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Related papers: Extending and Exploring the 2 cm Survey Sample

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We present the results of our search for highly variable active galactic nuclei (AGNs) the X-ray flux from which changed by more than an order of magnitude during the SRG/eROSITA all-sky survey. Using the eROSITA data obtained in the period…

High Energy Astrophysical Phenomena · Physics 2023-09-21 Pavel Medvedev , Marat Gilfanov , Sergey Sazonov , Rashid Sunyaev , Georgii Khorunzhev

We present recent Very Long Baseline Array (VLBA) 5 GHz radio observations of the nearby, luminous Seyfert 2 galaxy NGC 1068 for comparison to similar VLBA observations made on 1997 April 26. By cross-correlating the positions of emitting…

Astrophysics of Galaxies · Physics 2023-08-16 Travis C. Fischer , Megan C. Johnson , Nathan J. Secrest , D. Michael Crenshaw , Steven B. Kraemer

Time variability is a strong probe of energetic phenomena which occur at small spatial scales, like Active Galactic Nuclei (AGN). We use ALMA observations at 100 GHz executed over a period of 2.5 months to look for time variability in the…

We have used the VLBA at 5 GHz to observe all galaxies with nuclear radio flux densities above 3.5 mJy found in a VLA survey at 15 GHz of a sample of nearby LINER galaxies. All galaxies were detected revealing high brightness temperature…

Astrophysics · Physics 2009-10-31 Heino Falcke , Neil M. Nagar , Andrew S. Wilson , James S. Ulvestad

We report on the results of active galactic nuclei (AGNs) detection by NuSTAR performed in three extragalactic survey fields (COSMOS, UDS, ECDFS) in three hard bands, namely H1 (8-16 keV), H2 (16-24 keV) and VH (35-55 keV). The aggregated…

TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) is a monitoring program to study the parsec-scale structures and dynamics of relativistic jets in active galactic nuclei (AGN) of the Southern Hemisphere…

Using the most recent (April 2003) version of the VLA FIRST survey radio catalog, we have searched for radio emission from $>2800$ AGN taken from the most recent (2001) version of the Veron-Cetty and Veron AGN catalog. These AGN lie in the…

Astrophysics · Physics 2009-11-10 Yogesh Wadadekar

Results of high-resolution simultaneous multi-frequency 8.1-15.4 GHz VLBA polarimetric observations of relativistic jets in active galactic nuclei (the MOJAVE-2 project) are analyzed. We compare characteristics of VLBI features with jet…

Astrophysics · Physics 2008-12-31 A. B. Pushkarev , Y. Y. Kovalev , A. P. Lobanov

We present the second catalogue of accurate positions and correlated flux densities for 1100 compact extragalactic radio sources that were not observed before 2008 at high angular resolution. The catalogue spans the declination range -90…

Instrumentation and Methods for Astrophysics · Physics 2019-04-15 Leonid Petrov , Alet de Witt , Elaine M. Sadler , Chris Phillips , Shinji Horiuchi

Radio-loud active galactic nuclei (AGN) are among the most luminous objects in the Universe, emitting radiation from low-energy radio waves to high energy $\gamma$-rays. They are well known to exhibit flux variations at nearly all…

Astrophysics of Galaxies · Physics 2026-03-19 M. Reshma , C. S. Stalin , Amit Kumar Mandal , S. B. Gudennavar , Senorita Benedict , Prajwel Joseph

We report on candidate active galactic nuclei (AGN) discovered during the monitoring of $\sim$500 bright (r < 18 mag) galaxies over several years with the Kepler Mission. Most of the targets were sampled every 30 minutes nearly continuously…

High Energy Astrophysical Phenomena · Physics 2015-12-09 Edward J. Shaya , Robert Olling , Richard Mushotzky

We present the first results of an ongoing variability monitoring program of active galactic nuclei (AGNs) using the 46\,cm telescope of the Wise observatory in Israel. The telescope has a field of view of $1.25^{\circ} \times 0.84^{\circ}$…

Astrophysics of Galaxies · Physics 2017-07-26 F. Pozo Nuñez , D. Chelouche , S. Kaspi , S. Niv

We have a project to measure magnetic fields in the obscuring tori of AGNs. We observed five free-free absorbed jets in radio galaxies with polarimetric VLBI at 15 GHz to determine Faraday rotation measures. Surprisingly, all sources are…

Astrophysics · Physics 2007-05-23 E. Middelberg

High redshift active galactic nuclei (AGN) provide key insights into early supermassive black hole growth and cosmic evolution. This study investigates the parsec-scale properties of 86 radio-loud quasars at z $\geq$ 3 using very long…

High Energy Astrophysical Phenomena · Physics 2025-02-24 Shaoguang Guo , Tao An , Yuanqi Liu , Chuanzeng Liu , Zhijun Xu , Yulia Sotnikova , Timur Mufakharov , Ailing Wang

We present a short overview of radio surveys for AGN, including the `complete' flux limited surveys and `filtered' surveys. We also describe our ultra-steep spectrum search for the highest redshift radio galaxies, and our follow-up VLA and…

Astrophysics · Physics 2007-05-23 Carlos De Breuck , Wil van Breugel , Huub Rottgering , Chris Carilli

Imaging relativistic jets in active galactic nuclei (AGN) at angular resolution significantly surpassing that of the ground-based VLBI at centimetre wavelengths is one of the key science objectives of the RadioAstron space-VLBI mission.…

Astrophysics of Galaxies · Physics 2020-01-10 Gabriele Bruni , Tuomas Savolainen , Jose Luis Gómez , Andrei P. Lobanov , Yuri Y. Kovalev

We present the third phase of the largest high-frequency, high-resolution imaging survey of 231 nearby, hard X-ray selected AGN, with a very high $98 \pm 1\%$ detection fraction. This survey presents VLA 22 GHz radio observations with 1"…

We investigate the high-frequency radio spectra of twenty low-luminosity active galactic nuclei (LLAGNs) with compact radio cores. Our millimetre survey with the Nobeyama Millimetre Array (NMA) and analyses of submillimetre archival data…

Astrophysics · Physics 2009-11-13 A. Doi , S. Kameno , K. Kohno , K. Nakanishi , M. Inoue

This paper presents accurate absolute positions from a 24 GHz Very Long Baseline Array (VLBA) search for compact extragalactic sources in an area where the density of known calibrators with precise coordinates is low. The goals were to…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 L. Petrov , Y. Y. Kovalev , E. B. Fomalont , D. Gordon

A sample of radio-loud active galactic nuclei (AGN) at 2cm is studied to test the isotropic distribution of radio sources in the sky and their uniform distribution in space. The sample is complete flux-density limits of 1.5Jy for positive…

Astrophysics · Physics 2017-08-23 T. G. Arshakian , E. Ros , J. A. Zensus , M. L. Lister
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