Recycled radio pulsars

We review the various radio surveys which have been designed primarily for discovering recycled pulsars. In the 11 years since the first millisecond pulsar, PSR 1937+21, was found, a total of about 55 have been discovered, although most of these have only been found since 1988. Around that time, the first millisecond pulsar was found in a globular cluster and by now a total of 34 pulsars have been found in these objects. These include a total of 29 pulsars with period less than 50 ms and 14 are in binary systems. New galactic surveys have now discovered 21 millisecond pulsars, mostly discovered in the past 2 years. These constitute a very nearby population which has a space density similar to that of normal pulsars. However, their formation rate is only one every 104–105 years.