EXTRAORDINARY LUMINOUS SOFT X-RAY TRANSIENT MAXI J0158−744 AS AN IGNITION OF A NOVA ON A VERY MASSIVE O–Ne WHITE DWARF

We present the observation of an extraordinary luminous soft X-ray transient, MAXI J0158−744, by the Monitor of All-sky X-ray Image (MAXI) on 2011 November 11. This transient is characterized by a soft X-ray spectrum, a short duration (1.3 × 103 s  <  ΔTd < 1.10 × 104 s), a rapid rise (<5.5 × 103 s), and a huge peak luminosity of 2 × 1040 erg s−1 in 0.7–7.0 keV band. With Swift observations and optical spectroscopy from the Small and Moderate Aperture Research Telescope System, we confirmed that the transient is a nova explosion, on a white dwarf in a binary with a Be star, located near the Small Magellanic Cloud. An early turn-on of the super-soft X-ray source (SSS) phase (<0.44 days), the short SSS phase duration of about one month, and a 0.92 keV neon emission line found in the third MAXI scan, 1296 s after the first detection, suggest that the explosion involves a small amount of ejecta and is produced on an unusually massive O–Ne white dwarf close to, or possibly over, the Chandrasekhar limit. We propose that the huge luminosity detected with MAXI was due to the fireball phase, a direct manifestation of the ignition of the thermonuclear runaway process in a nova explosion.

[1]  H. Tomida,et al.  Is the Cygnus Superbubble a Hypernova Remnant , 2012, 1211.3737.

[2]  H. Bond,et al.  The Stony Brook/SMARTS Atlas of (mostly) Southern Novae , 2012, 1209.1583.

[3]  N. Masetti,et al.  A LUMINOUS Be+WHITE DWARF SUPERSOFT SOURCE IN THE WING OF THE SMC: MAXI J0158-744 , 2012, 1207.5023.

[4]  D. V. Rossum.  A PUBLIC SET OF SYNTHETIC SPECTRA FROM EXPANDING ATMOSPHERES FOR X-RAY NOVAE. I. SOLAR ABUNDANCES , 2012, 1205.4267.

[5]  N. Kawai,et al.  MAXI GSC Monitoring of the Crab Nebula and Pulsar during the GeV Gamma-Ray Flare in 2010 September , 2011 .

[6]  N. Kawai,et al.  A Spectral Study of the Black Hole Candidate XTE J1752-223 in the High/Soft State with MAXI, Suzaku and Swift , 2011, 1109.1378.

[7]  N. Kawai,et al.  The First MAXI/GSC Catalog in the High Galactic-Latitude Sky , 2011, 1108.5516.

[8]  K. Nomoto,et al.  A SINGLE DEGENERATE PROGENITOR MODEL FOR TYPE Ia SUPERNOVAE HIGHLY EXCEEDING THE CHANDRASEKHAR MASS LIMIT , 2011, 1106.3510.

[9]  T. Goto,et al.  THE CURRENT STAR FORMATION RATE OF K+A GALAXIES , 2011, 1106.0757.

[10]  Naoki Isobe,et al.  Gas Slit Camera (GSC) onboard MAXI on ISS , 2011, 1103.4224.

[11]  Naoki Isobe,et al.  In-Orbit Performance of MAXI Gas Slit Camera (GSC) on ISS , 2011, 1102.0891.

[12]  V. Mangano,et al.  Swift Follow-up Observations of MAXI Discovered Galactic Transients , 2011, 1101.6055.

[13]  Naoki Isobe,et al.  Solid-state Slit Camera (SSC) on Board MAXI , 2011 .

[14]  M. Valle,et al.  X-ray monitoring of classical novae in the central region of M 31 - II. Autumn and winter 2007/2008 and 2008/2009 , 2010, 1010.1461.

[15]  Haruyoshi Katayama,et al.  In-Orbit Performance of the MAXI/SSC onboard the ISS , 2010 .

[16]  F. Di Mille,et al.  A CENSUS OF THE SUPERSOFT X-RAY SOURCES IN M31 , 2010 .

[17]  Baltimore,et al.  NON-LOCAL THERMAL EQUILIBRIUM MODEL ATMOSPHERES FOR THE HOTTEST WHITE DWARFS: SPECTRAL ANALYSIS OF THE COMPACT COMPONENT IN NOVA V4743 Sgr , 2010, 1006.2918.

[18]  Naoki Isobe,et al.  The MAXI Mission on the ISS: Science and Instruments for Monitoring All-Sky X-Ray Images , 2009, 0906.0631.

[19]  R. Carrera,et al.  THE CHEMICAL ENRICHMENT HISTORY OF THE SMALL MAGELLANIC CLOUD AND ITS GRADIENTS , 2008, 0806.4465.

