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Information × Registration Number 0224U032971, (0124U003926) , R & D reports Title Thermal free-free absorption in supernova remnants at radio emission frequencies below 80 MHz popup.stage_title Властивості поглинання випромінювання у залишках наднових 3C461 та 3C10 Head Stanislavsky Oleksandr O., Доктор фізико-математичних наук Registration Date 13-12-2024 Organization Radio Astronomical Institute of the National Academy of Sciences of Ukraine popup.description1 The purpose of this work is to study the radio emission of supernova remnants 3C461 and 3C10 from spectral observations using 3C405 as a calibrator. Measurements of such spectra on the Ukrainian GURT and URAN-2 radio telescopes with the French NenuFAR one due to the contribution of ionized gas inside and outside remnants will be a significant result. This will allow us to estimate the temperature, average ionization, and emission measure of the absorbing gas into the remnants and the surrounding interstellar medium. popup.description2  Based on the latest achievements of Ukrainian low-frequency radio astronomy, the study of low-frequency spectra of various supernova remnants and the evolution of their radiation over time opens up new possibilities in measuring the properties of thermal absorption in ionized gas inside and outside such radio sources. To conduct high-precision observations of the spectra of supernova remnants, the radiation of the radio galaxy Cygnus A is used as a calibration source, which has an extragalactic origin, a convenient location on the sky and practically does not change in intensity over time. For the reliability of observations, three low-frequency radio telescopes are used in the studies, two Ukrainian, GURT and URAN-2, and one French NenuFAR, which have the appropriate characteristics for conducting measurements. This allows avoiding significant harmful effects of such factors as radio interference, ionospheric disturbances caused by high solar activity during observations. With the help of such observations, it was possible to establish that the radio source 3C461 is no longer the most intense among all point-like radio sources in the current radio sky, as it was many years ago. Its place in terms of intensity has now been given to Cygnus A, which is not a supernova remnant. On the other hand, observations of the supernova remnant 3C10 showed that its radiation is about 62 times weaker than that of 3C461, which is explained by the different type of explosion of the corresponding supernova, but at the same time they have an almost similar shell shape of the radio image, which is very useful for their comparison. It is shown that by using adaptive beamforming of a multi-baseline interferometer, it is possible to distinguish the radiation of weakly intense sources of supernova remnants (in the example of 3C10) against the background of more powerful radio interference and other very bright radio sources such as Cygnus A and 3C461. Product Description popup.authors Bubnov Ihor M. Vashchyshyn Rostyslav V. Myrhorod Viacheslav I. Stanyslavskyi Lev O. Stanyslavskyi Oleksandr O. popup.nrat_date 2024-12-13 Close