Russian astronomers searched for rotating radio transients using the Pushchino Radio Astronomy Observatory (PRAO) (RRATs). They report the discovery of two new RRATs as part of this observational campaign in a recently published paper on the arXiv pre-print server.
RRATs are a type of pulsar that emits sporadic radiation. The first of these objects was discovered in 2006 as sporadic appearing dispersed pulses with frequencies ranging from several minutes to several hours. However, the nature of these transients remains unknown. In general, they are assumed to be ordinary pulsars with strong pulses.
A team of astronomers led by PRAO’s Sergey Tyul’bashev has discovered two new RRATs, J1550+09 and J2047+13. The discovery was made using PRAO’s Large Phased Array, which has a channel width of 78 kHz and a readout time of 12.5 milliseconds. The observations were carried out in 96 spatial beams at declinations ranging from -7 to +42 degrees.
“The radio telescope’s large effective area of approximately 45,000 m2 provides high fluctuation sensitivity, allowing us to search for RRATs,” the researchers explained.
Both RRATs were discovered far beyond the Milky Way galaxy’s plane. For J1550+09 and J2047+13, the distances were estimated to be around 3,100 and 7,200 light years, respectively, which is typical for pulsars. J1549+09 and J2047+12 dispersion measures were calculated to be 21 and 35 pc/cm3, respectively.
According to the study, J1549+09 was discovered four times in a four-year period, and J2047+12 was discovered seven times. On one of the days, J2047+12, two pulses were detected in a time span of 2.925 seconds. J1550+09 and J2047+13 pulse half-widths were measured to be 18 and 35 milliseconds, respectively.
The observation time before the appearance of the pulse from J1550+09 was 20 hours, and for J2047+12 it was approximately 11 hours. The researchers concluded that this proves the existence of RRATs, which have a single pulse lasting 10 hours or more. “The study demonstrates the existence of rotating transients with pulses that appear less frequently than once every ten hours of observations.(…) Detecting such rarely flashing rotating radio transients requires a long series of observations and the use of the programmes described above “the paper’s authors wrote.