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PSR J2129-0429 is a redback eclipsing millisecond pulsar binary with an unusually long 15.2 hour orbit. It was discovered by the Green Bank Telescope in a targeted search of unidentified Fermi gamma-ray sources. The pulsar companion is optically bright (mean $m_R = 16.6$ mag), allowing us to construct the longest baseline photometric dataset available for such a system. We present ten years of archival and new photometry of the companion from LINEAR, CRTS, PTF, the Palomar 60-inch, and LCOGT. Radial velocity spectroscopy using the Double-Beam Spectrograph on the Palomar 200-inch indicates that the pulsar is massive: $1.74pm0.18 M_odot$. The G-type pulsar companion has mass $0.44pm0.04 M_odot$, one of the heaviest known redback companions. It is currently 95% Roche-lobe filling and only mildly irradiated by the pulsar. We identify a clear 13.1 mmag yr$^{-1}$ secular decline in the mean magnitude of the companion as well as smaller-scale variations in the optical lightcurve shape. This behavior may indicate that the companion is cooling. Binary evolution calculations indicate that PSR J2129-0429 has an orbital period almost exactly at the bifurcation period between systems that converge into tighter orbits as black widows and redbacks and those that diverge into wider pulsar--white dwarf binaries. Its eventual fate may depend on whether it undergoes future episodes of mass transfer and increased irradiation.
We have investigated the intrabinary shock emission from the redback millisecond pulsar PSR J2129-0429 with XMM-Newton and Fermi. Orbital modulation in X-ray and UV can be clearly seen. Its X-ray modulation has a double-peak structure with a dip in b
Linares et al. (2016) obtained quasi-simultaneous g, r and i-band light curves and an absorption line radial velocity curve of the secondary star in the redback system 3FGL J0212.1+5320. The light curves showed two maxima and minima primarily due to
We present time-resolved optical spectroscopy of the `redback binary millisecond pulsar system PSR J1023+0038 during both its radio pulsar (2009) and accretion disc states (2014 and 2016). We provide observational evidence for the companion star bein
We present a study of PSR J1723-2837, an eclipsing, 1.86 ms millisecond binary radio pulsar discovered in the Parkes Multibeam survey. Radio timing indicates that the pulsar has a circular orbit with a 15 hr orbital period, a low-mass companion, and
PSR,J1723$-$2837 is a redback millisecond pulsar (MSP) with a low-mass companion in a 14.8,h orbit. The systems properties closely resemble those of transitional MSPs that alternate between spin-down and accretion-powered states. In this paper we rep