Determining the Masses of White Dwarfs in Magnetic Cataclysmic Variables from X-Ray Observations

1997 ◽  
pp. 115-118
Author(s):  
Kinwah Wu ◽  
Mark Cropper ◽  
Gavin Ramsay
Keyword(s):  
White Dwarfs ◽  
Cataclysmic Variables ◽  
X Ray ◽  
Magnetic Cataclysmic Variables ◽  
The Masses

scholarly journals Determining the masses of white dwarfs in magnetic cataclysmic variables from x-ray observations

1997 ◽  
Vol 189 ◽  
pp. 115-118
Author(s):  
Kinwah Wu ◽  
Mark Cropper ◽  
Gavin Ramsay
Keyword(s):  
White Dwarfs ◽  
Cataclysmic Variables ◽  
Orbital Inclination ◽  
X Ray ◽  
Magnetic Cataclysmic Variables ◽  
The Masses

A method to determine the masses of white dwarfs in magnetic cataclysmic variables from X-ray observations is presented. The method is appropriate for both eclipsing and non-eclipsing systems, for it is insensitive to the orbital inclination of the systems.

scholarly journals Measuring the masses of magnetic white dwarfs: a NuSTAR legacy survey

2020 ◽  
Vol 498 (3) ◽  
pp. 3457-3469
Author(s):  
A W Shaw ◽  
C O Heinke ◽  
K Mukai ◽  
J A Tomsick ◽  
V Doroshenko ◽  
...  
Keyword(s):  
Angular Momentum ◽  
White Dwarf ◽  
White Dwarfs ◽  
Cataclysmic Variables ◽  
Weighted Average ◽  
Velocity Measurements ◽  
X Ray ◽  
Common Envelope ◽  
Magnetic Cataclysmic Variables ◽  
The Masses

ABSTRACT The hard X-ray spectrum of magnetic cataclysmic variables can be modelled to provide a measurement of white dwarf mass. This method is complementary to radial velocity measurements, which depend on the (typically rather uncertain) binary inclination. Here, we present results from a Legacy Survey of 19 magnetic cataclysmic variables with NuSTAR. We fit accretion column models to their 20–78 keV spectra and derive the white dwarf masses, finding a weighted average $\bar{M}_{\rm WD}=0.77\pm 0.02$ M⊙, with a standard deviation σ = 0.10 M⊙, when we include the masses derived from previous NuSTAR observations of seven additional magnetic cataclysmic variables. We find that the mass distribution of accreting magnetic white dwarfs is consistent with that of white dwarfs in non-magnetic cataclysmic variables. Both peak at a higher mass than the distributions of isolated white dwarfs and post-common-envelope binaries. We speculate as to why this might be the case, proposing that consequential angular momentum losses may play a role in accreting magnetic white dwarfs and/or that our knowledge of how the white dwarf mass changes over accretion–nova cycles may also be incomplete.

scholarly journals Mass Measurement of Accreting Magnetic White Dwarfs with Hard X-Ray Spectroscopy

1998 ◽  
Vol 188 ◽  
pp. 97-100
Author(s):  
M. Ishida ◽  
R. Fujimoto
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Mass Measurement ◽  
Cataclysmic Variables ◽  
Magnetic Pole ◽  
X Ray ◽  
Secondary Star ◽  
Magnetic Cataclysmic Variables ◽  
Image Position ◽  
The Magnetic Field

Accreting magnetic white dwarfs are usually found as component stars in Magnetic Cataclysmic Variables (MCVs), in which a white dwarf with B = 105-8 G accepts mass from a late type (secondary) star via Roche Lobe overflow. Matter from the secondary is funneled by the magnetic field and concentrates on the magnetic pole(s) of the white dwarf. Since the accretion flow becomes highly supersonic, a standing shock wave is formed close to the white dwarf. The temperature of the plasma at the shock front reflects the gravitational potential and can be denoted as a function of the mass (M) and the radius (R) of the white dwarf as: Note here that the height of the shock is expected to be within 10% of the white dwarf radius, and hence neglected here.

scholarly journals X-ray reflection from cold white dwarfs in magnetic cataclysmic variables

2017 ◽  
Vol 474 (2) ◽  
pp. 1810-1825 ◽  
Author(s):  
Takayuki Hayashi ◽  
Takao Kitaguchi ◽  
Manabu Ishida
Keyword(s):  
White Dwarfs ◽  
Cataclysmic Variables ◽  
X Ray ◽  
Magnetic Cataclysmic Variables

scholarly journals Statistics of white dwarf properties in intermediate polars

2019 ◽  
Vol 15 (S357) ◽  
pp. 202-205
Author(s):  
Valery F. Suleimanov ◽  
Victor A. Doroshenko ◽  
Klaus Werner
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Luminosity Function ◽  
Cataclysmic Variables ◽  
X Ray ◽  
Intermediate Polars ◽  
The Masses

