Daily Image
10-04-2018
Today's Colloquium: Low-frequency polarimetry on the path to the SKA: the POGS project
| Submitter: | Christopher Riseley |
| Description: | (NB: Note the unusual day!) Investigating the origin of cosmic magnetic fields is a key science driver behind the Square Kilometre Array (SKA). With the typical sensitivity predicted for surveys with the SKA, it should be possible to probe magnetic fields in the Universe statistically, using a grid of rotation measures (RMs). Historically, the majority of large polarimetric surveys have been performed in the 21cm band, with poor frequency sampling and limited sensitivity, dramatically hindering the accuracy with which RMs can be recovered. In the current era of the SKA precursors, however, observers have access to low-frequency instruments that are both highly sensitive and possess large fractional bandwidth, enabling high Faraday-space precision. In this talk, I will present the first results from the POlarization from the GLEAM Survey (POGS) project. This is an ongoing effort to exploit the excellent sky coverage and unparalleled fractional bandwidth of the Galactic and Extragalactic All-sky MWA (GLEAM) survey to extract a catalog of sources that are linearly-polarized at low frequencies. I will present a catalog of polarized sources detected at 200 MHz, including measured Faraday depths and polarization properties. Polarized sources detected by the MWA at 200 MHz as part of the POGS project, overlain on the Oppermann et al. (2014) map of Galactic Faraday depth. The initial region covered in this talk is bounded by the dashed contours, with the sign of the source FD indicated by the marker color, and the size scaled according to the magnitude of the FD. The GLEAM survey boundary is denoted by the dot-dashed contour. |
| Copyright: | Colloquium |
| Tweet |  |