Pulsar Timescales and Time Synchronization

Observations of astrophysical pulsars have been used to develop time-scales, as well as for time synchronization.Pulsar-based time-scales have already been developed and have long-term precision of relevance to the terrestrial time keeping community.Such pulsar-based time-scales have been created using observations from pulsar timing arrays where millisecond pulsars are observed with high precision over decades.The most recent large-scale pulsar-based time-scale was developed from the International Pulsar Timing Array data set in 2020.This timesclae agreed with TT(BIPM), but showed that the stability of future pulsar-based time-scale is likely to be limited by our knowledge of solar-system dynamics.Since that time the data available to the pulsar timing array communities has significantly improved.These data sets are formed after the observations have been completed.However, the "PULCHRON" system generates a real-time timescale.Observations of millisecond pulsars from the European Pulsar Timing Array are being used to provide steering (on a monthly timescale) of a hydrogen maser.This concept is based on the assumption that short-to-medium-term stability is provided by a hydrogen maser, whereas the pulsars provide the longer-term stability.However, it is likely that years to decades will be needed before the value of the PULCHRON timing system will be realized.