiu ◽  
Hua Feng
Keyword(s):  
Optical Emission ◽  
Current Data ◽  
Compact Objects ◽  
X Rays ◽  
Optical Counterpart ◽  
X Ray ◽  
Outer Disk ◽  
Stringent Constraint ◽  
Supercritical Accretion ◽  
Key Questions

Abstract Most ultraluminous X-ray sources (ULXs) are argued to be powered by supercritical accretion onto compact objects. One of the key questions regarding these objects is whether or not the hard X-rays are geometrically beamed toward the symmetric axis. We propose testing the scenario using disk irradiation to see how much the outer accretion disk sees the central hard X-rays. We collect a sample of 11 bright ULXs with an identification of a unique optical counterpart, and model their optical fluxes considering two irradiating sources: soft X-rays from the photosphere of the optically thick wind driven by supercritical accretion, and if needed in addition, hard X-rays from the Comptonization component. Our results indicate that the soft X-ray irradiation can account for the optical emission in the majority of ULXs, and the fraction of hard X-rays reprocessed on the outer disk is constrained to be no more than ∼10−2 in general. Such an upper limit is well consistent with the irradiation fraction expected in the case of no beaming. Therefore, no stringent constraint on the beaming effect can be placed according to the current data quality.

Supercritical accretion and ULXs

2011 ◽  
Vol 332 (4) ◽  
pp. 402-407 ◽  
Author(s):  
S. Mineshige ◽  
K. Ohsuga
Keyword(s):  
Supercritical Accretion

scholarly journals X-ray binaries with neutron stars at different accretion stages

2018 ◽  
Vol 14 (S346) ◽  
pp. 219-227
Author(s):  
Konstantin A. Postnov ◽  
Alexander G. Kuranov ◽  
Lev R. Yungelson
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
Orbital Period ◽  
Population Synthesis ◽  
Circular Orbits ◽  
X Ray ◽  
Accretion Rates ◽  
Supercritical Accretion ◽  
Binary Evolution ◽  
X Ray Binaries

Abstract. Different accretion regimes onto magnetized NSs in HMXBs are considered: wind-fed supersonic (Bondi) regime at high accretion rates <math/> g s-1, subsonic settling regime at lower <math/> and supercritical disc accretion during Roche lobe overflow. In wind-fed stage, NSs in HMXBs reach equilibrium spin periods P* proportional to binary orbital period Pb. At supercritical accretion stage, the system may appear as a pulsating ULX. Population synthesis of Galactic HMXBs using standard assumptions on the binary evolution and NS formation is presented. Comparison of the model P* – Pb (the Corbet diagram), P* – Lx and Pb – Lx distributions with those for the observed HMXBs (including Be X-ray binaries) and pulsating ULXs suggests the importance of the reduction of P* in non-circular orbits, explaining the location of Be X-ray binaries in the model Corbet diagram, and the universal parameters of pulsating ULXs depending only on the NS magnetic fields.

scholarly journals Face-on SS 433 Stars as a Possible New Type of Extragalactic X-Ray Sources

2001 ◽  
Vol 205 ◽  
pp. 268-269 ◽  
Author(s):  
S. Fabrika ◽  
A. Mescheryakov
Keyword(s):  
X Rays ◽  
Relativistic Jets ◽  
Expected Frequency ◽  
X Ray ◽  
Ss 433 ◽  
Sky Survey ◽  
Supercritical Accretion ◽  
The Face ◽  
New Type ◽  
Positive Correlations

The object SS433 is a well-known source of relativistic jets, which are formed in supercritical accretion disk. It is very probable that the disk has polar channels and their radiation is collimated (the photo-cones). A face-on SS433 object can appear as ultra-bright and highly variable X-ray source, Lx ˜ 1040 − 1042 erg/s. We discuss the properties of these hypothetical objects and their frequency expected in galaxies. We describe a search for such objects using the ROSAT All Sky Survey and RC3 catalog of galaxies. Among the total 418 positive correlations we find that 142 sources in S and Irr galaxies are unknown as AGNs. Nuclear sources among them still contain many AGNs. Non-nuclear (offset) sources are rather hard, their X-ray luminosities are 1039 − 1041 erg/s. Their observed frequency is about 4–5% per galaxy, that is in agreement with expected frequency of the face-on SS 433 stars. The only way to recognize such stars is their expected violent variability in X rays.

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