A VARIABLE MID-INFRARED SYNCHROTRON BREAK ASSOCIATED WITH THE COMPACT JET IN GX 339-4
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)
- Astronomical Institute 'Anton Pannekoek', University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam (Netherlands)
- School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)
- Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France)
- Universite Paris 7 Denis Diderot and Service d'Astrophysique, UMR AIM, CEA Saclay, F-91191 Gif sur Yvette (France)
- INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807, Merate (Italy)
- Faulkes Telescope Project, Division of Earth, Space and Environment, University of Glamorgan, Pontypridd CF37 1DL (United Kingdom)
- INTEGRAL Science Operations Centre Science Operations Department, European Space Astronomy Centre, Post Office Box 78, E-28691, Villanuevade la Caada, Madrid (Spain)
- Laboratoire Astroparticule et Cosmologie, 10 rue A. Domon et L. Duquet, 75205 Paris Cedex 13 (France)
- Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
Many X-ray binaries remain undetected in the mid-infrared, a regime where emission from their compact jets is likely to dominate. Here, we report the detection of the black hole binary GX 339-4 with the Wide-field Infrared Survey Explorer (WISE) during a very bright, hard accretion state in 2010. Combined with a rich contemporaneous multiwavelength data set, clear spectral curvature is found in the infrared, associated with the peak flux density expected from the compact jet. An optically thin slope of {approx} -0.7 and a jet radiative power of >6 x 10{sup 35} erg s{sup -1} (d/8 kpc){sup 2} are measured. A {approx}24 hr WISE light curve shows dramatic variations in mid-infrared spectral slope on timescales at least as short as the satellite orbital period {approx}95 minutes. There is also significant change during one pair of observations spaced by only 11 s. These variations imply that the spectral break associated with the transition from self-absorbed to optically thin jet synchrotron radiation must be varying across the full wavelength range of {approx}3-22 {mu}m that WISE is sensitive to, and more. Based on four-band simultaneous mid-infrared detections, the break is constrained to frequencies of {approx}4.6{sup +3.5} {sub -2.0} x 10{sup 13} Hz in at least two epochs of observation, consistent with a magnetic field B {approx} 1.5({+-} 0.8) x 10{sup 4} G assuming a single-zone synchrotron emission region. The observed variability implies that either B or the size of the acceleration zone above the jet base is being modulated by factors of {approx}10 on relatively short timescales.
- OSTI ID:
- 21565398
- Journal Information:
- Astrophysical Journal Letters, Vol. 740, Issue 1; Other Information: DOI: 10.1088/2041-8205/740/1/L13; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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