A 'high-hard' outburst of the black hole X-ray binary GS 1354-64

K. I.I. Koljonen, Dave Russell, J. M. Corral-Santana, M. Armas Padilla, T. Muñoz-Darias, F. Lewis, M. Coriat, E. Bauer

    Research output: Contribution to journalArticle

    Abstract

    We study in detail the evolution of the 2015 outburst of GS 1354-64 (BW Cir) at optical, UV and X-ray wavelengths using Faulkes Telescope South/Las Cumbres Observatory Global Telescope Network, Small & Moderate Aperture Research Telescope System and Swift. The outburst was found to stay in the hard X-ray state, albeit being anomalously luminous with a peak luminosity of LX > 0.15 LEdd, which could be the most luminous hard state observed in a black hole X-ray binary. We found that the optical/UV emission is tightly correlated with the X-ray emission, consistent with accretion disc irradiation and/or a jet producing the optical emission. The X-ray spectra can be fitted well with a Comptonization model, and show softening towards the end of the outburst. In addition, we detect a QPO in the X-ray light curves with increasing centroid frequency during the peak and decay periods of the outburst. The long-term optical light curves during quiescence show a statistically significant, slow rise of the source brightness over the 7 years prior to the 2015 outburst. This behaviour as well as the outburst evolution at all wavelengths studied can be explained by the disc instability model with irradiation and disc evaporation/condensation.

    Original languageEnglish (US)
    Pages (from-to)942-955
    Number of pages14
    JournalMonthly Notices of the Royal Astronomical Society
    Volume460
    Issue number1
    DOIs
    StatePublished - Jul 21 2016

    Fingerprint

    outburst
    x rays
    telescopes
    light curve
    irradiation
    wavelength
    guy wires
    softening
    wavelengths
    accretion disks
    centroids
    light emission
    condensation
    observatories
    brightness
    observatory
    evaporation
    apertures
    accretion
    luminosity

    Keywords

    • Accretion, accretion discs
    • Binaries: close
    • X-rays: binaries
    • X-rays: individual: GS 1354-64
    • X-rays: stars

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Koljonen, K. I. I., Russell, D., Corral-Santana, J. M., Padilla, M. A., Muñoz-Darias, T., Lewis, F., ... Bauer, E. (2016). A 'high-hard' outburst of the black hole X-ray binary GS 1354-64. Monthly Notices of the Royal Astronomical Society, 460(1), 942-955. https://doi.org/10.1093/mnras/stw1007

    A 'high-hard' outburst of the black hole X-ray binary GS 1354-64. / Koljonen, K. I.I.; Russell, Dave; Corral-Santana, J. M.; Padilla, M. Armas; Muñoz-Darias, T.; Lewis, F.; Coriat, M.; Bauer, E.

    In: Monthly Notices of the Royal Astronomical Society, Vol. 460, No. 1, 21.07.2016, p. 942-955.

    Research output: Contribution to journalArticle

    Koljonen, KII, Russell, D, Corral-Santana, JM, Padilla, MA, Muñoz-Darias, T, Lewis, F, Coriat, M & Bauer, E 2016, 'A 'high-hard' outburst of the black hole X-ray binary GS 1354-64', Monthly Notices of the Royal Astronomical Society, vol. 460, no. 1, pp. 942-955. https://doi.org/10.1093/mnras/stw1007
    Koljonen KII, Russell D, Corral-Santana JM, Padilla MA, Muñoz-Darias T, Lewis F et al. A 'high-hard' outburst of the black hole X-ray binary GS 1354-64. Monthly Notices of the Royal Astronomical Society. 2016 Jul 21;460(1):942-955. https://doi.org/10.1093/mnras/stw1007
    Koljonen, K. I.I. ; Russell, Dave ; Corral-Santana, J. M. ; Padilla, M. Armas ; Muñoz-Darias, T. ; Lewis, F. ; Coriat, M. ; Bauer, E. / A 'high-hard' outburst of the black hole X-ray binary GS 1354-64. In: Monthly Notices of the Royal Astronomical Society. 2016 ; Vol. 460, No. 1. pp. 942-955.
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