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Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE, Astrophysics, Instrumentation and Methods for Astrophysics, astro-ph.IM
Abstract:
We present new discoveries and results from long-term timing of 72 pulsars
discovered in the Arecibo PALFA survey, including precise determination of
astrometric and spin parameters, and flux density and scatter broadening
measurements at 1.4 GHz. Notable discoveries include two young pulsars
(characteristic ages $\sim$30 kyr) with no apparent supernova remnant
associations, three mode changing, 12 nulling and two intermittent pulsars. We
detected eight glitches in five pulsars. Among them is PSR J1939+2609, an
apparently old pulsar (characteristic age $\sim$1 Gy), and PSR J1954+2529,
which likely belongs to a newly-emerging class of binary pulsars. The latter is
the only pulsar among the 72 that is clearly not isolated: a non-recycled
neutron star with a 931-ms spin period in an eccentric ($e\,=\,0.114$) wide
($P_b\,=\,82.7\,$d) orbit with a companion of undetermined nature having a
minimum mass of $\sim0.6\,M_{\odot}$. Since operations at Arecibo ceased in
2020 August, we give a final tally of PALFA sky coverage, and compare its 207
pulsar discoveries to the known population. On average, they are 50% more
distant than other Galactic plane radio pulsars; PALFA millisecond pulsars
(MSP) have twice the dispersion measure per unit spin period than the known
population of MSP in the Plane. The four intermittent pulsars discovered by
PALFA more than double the population of such objects, which should help to
improve our understanding of pulsar magnetosphere physics. The statistics for
these, RRATS, and nulling pulsars suggest that there are many more of these
objects in the Galaxy than was previously thought.
