Three little radio galaxies in the early Universe
| Autor: | Tullia Sbarrato, Kristóf Rozgonyi, Zsolt Paragi, György Mező, Sándor Frey, Leonid I. Gurvits, Tao An, Hongmin Cao, Krisztina É. Gabányi, K. Perger |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics
education.field_of_study 010504 meteorology & atmospheric sciences Radio galaxy Astrophysics::High Energy Astrophysical Phenomena Population FOS: Physical sciences Quasar Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Astrophysics - Astrophysics of Galaxies Redshift Lorentz factor symbols.namesake Relativistic beaming Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences symbols Blazar education 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences Luminosity function (astronomy) |
| Zdroj: | Proceedings of 14th European VLBI Network Symposium & Users Meeting — PoS(EVN2018) Scopus-Elsevier |
| Popis: | Volonteri et al. (2011) found that the number of radio-loud quasars above redshift 4 calculated from the luminosity function (based upon Swift/BAT observations) is much smaller than the number estimated from the known high-redshift beamed sources, blazars, assuming that for every beamed source with a Lorentz factor of $\Gamma$, statistically $2 \Gamma^2$ non-beamed sources should exist. To explain the missing misaligned (non-beamed) population of high-redshift sources, they proposed various explanations, involving heavy optical obscuration and significantly different Lorentz factors at early cosmological epochs. Our EVN observations targeting high-redshift ($z>4$) blazar candidates revealed 3 sources not showing relativistic beaming, but rather kpc-scale double structures. These three sources have significant radio emission resolved out with the EVN, while they are compact on $\sim 5-10$ arcsec scale. Our dual-frequency ($1.5$ and $5$ GHz) e-MERLIN observations of these three sources revealed a rich morphology, bending jets, and hot spots with possible sites of interaction between the jets and the surrounding medium at intermediate scales. Comment: 6 pages, 3 figures, 1 table, accepted for the Proceedings of the 14th European VLBI Network Symposium & Users Meeting |
| Databáze: | OpenAIRE |
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