分类： 天文学 >> 天文学 提交时间： 2023-02-19
Leonid I. Gurvits
Sándor Frey
Máté Krezinger
Oleg Titov
Tao An
Yingkang Zhang
Alexander G. Polnarev
Krisztina É. Gabányi
Krisztina Perger
Alexey Melnikov
摘要： We present and briefly discuss results of several studies of the source J2102+6015 with tentatively defined redshift z=4:575 which demonstrates unusual properties in imaging and astrometric VLBI observations. Its properties might be considered as indications on the supermassive black hole binary which can be considered as a so far rare example of a high-redshift source of known electromagnetic and, possibly, predictable gravitational wave emissions.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Krisztina Perger
Yingkang Zhang
Sándor Frey
Tao An
Krisztina É. Gabányi
Leonid I. Gurvits
Chorng-Yuan Hwang
Ekaterina Koptelova
Zsolt Paragi
Ailing Wang
摘要： There are approximately 250 quasars discovered at redshift $z\geq6$, of which only a handful were detected in radio bands, and even fewer were imaged with the highest resolution very long baseline interferometry (VLBI) technique. Here we report the results of our dual-frequency observations with the Very Long Baseline Array (VLBA) of two such recently discovered quasars, VIKING J231818.35$-$311346.3 at $z=6.44$ and FIRST J233153.20$+$112952.11 at $z=6.57$. Both extremely distant sources were imaged with VLBI for the first time. The radio properties of the former are consistent with those of quasars with young radio jets. The latter has an UV/optical spectrum characteristic of BL Lac objects, of which no others have been found beyond redshift 4 so far. Our VLBA observations revealed a flat-spectrum compact radio source.
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