Series: Astronomy Colloquium
Date: Wednesday 08-Nov-2023
Time: 16:05-17:00 (4:05-5:00 pm)
Location: ATL 2400
Speaker: Dr. Natasha Hurley-Walker (Curtin University-Australia)
Title: Long-period radio transients
Pulsars have long been known to produce periodic pulsed radio emission as they rotate with periods of milliseconds to seconds, generating radio waves that sweep across our line-of-sight. They allow us to probe extremes of magnetism, gravity, neutron star composition, and have been used to test general relativity to high precision. While the exact radio emission mechanism is not well- understood, they are thought to be jointly powered by their magnetic fields and fast rotation, persisting for millions of years before slowing to rotation rates (~minutes) that no longer generate radio waves (crossing the “death lines”). Magnetars, which are highly magnetized, young neutron stars, are known for their sporadic periodic bursts of X-rays, gamma-rays, and radio waves, believed to be triggered by intense magnetic activity.
Using the Murchison Widefield Array, we have detected two long-period radio transients, with periods of 18 and 22 minutes. Timing estimates place the most recently discovered source below the conventional death lines of physical mechanisms that produce radio emission from pulsars, or rescaled death lines for white dwarf pulsars. However, its long-lived activity makes it challenging to interpret as a magnetar. The sources' bright radio emission is therefore a puzzle which new observations with MeerKAT and new physical modelling is beginning to illuminate. I will describe the sources, show our current thinking on the origin of the radio emission, and conclude with future survey plans across a range of telescopes.
In-person colloquia are usually preceded by espresso and ice cream at 1:45 pm outside room PSC 1150 and are followed by an informal reception at 5:15 pm in that room. Anyone interested in talking with the speaker, or being added to the colloquium announcement email list, should contact the colloquium organizer Dr. Leslie Sage. Lunch will normally be reserved for the speaker to talk to graduate students. Anyone asking a question during a talk is asked to raise their hand and be acknowledged before speaking. Contact Dr. Leslie Sage for details.
Colloquium Organizer:
Dr. Leslie Sage
Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.
