A Census of Rotating Radio Transients at 150 MHz with the Irish LOFAR Station
Rotating radio transients (RRATs) are neutron stars that emit detectable radio bursts sporadically. They are outliers in the neutron star population, in many observable properties, but by their nature are practically difficult to study in depth. In this paper, we present the results from 1408 h of observations of RRAT candidates using the Irish Low Frequency Array (LOFAR) station at 150 MHz. As of October 2022, this census involved observing 113 sources, leading to 29 detections which were then followed up systematically. Single-pulse emission was detected from 25 sources, and periodic emission from 14 sources. 18 sources were found to have emission behaviour that is not discussed in prior works using LOFAR instruments. Four novel or modified source periods have been determined, ranging from 1.507-3.921 s, and 8 new or updated phase-coherent pulsar timing ephemerides have been produced using detected bursts. One unexpected single-pulse with a clearly-Galactic dispersion measure was detected as a part of this work, but has not been re-detected in follow-up observations. Observations are ongoing to expand the number of observed sources and further characterise and improve ephemerides for the detected sources. This census has demonstrated the capability for international LOFAR stations to detect, monitor and characterise a significant fraction of these unique sources.
- Pub Date:
- February 2023
- Astrophysics - High Energy Astrophysical Phenomena
- Submitted to MNRAS. 21 pages, 7 figures, 8 tables