899 datasets found

The paper reports the results of ten-year centimeter-wavelength observations with the RATAN-600 radio telescope of a complete sample of 83 flat-spectrum sources from the GB6...

We present the results of spectroscopy of 71 objects with steep and ultra-steep spectra (alpha<-0.9, S{prop.to}nu^alpha^) from the "Big Trio" (RATAN-600-VLA-BTA) project,...

A complete sample of radio sources has been studied using the interplanetary scintillation method. In total, 32 sources were observed, with scintillations detected in 12 of...

A complete sample of core-dominated radio sources has been studied using the interplanetary-scintillation method. In total, 72 sources were observed, with scintillations...

The results of VRI photometry of the gravitationally lensed system Q2237+0305 carried out on the 1.5-m telescope of Maidanak observatory in 2004-2005 are presented. The distance...

The results of 19-year optical monitoring of ON 231 are presented. Photographic B-band observations were obtained during 123 nights from April 1972 to March 1990 as part of the...

A new catalog of 8382 close quasar-galaxy pairs is presented. The catalog was composed using published catalogued quasars and active galactic nuclei containing 11358 objects, as...

Results of long-term monitoring of the quasar 3C345 from 1984 to 1991 are presented. Observations has been conducted on the Byurakanskii station of the St. Petersburg...

We report lambda-18 cm VLBI observations made in 1991 September of a further 25 objects from the first Caltech-Jodrell Bank VLBI Survey (the CJ1 survey). The CJ1 sample is a...

We present the first results from the first Caltech-Jodrell Bank VLBI survey (the CJ1 survey). The CJ1 sample includes 135 radio sources with total flux density...

Sensitive H I 21cm emission line spectra have been measured for the directions to 143 quasars and AGNs chosen from the observing lists for the HST Quasar Absorption Line Key...

In this work, we obtained a sample of 979 Fermi blazars with broad emission lines, including 701 objects collected from published works and 278 objects developed in this work....

The time delay between multiple images of strongly lensed quasars is a powerful tool for measuring the Hubble constant (H0). To achieve H0 measurements with higher precision and...

We report the first results of a high-redshift (z>~5) quasar survey using the Dark Energy Spectroscopic Instrument (DESI). As a DESI secondary target program, this survey is...

We study the general physical properties of Fermi blazars using the Fermi fourth source catalog data (4FGL-DR2). The quasi-simultaneous multiwavelength data of Fermi blazars are...

We search for quasi-stellar objects (QSOs) in a wide area of the south ecliptic pole (SEP) field, which has been and will continue to be intensively explored through various...

Studies and constraints on the emission region are crucial to the blazar radiation mechanism. Yet previous works have mainly focused on individual sources. In this work, we make...

We have collected 10025 foreground-background quasar pairs with projected distances d_p_<500kpc from the large quasar catalog of the Sloan Digital Sky Survey DR16Q. We...

The identification of bright quasars at z>~6 enables detailed studies of supermassive black holes, massive galaxies, structure formation, and the state of the intergalactic...

We report the fourth installment in the series of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) quasar survey, which includes quasars observed between...