Related papers: Resolving the Nuclear Radio Emission from M32 with…
The compact radio source Sgr\,A*, associated with the super massive black hole at the center of the Galaxy, has been studied with VLBA observations at 3 frequencies (22, 43, 86\,GHz) performed on 10 consecutive days in May 2007. The total…
Radio emission from the high- and super-Eddington accreting active galactic nuclei (AGNs) has various origins: a persistent jet, the magnetized corona and the wind-like outflows. It is now still unclear which is the leading mechanism…
We present results from the Very Long Baseline Array (VLBA) multi-frequency (1.6, 4.4, 8.6, 22 GHz), high-sensitivity (~25 microJy beam^-1), sub-parsec scale (<1 pc) observations and Spectral Energy Distributions (SEDs) for a sample of 12…
We present archival high spatial resolution VLA and VLBA data of the nuclei of seven of the nearest and brightest Seyfert galaxies in the Southern Hemisphere. At VLA resolution (~0.1 arcsec), the nucleus of the Seyfert galaxies is…
Owing to their quiet evolutionary histories, nearby dwarf galaxies (stellar masses $M_\star \lesssim 3 \times 10^9 M_\odot$) have the potential to teach us about the mechanism(s) that 'seeded' the growth of supermassive black holes, and…
There exists a well known relation between the mass of the supermassive black hole (SMBH) in the center of galaxies and their bulge mass or central velocity dispersion. This suggests a co-evolution between SMBH and their galaxy hosts. Our…
The Andromeda galaxy (M\,31) hosts one of the nearest and most quiescent super-massive black holes, which provides a rare, but promising opportunity for studying the physics of black hole accretion at the lowest state. We have conducted a…
We present continent-scale VLBI - obtained with the European VLBI Network (EVN) at a wavelength of 18cm - of six distant, luminous submm-selected galaxies (SMGs). Our images have a synthesized beam width of ~30 milliarcsec FWHM - three…
Extended, steep-spectrum radio synchrotron sources are pre-dominantly found in massive galaxy clusters as opposed to groups. LOFAR Two-Metre Sky Survey images have revealed a diffuse, ultra-steep spectrum radio source in the low-mass…
We present radio very long baseline interferometry (VLBI) and X-ray studies of the starburst galaxy NGC 3628. The VLBI observation at 1.5 GHz reveals seven compact (0.7$-$7 parsec) radio sources in the central $\sim$250 parsec region of NGC…
Two independent sets of Chandra and HST images of the nuclear region of M31 allow registration of X-ray and optical images to 0.1''. This registration shows that none of the bright (10^{37} erg/s) X-ray sources near the nucleus is…
Radio minihalos are diffuse synchrotron sources of unknown origin found in the cool cores of some galaxy clusters. We use GMRT and VLA data to expand the sample of minihalos by reporting three new minihalo detections (A 2667, A 907 and PSZ1…
FRB 121102 is the first fast radio burst source to be spatially associated with a persistent radio source (QRS121102), the nature of which remains unknown. We present a detailed observational study of QRS121102 and its host galaxy. We…
We employed the Very Large Array (VLA) of the National Radio Astronomy Observatory in C configuration to map 39 ultraluminous IRAS galaxies at 6~cm and 20~cm, at resolutions of ~ 4" and 15", respectively, and 24 sources at 6~cm with in the…
Using recently published estimates - based on high spatial resolution spectroscopy - of the mass M_{BH} of nuclear black holes for a sample of nearby galaxies, we explore the dependence of galaxy nucleus emissivity at various wavelengths on…
Observational searches for intermediate-mass black holes (IMBHs; $10^2 - 10^6$ $M_\odot$) include relatively isolated dwarf galaxies. For those that host active galactic nuclei (AGNs), the IMBH nature may be discerned through the accretion…
We present here the results of a 325 MHz radio survey of M31, conducted with the A-configuration of the Very Large Array. The survey covered an area of 7.6 deg$^2$, and a total of 405 radio sources between $\la$6\arcsec and 170\arcsec in…
We present deep 3 GHz VLA observations of the potentially recoiling black hole CID-42 in the COSMOS field. This galaxy shows two optical nuclei in the HST/ACS image and a large velocity offset of ~ 1300 km/s between the broad and narrow H…
We have made a deep search for radio emission from all the northern hemisphere supersoft X-ray sources using the VLA and MERLIN telescopes, at 5 and 8.4 GHz. Three previously undetected sources: T Pyx, V1974 Cygni and RX J0019.8+2156 were…
Synergies between the {\em James Webb Space Telescope} ({\em JWST}) and the {\em Chandra} X-ray observatory have advanced the observational frontier by detecting a handful of active galactic nuclei (AGNs) beyond $z \sim$ 10. In particular,…