| Download | - View final version: Extended radio halo of the supernova remnant CTB87 (G74.9+1.2) (PDF, 883 KiB)
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| DOI | Resolve DOI: https://doi.org/10.1051/0004-6361/202244741 |
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| Author | Search for: Reich, Wolfgang; Search for: Reich, Patricia; Search for: Kothes, Roland1 |
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| Affiliation | - National Research Council of Canada. Herzberg Astronomy and Astrophysics
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| Format | Text, Article |
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| Subject | supernovae: individual: CTB87; radiation mechanisms: non-thermal |
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| Abstract | Context. Breaks in the radio spectra of supernova remnants (SNRs) reflect the maximum energy of either shock-accelerated electrons or – in the case of pulsar wind nebulae – of electrons injected by the central pulsar. Otherwise, the break may result from energy losses due to synchrotron ageing or it is caused by energy-dependent diffusion. A spectral steepening of the plerionic SNR CTB87 at around 11 GHz was observed in the 1980s, but a recent analysis of CTB87’s energetic properties based on new radio data raised doubt on it. CTB87 consists of a central compact component surrounded by a diffuse, centrally peaked, almost circular halo. Missing faint halo emission due to insufficient sensitivity of early high-frequency observations may be the reason for the reported spectral break.
Aims. We intend to clarify the high-frequency spectrum of CTB87 by new sensitive observations.
Methods. We used the broad-band λ2 cm receiver at the Effelsberg 100-m telescope for sensitive continuum observations of CTB87 and its halo in two frequency bands.
Results. The new λ2 cm maps of CTB87 show halo emission with a diameter of about 17′ or 30 pc for a distance of 6.1 kpc in agreement with lower-frequency data. The measured flux densities are significantly higher than those reported earlier.
Conclusions. The new λ2 cm data establish the high-frequency continuation of CTB87’s low-frequency spectrum. Any significant high-frequency spectral bend or break is constrained to frequencies well above about 18 GHz. The extended halo of CTB87 has a faint counterpart in γ rays (VER J2016+37) and thus indicates a common origin of the emitting electrons. |
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| Publication date | 2022-12 |
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| Publisher | EDP Sciences |
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| Licence | |
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| Language | English |
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| Peer reviewed | Yes |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | adaf2a75-276a-46cd-a50e-28308c5864a0 |
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| Record created | 2024-02-20 |
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| Record modified | 2024-02-20 |
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