INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY
Purpose: The analytical review of the main results of research in the new direction of the low-frequency radio astronomy, the interstellar medium radio spectroscopy at decameter waves, which had led to astrophysical discovery, recording of the radio recombination lines in absorption for highly excit...
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| Format: | Article |
| Language: | English |
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National Academy of Sciences of Ukraine, Institute of Radio Astronomy
2021-12-01
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| Series: | Radio Physics and Radio Astronomy |
| Subjects: | |
| Online Access: | http://rpra-journal.org.ua/index.php/ra/article/view/1369/pdf |
| _version_ | 1818388550420267008 |
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| author | S. V. Stepkin O. O. Konovalenko Y. V. Vasylkivskyi D. V. Mukha |
| author_facet | S. V. Stepkin O. O. Konovalenko Y. V. Vasylkivskyi D. V. Mukha |
| author_sort | S. V. Stepkin |
| collection | DOAJ |
| description | Purpose: The analytical review of the main results of research in the new direction of the low-frequency radio astronomy, the interstellar medium radio spectroscopy at decameter waves, which had led to astrophysical discovery, recording of the radio recombination lines in absorption for highly excited states of interstellar carbon atoms (more than 600).
Design/methodology/approach: The UTR-2 world-largest broadband radio telescope of decameter waves optimally connected with the digital correlation spectrum analyzers has been used. Continuous modernization of antenna system and devices allowed increasing the analysis band from 100 kHzto 24 MHz and a number of channels from 32 to 8192. The radio telescope and receiving equipment with appropriate software allowed to have a long efficient integration time enough for a large line series simultaneously with high resolution, noise immunity and relative sensitivity.
Findings: A new type of interstellar spectral lines has been discovered and studied, the interstellar carbon radio recombination lines in absorption for the record high excited atoms with principal quantum numbers greater than 1000. The line parameters (intensity, shape, width, radial velocity) and their relation ship with the interstellar medium physical parameters have been determined. The temperature of line forming regions is about 100 K, the electron concentration up to 0.1 cm–3 and the size of a line forming region is about 10 pc. For the first time, radio recombination lines were observed in absorption. They have significant broadening and are amplified by the dielectronic-like recombination mechanism and are also the lowest frequency lines in atomic spectroscopy.
Conclusions: The detected low-frequency carbon radio recombination lines and their observations have become a new highly effective tool for the cold partially ionized interstellar plasma diagnostics. Using them allows obtaining the information which is not available with the other astrophysical methods. For almost half a century of their research, a large amount of hardware-methodical and astrophysical results have been obtained including a record number of Galaxy objects, where there levant lines have been recorded. The domestic achievements have stimulated many theoretical and experimental studies in other countries, but the scientific achievements of Ukrainian scientists prove the best prospects for further development of this very important area of astronomical science. |
| first_indexed | 2024-12-14T04:27:37Z |
| format | Article |
| id | doaj.art-213b294af0524932ae4797cf9ac32bbe |
| institution | Directory Open Access Journal |
| issn | 1027-9636 2415-7007 |
| language | English |
| last_indexed | 2024-12-14T04:27:37Z |
| publishDate | 2021-12-01 |
| publisher | National Academy of Sciences of Ukraine, Institute of Radio Astronomy |
| record_format | Article |
| series | Radio Physics and Radio Astronomy |
| spelling | doaj.art-213b294af0524932ae4797cf9ac32bbe2022-12-21T23:17:09ZengNational Academy of Sciences of Ukraine, Institute of Radio AstronomyRadio Physics and Radio Astronomy1027-96362415-70072021-12-0126431432510.15407/rpra26.04.314INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPYS. V. Stepkin0O. O. Konovalenko1Y. V. Vasylkivskyi2D. V. Mukha3Institute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Mystetstv St., Kharkiv, 61002, UkraineInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Mystetstv St., Kharkiv, 61002, UkraineInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Mystetstv St., Kharkiv, 61002, UkraineInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Mystetstv St., Kharkiv, 61002, UkrainePurpose: The analytical review of the main results of research in the new direction of the low-frequency radio astronomy, the interstellar medium radio spectroscopy at decameter waves, which had led to astrophysical discovery, recording of the radio recombination lines in absorption for highly excited states of interstellar carbon atoms (more than 600). Design/methodology/approach: The UTR-2 world-largest broadband radio telescope of decameter waves optimally connected with the digital correlation spectrum analyzers has been used. Continuous modernization of antenna system and devices allowed increasing the analysis band from 100 kHzto 24 MHz and a number of channels from 32 to 8192. The radio telescope and receiving equipment with appropriate software allowed to have a long efficient integration time enough for a large line series simultaneously with high resolution, noise immunity and relative sensitivity. Findings: A new type of interstellar spectral lines has been discovered and studied, the interstellar carbon radio recombination lines in absorption for the record high excited atoms with principal quantum numbers greater than 1000. The line parameters (intensity, shape, width, radial velocity) and their relation ship with the interstellar medium physical parameters have been determined. The temperature of line forming regions is about 100 K, the electron concentration up to 0.1 cm–3 and the size of a line forming region is about 10 pc. For the first time, radio recombination lines were observed in absorption. They have significant broadening and are amplified by the dielectronic-like recombination mechanism and are also the lowest frequency lines in atomic spectroscopy. Conclusions: The detected low-frequency carbon radio recombination lines and their observations have become a new highly effective tool for the cold partially ionized interstellar plasma diagnostics. Using them allows obtaining the information which is not available with the other astrophysical methods. For almost half a century of their research, a large amount of hardware-methodical and astrophysical results have been obtained including a record number of Galaxy objects, where there levant lines have been recorded. The domestic achievements have stimulated many theoretical and experimental studies in other countries, but the scientific achievements of Ukrainian scientists prove the best prospects for further development of this very important area of astronomical science.http://rpra-journal.org.ua/index.php/ra/article/view/1369/pdflow-frequency radio astronomyradio telescopeinterstellar mediumradio recombination linescarbonhydrogenspectral analyzer |
| spellingShingle | S. V. Stepkin O. O. Konovalenko Y. V. Vasylkivskyi D. V. Mukha INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY Radio Physics and Radio Astronomy low-frequency radio astronomy radio telescope interstellar medium radio recombination lines carbon hydrogen spectral analyzer |
| title | INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY |
| title_full | INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY |
| title_fullStr | INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY |
| title_full_unstemmed | INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY |
| title_short | INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY |
| title_sort | interstellar medium and decameter radio spectroscopy |
| topic | low-frequency radio astronomy radio telescope interstellar medium radio recombination lines carbon hydrogen spectral analyzer |
| url | http://rpra-journal.org.ua/index.php/ra/article/view/1369/pdf |
| work_keys_str_mv | AT svstepkin interstellarmediumanddecameterradiospectroscopy AT ookonovalenko interstellarmediumanddecameterradiospectroscopy AT yvvasylkivskyi interstellarmediumanddecameterradiospectroscopy AT dvmukha interstellarmediumanddecameterradiospectroscopy |