Non-lte model atmosphere analysis of the large magellanic cloud supersoft x-ray source CAL 83

Thierry Lanz, Gisela A. Telis, Marc Audard, Frits Paerels, Andrew P. Rasmussen, Ivan - Hubeny

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

We present a non-LTE (NLTE) model atmosphere analysis of Chandra High Resolution Camera (HRC-S) and Low Energy Transmission Grating (LETG) and XMM-Newton Reflection Grating Spectrometer (RGS) spectroscopy of the prototypical supersoft source CAL 83 in the Large Magellanic Cloud. Taken with a 16 month interval, the Chandra and XMM-Newton spectra are very similar. They reveal a very rich absorption-line spectrum from the hot white dwarf photosphere but no spectral signatures of a wind. We also report a third X-ray off-state during a later Chandra observation, demonstrating the recurrent nature of CAL 83. Moreover, we found evidence of short-timescale variability in the soft X-ray spectrum. We completed the analysis of the LETG and RGS spectra of CAL 83 with new NLTE line-blanketed model atmospheres that explicitly include 74 ions of the 11 most abundant species. We successfully matched the Chandra and XMM-Newton spectra assuming a model composition with LMC metallicity. We derived the basic stellar parameters of the hot white dwarf, but the current state of atomic data in the soft X-ray domain precludes a detailed chemical analysis. We have obtained the first direct spectroscopic evidence that the white dwarf is massive (MWD ≳ M⊙). The short timescale of the X-ray off-states is consistent with a high white dwarf mass. Our analysis thus provides direct support for supersoft sources as likely progenitors of Type la supernovae (SNe Ia).

Original languageEnglish (US)
Pages (from-to)517-526
Number of pages10
JournalAstrophysical Journal
Volume619
Issue number1 I
DOIs
StatePublished - Jan 20 2005

Fingerprint

x ray sources
Magellanic clouds
XMM-Newton telescope
gratings
newton
atmospheres
atmosphere
x rays
spectrometers
spectrometer
spectral signatures
timescale
photosphere
chemical analysis
metallicity
line spectra
supernovae
cameras
energy
intervals

Keywords

  • Binaries: close
  • Stars: atmospheres
  • Stars: fundamental parameters
  • White dwarfs
  • X-rays: binaries
  • X-rays: individual (CAL 83)

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Non-lte model atmosphere analysis of the large magellanic cloud supersoft x-ray source CAL 83. / Lanz, Thierry; Telis, Gisela A.; Audard, Marc; Paerels, Frits; Rasmussen, Andrew P.; Hubeny, Ivan -.

In: Astrophysical Journal, Vol. 619, No. 1 I, 20.01.2005, p. 517-526.

Research output: Contribution to journalArticle

Lanz, Thierry ; Telis, Gisela A. ; Audard, Marc ; Paerels, Frits ; Rasmussen, Andrew P. ; Hubeny, Ivan -. / Non-lte model atmosphere analysis of the large magellanic cloud supersoft x-ray source CAL 83. In: Astrophysical Journal. 2005 ; Vol. 619, No. 1 I. pp. 517-526.
@article{b8c8352a221f49538d21ff0721672983,
title = "Non-lte model atmosphere analysis of the large magellanic cloud supersoft x-ray source CAL 83",
abstract = "We present a non-LTE (NLTE) model atmosphere analysis of Chandra High Resolution Camera (HRC-S) and Low Energy Transmission Grating (LETG) and XMM-Newton Reflection Grating Spectrometer (RGS) spectroscopy of the prototypical supersoft source CAL 83 in the Large Magellanic Cloud. Taken with a 16 month interval, the Chandra and XMM-Newton spectra are very similar. They reveal a very rich absorption-line spectrum from the hot white dwarf photosphere but no spectral signatures of a wind. We also report a third X-ray off-state during a later Chandra observation, demonstrating the recurrent nature of CAL 83. Moreover, we found evidence of short-timescale variability in the soft X-ray spectrum. We completed the analysis of the LETG and RGS spectra of CAL 83 with new NLTE line-blanketed model atmospheres that explicitly include 74 ions of the 11 most abundant species. We successfully matched the Chandra and XMM-Newton spectra assuming a model composition with LMC metallicity. We derived the basic stellar parameters of the hot white dwarf, but the current state of atomic data in the soft X-ray domain precludes a detailed chemical analysis. We have obtained the first direct spectroscopic evidence that the white dwarf is massive (MWD ≳ M⊙). The short timescale of the X-ray off-states is consistent with a high white dwarf mass. Our analysis thus provides direct support for supersoft sources as likely progenitors of Type la supernovae (SNe Ia).",
keywords = "Binaries: close, Stars: atmospheres, Stars: fundamental parameters, White dwarfs, X-rays: binaries, X-rays: individual (CAL 83)",
author = "Thierry Lanz and Telis, {Gisela A.} and Marc Audard and Frits Paerels and Rasmussen, {Andrew P.} and Hubeny, {Ivan -}",
year = "2005",
month = "1",
day = "20",
doi = "10.1086/426382",
language = "English (US)",
volume = "619",
pages = "517--526",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1 I",

