We discovered 24 new millisecond pulsars in the globular cluster Terzan
5 using the S-band receiver of the Green Bank Telescope. This is now the
globular cluster with the largest number of known pulsars, 27. These
discoveries confirm fundamental predictions of globular cluster and
binary system evolution. Thirteen of the new MSPs are in binary systems,
of which two show eclipses and two have highly eccentric orbits. The
relativistic periastron advance for the two eccentric systems indicates
that at least one of these pulsars has a mass > 1.68 Msun at 95%
confidence. Such large neutron star masses constrain the equation of
state of matter above beyond the nuclear equilibrium density. The
luminosity distribution indicates that there are about 100 active
millisecond pulsars in the cluster detectable with an Arecibo-class
radio telescope in the southern hemisphere. A survey effort is underway
to use the same observing system to search for pulsars in other
similarly rich globular clusters.
Reference:
"Twenty-One Millisecond Pulsars in Terzan 5 Using the Green Bank Telescope",
Scott M. Ransom, Jason W. T. Hessels, Ingrid H. Stairs, Paulo
C. C. Freire, Fernando Camilo, Victoria M. Kaspi, David L. Kaplan,
Science, 307, 892 (11 Feb. 2005)