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We have developed a spectrum synthesis method for modeling the UV emission from the accretion disk from cataclysmic variables (CVs). The disk is separated into concentric rings, with an internal structure from the Wade & Hubeny…

Solar and Stellar Astrophysics · Physics 2015-05-28 Raul E. Puebla , Marcos P. Diaz , D. John Hillier , Ivan Hubeny

Outbursting AM CVn stars exhibit outbursts similar to those observed in different types of dwarf novae. Their light-curves combine the characteristic features of SU UMa, ER UMa, Z Cam, and WZ Sge-type systems but also show a variety of…

Solar and Stellar Astrophysics · Physics 2012-08-20 Iwona Kotko , Jean-Pierre Lasota , Guillaume Dubus , Jean-Marie Hameury

We have carried out a synthetic spectral analysis of archival IUE spectra of the old nova V841 Oph (Nova Oph 1848) taken 15 years apart. The spectra reveal a rising continuum shortward of 1560\AA, a C {\sc iv} P-Cygni profile indicative of…

Astrophysics · Physics 2009-11-11 Scott G. Engle , Edward M. Sion

We present HST/STIS (1160--1700A) echelle spectra of the cataclysmic variable (CV) star, QU Car, observed in time-tag mode at three epochs. In catalogues this binary is classified as a nova-like variable. We find evidence of a high-state…

Astrophysics · Physics 2009-11-07 L. E. Hartley , J. E. Drew , K. S. Long

EX Draconis is an eclipsing dwarf nova that shows outbursts with moderate amplitude ($\simeq 2$ mag) and a recurrence timescale of $\simeq 20$-30 d. Dwarf novae outbursts are explained in terms of either a thermal-viscous instability in the…

Solar and Stellar Astrophysics · Physics 2024-11-05 Wagner Schlindwein , Raymundo Baptista

The Outburst Catalogue contains a wide variety of observational properties for 722 dwarf nova-type (DN) cataclysmic variables (CVs) and 309 CVs of other types from the Catalina Real-time Transient Survey. In particular, it includes the…

Highly-ionized fast accretion-disk winds have been suggested as an explanation for a variety of observed absorption and emission features in the X-ray spectra of Active Galactic Nuclei. Simple estimates have suggested that these flows may…

High Energy Astrophysical Phenomena · Physics 2015-05-18 S. A. Sim , L. Miller , K. S. Long , T. J. Turner , J. N. Reeves

A significant number of tidal disruption events (TDEs) radiate primarily at optical and ultraviolet (UV) wavelengths, with only weak soft X-ray components. One model for this optical excess proposes that thermal X-ray emission from a…

High Energy Astrophysical Phenomena · Physics 2022-01-19 Edward J. Parkinson , Christian Knigge , James H. Matthews , Knox S. Long , Nick Higginbottom , Stuart A. Sim , Samuel W. Mangham

Here we compute detailed model spectra of recently published optically thick one-dimensional radial baundary layer (BL) models in cataclysmic variables and compare them with observed soft X-ray/extreme ultraviolet (EUV) spectra of dwarf…

Solar and Stellar Astrophysics · Physics 2014-11-11 V. Suleimanov , M. Hertfelder , K. Werner , W. Kley

Recent X-ray observations of blue-shifted absorption lines revealed an existence of the extremely fast disk winds with outflow velocities of ~0.1-0.3c. Such fast outflows would have a large impact on the coevolution of black holes and host…

High Energy Astrophysical Phenomena · Physics 2017-02-08 Kouichi Hagino , Hirokazu Odaka , Chris Done , Shin Watanabe , Tadayuki Takahashi

As a class of compact binaries with large binding energy, cataclysmic variables formed through close encounters play an important role in the dynamical evolution of globular clusters. As part of a systematic search for CVs undergoing dwarf…

High Energy Astrophysical Phenomena · Physics 2015-05-28 A. P. Hourihane , P. J. Callanan , A. M. Cool , M. T. Reynolds

The disk instability model attributes the outbursts of dwarf novae to a thermal-viscous instability of their accretion disk, an instability to which nova-like stars are not subject. We aim to test the fundamental prediction of the disk…

High Energy Astrophysical Phenomena · Physics 2018-09-19 Guillaume Dubus , Magdalena Otulakowska-Hypka , Jean-Pierre Lasota

We present a model for one cycle of a classical nova outburst based on a self-consistent wind mass loss accelerated by the gradient of radiation pressure, i.e., the so-called optically thick winds. Evolution models are calculated by a…

Solar and Stellar Astrophysics · Physics 2022-07-27 Mariko Kato , Hideyuki Saio , Izumi Hachisu

The disc instability model accounts well for most of the observed properties of dwarf novae and soft X-ray transients, but the rebrightenings, reflares, and echoes occurring at the end of outbursts or shortly after in WZ Sge stars or soft…

Solar and Stellar Astrophysics · Physics 2021-06-16 J. -M. Hameury , J. -P. Lasota

Outbursts from cataclysmic variables, such as dwarf novae (DNe), are prevalent throughout the galaxy and are known to emit strongly in the ultraviolet (UV). However, the UV emission of DNe has not been studied extensively compared with the…

High Energy Astrophysical Phenomena · Physics 2022-08-31 David Modiano , Rudy Wijnands , David A. H. Buckley , Mariusz Gromadzki , Sill Verberne , Marieke van Etten

Previous theoretical studies indicate that the inner disk in dwarf novae evaporates into a high-temperature, optically thin, and geometrically thick accretion flow during quiescence, with the inner edge moving toward the white dwarf at the…

High Energy Astrophysical Phenomena · Physics 2026-04-15 Mariko Kimura , Osaki Yoji

UltraFast Outflows (UFO) are observed in some active galactic nuclei (AGN), with blueshifted and highly ionised Fe-K absorption features. AGN typically have a UV bright accretion flow, so UV line driving is an obvious candidate for…

High Energy Astrophysical Phenomena · Physics 2020-11-25 Misaki Mizumoto , Mariko Nomura , Chris Done , Ken Ohsuga , Hirokazu Odaka

Radiation from accretion discs in cataclysmic variable stars (CVs) provides fundamental information about the properties of these close binary systems and about the physics of accretion in general. The detailed diagnostics of accretion disc…

Astrophysics · Physics 2015-03-13 Irit Idan , Jean-Pierre Lasota , Jean-Marie Hameury , Giora Shaviv

Some tidal disruption events (TDEs) exhibit blueshifted broad absorption lines (BALs) in their rest-frame ultraviolet (UV) spectra, while others display broad emission lines (BELs). Similar phenomenology is observed in quasars and accreting…

High Energy Astrophysical Phenomena · Physics 2020-04-20 Edward J. Parkinson , Christian Knigge , Knox S. Long , James H. Matthews , Nick Higginbottom , Stuart A. Sim , Henrietta A. Hewitt

We present ASCA observations of the dwarf nova Z Camelopardalis during outburst and during a transition from quiescence to another outburst. At the beginning of the transition the X-ray count rate was an order of magnitude higher and the…

Astrophysics · Physics 2009-11-07 D. S. Baskill , P. J. Wheatley , J. P. Osborne