Results 51 to 60 of about 47,708 (236)

The largest black holes and the most luminous galaxies [PDF]

open access: yes, 2002
The empirical relationship between the broad line region size and the source luminosity in active galactic nuclei (AGNs) is used to obtain black holes (BH) masses for a large number of quasars in three samples. The largests BH masses found exceed 10^{10}
Hagai Netzer, Kormendy J.
core   +2 more sources

A new delivery route to Galactic Nuclei: Warm halo cloud impacts

open access: yes, 2010
We propose a new mechanism for the delivery of gas to the heart of galactic nuclei. We show that warm halo clouds must periodically impact galactic centers and potentially deliver a large (~10^{4-6} M_{solar}) mass of gas to the galactic nucleus in a ...
Blitz   +22 more
core   +1 more source

The dust origin of the Broad Line Region and the model consequences for AGN unification scheme [PDF]

open access: yes, 2015
We propose a very simple physical mechanism responsible for the formation of the Low Ionization Line part of the Broad Line Region in Active Galactic Nuclei.
Adhikari, Tek P.   +9 more
core   +1 more source

NEUTRINO AND COSMIC-RAY EMISSION AND CUMULATIVE BACKGROUND FROM RADIATIVELY INEFFICIENT ACCRETION FLOWS IN LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI [PDF]

open access: yes, 2014
We study high-energy neutrino and cosmic-ray (CR) emission from the cores of low-luminosity active galactic nuclei (LLAGN). In LLAGN, the thermalization of particles is expected to be incomplete in radiatively inefficient accretion flows (RIAF), allowing
S. Kimura, K. Murase, K. Toma
semanticscholar   +1 more source

The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys [PDF]

open access: yes, 2011
Significant progress has been made in the last few years on understanding how supermassive black holes form and grow. In this paper, we begin by reviewing the spectral signatures of Active Galactic Nuclei (AGN) ranging from radio to hard X-ray ...
Treister, Ezequiel, Urry, C. Megan
core   +3 more sources

Evidence for Jet Domination of the Nuclear Radio Emission in Low-Luminosity Active Galactic Nuclei [PDF]

open access: yes, 2001
We present simultaneous, subarcsecond (≤50 pc) resolution 5, 8.4, and 15 GHz Very Large Array observations of a well-defined sample of 16 low-luminosity active galactic nuclei. The radio emission in most of these nuclei does not show the rising spectrum (
N. Nagar, A. Wilson, H. Falcke
semanticscholar   +1 more source

Multiwavelength and Environmental Properties of Variability Selected Low-luminosity Active Galactic Nuclei

open access: yesThe Astrophysical Journal
We present the multiwavelength and environmental properties of 37 variability-selected active galactic nuclei (AGNs), including 30 low-luminosity AGNs (LLAGNs), using a high cadence time-domain survey (All-Sky Automated Survey for SuperNovae) from a ...
Heechan Yuk, Xinyu Dai, Marko Mićić
doaj   +1 more source

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

open access: yesThe Astrophysical Journal Letters, 2021
In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting ...
The EHT MWL Science Working Group   +745 more
doaj   +1 more source

WFPC2 Observations of Compact Star Cluster Nuclei in Low Luminosity Spiral Galaxies [PDF]

open access: yes, 1999
We have used the Wide Field Planetary Camera 2 aboard the Hubble Space Telescope to image the compact star cluster nuclei of the nearby, late-type, low-luminosity spiral galaxies NGC 4395, NGC 4242, and ESO 359-029.
Alan M. Watson   +54 more
core   +2 more sources

Deep learning Bayesian inference for low-luminosity active galactic nuclei spectra

open access: yesMonthly Notices of the Royal Astronomical Society, 2021
ABSTRACT Most active supermassive black holes in present-day galaxies are underfed and consist of low-luminosity active galactic nuclei (LLAGN). LLAGNs display complex multiwavelength broadband spectral energy distributions (SED), dominated by non-thermal processes which are explained to first order by a radiatively inefficient accretion
Ivan Almeida   +2 more
openaire   +1 more source

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