A remarkable recurrent nova in M 31: The X-ray observations

M. Henze; J. U. Ness; M. J. Darnley; M. F. Bode; S. C. Williams; A. W. Shafter; M. Kato; I. Hachisu

doi:10.1051/0004-6361/201423410

A remarkable recurrent nova in M 31: The X-ray observations

M. Henze, J. U. Ness, M. J. Darnley, M. F. Bode, S. C. Williams, A. W. Shafter, M. Kato, I. Hachisu

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40 Citations (Scopus)

Abstract

Context. Another outburst of the recurrent M 31 nova M31N 2008-12a was announced in late November 2013. Optical data suggest an unprecedentedly short recurrence time of approximately one year. Aims. In this Letter we address the X-ray properties of M31N 2008-12a. Methods. We requested Swift monitoring observations shortly after the optical discovery. We estimated source count rates and extracted X-ray spectra from the resulting data. The corresponding ultraviolet (UV) data were also analysed. Results. The nova M31N 2008-12a was clearly detected as a bright supersoft X-ray source (SSS) only six days after the well-constrained optical discovery. It displayed a short SSS phase of two weeks' duration and an exceptionally hot X-ray spectrum with an effective black-body temperature of ~97 eV. During the SSS phase the X-ray light curve displayed significant variability that might have been accompanied by spectral variations. The very early X-ray variability was found to be anti-correlated with simultaneous variations in the UV flux. Conclusions. The X-ray properties of M31N 2008-12a coherently point towards a high-mass white dwarf in the nova system. This object might be a promising Type Ia supernova progenitor. We rediscovered additional X-ray detections of M31N 2008-12a that are consistent with our data and increase the number of known nova outbursts to seven. This nova is an exceptional object that merits further attention in the future.

Original language	English
Article number	L8
Journal	Astronomy and Astrophysics
Volume	563
DOIs	https://doi.org/10.1051/0004-6361/201423410
Publication status	Published - 2014 Mar
Externally published	Yes

Keywords

Galaxies: individual: M 31
Novae, cataclysmic variables
Stars: individual: M31N 2008-12a
X-rays: binaries

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1051/0004-6361/201423410

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@article{c975ab45b0c042bb852146a22863c274,

title = "A remarkable recurrent nova in M 31: The X-ray observations",

abstract = "Context. Another outburst of the recurrent M 31 nova M31N 2008-12a was announced in late November 2013. Optical data suggest an unprecedentedly short recurrence time of approximately one year. Aims. In this Letter we address the X-ray properties of M31N 2008-12a. Methods. We requested Swift monitoring observations shortly after the optical discovery. We estimated source count rates and extracted X-ray spectra from the resulting data. The corresponding ultraviolet (UV) data were also analysed. Results. The nova M31N 2008-12a was clearly detected as a bright supersoft X-ray source (SSS) only six days after the well-constrained optical discovery. It displayed a short SSS phase of two weeks' duration and an exceptionally hot X-ray spectrum with an effective black-body temperature of ~97 eV. During the SSS phase the X-ray light curve displayed significant variability that might have been accompanied by spectral variations. The very early X-ray variability was found to be anti-correlated with simultaneous variations in the UV flux. Conclusions. The X-ray properties of M31N 2008-12a coherently point towards a high-mass white dwarf in the nova system. This object might be a promising Type Ia supernova progenitor. We rediscovered additional X-ray detections of M31N 2008-12a that are consistent with our data and increase the number of known nova outbursts to seven. This nova is an exceptional object that merits further attention in the future.",

keywords = "Galaxies: individual: M 31, Novae, cataclysmic variables, Stars: individual: M31N 2008-12a, X-rays: binaries",

author = "M. Henze and Ness, {J. U.} and Darnley, {M. J.} and Bode, {M. F.} and Williams, {S. C.} and Shafter, {A. W.} and M. Kato and I. Hachisu",

note = "Funding Information: We thank the referee, Eric Schlegel, for a careful reading of the manuscript. We wish to thank Margarita Hernanz for constructive comments on an early version of this Letter. We are grateful to the Swift Team for making the ToO observations possible, in particular N. Gehrels, the duty scientists, as well as the science planners. M.H. acknowledges support from an ESA fellowship. S.C.W. acknowledges PhD funding from STFC. A.W.S. acknowledges support from NSF grant AST1009566.",

year = "2014",

month = mar,

doi = "10.1051/0004-6361/201423410",

language = "English",

volume = "563",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

}

TY - JOUR

T1 - A remarkable recurrent nova in M 31

T2 - The X-ray observations

AU - Henze, M.

