The complex X-ray spectrum of the supersoft source

Bearda, H.; Hartmann, Wouter; Ebisawa, Ken; Heise, J.; Kaastra, J. S.; Meer, Robert van der; Verbunt, F.; Motch, C.

doi:10.1051/0004-6361:20020104

Cited by 19 publications

(22 citation statements)

References 18 publications

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“…Lanz et al 2005, Rajoelimanana et al 2013) has shown that they indeed consist of a hot WD in a close orbit with a non-degenerate donor, where hydrogen accreted from the donor, at roughly the above rates, burns more-or-less stably into helium on the WD surface (van den Heuvel et al 1992). However, not all supersoft source spectra are easily interpreted in this way, as some show P-Cygni profiles indicative of a wind rather than a WD atmosphere (Bearda et al 2002). Because of interstellar absorption of their soft X-ray spectrum, supersoft sources have been discovered mainly in external nearby galaxies.…”

Section: Recurrent Novaementioning

confidence: 99%

Observational Clues to the Progenitors of Type Ia Supernovae

Maoz

Mannucci

Nelemans

2014

Annu. Rev. Astron. Astrophys.

965

894

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Type-Ia supernovae (SNe Ia) are important distance indicators, element factories, cosmic-ray accelerators, kinetic-energy sources in galaxy evolution, and endpoints of stellar binary evolution. It has long been clear that a SN Ia must be the runaway thermonuclear explosion of a degenerate carbon-oxygen stellar core, most likely a white dwarf (WD). However, the specific progenitor systems of SNe Ia, and the processes that lead to their ignition, have not been identified. Two broad classes of progenitor binary systems have long been considered: single-degenerate (SD), in which a WD gains mass from a non-degenerate star; and doubledegenerate (DD), involving the merger of two WDs. New theoretical work has enriched these possibilities with some interesting updates and variants. We review the significant recent observational progress in addressing the progenitor problem. We consider clues that have emerged from the observed properties of the various proposed progenitor populations, from studies of their sites -pre-and post-explosion, from analysis of the explosions themselves, and from the measurement of event rates. The recent nearby and well-studied event, SN 2011fe, has been particularly revealing. The observational results are not yet conclusive, and sometimes prone to competing theoretical interpretations. Nevertheless, it appears that DD progenitors, long considered the underdog option, could be behind some, if not all, SNe Ia. We point to some directions that may lead to future progress.

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Section: Recurrent Novaementioning

confidence: 99%

Observational Clues to the Progenitors of Type Ia Supernovae

Maoz

Mannucci

Nelemans

2014

Annu. Rev. Astron. Astrophys.

965

894

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“…The blue edge of the mean Ly α O  P Cygni profile shown in Fig. 7 is at velocities close to 2000 km s −1 slightly larger than the 1500 km s −1 derived by Bearda et al (2002), but much less than that of the transient collimated wind or jet discovered by Motch (1998).…”

Section: Overall Spectrummentioning

confidence: 52%

“…Figure 8 shows the ratio of the high to low EPIC pn spectra plotted for the merged revolutions 187 and 188 data. Although the NLTE model atmosphere of Bearda et al (2002) does not satisfactorily fit the EPIC pn spectrum, it provides a better representation than black body spectra and can be used to estimate the expected distortion of the energy distribution if it was only due to photoelectric absorption. In the 0.5-1.0 keV range the high to low ratio of 1.277 can be mimicked by a change from N H = 1.485 × 10 22 to 1.540 × 10 22 cm −2 , keeping all other parameters constant.…”

Section: Variability With Orbital Phases and Flux Levelmentioning

confidence: 99%

“…Among supersoft sources, RX J0925.7-4758 is unusual by its relatively high X-ray temperature and long orbital period of 4.0287 d (Schmidtke & Cowley 2001). Previous X-ray observations have been reported from a number of satellites (ASCA; Ebisawa et al 2001, BeppoSAX;Hartmann et al 1999 and recently using the HETG on board Chandra; Bearda et al 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Higher resolution spectra with ASCA (e.g. Ebisawa et al 1996) started to reveal complex structures later emphasized by Chandra and XMM-Newton grating spectroscopy (Paerels et al 2001;Bearda et al 2002). Fitting model atmospheres of hot white dwarfs usually imply bolometric luminosities below but close to Eddington.…”

Section: Introductionmentioning

confidence: 99%

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XMM-Newton observations of MR Vel/RX J0925.7-4758

Motch

Bearda

Neiner³

2002

A&A

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Abstract. We report on XMM-Newton observations of the galactic supersoft X-ray source RX J0925.7-4758. The RGS spectrum exhibits a wealth of spectral features from iron and oxygen. XMM-Newton data confirm the finding of previous Chandra HETGS/MEG observations that NLTE models of hot white dwarf atmospheres fail to represent the complex spectrum. There are clear evidences for P Cygni profiles with wind velocities of up to 2000 km s −1 . Small flux variations with time scales larger than 1000 s are present. The strongest power is at ∼0.21 d, a period close to that seen in V band optical light curves. A detailed analysis of the associated changes in the RGS and EPIC pn spectra hint at a mostly grey mechanism suggesting a variation of the visibility of the white dwarf due to occulting material in the accretion disk. Finally, we detect radial velocity changes of 173 ± 47 km s −1 between two RGS observations obtained half an orbital cycle apart. The amplitude of the RGS velocity shift is consistent with that of the optical He  λ 4686 and thus supports the idea that most of the He  optical line emission arises from the accretion disk.

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X‐ray energy spectra of CAL87

Ebisawa¹,

Rauch²,

Takei

2010

Astron Nachr

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We present X-ray spectral analysis of the super-soft source CAL87 using ASCA, Chandra, XMM-Newton observations. Early ASCA CCD spectrum reported a strong oxygen absorption edge, which is considered to originate in the an optically thick white-dwarf atmosphere. On the other hand, contemporaneous grating observations by Chandra and XMM-Newton indicate emission line dominated spectra, which obviously indicate the optically thin origin. Fitting all the available CCD (ASCA and XMM-Newton) and grating spectra (XMM-Newton and Chandra) simultaneously, we show that the CAL87 Xray energy spectrum is in fact composed of both an optically thick component with deep absorption edges and an optically thin component with numerous emission lines. The current result supports the standard SSS model that the primary source of X-ray emission is nuclear burning in the white dwarf atmosphere, surrounded by a highly photoionised, optically thin corona.

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The complex X-ray spectrum of the supersoft source

Cited by 19 publications

References 18 publications

Observational Clues to the Progenitors of Type Ia Supernovae

Observational Clues to the Progenitors of Type Ia Supernovae

XMM-Newton observations of MR Vel/RX J0925.7-4758

X‐ray energy spectra of CAL87

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