Beijing, October 2 (Reporter Sun Zifa) The National Astronomical Observatory of the Chinese Academy of Sciences announced to the media on October 2 that using the 500-meter aperture spherical radio telescope (FAST), known as the "eye of China's sky", the "Wang Shouqian Sky Survey Commando Team" led by researcher Han Jinlin of the station recently discovered 76 new occasional pulsars in the "Gilactic Plane Pulsar Snapshot Survey", including the faintest celestial objects known to mankind.
The newly discovered and known rotational radio transient source RRAT, the "Chinese Sky Eye", has a flow rate about an order of magnitude lower than that of ordinary pulsars. Photo courtesy of National Astronomical Observatories, Chinese Academy of Sciences
This group of faint objects only occasionally radiates pulses during only a few rotational periods, and is internationally known as the "rotational radio transient source" (RRAT). The "Wang Shouqian Sky Survey Commando" also used the "Chinese Sky Eye" to make high-sensitivity observations of 59 internationally known RRATs, confirming that RRATs are occasional pulsars.
The new discovery and related research results of "Chinese Sky Eye" were published in the Chinese astronomy international academic journal Astronomy and Astrophysics Research (RAA) on October 2. Corresponding author Han Jinlin, a researcher who said that this study is of great significance for understanding the dense debris and its radiation characteristics after the death of stars in the Milky Way, and highly sensitive observations are the key to revealing such astrophysical characteristics.
The Chinese astronomical international academic journal Astronomy and Astrophysics Research (RAA) published the newly discovered research results of "China's Sky Eye" with a cover paper. Photo courtesy of National Astronomical Observatories, Chinese Academy of Sciences
Han Jinlin said that the RRAT discovered earlier is very special, unlike most pulsars like continuous radiation pulses, generally many cycles of accidental emission of a pulse, so it is difficult to capture in the normal pulsar search system, need to detect a pulse by pulse from the high-sensitivity telescope observation data, and dig out the public period after detecting several pulses. Since the discovery of the first RRAT in 2006, radio telescopes around the world have discovered more than 160 RRATs. Based on a handful of previous RRAT studies, astronomers realized they should be pulsars with special properties, accounting for about 5% of the total number of pulsars.
The scientific research team of the National Astronomical Observatory of the Chinese Academy of Sciences used the self-developed efficient single-pulse search program to systematically search for single pulses from the data of the "China Sky Eye" galactic pulsar snapshot survey, and found 76 new faint RRTs this time, and divided them into four categories: first, 26 radio transient sources whose rotation period has not yet been found; the second is 16 standard RRTs with a determined period; the third is 10 extreme zeroing pulsars that are silent for a long time but emit periodic signals for a short time; The fourth is 24 extremely faint pulsars with occasional strong pulses.
A newly discovered sporadic pulsar in the "Chinese Sky Eye". Left: Classic RRAT; Medium: extreme zeroing pulsar; Right: Faint pulsars with occasional intense pulses. Photo courtesy of National Astronomical Observatories, Chinese Academy of Sciences
Han Jinlin said that the occasional pulsars detected by single-pulse search technology accounted for about 12% of the total number of pulsars found by the "China Sky Eye" sky survey, which indicates that there are more than twice as many such occasional pulsars in the Milky Way than originally known. In order to deeply understand the physical properties of RRAT, the team also used the "Chinese Sky Eye" to observe 59 internationally reported known RRATs, and found that 25 RRTs appeared as ordinary pulsars in the "Chinese Sky Eye" observation data; 5 are extreme zeroing pulsars; 13 faint pulsars with occasional strong pulses; 5 also detected only a few pulses during the limited observation time of the "Chinese Sky Eye"; The other 11 may have been extinguished at the time, leaving no signal detected by the Chinese Sky Eye.
He pointed out that according to the highly sensitive observations of the "Chinese Sky Eye", none of the 59 RRTs exhibited the characteristics of typical RRATs. At the same time, the "Chinese Sky Eye" also detected the polarization signal of these occasional pulses and found that their polarization position angle followed the polarization position angle curve of the average pulse profile, which indicates that the occasional strong pulse of RRAT and the extremely weak pulse of normal radiation both come from the same radiation region of the neutron star's magnetosphere. (End)