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Published June 20, 2015 | Published + Submitted
Journal Article Open

Coordinated X-Ray, Ultraviolet, Optical, and Radio Observations of the PSR J1023+0038 System in a Low-mass X-Ray Binary State


The PSR J1023+0038 binary system hosts a neutron star and a low-mass, main-sequence-like star. It switches on year timescales between states as an eclipsing radio millisecond pulsar and a low-mass X-ray binary (LMXB). We present a multi-wavelength observational campaign of PSR J1023+0038 in its most recent LMXB state. Two long XMM-Newton observations reveal that the system spends ~70% of the time in a ≈3 × 10^(33) erg s^(−1) X-ray luminosity mode, which, as shown in Archibald et al., exhibits coherent X-ray pulsations. This emission is interspersed with frequent lower flux mode intervals with ≈5 x 10^(32) erg s^(−1) and sporadic flares reaching up to ≈10^(34) erg s^(−1), with neither mode showing significant X-ray pulsations. The switches between the three flux modes occur on timescales of order 10 s. In the UV and optical, we observe occasional intense flares coincident with those observed in X-rays. Our radio timing observations reveal no pulsations at the pulsar period during any of the three X-ray modes, presumably due to complete quenching of the radio emission mechanism by the accretion flow. Radio imaging detects highly variable, flat-spectrum continuum radiation from PSR J1023+0038, consistent with an origin in a weak jet-like outflow. Our concurrent X-ray and radio continuum data sets do not exhibit any correlated behavior. The observational evidence we present bears qualitative resemblance to the behavior predicted by some existing "propeller" and "trapped" disk accretion models although none can account for key aspects of the rich phenomenology of this system.

Additional Information

© 2015 American Astronomical Society. Received 2014 December 16; accepted 2015 April 16; published 2015 June 15. A.M.A. and J.W.T.H. acknowledge support from a Vrije Competitie grant from NWO. A.T.D. acknowledges support from an NWO Veni Fellowship. J.W.T.H. and A.P. acknowledge support from NWO Vidi grants. J.W.T.H. also acknowledges funding from an ERC Starting Grant "DRAGNET" (337062). A portion of the results presented was based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. This work was based in part on observations obtained at the MDM Observatory, operated by Dartmouth College, Columbia University, Ohio State University, Ohio University, and the University of Michigan. This research is based in part on observations made with ESO Telescopes at the Paranal Observatory under programme ID 292-5011. The WSRT is operated by ASTRON (Netherlands Institute for Radio Astronomy) with support from The Netherlands Foundation for Scientific Research. Access to the Lovell Telescope is supported through an STFC consolidated grant. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The EVN (http://www.evlbi.org) is a joint facility of European, Chinese, South African, and other radio astronomy institutes funded by their national research councils. LOFAR, the Low Frequency Array designed and constructed by ASTRON, has facilities in several countries, that are owned by various parties (each with their own funding sources), and that are collectively operated by the International LOFAR Telescope (ILT) foundation under a joint scientific policy. This research has made use of the NASA Astrophysics Data System (ADS). Facilities: XMM, Swift

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Published - 0004-637X_806_2_148.pdf

Submitted - 1412.5145v3.pdf


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August 22, 2023
August 22, 2023