PSR J2021 Research Articles

A Survey for Millisecond Pulsars

We have searched 960 square degrees of sky for radio pulsars, using the 305 m telescope at Arecibo, Puerto Rico. The 430 MHz survey reached a limiting sensitivity for slow pulsars of 0.7 mJy using a dual-polarization, 32 channel filter bank over 8 MHz of bandwidth. We have detected one new millisecond pulsar, 11 new slow pulsars, one previously known millisecond pulsar, and eight previously known slow pulsars. The new millisecond pulsar, PSR J2033 +17, with a period of 5.9 ms, has been found to be in a binary system. The Keplerian circular orbital solution has a period of 56.2 days and a semimajor axis of 20.7 lt-s. One of the slow pulsars, PSR J2043+2740, is the second fastest pulsar that is not either recycled or associated with a supernova remnant. It is near the Cygnus Loop remnant, but timing measurements imply a pulsar characteristic age of 1.2 Myr, which makes an association unlikely.

A 143 Millisecond Radio Pulsar in the Supernova Remnant S147

We report the discovery of a 143 ms pulsar, PSR J0538+2817, in the supernova remnant S147 (G180.0-1.7). The pulsar is located 40' west of the center of S147, well within its evolved, roughly circular radio structure. An upper limit to the pulsar's age of 6 × 105 yr is consistent with the age of the remnant, estimated to be ~(8 × 104)-(2 × 105) yr. A dispersion measure-derived distance to PSR J0538+2817 is ~1.8 kpc, in reasonable agreement with a 0.8-1.6 kpc distance estimate for S147. These data provide sufficient evidence to hypothesize that the two objects are physically related and form a new association between a radio pulsar and an old supernova remnant.

Probing the Eclipse Region of a Binary Millisecond Pulsar

We report the discovery of a new eclipsing millisecond binary pulsar system, PSR J2051-0827. The pulsar has a period of 4.5 ms and is in a very compact circular orbit with a companion of mass ~0.03 M☉. Observations at low frequencies show that the eclipse duration is approximately 10% of the orbital period. However, at high radio frequencies, pulses are often detected throughout the eclipse region, revealing interesting time-variable density structure in the eclipsing plasma.

X-ray observations of PSR J0218+4232 and of PSR B1937+21

Navarro et al. (1995) have discovered a 2.3 ms radio pulsar in a 2.0 day orbit around a low-mass companion. An interesting feature of this pulsar, PSR J0218+4232, is that radio emission is discovered throughout the pulse period; this is taken by Navarro et al. as an indication that the pulsar magnetic field is almost aligned with the rotation axis, and may also be related to the rather high radio luminosity of this pulsar,L400MHZ> 2700 mJy kpc2. The dispersion measureDM= 61.25pc cm−3indicates a minimum distance of 5.7 kpc, according to the model for the free electron distribution in the Galaxy by Taylor and Cordes (1993).