AbstractMany intermediate polars are hard X-ray sources. The theory of their hard X-ray radiation is well developed and allows us to determine white dwarf masse in this kind of cataclysmic variables. Here we present the results of determination the masses of 35 white dwarfs in the intermediate polars observed by observatories NuSTAR (10 sources) and Swift/BAT (25 sources). The corresponding mass accrerion rates and the luminosity function were also derived due to accurate distance to the sources well known now after Gaia DR2.

scholarly journals Hard X-ray Observations of Magnetic Cataclysmic Variables

2004 ◽  
Vol 190 ◽  
pp. 135-141 ◽  
Author(s):  
K. P. Singh ◽  
V. R. Rana ◽  
K. Mukerjee ◽  
P. Barrett ◽  
E. M. Schlegel
Keyword(s):  
Cataclysmic Variables ◽  
Type Systems ◽  
Light Curves ◽  
Average Intensity ◽  
Spectral Parameters ◽  
X Ray ◽  
Orbital Modulation ◽  
Magnetic Cataclysmic Variables ◽  
The Masses ◽  
First Time

AbstractHard X-ray light curves and spectral parameters from our analysis of X-ray data of five AM Her type systems – V2301 Oph, V1432 Aql, EP Draconis, GG Leonis, & V834 Cen, and one intermediate polar – TV Col, observed using the Rossi X — ray Timing Explorer (RXTE) satellite are presented. A new improved ephemeris has been derived for V2301 Oph using the mid-eclipse timings. Average intensity variations, without any change of shape of the light curve or hardness ratio, are observed on timescales of a few days to a few months in V2301 Oph. V1432 Aql shows erratic variations on a timescale of a day, at least two sharp dips near orbital phases 0.35 and 0.5, and a total eclipse. Hard X-ray eclipses are also reported in EP Dra and GG Leo. V834 Cen shows intensity variations on yearly timescale and is found to be in a low state in 2002. In TV Col, a binary orbital modulation at 5.5h, in addition to the spin period of 1910s, is reported for the first time. Maximum spectral temperatures in Polars have been determined and used to estimate the masses of the white dwarfs.

scholarly journals Simulating AXAF Grating Spectra of Accreting White Dwarfs

1998 ◽  
Vol 15 (3) ◽  
pp. 339-347 ◽  
Author(s):  
Allyn F. Tennant ◽  
Kinwah Wu ◽  
Stephen L. O'Dell ◽  
Martin C. Weisskopf
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Accretion Rate ◽  
Cataclysmic Variables ◽  
High Energy ◽  
High Spectral Resolution ◽  
X Ray ◽  
Transmission Grating ◽  
Magnetic Cataclysmic Variables ◽  
Very High

AbstractWe present simulated AXAF spectra of accreting white dwarfs, using parameters appropriate for magnetic cataclysmic variables. The very high spectral resolution that can be obtained with the High-Energy Transmission Grating of AXAF can resolve the keV X-ray emission lines that characterise the temperature, density and velocity profiles of the shock-heated emission regions of these systems. These simulations demonstrate that actual spectra will allow us to place constraints on the white-dwarf mass and the accretion rate of the systems. The high-resolution spectra also allow the measurement of the velocity of the accretion flow in regions close to the white-dwarf surface.

scholarly journals Extreme Ultraviolet Spectroscopy of Magnetic Cataclysmic Variables

1996 ◽  
Vol 152 ◽  
pp. 309-316
Author(s):  
Frits Paerels ◽  
Min Young Hur ◽  
Christopher W. Mauche
Keyword(s):  
High Resolution ◽  
White Dwarf ◽  
Extreme Ultraviolet ◽  
Cataclysmic Variables ◽  
Ultraviolet Spectroscopy ◽  
Temperature Structure ◽  
Polar Cap ◽  
Ultraviolet Emission ◽  
X Ray ◽  
Magnetic Cataclysmic Variables

A longstanding problem in the interpretation of the X-ray and extreme ultraviolet emission from strongly magnetic cataclysmic variables can be addressed definitively with high resolution EUV spectroscopy. A detailed photospheric spectrum of the accretion-heated polar cap of the white dwarf is sensitive in principle to the temperature structure of the atmosphere. This may allow us to determine where and how the bulk of the accretion energy is thermalized. The EUVE data on AM Herculis and EF Eridani are presented and discussed in this context.

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