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Title: DISCOVERY OF AN ULTRACOMPACT GAMMA-RAY MILLISECOND PULSAR BINARY CANDIDATE

We report multi-wavelength observations of the unidentified Fermi object 2FGL J1653.6-0159. With the help of high-resolution X-ray observations, we have identified an X-ray and optical counterpart to 2FGL J1653.6-0159. The source exhibits a periodic modulation of 75 minutes in the optical and possibly also in the X-ray. We suggest that 2FGL J1653.6-0159 is a compact binary system with an orbital period of 75 minutes. Combining the gamma-ray and X-ray properties, 2FGL J1653.6-0159 is potentially a black-widow-/redback-type gamma-ray millisecond pulsar (MSP). The optical and X-ray light curve profiles show that the companion is mildly heated by the high-energy emission and that the X-rays are from intrabinary shock. Although no radio pulsation has yet been detected, we estimated that the spin period of the MSP is ∼ 2 ms based on a theoretical model. If pulsation can be confirmed in the future, 2FGL J1653.6-0159 will become the first ultracompact rotation-powered MSP.
Authors:
; ; ; ;  [1] ;  [2] ; ;  [3] ; ;  [4] ;  [5]
  1. Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)
  2. Graduate Institute of Astronomy, National Central University, Jhongli 32001, Taiwan (China)
  3. Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of)
  4. Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong)
  5. Department of Physics and Astronomy, Seoul National University (Korea, Republic of)
Publication Date:
OSTI Identifier:
22364592
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 794; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC X-RAY SOURCES; DIAGRAMS; GAMMA RADIATION; MODULATION; PERIODICITY; POTENTIALS; PULSARS; PULSATIONS; RESOLUTION; ROTATION; SPIN; STARS; VISIBLE RADIATION; X RADIATION