Radio observations of supernova remnant G1.9+0.3
Abstract
We present 1-10 GHz radio continuum flux density, spectral index, polarization, and rotation measure (RM) images of the youngest known Galactic supernova remnant (SNR) G1.9+0.3, using observations from the Australia Telescope Compact Array. We have conducted an expansion study spanning eight epochs between 1984 and 2017, yielding results consistent with previous expansion studies of G1.9+0.3. We find a mean radio continuum expansion rate of (0.78 ± 0.09) per cent yr-1 (or ∼8900 km s-1 at an assumed distance of 8.5 kpc), although the expansion rate varies across the SNR perimetre. In the case of the most recent epoch between 2016 and 2017, we observe faster-than-expected expansion of the northern region. We find a global spectral index for G1.9+0.3 of -0.81 ± 0.02 (76 MHz-10 GHz). Towards the northern region, however, the radio spectrum is observed to steepen significantly (∼-1). Towards the two so-called (east and west) `ears' of G1.9+0.3, we find very different RM values of 400-600 and 100-200 rad m2, respectively. The fractional polarization of the radio continuum emission reaches (19 ± 2) per cent, consistent with other, slightly older, SNRs such as Cas A.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2020
- DOI:
- 10.1093/mnras/stz3439
- arXiv:
- arXiv:1912.01771
- Bibcode:
- 2020MNRAS.492.2606L
- Keywords:
-
- supernovae: general;
- ISM: individual objects: G1.9+0.3;
- ISM: supernova remnants;
- radio continuum: ISM;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 17 Pages, 13 Figures