22 MARZO 2022 ore 11:00

An ultra-long period radio transient

Dr. Natasha Hurley-Walker (ICRAR - Curtin University, Australia)
An ultra-long period radio transient

In the two decades, several puzzling radio transients have been detected using low-frequency radio telescopes, signalling intriguing high-energy events in our sky. The paucity of data on these objects has made it impossible to understand their nature. New wideband widefield telescopes are expanding the parameter space, improving our ability to detect and understand these events. We have detected a new type of low-frequency radio transient using a sky survey performed by the Murchison Widefield Array. The source's emission is bright, highly polarised, and periodic on a timescale of ~20 minutes. Its dynamic spectrum shows high-fluence narrow-timescale “spikes” which are unresolved by our data, with fluence on par with Fast Radio Bursts generated by the Galactic centre magnetar. I will highlight the object’s main  observational features, including its window of appearance, dispersion measure, polarisation attributes, and changes in its pulse profile over time. Along with X-ray and optical observations, these features have allowed us to constrain its physical attributes such as location in the Galaxy, radio luminosity, and potential magnetic field strength, which I will detail in this talk. The source is potentially an “ultra-long period” (ULP) magnetar, which are candidate progenitors for Fast Radio Bursts. I will also postulate some alternative explanations and describe how we could narrow the possibilities with future observations. Finally, I will describe upcoming observing campaigns that will help us detect further examples, and perform rapid follow-up.


Breve CV della Dr. Natasha Hurley-Walker:

La Dr. Natasha Hurley-Walker è un Senior Lecturer ed un ARC Future Fellow all'International Centre for Radio Astronomy Research presso la Curtin University. Dopo aver ricevuto il suo PhD in Radio Astronomia dall'Università di Cambridge, si è trasferita in Australia per aiutare nel commissioning del Murchison Widefield Array, uno strumento percursore per lo Square Kilometer Array. Ha condotto diverse survey del cielo su ampia scala come GLEAM, ed ha interessi di ricerca nei cicli vitali delle radio galassie, resti di supernova, e tansienti. Per la sua scienza, il lavoro sulle parità di genere, ed attività di divulgazione, è stata nominata come WA Tall Poppies Scientist of the Year (2017), ABC Top 5 Scientist (2018) e Superstar of STEM (2019–2020). E' a capo del gruppo di radio astronomia extragalattica dell'ICRAR-Curtin, ed attualmente dirige la GLEAM-X survey per esplorare il cielo radio dell'emisfero sud, che ha portato alla recente scoperta di un nuovo e inaspettato tipo di transiente radio periodico.