}

TY - JOUR

T1 - Non-lte model atmosphere analysis of the large magellanic cloud supersoft x-ray source CAL 83

AU - Lanz, Thierry

AU - Telis, Gisela A.

AU - Audard, Marc

AU - Paerels, Frits

AU - Rasmussen, Andrew P.

AU - Hubeny, Ivan -

PY - 2005/1/20

Y1 - 2005/1/20

N2 - We present a non-LTE (NLTE) model atmosphere analysis of Chandra High Resolution Camera (HRC-S) and Low Energy Transmission Grating (LETG) and XMM-Newton Reflection Grating Spectrometer (RGS) spectroscopy of the prototypical supersoft source CAL 83 in the Large Magellanic Cloud. Taken with a 16 month interval, the Chandra and XMM-Newton spectra are very similar. They reveal a very rich absorption-line spectrum from the hot white dwarf photosphere but no spectral signatures of a wind. We also report a third X-ray off-state during a later Chandra observation, demonstrating the recurrent nature of CAL 83. Moreover, we found evidence of short-timescale variability in the soft X-ray spectrum. We completed the analysis of the LETG and RGS spectra of CAL 83 with new NLTE line-blanketed model atmospheres that explicitly include 74 ions of the 11 most abundant species. We successfully matched the Chandra and XMM-Newton spectra assuming a model composition with LMC metallicity. We derived the basic stellar parameters of the hot white dwarf, but the current state of atomic data in the soft X-ray domain precludes a detailed chemical analysis. We have obtained the first direct spectroscopic evidence that the white dwarf is massive (MWD ≳ M⊙). The short timescale of the X-ray off-states is consistent with a high white dwarf mass. Our analysis thus provides direct support for supersoft sources as likely progenitors of Type la supernovae (SNe Ia).

AB - We present a non-LTE (NLTE) model atmosphere analysis of Chandra High Resolution Camera (HRC-S) and Low Energy Transmission Grating (LETG) and XMM-Newton Reflection Grating Spectrometer (RGS) spectroscopy of the prototypical supersoft source CAL 83 in the Large Magellanic Cloud. Taken with a 16 month interval, the Chandra and XMM-Newton spectra are very similar. They reveal a very rich absorption-line spectrum from the hot white dwarf photosphere but no spectral signatures of a wind. We also report a third X-ray off-state during a later Chandra observation, demonstrating the recurrent nature of CAL 83. Moreover, we found evidence of short-timescale variability in the soft X-ray spectrum. We completed the analysis of the LETG and RGS spectra of CAL 83 with new NLTE line-blanketed model atmospheres that explicitly include 74 ions of the 11 most abundant species. We successfully matched the Chandra and XMM-Newton spectra assuming a model composition with LMC metallicity. We derived the basic stellar parameters of the hot white dwarf, but the current state of atomic data in the soft X-ray domain precludes a detailed chemical analysis. We have obtained the first direct spectroscopic evidence that the white dwarf is massive (MWD ≳ M⊙). The short timescale of the X-ray off-states is consistent with a high white dwarf mass. Our analysis thus provides direct support for supersoft sources as likely progenitors of Type la supernovae (SNe Ia).

KW - Binaries: close

KW - Stars: atmospheres

KW - Stars: fundamental parameters

KW - White dwarfs

KW - X-rays: binaries

KW - X-rays: individual (CAL 83)

UR - http://www.scopus.com/inward/record.url?scp=14544272699&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=14544272699&partnerID=8YFLogxK

U2 - 10.1086/426382

DO - 10.1086/426382

M3 - Article

AN - SCOPUS:14544272699

VL - 619

SP - 517

EP - 526

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 I

ER -