English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Breaks in the radio spectra of supernova remnants (SNRs) reflect the maximumenergy of either shock-accelerated electrons or - in the case of pulsar windnebulae - of electrons injected by the central pulsar. Otherwise, the break mayresult from energy losses due to synchrotron aging or it is caused byenergy-dependent diffusion. A spectral steepening of the plerionic SNR CTB87 ataround 11 GHz was observed in the eighties, but a recent analysis of CTB87'senergetic properties based on new radio data raised doubt on it. CTB87 consistsof a central compact component surrounded by a diffuse centrally peaked almostcircular halo. Missing faint halo emission due to insufficient sensitivity ofearly high-frequency observations may be be the reason for the reportedspectral break. We intend to clarify the high-frequency spectrum of CTB87 bynew sensitive observations. We used the broad-band 2-cm receiver at theEffelsberg 100-m telescope for sensitive continuum observations of CTB87 andits halo in two frequency bands. The new 2-cm maps of CTB87 show halo emissionwith a diameter of about 17' or 30 pc for a distance of 6.1 kpc in agreementwith lower-frequency data. The measured flux densities are significantly higherthan those reported earlier. The new 2-cm data establish the high-frequencycontinuation of CTB87's low-frequency spectrum. Any significant high-frequencyspectral bend or break is constrained to frequencies well above about 18 GHz.The extended halo of CTB87 has a faint counterpart in gamma-rays (VER J2016+37)and thus indicates a common origin of the emitting electrons.

Extended radio halo of the supernova remnant CTB87 (G74.9+1.2)