[20]  E. Ofek,et al.  An extremely luminous X-ray outburst at the birth of a supernova , 2008, Nature.

[21]  D. Psaltis,et al.  Thermonuclear (Type I) X-Ray Bursts Observed by the Rossi X-Ray Timing Explorer , 2006, astro-ph/0608259.

[22]  Brian Warner.  Classical Novae: Properties of novae: an overview , 2008 .

[23]  Joachim Krautter,et al.  Classical Novae: X-ray emission from classical novae in outburst , 2008 .

[24]  Sumner Starrfield,et al.  Classical Novae: Thermonuclear processes , 2008 .

[25]  M. J. Page,et al.  Photometric calibration of the Swift ultraviolet/optical telescope , 2007, 0708.2259.

[26]  J. Zorec,et al.  Be star disc characteristics near the central object , 2007 .

[27]  N. Gehrels,et al.  Swift X-Ray Observations of Classical Novae , 2007, astro-ph/0703286.

[28]  M. Tamura,et al.  Herbig Ae/Be Stars in the Magellanic Bridge , 2007, astro-ph/0702504.

[29]  I. Hachisu,et al.  A Universal Decline Law of Classical Novae , 2006, astro-ph/0607609.

[30]  Scott J. Kenyon,et al.  An X-ray-emitting blast wave from the recurrent nova RS Ophiuchi , 2006, Nature.

[31]  P. Ubertini,et al.  Unveiling Supergiant Fast X-Ray Transient Sources with INTEGRAL , 2006, astro-ph/0603756.

[32]  G. Sala.  X‐Ray Emission from Classical Novae , 2004 .

[33]  A. Szalay,et al.  The On-Orbit Performance of the Galaxy Evolution Explorer , 2004, astro-ph/0411310.

[34]  W. Sherry,et al.  V1647 Orionis (IRAS 05436−0007) in Outburst: The First Three Months , 2004, astro-ph/0406618.

[35]  C. Thompson,et al.  Soft gamma repeaters and anomalous X-ray pulsars: magnetar candidates , 2004, astro-ph/0406133.

[36]  Alan A. Wells,et al.  The Swift Gamma-Ray Burst Mission , 2004, astro-ph/0405233.

[37]  N. Langer,et al.  Presupernova evolution of accreting white dwarfs with rotation , 2004, astro-ph/0402287.

[38]  V. Kaspi,et al.  Soft Gamma Repeaters and Anomalous X-ray Pulsars: Together Forever , 2004, astro-ph/0402175.

[39]  R. Hilditch,et al.  Forty eclipsing binaries in the Small Magellanic Cloud: fundamental parameters and Cloud distance , 2003, astro-ph/0411672.

[40]  M. Begelman.  Super-Eddington Atmospheres That Do Not Blow Away , 2000, astro-ph/0012360.

[41]  D. Schlegel,et al.  Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds , 1998 .

[42]  J. Truran,et al.  Evolutionary sequences for Nova V1974 Cygni using new nuclear reaction rates and opacities , 1998 .

[43]  D. Schlegel,et al.  Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds , 1997, astro-ph/9710327.

[44]  B. Warner.  Cataclysmic Variable Stars by Brian Warner , 1995 .

[45]  Mario Livio,et al.  The Calibration of Novae as Distance Indicators , 1995 .

[46]  B. Warner.  Cataclysmic Variable Stars: Novae in Eruption , 1995 .

[47]  D. Palmer,et al.  BATSE observations of gamma-ray burst spectra. I: Spectral diversity , 1993 .

[48]  J. Dickey,et al.  H I in the Galaxy , 1990 .

[49]  N. Grevesse,et al.  Abundances of the elements: Meteoritic and solar , 1989 .

[50]  Mariko Kato,et al.  Optically thick winds and nova outbursts , 1994 .

[51]  M. Fujimoto.  A theory of hydrogen shell flashes on accreting white dwarfs. I - Their progress and the expansion of the envelope. II - The stable shell burning and the recurrence period of shell flashes , 1982 .

[52]  W. Cash,et al.  Parameter estimation in astronomy through application of the likelihood ratio. [satellite data analysis techniques , 1979 .

[53]  B. Savage,et al.  A survey of interstellar H I from L-alpha absorption measurements. II , 1978 .

[54]  S. Holt,et al.  Variable X-Ray Sources , 1977 .

[55]  M. Nauenberg,et al.  ANALYTIC APPROXIMATIONS TO THE MASS--RADIUS RELATION AND ENERGY OF ZERO- TEMPERATURE STARS. , 1972 .