Revealing a New Black Widow Binary 4FGL J0336.0+7502. (arXiv:2103.01557v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Li_K/0/1/0/all/0/1">Kwan-Lok Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yap_Y/0/1/0/all/0/1">Y. X. Jane Yap</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hui_C/0/1/0/all/0/1">Chung Yue Hui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kong_A/0/1/0/all/0/1">Albert K. H. Kong</a>
We report on a discovery of a promising candidate as a black widow
millisecond pulsar binary, 4FGL J0336.0+7502, which shows many pulsar-like
properties in the 4FGL-DR2 catalog. Within the 95% error region of the LAT
source, we identified an optical counterpart with a clear periodicity at P(orb)
= 3.718178(9) hours using the Bohyunsan 1.8-m Telescope, Lulin One-meter
Telescope, Canada-France-Hawaii Telescope, and Gemini-North. At the optical
position, an X-ray source was marginally detected in the Swift/XRT archival
data, and the detection was confirmed by our Chandra/ACIS DDT observation. The
spectrum of the X-ray source can be described by a power-law model of Gamma =
1.6+/-0.7 and F(0.3-7keV) = 3.5e-14 erg/cm^2/s. The X-ray photon index and the
low X-ray-to-gamma-ray flux ratio (i.e., < 1%) are both consistent with that of
many known black widow pulsars. There is also a hint of an X-ray orbital
modulation in the Chandra data, although the significance is very low (1.3
sigma). If the pulsar identity and the X-ray modulation are confirmed, it would
be the fifth black widow millisecond pulsar binary that showed an
orbitally-modulated emission in X-rays.
We report on a discovery of a promising candidate as a black widow
millisecond pulsar binary, 4FGL J0336.0+7502, which shows many pulsar-like
properties in the 4FGL-DR2 catalog. Within the 95% error region of the LAT
source, we identified an optical counterpart with a clear periodicity at P(orb)
= 3.718178(9) hours using the Bohyunsan 1.8-m Telescope, Lulin One-meter
Telescope, Canada-France-Hawaii Telescope, and Gemini-North. At the optical
position, an X-ray source was marginally detected in the Swift/XRT archival
data, and the detection was confirmed by our Chandra/ACIS DDT observation. The
spectrum of the X-ray source can be described by a power-law model of Gamma =
1.6+/-0.7 and F(0.3-7keV) = 3.5e-14 erg/cm^2/s. The X-ray photon index and the
low X-ray-to-gamma-ray flux ratio (i.e., < 1%) are both consistent with that of
many known black widow pulsars. There is also a hint of an X-ray orbital
modulation in the Chandra data, although the significance is very low (1.3
sigma). If the pulsar identity and the X-ray modulation are confirmed, it would
be the fifth black widow millisecond pulsar binary that showed an
orbitally-modulated emission in X-rays.
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