<i>XMM-Newton</i>observations of the X-ray soft polar QS Telescopii

Traulsen, I.; Reinsch, K.; Schwope, A. D.; Burwitz, V.; Schwarz, R.; Walter, Frederick M.

doi:10.1051/0004-6361/201016352

Cited by 7 publications

(9 citation statements)

References 27 publications

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“…Up to now, we have studied three systems with a clear soft X-ray excess during (intermediate) high states of accretion in the ROSAT and in our pointed XMM-Newton observations: AI Tri (Traulsen et al 2010), QS Tel (Traulsen et al 2011), and RS Cae. Their soft X-ray luminosity correlates with their accretion state and can change drastically on time scales as short as days, in agreement with the dependence of the soft-to-hard luminosity ratio on the accretion state as described by .…”

Section: Discussionmentioning

confidence: 99%

“…Reflection features were detected, for example, by Beardmore et al (1995) for AM Her, by Done & Magdziarz (1998) for BY Cam, or by Bernardini et al (2012) for hard X-ray selected polars, and theoretically investigated by van Teeseling et al (1996);Matt (2004);McNamara et al (2008). In the EPIC spectra of RS Cae, there is no direct evidence of a Fe Kα fluorescent line at 6.4 keV, since the components of the line complex are not resolved.…”

Section: The Plasma Componentmentioning

confidence: 99%

“…By exploiting new XMM-Newton data of polars that had not been observed in X-rays since ROSAT, we are studying their system properties and the energy balance, in particular during high states (AI Tri, Traulsen et al 2010, RS Cae, this work) and intermediate high states of accretion (AI Tri, QS Tel, Traulsen et al 2010Traulsen et al , 2011. In this paper, we present our third pointed XMM-Newton observation of a soft X-ray selected polar.…”

Section: Introductionmentioning

confidence: 99%

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Phase-resolved X-ray spectroscopy and spectral energy distribution of the X-ray soft polar RS Caeli

Traulsen

Reinsch

Schwope

et al. 2014

A&A

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Context. RS Cae is the third target in our series of XMM-Newton observations of soft X-ray-dominated polars. Aims. Our observational campaign aims to better understand and describe the multiwavelength data, the physical properties of the system components, and the short-and long-term behavior of the component fluxes in RS Cae. Methods. We employ stellar atmosphere, stratified accretion-column, and widely used X-ray spectral models. We fit the XMM-Newton spectra, model the multiband light curves, and opt for a mostly consistent description of the spectral energy distribution. Results. Our XMM-Newton data of RS Cae are clearly dominated by soft X-ray emission. The X-ray light curves are shaped by emission from the main accretion region, which is visible over the whole orbital cycle, interrupted only by a stream eclipse. The optical light curves are formed by cyclotron and stream emission. The XMM-Newton X-ray spectra comprise a black-body-like and a plasma component at mean temperatures of 36 eV and 7 keV. The spectral fits give evidence of a partially absorbing and a reflection component. Multitemperature models, covering a broader temperature range in the X-ray emitting accretion regions, reproduce the spectra appropriately well. Including archival data, we describe the spectral energy distribution with a combination of models based on a consistent set of parameters and derive a lower limit estimate of the distance d 750 pc. Conclusions. The high bolometric soft-to-hard flux ratios and short-term variability of the (X-ray) light curves are characteristic of inhomogeneous accretion. RS Cae clearly belongs in the group of polars that show a very strong soft X-ray flux compared to their hard X-ray flux. The different black-body fluxes and similar hard X-ray and optical fluxes during the XMM-Newton and ROSAT observations show that soft and hard X-ray emission are not directly correlated.

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Section: Discussionmentioning

confidence: 99%

Section: The Plasma Componentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phase-resolved X-ray spectroscopy and spectral energy distribution of the X-ray soft polar RS Caeli

Traulsen

Reinsch

Schwope

et al. 2014

A&A

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“…: Observed SEDs of three X-ray soft polars from IR to X-rays: our XMM-Newton and optical plus archival data at different epochs and accretion states (cf. Traulsen et al 2010Traulsen et al , 2011Traulsen et al , 2014. The Xray spectra are unfolded using the best-fit models.…”

Section: Observed Sedsmentioning

confidence: 99%

Probing the Accretion Processes in Soft X-Ray Selected Polars

Traulsen

Reinsch

Schwope

2015

APP

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High-energy data of accreting white dwarfs give access to the regime of the primary accretion-induced energy release and the different proposed accretion scenarios. We perform XMM-Newton observations of polars selected due to their ROSAT hardness ratios close to -1.0 and model the emission processes in accretion column and accretion region. Our models consider the multi-temperature structure of the emission regions and are mainly determined by mass-flow density, magnetic field strength, and white-dwarf mass. To describe the full spectral energy distribution from infrared to X-rays in a physically consistent way, we include the stellar contributions and establish composite models, which will also be of relevance for future X-ray missions. We confirm the X-ray soft nature of three polars.

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“…This latter can be evaluated by multiplying σ T 4 by the Planck mean opacity, where σ is the Stefan-Boltzmann constant. At the astrophysical scale, we can estimate the order of magnitude for the velocity, density and temperature in the plasma by an analysis of spectroscopic and photometric data (see, e.g., Traulsen et al 2011). The Mach number which characterizes the reverse shock is of the order of 15-20, and the cooling parameter is very small compared to 1: radiative processes completely structure the post-shock region through their cooling effect.…”

Section: Astrophysical Relevance Of Laboratory Experimentsmentioning

confidence: 99%

POLAR project: a numerical study to optimize the target design

et al. 2013

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Modern high-energy density facilities allow us to bring matter to extreme states of density, temperature and velocity. Rigorous scaling laws proved that the relevant regimes could be reached, and those regimes are reproducibly achievable. Using powerful lasers and adapted target designs, similarity experiments in the POLAR project aim at studying the formation and dynamics of accretion shocks as found in magnetic cataclysmic variables. At the astrophysical scale, the system we consider is a column of infalling plasma collimated by a magnetic field onto the surface of a white dwarf. As matter hits the surface with supersonic velocity, a shock forms at the basis of the column and propagates upstream. In this paper, numerical simulations are presented in order to describe the experience and to give expectations concerning physical regimes reachable for future experiments on a kilojoule facility. In particular, our target design is discussed and improvements are detailed.

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XMM-Newtonobservations of the X-ray soft polar QS Telescopii

Cited by 7 publications

References 27 publications

Phase-resolved X-ray spectroscopy and spectral energy distribution of the X-ray soft polar RS Caeli

Phase-resolved X-ray spectroscopy and spectral energy distribution of the X-ray soft polar RS Caeli

Probing the Accretion Processes in Soft X-Ray Selected Polars

POLAR project: a numerical study to optimize the target design

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