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Astrophysics, Solar and Stellar Astrophysics, astro-ph.SR
Abstract:
We present two millisecond pulsar discoveries from the PALFA survey of the
Galactic plane with the Arecibo telescope. PSR J1955+2527 is an isolated pulsar
with a period of 4.87 ms, and PSR J1949+3106 has a period of 13.14 ms and is in
a 1.9-day binary system with a massive companion. Their timing solutions, based
on 4 years of timing measurements with the Arecibo, Green Bank, Nan\c{c}ay and
Jodrell Bank telescopes, allow precise determination of spin and astrometric
parameters, including precise determinations of their proper motions. For PSR
J1949+3106, we can clearly detect the Shapiro delay. From this we measure the
pulsar mass to be 1.47(+0.43/-0.31) solar masses, the companion mass to be
0.85(+0.14/-0.11) solar masses and the orbital inclination to be i =
79.9(+1.6/-1.9) degrees, where uncertainties correspond to +/- 1-\sigma\
confidence levels. With continued timing, we expect to also be able to detect
the advance of periastron for the J1949+3106 system. This effect, combined with
the Shapiro delay, will eventually provide very precise mass measurements for
this system and a test of general relativity.
