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- Title
Radio Emission Spectrum of Supernova Remnant G74.9+1.2.
- Authors
Ivanov, V. P.; Ipatov, A. V.; Rahimov, I. A.; Andreeva, T. S.
- Abstract
Measurements of the flux densities of the supernova remnant (SNR) G74.9+1.2 (CTB 87) at frequencies of 4840 and 8450 MHz were carried out with the RT-32 radio telescope of the Svetloye observatory of the Institute of Applied Astronomy, Russian Academy of Sciences (IAA RAS), in 2018–2019. The data contain signs of the presence of a source of a variable component in the radio emission on a time scale of a month or more. The flux densities of G74.9+1.2 over the time interval 1959.7–2010 are determined from published data, which allow the intensity of G74.9+1.2 to be compared with standard sources. All the data are presented in a single system based on the exact scale of "artificial moon" (AM) fluxes. A refined spectrum of SNR G74.9+1.2 was obtained. The totality of available data is approximated by two power-law sections with different spectral indices: at frequencies and at . The projections of two power-law sections intersect at a frequency MHz. The break in the radio spectrum of the source, considering its age (more than 4000 years), could form as a result of synchrotron losses. The increase in the steepness of the spectrum close to 0.5 above the frequency is an argument in favor of such an assumption. The totality of data obtained during measurements on the RT-32 and on the basis of published works allows us to state that the variable component in the G74.9+1.2 radio emission on all time scales is much less pronounced compared to younger PWNs. As a possible mechanism for the observed variability, a reconnection of the magnetic field lines in the pulsar magnetosphere is proposed.
- Subjects
SUPERNOVA remnants; SUPERNOVAE spectra; MOLECULAR spectra; MAGNETIC reconnection; ACTINIC flux; RADIO telescopes
- Publication
Astronomy Reports, 2023, Vol 67, Issue 10, p963
- ISSN
1063-7729
- Publication type
Article
- DOI
10.1134/S1063772923100062