Six New Recycled Globular Cluster Pulsars Discovered with the Green Bank
  Telescope
  We have completed sensitive searches for new pulsars in seven globular
clusters using the Robert C. Byrd Green Bank Telescope, and have discovered six
new recycled pulsars (four in NGC 6517 and two in M22), five of which are fully
recycled millisecond pulsars with P < 10 ms. We report full timing solutions
for all six new pulsars and provide estimates of their flux densities and
spectral indices. None of the pulsars are detected in archival Chandra data
down to L_X~10^32 erg/s for NGC 6517 and L_X~10^31 erg/s for M22. One of the
millisecond pulsars in M22 appears to have a very low mass companion, and is
likely a new "black widow". A second binary pulsar in NGC 6517 is in a
long-period, mildly eccentric orbit. We are able to set some lower limits on
the age of the system, and find that it may be less than a few hundred million
years old, which would indicate recent pulsar recycling in NGC 6517. An
isolated pulsar in NGC 6517 that lies about 20 core radii from the cluster
center appears to have been ejected from the core by interacting with a massive
binary. By analyzing the luminosity function of the pulsars in NGC 6517, we
predict the cluster to harbor roughly a dozen pulsars. We use the observed
period derivatives of three pulsars to set lower limits on the mass-to-light
ratios in the cores of their host clusters, and find no evidence for large
amounts of low-luminosity matter. We also discuss reasons for non-detections in
some of the clusters we searched.
