The Millisecond Pulsars in NGC 6760

We present the results of recent Arecibo and Green Bank observations of theglobular cluster NGC 6760. Using Arecibo, a phase-coherent timing solution hasbeen obtained for the previously known binary pulsar in this cluster, PSRJ1911+0102A. We have also discovered a new millisecond pulsar in NGC 6760, PSRJ1911+0101B, an isolated object with a rotational period of 5.38 ms and adispersion measure DM = 196.7 cm-3 pc. Both pulsars are located within 1.3 coreradii of the cluster center and have negative period derivatives. The resultinglower limits for the accelerations of the pulsars are within the range expectedgiven a simple model of the cluster. A search for eclipses in the PSRJ1911+0102A binary system using both telescopes yielded negative results. Thecorresponding limits on the extra gas column density at superior conjunctionare consistent with the hypothesis that the observational properties ofultra-low-mass binary pulsars like PSR J1911+0102A are strongly affected by theinclination of the orbital plane of the system. Among globular cluster pulsarpopulations, that of NGC 6760 exhibits one of the largest known spreads in DM.This quantity seems to be roughly proportional to a cluster's central DM; thissuggests that the observed spread is caused by a turbulent interstellar mediumat spatial scales of 1 pc.Comment: 10 pages in referee format, 4 figures, one table, re-submitted to the Astrophysical Journa