Spectrophotometric monitoring of high luminosity active galactic nuclei - II. First results

1989 ◽  
Vol 239 (1) ◽  
pp. 75-90 ◽  
Author(s):  
E. Perez ◽  
M. V. Penston ◽  
M. Moles
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
High Luminosity ◽  
First Results

scholarly journals Intra-Day Variability Observations of Two Dozens of Blazars at 4.8 GHz

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 15
Author(s):  
Xiang Liu ◽  
Xin Wang ◽  
Ning Chang ◽  
Jun Liu ◽  
Lang Cui ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Forthcoming Paper ◽  
Galactic Latitude ◽  
Local Interstellar Medium ◽  
Bl Lac Objects ◽  
Spectrum Radio ◽  
First Results ◽  
First Time ◽  
Source Structure

Two dozens of radio loud active galactic nuclei (AGNs) have been observed with Urumqi 25 m radio telescope in order to search for intra-day variability (IDV). The target sources are blazars (namely flat spectrum radio quasars and BL Lac objects) which are mostly selected from the observing list of RadioAstron AGN monitoring campaigns. The observations were carried out at 4.8 GHz in two sessions of 8–12 February 2014 and 7–9 March respectively. We report the data reduction and the first results of observations. The results show that the majority of the blazars exhibit IDV in 99.9% confidence level, some of them show quite strong IDV. We find the strong IDV of blazar 1357 + 769 for the first time. The IDV at centimeter-wavelength is believed to be predominately caused by the scintillation of blazar emission through the local interstellar medium in a few hundreds parsecs away from Sun. No significant correlation between the IDV strength and either redshift or Galactic latitude is found in our sample. The IDV timescale along with source structure and brightness temperature analysis will be presented in a forthcoming paper.

Very long baseline interferometry polarization studies of quasars and active galactic nuclei

1986 ◽  
Vol 64 (4) ◽  
pp. 434-439 ◽  
Author(s):  
J. F. C. Wardle ◽  
D. H. Roberts
Keyword(s):  
Active Galactic Nuclei ◽  
Linear Polarization ◽  
Very Long Baseline Interferometry ◽  
Galactic Nuclei ◽  
Radio Sources ◽  
Long Baseline ◽  
First Results ◽  
Polarization Studies ◽  
Theoretical Issues

We present some first results of a program to map the distribution of linear polarization in compact radio sources with milliarcsecond resolution. We show first-epoch maps of 3C345 and 0735 + 178 and first- and second-epoch maps of OJ287. In general, the polarization is mainly associated with optically thin (jet) components. In the case of OJ287, polarization maps made 1 year apart are strikingly different. We also discuss some of the theoretical issues raised by these observations.

scholarly journals Cosmological Evolution of the Central Engine in High-Luminosity, High-Accretion Rate AGN

2014 ◽  
Vol 1 (1) ◽  
pp. 90-95
Author(s):  
Matteo Guainazzi
Keyword(s):  
Active Galactic Nuclei ◽  
Accretion Rate ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Cosmological Evolution ◽  
High Luminosity ◽  
X Ray ◽  
Central Engine ◽  
The Status ◽  
Multi Wavelength

In this paper I discuss the status of observational studies aiming at probing the cosmological evolution of the central engine in high-luminosity, high-accretion rate Active Galactic Nuclei (AGN). X-ray spectroscopic surveys, supported by extensive multi-wavelength coverage, indicate a remarkable invariance of the accretion disk plus corona system, and of their coupling up to redshifts z≈6. Furthermore, hard X-ray (<em>E</em> &gt;10 keV) surveys show that nearby Seyfert Galaxies share the same central engine notwithstanding their optical classication. These results suggest that the high-luminosity, high accretion rate quasar phase of AGN evolution is homogeneous over cosmological times.

scholarly journals The narrow-line region of high-luminosity active galactic nuclei

1993 ◽  
Vol 410 ◽  
pp. 534 ◽  
Author(s):  
Beverley J. Wills ◽  
H. Netzer ◽  
M. S. Brotherton ◽  
Mingsheng Han ◽  
D. Wills ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Narrow Line ◽  
High Luminosity ◽  
Line Region ◽  
Narrow Line Region

scholarly journals The spatial extension of extended narrow line regions in MaNGA AGN

2019 ◽  
Vol 489 (1) ◽  
pp. 855-867 ◽  
Author(s):  
Jianhang Chen ◽  
Yong Shi ◽  
Ross Dempsey ◽  
David R Law ◽  
Yanmei Chen ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Large Distance ◽  
Linear Relation ◽  
Galactic Nuclei ◽  
Narrow Line ◽  
High Luminosity ◽  
Large Sample ◽  
Spatially Resolved ◽  
Nearby Galaxies ◽  
Log Linear

ABSTRACT In this work, we revisit the size–luminosity relation of the extended narrow line regions (ENLRs) using a large sample of nearby active galactic nuclei (AGNs) from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. The ENLRs ionized by the AGN are identified through the spatially resolved BPT diagram, which results in a sample of 152 AGN. By combining our AGN with the literature high-luminosity quasars, we found a tight log-linear relation between the size of the ENLR and the AGN $\rm [O\, III]$λ5007 Å luminosity over four orders of magnitude of the $\rm [O\, III]$ luminosity. The slope of this relation is 0.42 ± 0.02 which can be explained in terms of a distribution of clouds photoionized by the AGN. This relation also indicates that the AGNs have the potential to ionize and heat the gas clouds at a large distance from the nuclei without the aids of outflows and jets for the low-luminosity Seyferts.†

The X-ray spectra of high-luminosity active galactic nuclei observed by Ginga

1992 ◽  
Vol 389 ◽  
pp. 157 ◽  
Author(s):  
O. R. Williams ◽  
M. J. L. Turner ◽  
G. C. Stewart ◽  
R. D. Saxton ