GBT24B-410

Long Term Timing of 76 Recycled Pulsars in Bulge Globular Clusters

Abstract

We propose to continue timing 76 (and still counting) recycled pulsars in the bulge globular clusters Terzan 5, M28, NGC6440, NGC6652, and NGC6544 over the next three years using L-band (2024) and then eventually the Ultrawideband receiver, with the coherent filterbank mode of VEGAS. The vast majority of these pulsars were discovered with the GBT and many of them are exotic or even unique pulsar systems. They include almost 50 binary pulsars, 16 of which are in highly eccentric orbits and several of which appear to be massive neutron stars. There are at least 8 eclipsing systems, all of which are X-ray sources, one of which switches on as a LMXB (M28I), and one of which contains the fastest rotating neutron star known. Our proposed observations, totaling 70 hours per year and including high quality polarization measurements, will extend and improve our timing solutions and allow new insights into pulsar astronomy, neutron star physics, binary and globular cluster evolution, the interstellar medium, the Galactic magnetic field and gravitational potential, and globular cluster dynamics. This 20-year-long and growing data set is a truly unique and phenomenally valuable resource for astrophysics.

Investigators

Name	Institution
Scott Ransom *	National Radio Astronomy Observatory; Virginia, University of
Paulo Freire	Max-Planck-Institut für Radioastronomie
Ingrid Stairs	British Columbia, University of
Jason Hessels	Netherlands Institute for Radio Astronomy; Amsterdam, Universiteit van
Ryan Lynch	Green Bank Observatory
Megan DeCesar	George Mason University
Kyle Corcoran	Virginia, University of

* indicates the PI