Near-Infrared and X-Ray Observations of XSS J12270-4859

Abstract

XSS J12270-4859 (J12270) is an enigmatic source of unknown nature. Previous studies revealed that the source has unusual X-ray temporal characteristics, including repetitive short-term flares followed by spectral hardening, non-periodic dips, and dichotomy in activity; i.e. intervals filled with flares and those without. Together with a power-law X-ray spectrum, it is suggested to be a low-mass X-ray binary (LMXB). In order to better understand the object, we present the results of our near-infrared (NIR) photometry and linear polarimetry observations as well as X-ray spectroscopy observations, which overlap with each other partially in time, taken respectively with the InfraRed Survey Facility (IRSF) and the Rossi X-ray Timing Explorer (RXTE). We detected several simultaneous NIR and X-ray flares for the first time. No significant NIR polarization was obtained. We assembled data taken with IRSF, RXTE, Suzaku, Swift, and other missions in the literature and compared the flare profile and the spectral energy distribution (SED) with some representative high-energy sources. Based on some similarities of the repetitive NIR and X-ray flaring characteristics and the broad SED, we argue that J12270 is reminiscent of microquasars with a synchrotron jet, which is at a very low luminosity state of ~1e-4 Eddington luminosity for a stellar mass black hole or neutron star at a reference distance of 1 kpc.

12 pages, 9 figures, accepted for publication in PASJ

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• The 3rd IBIS/ISGRI soft gamma-ray survey catalog
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• Time-resolved optical observations of five cataclysmic variables detected by INTEGRAL
• The first polarimetric signatures of infrared jets in X-ray binaries
• RXTE determination of the intermediate polar status of XSS J00564+4548, IGR J17195-4100, and XSS J12270-4859
• The Swift X-ray flaring afterglow of GRB 050607

Cited by in corpus (6)

• X-ray follow-ups of XSSJ12270-4859: a low-mass X-ray binary with gamma ray FERMI-LAT association
• Transitional millisecond pulsars
• Unveiling the redback nature of the low-mass X-ray binary XSSJ1227.0-4859 through optical observations
• Discovery of X-ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku
• $p\gamma$ interactions in Galactic jets as a plausible origin of the positron excess
• Probing multi-band variability and mode switching in the candidate transitional millisecond pulsar 3FGL J1544.6-1125