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Title: 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 × 10{sup 3} s < ΔT{sub d} < 1.10 × 10{sup 4} s), a rapid rise (<5.5 × 10{sup 3} s), and a huge peak luminosity of 2 × 10{sup 40} erg s{sup –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,more » a direct manifestation of the ignition of the thermonuclear runaway process in a nova explosion.« less
Authors:
; ; ;  [1] ; ; ;  [2] ; ;  [3] ; ;  [4] ; ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ; ;  [10] ;  [11] more »; « less
  1. MAXI Team, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
  2. ISS Science Project Office, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan)
  3. Department of Physics, Nihon University, 1-8-14 Surugadai, Chiyoda, Tokyo 101-8308 (Japan)
  4. Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)
  5. Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)
  6. International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia)
  7. Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)
  8. Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)
  9. Department of Astronomy, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)
  10. Department of Physics, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551 (Japan)
  11. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
Publication Date:
OSTI Identifier:
22348454
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APERTURES; DETECTION; EMISSION; EXPLOSIONS; FLAMES; IMAGES; KEV RANGE; LUMINOSITY; MAGELLANIC CLOUDS; NOVAE; SOFT X RADIATION; SPECTRA; SPECTROSCOPY; TELESCOPES; TRANSIENTS; WHITE DWARF STARS