Issue |
A&A
Volume 655, November 2021
|
|
---|---|---|
Article Number | A10 | |
Number of page(s) | 8 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/202140844 | |
Published online | 28 October 2021 |
Radio properties of the optically identified supernova remnant G107.0+9.0★
1
Max-Planck-Institut für Radioastronomie,
Auf dem Hügel 69,
53121
Bonn,
Germany
e-mail: wreich@mpifr-bonn.mpg.de; preich@mpifr-bonn.mpg.de
2
National Astronomical Observatories, Chinese Academy of Sciences,
Jia-20 Datun Road, Chaoyang District,
Beijing
100101, PR China
e-mail: xygao@nao.cas.cn
3
School of Astronomy and Space Sciences, University of Chinese Academy of Sciences,
Beijing
100049,
PR China
4
CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences,
Beijing
100101, PR China
Received:
22
March
2021
Accepted:
13
July
2021
Context. The vast majority of Galactic supernova remnants (SNRs) were detected by their synchrotron radio emission. Recently, the evolved SNR G107.0+9.0 with a diameter of about 3° or 75 pc up to 100 pc in size was optically detected with an indication of faint associated radio emission. This SNR requires a detailed radio study.
Aims. We aim to search for radio emission from SNR G107.0+9.0 by analysing new data from the Effelsberg 100-m and the Urumqi 25-m radio telescopes in addition to available radio surveys.
Methods. Radio SNRs outside of the Galactic plane, where confusion is rare, must be very faint if they have not been identified so far. Guided by the Hα emission of G107.0+9.0, we separated its radio emission from the Galactic large-scale emission.
Results. Radio emission from SNR G107.0+9.0 is detected between 22 MHz and 4.8 GHz with a steep non-thermal spectrum, which confirms G107.0+9.0 as an SNR. Its surface brightness is among the lowest known for Galactic SNRs. Polarised emission is clearly detected at 1.4 GHz but is fainter at 4.8 GHz. We interpret the polarised emission as being caused by a Faraday screen associated with G107.0+9.0 and its surroundings. Its ordered magnetic field along the line of sight is below 1 μG. At 4.8 GHz, we identified a depolarised filament along the western periphery of G107.0+9.0 with a magnetic field strength along the line of sight B||~ 15 μG, which requires magnetic field compression.
Conclusions. G107.0+9.0 adds to the currently small number of known, evolved, large-diameter, low-surface-brightness Galactic SNRs. We have shown that such objects can be successfully extracted from radio-continuum surveys despite the dominating large-scale diffuse Galactic emission.
Key words: radio continuum: ISM / ISM: supernova remnants
Reduced images (FITS) shown in Figs. 4–9 and 11 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/655/A10
© W. Reich et al. 2021
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Open Access funding provided by Max Planck Society.
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