AU - Ness, J. U.

AU - Darnley, M. J.

AU - Bode, M. F.

AU - Williams, S. C.

AU - Shafter, A. W.

AU - Kato, M.

AU - Hachisu, I.

N1 - Funding Information: We thank the referee, Eric Schlegel, for a careful reading of the manuscript. We wish to thank Margarita Hernanz for constructive comments on an early version of this Letter. We are grateful to the Swift Team for making the ToO observations possible, in particular N. Gehrels, the duty scientists, as well as the science planners. M.H. acknowledges support from an ESA fellowship. S.C.W. acknowledges PhD funding from STFC. A.W.S. acknowledges support from NSF grant AST1009566.

PY - 2014/3

Y1 - 2014/3

N2 - Context. Another outburst of the recurrent M 31 nova M31N 2008-12a was announced in late November 2013. Optical data suggest an unprecedentedly short recurrence time of approximately one year. Aims. In this Letter we address the X-ray properties of M31N 2008-12a. Methods. We requested Swift monitoring observations shortly after the optical discovery. We estimated source count rates and extracted X-ray spectra from the resulting data. The corresponding ultraviolet (UV) data were also analysed. Results. The nova M31N 2008-12a was clearly detected as a bright supersoft X-ray source (SSS) only six days after the well-constrained optical discovery. It displayed a short SSS phase of two weeks' duration and an exceptionally hot X-ray spectrum with an effective black-body temperature of ~97 eV. During the SSS phase the X-ray light curve displayed significant variability that might have been accompanied by spectral variations. The very early X-ray variability was found to be anti-correlated with simultaneous variations in the UV flux. Conclusions. The X-ray properties of M31N 2008-12a coherently point towards a high-mass white dwarf in the nova system. This object might be a promising Type Ia supernova progenitor. We rediscovered additional X-ray detections of M31N 2008-12a that are consistent with our data and increase the number of known nova outbursts to seven. This nova is an exceptional object that merits further attention in the future.

AB - Context. Another outburst of the recurrent M 31 nova M31N 2008-12a was announced in late November 2013. Optical data suggest an unprecedentedly short recurrence time of approximately one year. Aims. In this Letter we address the X-ray properties of M31N 2008-12a. Methods. We requested Swift monitoring observations shortly after the optical discovery. We estimated source count rates and extracted X-ray spectra from the resulting data. The corresponding ultraviolet (UV) data were also analysed. Results. The nova M31N 2008-12a was clearly detected as a bright supersoft X-ray source (SSS) only six days after the well-constrained optical discovery. It displayed a short SSS phase of two weeks' duration and an exceptionally hot X-ray spectrum with an effective black-body temperature of ~97 eV. During the SSS phase the X-ray light curve displayed significant variability that might have been accompanied by spectral variations. The very early X-ray variability was found to be anti-correlated with simultaneous variations in the UV flux. Conclusions. The X-ray properties of M31N 2008-12a coherently point towards a high-mass white dwarf in the nova system. This object might be a promising Type Ia supernova progenitor. We rediscovered additional X-ray detections of M31N 2008-12a that are consistent with our data and increase the number of known nova outbursts to seven. This nova is an exceptional object that merits further attention in the future.

KW - Galaxies: individual: M 31

KW - Novae, cataclysmic variables

KW - Stars: individual: M31N 2008-12a

KW - X-rays: binaries

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U2 - 10.1051/0004-6361/201423410

DO - 10.1051/0004-6361/201423410

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VL - 563

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - L8

ER -

A remarkable recurrent nova in M 31: The X-ray observations

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Keywords

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