Wavelet-based Characterization of Small-scale Solar Emission Features at Low Radio Frequencies
A Suresh, R Sharma, D Oberoi, SB Das, V Pankratius, B Timar, CJ Lonsdale, JD Bowman, F Briggs, RJ Cappallo, BE Corey, AA Deshpande, D Emrich, R Goeke, LJ Greenhill, BJ Hazelton, M Johnston-Hollitt, DL Kaplan, JC Kasper, E Kratzenberg Show all
ASTROPHYSICAL JOURNAL | IOP PUBLISHING LTD | Published : 2017
Low radio frequency solar observations using the Murchison Widefield Array have recently revealed the presence of numerous weak short-lived narrowband emission features, even during moderately quiet solar conditions. These nonthermal features occur at rates of many thousands per hour in the 30.72 MHz observing bandwidth, and hence necessarily require an automated approach for their detection and characterization. Here, we employ continuous wavelet transform using a mother Ricker wavelet for feature detection from the dynamic spectrum. We establish the efficacy of this approach and present the first statistically robust characterization of the properties of these features. In particular, we e..View full abstract
This scientific work makes use of the Murchison Radioastronomy Observatory, operated by CSIRO. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site. Support for the operation of the MWA is provided by the Australian Government (NCRIS), under a contract to Curtin University administered by Astronomy Australia Limited. We acknowledge the Pawsey Supercomputing Centre, which is supported by the Western Australian and Australian Governments. A.S. would like to thank Atul Mohan (graduate student at the National Centre for Radio Astrophysics-Tata Institute of Fundamental Research (NCRA-TIFR), Pune, India) for thought-provoking discussions and providing timely, constructive criticisms. A.S. would also like to thank NCRA-TIFR for the computation and infrastructure support, and the Kishore Vaigyanik Protsahan Yojana scheme under the Department of Science and Technology, Government of India for the financial support provided during the period of this work.