PSR J1306–40: An X-ray Luminous Redback with an Evolved Companion. (arXiv:1903.09211v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Swihart_S/0/1/0/all/0/1">Samuel J. Swihart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Strader_J/0/1/0/all/0/1">Jay Strader</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chomiuk_L/0/1/0/all/0/1">Laura Chomiuk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shishkovsky_L/0/1/0/all/0/1">Laura Shishkovsky</a>
PSR J1306–40 is a millisecond pulsar binary with a non-degenerate companion
in an unusually long $sim$1.097 day orbit. We present new optical photometry
and spectroscopy of this system, and model these data to constrain fundamental
properties of the binary such as the component masses and distance. The optical
data imply a minimum neutron star mass of $1.75pm0.09,M_{odot}$ (1-sigma)
and a high, nearly edge-on inclination. The light curves suggest a large hot
spot on the companion, suggestive of a portion of the pulsar wind being
channeled to the stellar surface by the magnetic field of the secondary,
mediated via an intrabinary shock. The H$alpha$ line profiles switch rapidly
from emission to absorption near companion inferior conjunction, consistent
with an eclipse of the compact emission region at these phases. At our
optically-inferred distance of $4.7pm0.5$ kpc, the X-ray luminosity is
$sim$10$^{33}$ erg s$^{textrm{-1}}$, brighter than nearly all known redbacks
in the pulsar state. The long period, subgiant-like secondary, and luminous
X-ray emission suggest this system may be part of the expanding class of
millisecond pulsar binaries that are progenitors to typical field pulsar–white
dwarf binaries.
PSR J1306–40 is a millisecond pulsar binary with a non-degenerate companion
in an unusually long $sim$1.097 day orbit. We present new optical photometry
and spectroscopy of this system, and model these data to constrain fundamental
properties of the binary such as the component masses and distance. The optical
data imply a minimum neutron star mass of $1.75pm0.09,M_{odot}$ (1-sigma)
and a high, nearly edge-on inclination. The light curves suggest a large hot
spot on the companion, suggestive of a portion of the pulsar wind being
channeled to the stellar surface by the magnetic field of the secondary,
mediated via an intrabinary shock. The H$alpha$ line profiles switch rapidly
from emission to absorption near companion inferior conjunction, consistent
with an eclipse of the compact emission region at these phases. At our
optically-inferred distance of $4.7pm0.5$ kpc, the X-ray luminosity is
$sim$10$^{33}$ erg s$^{textrm{-1}}$, brighter than nearly all known redbacks
in the pulsar state. The long period, subgiant-like secondary, and luminous
X-ray emission suggest this system may be part of the expanding class of
millisecond pulsar binaries that are progenitors to typical field pulsar–white
dwarf binaries.
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