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abridged: We use XSCORT, together with the hydrodynamic accretion disc wind simulation from Proga & Kallman (2004), to calculate the impact that the accretion disk wind has on the X-ray spectrum from a 1E8 solar mass black hole Active…

Astrophysics · Physics 2011-02-11 N. J. Schurch , C. Done , D. Proga

We study AGN line driven disc winds using time-dependent radiation hydrodynamics. The key criterion for determining wind launching is the coupling strength of the UV radiation field via the spectral lines of the gas. The strength of these…

High Energy Astrophysical Phenomena · Physics 2023-10-31 Sergei Dyda , Shane W. Davis , Daniel Proga

We present the ultraviolet spectrum of the SW Sex star and nova-like variable DW UMa in an optical low state, as observed with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope (HST). The data are well described…

Astrophysics · Physics 2009-10-31 C. Knigge , K. S. Long , D. W. Hoard , P. Szkody , V. S. Dhillon

We present a comprehensive analysis of the post-outburst evolution of the FU Ori object HBC 722 in optical/near-infrared (NIR) photometry and spectroscopy. Using a modified viscous accretion disk model, we fit the outburst epoch SED to…

Solar and Stellar Astrophysics · Physics 2024-05-31 Adolfo S. Carvalho , Lynne A. Hillenbrand , Jerome Seebeck , Kevin Covey

We have carried out radiation-hydrodynamic simulations of thermally-driven accretion disc winds in low-mass X-ray binaries. Our main goal is to study the luminosity dependence of these outflows and compare with observations. The simulations…

High Energy Astrophysical Phenomena · Physics 2019-02-13 Nick Higginbottom , Christian Knigge , Knox S. Long , James H. Matthews , Edward J. Parkinson

Theoretical models of accretion discs and observational data indicate that the X-ray emission from the inner parts of an accretion disc can irradiate its outer regions and induce a thermal wind, which carries away the mass and angular…

High Energy Astrophysical Phenomena · Physics 2023-11-01 A. L. Avakyan , G. V. Lipunova , K. L. Malanchev

In recent years hydrodynamical (HD) models have become important to describe the gas kinematics in protoplanetary disks, especially in combination with models of photoevaporation and/or magnetic-driven winds. We focus on diagnosing the the…

Earth and Planetary Astrophysics · Physics 2021-01-04 Lizxandra Flores-Rivera , Mario Flock , Ryohei Nakatani

We present new models for illuminated accretion disks, their structure and reprocessed emission. We consider the effects of incident X-rays on the surface of an accretion disk by solving simultaneously the equations of radiative transfer,…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Javier Garcia , Timothy Kallman

To address the discrepancy where disk sizes exceed those predicted by standard models, we explore two extensions to disk size estimates within the UV/optical wavelength range: disk winds and color correction. We provide detailed,…

Astrophysics of Galaxies · Physics 2024-11-15 James Hung-Hsu Chan , Joshua Fagin , Henry Best , Matthew J. O'Dowd

We consider the stability of an accretion disk wind to cloud formation when subject to a central radiation force. For a vertical launch velocity profile that is Keplerian or flatter and the presence of a significant radiation pressure, the…

Astrophysics · Physics 2007-05-23 A. Y. Poludnenko , E. G. Blackman , A. Frank

We show that the distribution of observed accretion rates is a powerful diagnostic of protoplanetary disc physics. Accretion due to turbulent ("viscous") transport of angular momentum results in a fundamentally different distribution of…

Solar and Stellar Astrophysics · Physics 2023-07-12 R. Alexander , G. Rosotti , P. J. Armitage , G. J. Herczeg , C. F. Manara , B. Tabone

Mass-loss rates currently in use for hot, massive stars have recently been seriously questioned, mainly because of the effects of wind clumping. We investigate the impact of clumping on diagnostic ultraviolet resonance and optical…

Solar and Stellar Astrophysics · Physics 2015-05-27 J. O. Sundqvist , J. Puls , A. Feldmeier , S. P. Owocki

In the first paper of this series, using analytic tools, we examined how the evolution and structure of a massive accretion disk may be influenced by the deposition of mass and angular momentum by an infalling Bondi-Hoyle wind. Such a mass…

Astrophysics · Physics 2009-10-31 Robert F. Coker , Fulvio Melia , Heino Falcke

FU Ori is the prototype of FU Orionis systems which are outbursting protoplanetary disks. Magnetic fields in FU Ori's accretion disks have previously been detected using spectropolarimetry observations for Zeeman effects. We carry out…

Earth and Planetary Astrophysics · Physics 2020-04-15 Zhaohuan Zhu , Yan-Fei Jiang , James M. Stone

A $\widetilde{\chi}^2$ analysis of standard model accretion disk synthetic spectrum fits to combined $FUSE$ and STIS spectra of V3885 Sagittarius, on an absolute flux basis, selects a model that accurately represents the observed SED.…

Solar and Stellar Astrophysics · Physics 2015-05-13 Albert P. Linnell , Patrick Godon , Ivan Hubeny , Edward M. Sion , Paula Szkody , Paul E. Barrett

The standard equilibrium for radiation-dominated accretion disks has long been known to be viscously, thermally, and convectively unstable, but the nonlinear development of these instabilities---hence the actual state of such disks---has…

Astrophysics · Physics 2009-11-06 Eric Agol , Julian Krolik , Neal Turner , James Stone

Circumbinary (CB) disks have been proposed as a mechanism to extract orbital angular momentum from cataclysmic variables (CVs) during their evolution. As proposed by Taam & Spruit, these disks extend outwards to several a.u. and should be…

Astrophysics · Physics 2009-11-10 K. E. Belle , N. Sanghi , S. B. Howell , J. B. Holberg , P. T. Williams

We present the capabilities of our new code for obtaining Doppler maps implementing the maximum likelihood approach. As test data, we used observations of the dwarf nova V2051 Ophiuchi. The system was observed in quiescence at least 16 d…

Solar and Stellar Astrophysics · Physics 2016-10-04 Artur Rutkowski , Waclaw Waniak , George W. Preston , Wojciech Pych

The high state of black hole candidates is characterized by a quasi- thermal emission component at $kT \sim 1$ keV. In addition, this state tends to have very low variability which indicates that it is relatively stable, at least on {\it…

Astrophysics · Physics 2015-06-24 Michael A. Nowak , Robert V. Wagoner

The magnetic cataclysmic variables (MCVs) present a wealth of observational diagnostics for studying accretion flows interacting with a magnetosphere. Spin-period pulsations from the rotation of the white dwarf are seen in optical light, in…

Solar and Stellar Astrophysics · Physics 2015-06-18 Coel Hellier