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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="research-article" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Astronomy Reports</journal-id><journal-title-group><journal-title xml:lang="en">Astronomy Reports</journal-title><trans-title-group xml:lang="ru"><trans-title>Астрономический журнал</trans-title></trans-title-group></journal-title-group><issn publication-format="print">0004-6299</issn><issn publication-format="electronic">3034-5170</issn><publisher><publisher-name xml:lang="en">The Russian Academy of Sciences</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">647668</article-id><article-id pub-id-type="doi">10.31857/S0004629924080078</article-id><article-id pub-id-type="edn">ISZRDR</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>Articles</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>СТАТЬИ</subject></subj-group><subj-group subj-group-type="article-type"><subject>Research Article</subject></subj-group></article-categories><title-group><article-title xml:lang="en">Interstellar scintillation of sources B0821+394 and B1812+412 according to observations on the LPA LPI radio telescope</article-title><trans-title-group xml:lang="ru"><trans-title>Межзвездные мерцания источников В0821+394 и В1812+412 по наблюдениям на радиотелескопе БСА ФИАН</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Tyul'bashev</surname><given-names>S. A.</given-names></name><name xml:lang="ru"><surname>Тюльбашев</surname><given-names>С. А.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Astrospace center, Pushchino radio astronomy observatory</p></bio><bio xml:lang="ru"><p>Астрокосмический центр, Пущинская радиоастрономическая обсерватория</p></bio><email>serg@prao.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Chashei</surname><given-names>I. V.</given-names></name><name xml:lang="ru"><surname>Чашей</surname><given-names>И. В.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Astrospace center, Pushchino radio astronomy observatory</p></bio><bio xml:lang="ru"><p>Астрокосмический центр, Пущинская радиоастрономическая обсерватория</p></bio><email>serg@prao.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Grishanova</surname><given-names>I. A.</given-names></name><name xml:lang="ru"><surname>Гришанова</surname><given-names>И. А.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><email>serg@prao.ru</email><xref ref-type="aff" rid="aff2"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Tyul'basheva</surname><given-names>G. E.</given-names></name><name xml:lang="ru"><surname>Тюльбашева</surname><given-names>Г. Э.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><email>serg@prao.ru</email><xref ref-type="aff" rid="aff3"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Subaev</surname><given-names>I. A.</given-names></name><name xml:lang="ru"><surname>Субаев</surname><given-names>И. А.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Astrospace center, Pushchino radio astronomy observatory</p></bio><bio xml:lang="ru"><p>Астрокосмический центр, Пущинская радиоастрономическая обсерватория</p></bio><email>serg@prao.ru</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Lebedev Physical Institute</institution></aff><aff><institution xml:lang="ru">Физический институт им. П. Н. Лебедева</institution></aff></aff-alternatives><aff-alternatives id="aff2"><aff><institution xml:lang="en">Pushchino brunch of Russian Biotechnological University (Rosbiotech)</institution></aff><aff><institution xml:lang="ru">Пущинский филиал Российского биотехнологического университета, РОСБИОТЕХ</institution></aff></aff-alternatives><aff-alternatives id="aff3"><aff><institution xml:lang="en">Institute of Mathematical Problems of Biology RAS (IMPB RAS) brunch of Keldysh Institute of Applied Mathematics of Russian Academy of Sciences</institution></aff><aff><institution xml:lang="ru">Институт математических проблем биологии Российской академии наук (РАН), филиал ИПМ им. М. В. Келдыша РАН</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2024-08-15" publication-format="electronic"><day>15</day><month>08</month><year>2024</year></pub-date><volume>101</volume><issue>8</issue><issue-title xml:lang="ru"/><fpage>764</fpage><lpage>769</lpage><history><date date-type="received" iso-8601-date="2025-01-28"><day>28</day><month>01</month><year>2025</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2024, The Russian Academy of Sciences</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2024, Российская академия наук</copyright-statement><copyright-year>2024</copyright-year><copyright-holder xml:lang="en">The Russian Academy of Sciences</copyright-holder><copyright-holder xml:lang="ru">Российская академия наук</copyright-holder></permissions><self-uri xlink:href="https://journals.eco-vector.com/0004-6299/article/view/647668">https://journals.eco-vector.com/0004-6299/article/view/647668</self-uri><abstract xml:lang="en"><p>The search for long-term variability of compact components of radio sources B0821+394 and B1812+412 over an interval of 10 years was carried out. The LPA LPI radio telescope with an operating frequency of 111 MHz was used for observations. According to our estimates, the characteristic time of variability for both sources is 1.5–2.5 years. It is shown that the observed variability is not related to intrinsic variations in the radiation flux, but is due to refractive scintillation on inhomogeneities of the interstellar medium. From the obtained upper estimates of the apparent angular dimensions of the sources, it follows that the main contribution to the scattering of radio emission is made by turbulent plasma concentrated in sufficiently thin screens, the distance to which does not exceed 300–400 pc.</p></abstract><trans-abstract xml:lang="ru"><p>Проведен поиск долговременной переменности компактных компонентов радиоисточников В0821+394 и В1812+412 на интервале длительностью 10 лет. Для наблюдений использовался радиотелескоп БСА ФИАН с рабочей частотой 111 МГц. Характерные времена переменности для обоих источников по нашим оценкам составляют 1.5–2.5 года. Показано, что наблюдаемая переменность не связана с собственными вариациями потока излучения, а обусловлена рефракционными мерцаниями на неоднородностях межзвездной среды. Из полученных верхних оценок видимых угловых размеров источников следует, что основной вклад в рассеяние радиоизлучения вносит турбулентная плазма, сосредоточенная в достаточно тонких экранах, расстояние до которых не превосходит 300–400 пк.</p></trans-abstract><kwd-group xml:lang="en"><kwd>compact radio sources</kwd><kwd>interstellar scinitillation</kwd><kwd>interstellar scattering</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>компактные радиоисточники</kwd><kwd>межзвездные мерцани</kwd><kwd>межзвездное рассеяние</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>R. W. Hunstead, Astrophys. 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