J/A+A/655/A10 Supernova remnant G107.0+9.0 radio images (Reich+, 2021)
Radio properties of the optically identified supernova remnant G107.0+9.0.
Reich W., Gao X., Reich P.
<Astron. Astrophys. 655, A10 (2021)>
=2021A&A...655A..10R 2021A&A...655A..10R (SIMBAD/NED BibCode)
ADC_Keywords: Supernova remnants ; Radio sources ; Radio continuum
Keywords: radio continuum: ISM - ISM: supernova remnants
Abstract:
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 3D or 75pc up to 100pc in size
was optically detected with an indication of faint associated radio
emission. This SNR requires a detailed radio study.
We searched 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.
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.
Radio emission from SNR G107.0+9.0 is detected between 22MHz and
4.8GHz 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 1.4GHz but is fainter
at 4.8GHz. 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-microG. At
4.8GHz, we identified a depolarised filament along the western
periphery of G107.0+9.0 with a magnetic field strength along the line
of sight Bparallel∼15-microG, which requires magnetic field
compression.
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.
Description:
We extracted faint radio emission from the optically identified
SNR G107.0+9.0 from published surveys at 22MHz and 408MHz and new
observations at 1.4GHz and 4.8GHz.
G107.0+9.0 is clearly visible on the Effelsberg Medium Latitude Survey
(EMLS) 1.4-GHz maps (Uyaniker et al., 1998A&AS..132..401U 1998A&AS..132..401U,
1999A&AS..138...31U 1999A&AS..138...31U; Reich et al., 2004, in The Magnetized
Interstellar Medium, ed. B. Uyaniker, W. Reich, & R. Wielebinski
(Copernicus GmbH, Katlenburg-Lindau), 45). This section of the EMLS is
not yet published.
The Sino-German 4.8-GHz polarisation survey of the Galactic plane
within latitudes of ±5° was carried out with the Urumqi 25-m
telescope between 2004 and 2009 and published in a series of papers
(Gao et al., 2010A&A...515A..64G 2010A&A...515A..64G; Xiao et al., 2011A&A...529A..15X 2011A&A...529A..15X;
Sun et al., 2011A&A...527A..74S 2011A&A...527A..74S). A review and summary of the 4.8-GHz
survey results was given by Han et al. (2015, Highlights of Astronomy,
16, 394).
Objects:
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RA (2000) DE Designation(s)
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22 00 25 +66 26.0 G107.0+9.0 = SNR G107.0+09.0
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 144 20 List of fits images
fits/* . 20 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1 A1 --- --- [G]
2- 10 F9.5 deg GLON Galactic longitude of center (J2000)
11- 18 F8.5 deg GLAT Galactic latitude of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 38 F11.6 yr Obs.date Observation date
40- 44 F5.3 GHz Freq Observed frequency
46- 49 I4 Kibyte size Size of FITS file
51- 76 A26 --- FileName Name of FITS file, in subdirectory fits
78-144 A67 --- Title Title of the FITS file
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Acknowledgements:
Wolfgang Reich, wreich(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 06-Sep-2021