News and Views

Comment on “Spatial Modulation Search Applied to the Search and Confirmation of Highly Scintillated Pulsars at FAST with A Pulsar Discovered in M3”


News and Views for RAA 2021 Vol. 21, No. 8, 185

Author: Chen Wang

(CSIRO Data61, 13 Garden Street, Eveleigh, NSW 2015, Australia; at

One significant challenge in pulsar search is RFI mitigation. Existing search methods often have a separate stage to remove a certain segment or spectrum in the data that have RFI pattern before applying periodical signal search techniques. However, the search results may still contain many false positives and false negatives due to the diverse sources of RFI and the complex patterns of RFI signals. This leads to a confirmation stage for detected pulsar signals in practice, which often requires additional telescope time to re-observe the pulsar candidates and causes delay of discovery. For pulsars with intrinsic low detection probability, the re-observation may need a significant amount of observation time and results in inefficient use of the telescope.

This paper proposes a smart way to address this problem by exploiting the different patterns between pulsar signals and RFI signals in observation data. When the telescope is pointed to and away from the pulsar position with a carefully calibrated time interval, the pulsar signals and RFI signals show a clear pattern difference in data. The chance of mistaking an RFI signal for a pulsar signal is greatly reduced with this approach, hence the necessity of re-observing the signal for confirmation. This paper opens an important discussion thread about efficient utilization of telescope resources. It at least demonstrates that a time-division multiplexing of different observation tasks with the same telescope at the same time slot is a feasible approach for both pulsar discovery and confirmation. There are lots of potentials along this direction for efficiency improvement of telescope time sharing, meanwhile, the trade-off between the detection accuracy and efficiency of telescope utilization needs further study.