SIMBAD references

2015ApJ...808...17X - Astrophys. J., 808, 17 (2015/July-3)

Fermi observation of the transitional pulsar binary XSS J12270-4859.


Abstract (from CDS):

Because of the disappearance of its accretion disk during the time period of 2012 November-December, XSS J12270-4859 has recently been identified as a transitional millisecond pulsar binary, joining PSR J1023+0038. We have carried out a detailed analysis of the Fermi Large Area Telescope data for this binary. While both spectra are well-described by an exponentially cut-off power law before and after the disk-disappearance transition, which is typical for pulsars' emissions in Fermi's 0.2-300 GeV band, we have detected a factor of 2 flux decrease related to the transition. A weak orbital modulation is possibly seen, but is only detectable in the after-transition data, making it the same as orbital modulations found in X-rays. In the long-term light curve of the source before the transition, a factor of 3 flux variations are seen. Compared to the properties of J1023+0038, we discuss the implications from these results. We suggest that since the modulation is aligned with the modulations in X-rays in the orbital phase, it possibly arises due to the occultation of the γ-ray emitting region by the companion. The origin of the variations in the long-term light curve is not clear because the source field also contains unidentified radio or X-ray sources and their contamination cannot be excluded. Multi-wavelength observations of the source field will help identify the origin of the variations by detecting any related flux changes from the in-field sources.

Abstract Copyright:

Journal keyword(s): binaries: close - stars: individual: XSS J12270-4859 - stars: low-mass - stars: neutron

Simbad objects: 9

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