Discovery: A radio transient with unusually slow periodic emission

[DennisN]

TL;DR Summary

Discovery: A radio transient with unusually slow periodic emission

Paper: N. Hurley-Walker, X. Zhang et.al, A radio transient with unusually slow periodic emission (Nature, 26 January 2022)

Abstract:

The high-frequency radio sky is bursting with synchrotron transients from massive stellar explosions and accretion events, but the low-frequency radio sky has, so far, been quiet beyond the Galactic pulsar population and the long-term scintillation of active galactic nuclei. The low-frequency band, however, is sensitive to exotic coherent and polarized radio-emission processes, such as electron-cyclotron maser emission from flaring M dwarfs, stellar magnetospheric plasma interactions with exoplanets and a population of steep-spectrum pulsars, making Galactic-plane searches a prospect for blind-transient discovery. Here we report an analysis of archival low-frequency radio data that reveals a periodic, low-frequency radio transient. We find that the source pulses every 18.18 min, an unusual periodicity that has, to our knowledge, not been observed previously. The emission is highly linearly polarized, bright, persists for 30–60 s on each occurrence and is visible across a broad frequency range. At times, the pulses comprise short-duration (<0.5 s) bursts; at others, a smoother profile is observed. These profiles evolve on timescales of hours. By measuring the dispersion of the radio pulses with respect to frequency, we have localized the source to within our own Galaxy and suggest that it could be an ultra-long-period magnetar.

Article: Mysterious object unlike anything astronomers have seen before (EurekAlert!/AAAS)

Interesting, I think.

 

[lippyka]

Astronomers have discovered a mysterious object that is unlike anything they have ever seen before. The object, which pulses with radio waves every 18.18 minutes, was spotted using archival low-frequency radio data collected from the Galactic plane.The object was found to be highly linearly polarized, bright, and visible across a broad frequency range. At times, its pulses comprise short-duration (<0.5 second) bursts; at others, a smoother profile is observed. These profiles evolve on timescales of hours.By measuring the dispersion of the radio pulses with respect to frequency, astronomers localized the source to within our own Galaxy and suggest that it could be an ultra-long-period magnetar.The findings were recently published in Nature by a team of researchers led by Dr. Natasha Hurley-Walker and Dr. Xin Zhang.The team hopes the discovery of this new type of radio transient will catalyze further research into the low-frequency radio sky. In addition, they suggest that a dedicated survey of the Galactic plane may uncover additional examples of this peculiar and unique object.