ASKAP observations of known and new Galactic SNRs
Abstract
The Australian SKA Pathfinder (ASKAP), one of the three SKA precursors, entered its earlyscience phase in late 2017 and it is now approaching the full-regime period. During these last months many scientific programs have been carried out for commissioning purposes. Beside the technical value of reducing and analyzing these data, a surprisingly high scientific return also occurred. In the wide context of the preparation for the EMU survey, one of the large programs approved for ASKAP and planned to start by mid-2019, we used ASKAP in January and December 2018 to observe at 0.9 and 1.6 GHz the "SCORPIO field", a patch of about 40 square degrees on the Galactic plane, previously imaged with the Australia Telescope Compact Array to serve as validation for ASKAP. ASKAP is proving formidable in imaging Galactic fields, providing simultaneously a high resolution (20 arcsec) and a good sensitivity to extended structures (with a largest angular scale around 40 arcmin). Thanks to these features we were able to observe several tens of Galactic objects and in particular supernova remnants (SNRs). We detected all the 17 SNRs known from literature lying in our field. For these objects ASKAP data are allowing us to derive a very accurate flux density, disentangling the remnants from nearby sources (especially in particularly crowded regions), make a comparison with infrared images at about the same resolution, and build radio spectral index maps. The ASKAP images are also revealing several other previously undetected or unclassified sources that we are proposing as SNRs, highlighting in this way also the discovery capability of the instrument. We finally remark that the study of SNRs in SCORPIO is also part of the Italian project 'Gammaprop' aimed at studying cosmic accelerators (including SNRs and pulsar wind nebulae) in view of the construction of the CTA and SKA and their synergetic use.
- Publication:
-
Supernova Remnants: An Odyssey in Space after Stellar Death II
- Pub Date:
- June 2019
- Bibcode:
- 2019sros.confE..49I