Related papers: Demonstration of KVN phase referencing capability
The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading to a number of unique studies on black holes and…
We report 18cm VLBI continuum imaging observations at 5 mas resolution for UGC 5101, NGC 7469, and Mrk 231, all part of a sample of Luminous Infrared Galaxies which have been shown to have strong VLBI radio cores. The radio morphology of…
In this work, we examine the application of the wavelet transform to the X-ray timing analyses of active galactic nuclei (AGN) and quasi-periodic eruption sources (QPEs). Several scenarios are simulated to test the effectiveness of the…
Identifying active galactic nuclei (AGN) and isolating their contribution to a galaxy's energy budget is crucial for studying the co-evolution of AGN and their host galaxies. Brightness temperature ($T_b$) measurements from high-resolution…
Low-luminosity radio-loud active galactic nuclei (AGN) are of importance in studies concerning feedback from radio AGN since a dominant fraction of AGN belong to this class. We report high-resolution Very Large Array (VLA) and European VLBI…
We investigate a phase-reference VLBI observation that was conducted at 15.4 GHz by fast switching VLBA antennas between the compact steep-spectrum radio source 3C 138 and the quasar PKS 0528+134 which are about 4$^\circ$ away on the sky.…
We report multifrequency Very Long Baseline Array (VLBA) observations at 2.3 and 8.4GHz of three nearby ultraluminous infrared galaxies, identified via mid-infrared spectroscopic analyses as hosting deeply embedded active galactic nuclei…
Many massive early-type galaxies host central radio sources and hot X-ray atmospheres indicating the presence of radio-mechanical active galactic nucleus (AGN) feedback. The duty cycle and detailed physics of the radio-mode AGN feedback is…
VLBI now has the capability of imaging relatively large fields-of-view (~ 5 arcmin sq) with sub-mJy detection limits. In principle such observations can distinguish between starburst and AGN activity in cosmologically distant sources. We…
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…
Astrometric positions of radio-emitting active galactic nuclei (AGNs) can be determined with sub-milliarcsec accuracy using very long baseline interferometry (VLBI). The usually small apparent proper motion of distant extragalactic targets…
Active galactic nuclei (AGN) are a promising source of the binary black hole (BBH) mergers observed in gravitational waves with LIGO-Virgo-Kagra (LVK). Constraining the AGN channel allows us to limit AGN parameter space (disk density, size,…
We present a detailed multi-epoch analysis of 31 potential southern hemisphere radio calibrators that were originally observed as part of a program to maintain the International Celestial Reference Frame (ICRF). At radio wavelengths, the…
We observed at 22 GHz with the VLBI array VERA a sample of 1536 sources with correlated flux densities brighter than 200 mJy at 8 GHz. One half of target sources has been detected. The detection limit was around 200 mJy. We derived the…
The high angular resolution and sensitivity of Very Long Baseline Interferometry (VLBI) offer a unique tool to identify and study active galactic nuclei and star-formation activity over cosmic time. However, despite recent technical…
It is well-known that star-forming galaxies (SFGs) exhibit a tight correlation between their radio and infrared emissions, commonly referred to as the infrared-radio correlation (IRRC). Recent empirical studies have reported a dependence of…
The well-known phase problem which means image reconstruction from only spectrum magnitude without using any spectrum phase information is considered basically in application to VLBI mapping of compact extragalactic radio sources (active…
In this paper, we propose a new approach to determining cosmological distances to active galactic nuclei (AGN) via light travel-time arguments, which can be extended from nearby sources to very high redshift sources. The key assumption is…
It is believed that dual active galactic nuclei (dual AGN) will form during galaxies merge. Studying dual-AGN emission can provide valuable insights into galaxy merging and evolution. To investigate parsec-scale radio emission properties,…
We present the results of a 8.4 GHz Very Large Array radio survey of early-type galaxies extracted from the ACS Virgo Cluster Survey. The aim of this survey is to investigate the origin of radio emission in early-type galaxies and its link…