Related papers: The Nuclear Jet in M81
The Galactic center black hole candidate Sgr A* is the best target for studies of low-luminosity accretion physics, including with near-infrared and submillimeter wavelength long baseline interferometry experiments. Here we compare images…
Jet precession is sometimes invoked to explain asymmetries in radio galaxy (RG) jets and "X/S/Z-shape" radio galaxies, caused by the presence of a binary black hole companion to the source active galactic nucleus (AGN) or by accretion…
The compact radio source Sgr A* is coincident with a 4 million solar mass black hole at the dynamical center of the Galaxy and is surrounded by dense orbiting ionized and molecular gas. We present high resolution radio continuum images of…
Double-lobed radio sources associated with active galactic nuclei (DRAGNs) are typically found in elliptical galaxies, while supermassive black holes (SMBHs) in disk galaxies rarely produce powerful kpc-scale jets. However, the growing…
We present new, high dynamic range VLA images of the inner jet of the closest radio galaxy, Centaurus A. Over a ten-year baseline we detect apparent sub-luminal motions (v ~ 0.5c) in the jet on scales of hundreds of pc. The inferred speeds…
Context. The properties of the accretion flow surrounding the supermassive central black hole of the Galaxy, Sgr A*, will be scrutinized by the new-generation instrument GRAVITY and the Event Horizon Telescope (EHT). Developing fast,…
M87 hosts one of the closest jetted active galactic nucleus (AGN) to Earth. Thanks to its vicinity and to the large mass of is central black hole, M87 is the only source in which the jet can be directly imaged down to near-event horizon…
We present a model for the radio emission from radio-quiet quasar nuclei. We show that a thermal origin for the high brightness temperature, flat spectrum point sources (known as radio ``cores'') is possible provided the emitting region is…
We present optical long-slit spectroscopy of the nucleus of the nearby radio galaxy M84 (NGC 4374 = 3C 272.1) obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). Our spectra reveal that the…
The jet in active galactic nuclei (AGN) is a key ingredient in understanding the co-evolution of galaxies and their central supermassive black holes (SMBHs). Unfortunately, the mechanism of jet launching and collimation is still elusive.…
We present stellar and gaseous kinematics of the inner 120x250pc^2 of the Liner/Seyfert 1 galaxy M81, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini North telescope at a spatial resolution of 10pc. The…
The predicted radio flux for nearby ellipticals by the canonical ADAF(advection-dominated accretion flow) model is well above the observations. If the mass accretion rate favored by the numerical simulation were adopted, the ADAF model…
Active galactic nucleus (AGN) powered jets can accelerate cosmic ray electrons, leading to the observed radio synchrotron emission. To simulate this emission, jet dynamics in galaxy clusters must be coupled to electron spectral modelling.…
This paper summarizes some of our recent projects which try to illuminate the nature and importance of jets associated with active nuclei and compact objects. After a short introduction on jets in radio galaxies and radio loud quasars the…
The low-luminosity Active Galactic Nuclei M87, archetype of Fanaroff-Riley I radio-galaxies, was observed in a historically quiet state in 2017. While one-zone leptonic jet models alone cannot explain the core radio-to-gamma-ray spectrum,…
We present the results of 2.5-dimensional resistive magnetohydrodynamic (MHD) simulations of the magnetic interaction between a weakly magnetized neutron star and its accretion disk. General relativistic effects are simulated by using the…
Previous molecular gas observations at arcsecond-scale resolution of the Seyfert 2 galaxy M51 suggest the presence of a dense circumnuclear rotating disk, which may be the reservoir for fueling the active nucleus and obscures it from direct…
We present the results of a multi-frequency, multi-scale radio polarimetric study with the Very Large Array (VLA) of the Seyfert 1 galaxy and BALQSO, Mrk 231. We detect complex total and polarized intensity features in the source. Overall,…
We report detailed studies of the X-ray emission from the kpc scale jet in the nearest active galaxy, Cen A. 41 compact sources were found within the jet, 13 of which were newly identified. We construct the luminosity function for the…
We investigate various models of accretion disks for Sgr A*, one of the most puzzling sources in the Galaxy. The generic image we have taken into account consists of a black hole, an accretion disk, and a jet. Various accretion models are…