Kazan Federal University

About: Kazan Federal University is a education organization based out in Kazan’, Russia. It is known for research contribution in the topics: Population & Chemistry. The organization has 9868 authors who have published 14390 publications receiving 135726 citations. The organization is also known as: Kazan (Volga region) Federal University & Kazan State University.

SRG/eROSITA uncovers the most X-ray luminous quasar at z > 6

Abstract: We report the discovery of X-ray emission from CFHQS J142952+544717, the most distant known radio-loud quasar at z=6.18, on Dec. 10--11, 2019 with the eROSITA telescope on board the SRG satellite during its ongoing all-sky survey. The object was identified by cross-matching an intermediate SRG/eROSITA source catalog with the Pan-STARRS1 distant quasar sample at 5.6 6. Combining our X-ray measurements with archival and new photometric measurements in other wavebands (radio to optical), we estimate the bolometric luminosity of this quasar at $\sim (2$--$3) \times 10^{47}$ erg s$^{-1}$. Assuming Eddington limited accretion and isotropic emission, we infer a lower limit on the mass of the supermassive black hole of $\sim 2\times 10^9 M_\odot$. The most salient feature of CFHQS J142952+544717 is its X-ray brightness relative to the optical/UV emission. We argue that it may be linked to its radio-loudness (although the object is not a blazar according to its radio properties), specifically to a contribution of inverse Compton scattering of cosmic microwave background photons off relativistic electrons in the jets. If so, CFHQS J142952+544717 might be the tip of the iceberg of high-z quasars with enhanced X-ray emission, and SRG/eROSITA may find many more such objects during its 4 year all-sky survey.

Crystal Growth, Dynamic and Charge Transfer Properties of New Coronene Charge Transfer Complexes

Abstract: Two new coronene charge transfer complexes with F4-TCNQ of 2:1 and 1:1:1 (solvate with acetonitrile, MeCN) stoichiometry were obtained using crystal growth procedures from the solution and vapor phase. It was shown that mobility of coronene molecules in crystals is more affected by the asymmetry of its surrounding than by the composition and degree of charge transfer and interstack interactions. The combination of X-ray diffraction and electrochemistry in the solid state and a time-resolved one in solution allowed us to clarify the nucleation in solution showing that the formation of 2:1 coronene/F4-TCNQ complexes is thermodynamically preferable. The X-ray single crystal data for pristine coronene showed the crystal structure to be the same as at ambient temperature, raising doubt about the previously reported phase transitions at 140–180 K.