Speaker
Description
There is an observed discrepancy of nearly 700 sources between theory and observation for the supernova remnants (SNRs) population in the Galactic plane. Their mean radio spectral index of −0.5 makes these objects brighter at low frequencies.
The Murchison Widefield Array, a low-frequency radio interferometer, is a useful resource in detecting radio emissions from SNRs thanks to the wide field of view (10^2 −10^3 sq.deg.) and the observing band (72–300 MHz). The array has operated in two different configurations: Phase I used shorter baselines to resolve large-scale structures (2′− 15◦) reaching a noise level of 10 mJy/beam, and Phase II doubled the length of the baselines to capture the details of smaller scales (45′′ − 20′). Its lowered confusion limit enables better sensitivity over long integrations (∼1 mJy/beam).
To take advantage of both the resolution and sensitivity, we are jointly deconvolving those two sets of data using a GPU-based Image Domain Gridding (IDG, van der Tol et al., 2018) extension of WSCLEAN (Offringa et al., 2014) along part of the southern Galactic plane, 285◦ < l < 70◦ and |b| < 10◦. We aim to achieve a noise level between 10–2 mJy/beam across the observing band. This work will permit us to identify several more SNR candidates and investigate the free-free absorption of the unshocked ejecta (Arias et al., 2018). In this talk, I will examine the application of the IDG algorithm in detail and show preliminary results.
