East Asian VLBI Network Observations of Active Galactic Nuclei Jets: Imaging with KaVA+Tianma+Nanshan

Abstract

The East Asian very-long-baseline interferometry (VLBI) Network (EAVN) is a rapidly evolving international VLBI array that is currently promoted under joint efforts among China, Japan, and Korea. EAVN aims at forming a joint VLBI Network by combining a large number of radio telescopes distributed over East Asian regions. After the combination of the Korean VLBI Network (KVN) and the VLBI Exploration of Radio Astrometry (VERA) into KaVA, further expansion with the joint array in East Asia is actively promoted. Here we report the first imaging results (at 22 and 43 GHz) of bright radio sources obtained with KaVA connected to Tianma 65-m and Nanshan 26-m Radio Telescopes in China. To test the EAVN imaging performance for different sources, we observed four active galactic nuclei (AGN) having different brightness and morphology. As a result, we confirmed that Tianma 65-m Radio Telescope (TMRT) significantly enhances the overall array sensitivity, a factor of 4 improvement in baseline sensitivity and 2 in image dynamic range compared to the case of KaVA only. The addition of Nanshan 26-m Radio Telescope (NSRT) further doubled the east-west angular resolution. With the resulting high-dynamic-range, high-resolution images with EAVN (KaVA+TMRT+NSRT), various fine-scale structures in our targets, such as the counter-jet in M87, a kink-like morphology of the 3C273 jet and the weak emission in other sources, are successfully detected. This demonstrates the powerful capability of EAVN to study AGN jets and to achieve other science goals in general. Ongoing expansion of EAVN will further enhance the angular resolution, detection sensitivity and frequency coverage of the network.

19 pages, 9 figures, accepted by Research in Astronomy and Astrophysics (RAA)

References in corpus (20)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• Kinematics of Parsec-Scale Jets of Gamma-Ray Blazars at 43~GHz within the VLBA-BU-BLAZAR Program
• MOJAVE. XVII. Jet Kinematics and Parent Population Properties of Relativistically Beamed Radio-Loud Blazars
• The Inner Jet of the Radio Galaxy M87
• Kinematics of the M87 jet in the collimation zone: gradual acceleration and velocity stratification
• VLBI observations of bright AGN jets with KVN and VERA Array (KaVA): Evaluation of Imaging Capability
• Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron II. Observations of 3C 273 at minimum activity
• A 6.7 GHz Methanol Maser Survey II. Low Galactic Latitudes
• The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)
• Intra-day variability observations of S5 0716+714 over 4.5 years at 4.8 GHz
• BAT AGN Spectroscopic Survey -- XVII: The Parsec-scale Jet Properties of the Ultra Hard X-ray Selected Local AGN
• Observations of the Bursting Activity of the 6.7GHz Methanol Maser in G33.641-0.228
• Jet Kinematics of the Quasar 4C +21.35 from Observations with the KaVA Very Long Baseline Interferometry Array
• The relativistic jet of the $\gamma$-ray emitting narrow-line Seyfert 1 galaxy PKS J1222$+$0413
• Magnetic Field Structure of Orion Source I
• Overall variation of the $H_{2}O$ masers around W Hydrae in 28 years
• The follow-up EVN observations of twelve GPS radio sources at 5 GHz
• VLBI observations of a flared optical quasar CGRaBS J0809+5341

Cited by in corpus (4)

• Precessing jet nozzle connecting to a spinning black hole in M87
• Overview of the Observing System and Initial Scientific Accomplishments of the East Asian VLBI Network (EAVN)
• Multi-frequency VLBI Observations of the M 84 Inner Jet/Counterjet
• First Trigonometric Parallax Measurements with the KVN and VERA Array (KaVA)