Search for pairs of isolated radio pulsars—Components in disrupted binary systems

Abstract

We have developed a method for analyzing the kinematic association of isolated relativistic objects possible remnants of disrupted close binary systems. We investigate pairs of fairly young radio pulsars with known proper motions and estimated distances (dispersion measures) that are spaced no more than 2-3 kpc apart. Using a specified radial velocity distribution for these objects, we have constructed 100-300 thousand trajectories of their possible motion in the Galactic gravitational field on a time scale of several million years. The probabilities of their close encounters at epochs consistent with the age of the younger pulsar in the pair are analyzed. When these probabilities exceed considerably their reference values obtained by assuming a purely randomencounter between the pulsars under consideration, we conclude that the objects may have been gravitationally bound in the past. As a result, we have detected six pulsar pairs (J0543+2329/J0528+2200, J1453-6413/J1430-6623, J2354+6155/J2321+6024, J1915+1009/J1909+1102, J1832-0827/J1836-1008, and J1917+1353/J1926+1648) that are companions in disrupted binary systems with a high probability. Estimates of their kinematic ages and velocities at binary disruption and at the present epoch are provided.

Neutron Stars From Young Nearby Associations: The Origin of RX J1605.3+3249

“…To further reduce the number of potential former companion candidates, we follow the idea of Chmyreva, Beskin & Biryukov (2010). They used a reference probability as significance indicator that two objects approach to small distances taking into account the spatial density distribution of the objects (we refer to details on this method to Chmyreva et al 2010). Chmyreva et al (2010) investigated pairs of pulsars whereas we investigate NS-runaway star pairs.…”

“…They used a reference probability as significance indicator that two objects approach to small distances taking into account the spatial density distribution of the objects (we refer to details on this method to Chmyreva et al 2010). Chmyreva et al (2010) investigated pairs of pulsars whereas we investigate NS-runaway star pairs. Therefore, beside the spatial density distribution of NS, also the density distribution of runaway stars is needed.…”

“…We select those stars for which separations smaller than one parsec are found after three million runs, 28 in total. To further reduce the number of potential former companion candidates, we follow the idea of Chmyreva, Beskin & Biryukov (2010). They used a reference probability as significance indicator that two objects approach to small distances taking into account the spatial density distribution of the objects (we refer to details on this method to Chmyreva et al 2010).…”

Search for connections between isolated radio pulsars and supernova remnants

“…Searching for the kinematic association of a pulsar and a SNR is similar to associating two pulsars (see our previous work, [3]): it consists of determining the closest approaches of their reconstructed trajectories in the past.…”

“…As in our previous work of searching for pulsar associations [3], we solve the equation of motion for pulsars with various initial conditions, and simulate the trajectories of their possible motion. The trajectories are traced into the past on a timescale of up to 10 6 years, and the distances ρ min of closest approaches to the centers of SNRs are calculated.…”