We present a multi-wavelength study of the unassociated Fermi-LAT source, 3FGL J0954.8-3948, which is likely the gamma-ray counterpart of a 9.3-hour binary in the field. With more than 9 years of Pass 8 LAT data, we updated the gamma-ray spectral properties and the LAT localization of the gamma-ray source. While the binary lies outside the cataloged 95% error ellipse, the optimized LAT ellipse is 0.1 degrees closer and encloses the binary. The system is likely spectrally hard in X-rays (photon index ~ 1.4) with orbital modulations detected in optical, UV, and possibly X-rays. A steep spectrum radio counterpart (spectral index ~ -1.6) is also found in the TIFR GMRT Sky Survey (TGSS), implying that it is a pulsar system. We obtained a series of SOAR and Gemini spectroscopic observations in 2017/2018, which show a low-mass secondary orbiting in a close circular orbit with K2 = 272 km/s under strong irradiation by the primary compact object. All the observations as well as the modelling of the X/gamma-ray high-energy emission suggest that 3FGL J0954.8-3948 is a redback millisecond pulsar in a rotation-powered state.
@article{arxiv.1807.02508,
title = {Multi-wavelength observations of a new redback millisecond pulsar candidate: 3FGL J0954.8-3948},
author = {Kwan-Lok Li and Xian Hou and Jay Strader and Jumpei Takata and Albert K. H. Kong and Laura Chomiuk and Samuel J. Swihart and Chung Yue Hui and K. S. Cheng},
journal= {arXiv preprint arXiv:1807.02508},
year = {2018}
}
Comments
10 pages, including 5 figures and 3 tables. Accepted for publication in ApJ