The Leonard E Parker Center for Gravitation, Cosmology and Astrophysics holds frequent seminars on a broad range of ongoing cosmology and gravitation research topics. Unless otherwise noted, seminars are on Friday afternoons at 1:00 PM in KIRC 2175; there is a gathering for a brown bag lunch at 12:30.

Chasing Low Frequency Radio Bursts from Magnetically Active Stars
Dr. Christine Lynch, University of Sydney

Flaring activity is a common characteristic of magnetically active stellar systems. These events produce emission throughout the electromagnetic spectrum, implying a range of physical processes. A growing number of objects are observed to exhibit short-duration, narrow band, and highly circularly polarised (reaching 100%) radio bursts. The observed polarisation and frequency-time structure of these bursts points to a coherent emission mechanism such as the electron cyclotron maser. Due to the stochastic nature of these bursts and the sensitivity of current instruments, the number of stars where coherent emission has been detected is few, with numbers limited to a few tens of objects. Observations of a wider sample of active stellar systems are necessary in order to establish the percentage that exhibit coherent radio bursts and to relate occurrence of these bursts to basic physical parameters of these stellar objects. New wide-field, low frequency radio telescopes will probe a frequency regime that is mostly unexplored for many magnetically active star systems and where coherent radio emissions are expected to be more numerous. We are currently carrying out a targeted survey of M dwarf stars with known bright radio flares using the Murchison Widefield Array. The goal of this project is to confirm the flare detections made with single dish telescopes in the 1970s and to better constrain stellar flare rates at 154 MHz. In this talk I will present a recent detection of four coherent flares from the nearby M dwarf star UV Ceti and disscuss future prospects of detecting a larger sample of M dwarfs using what we know about our UV Ceti observation.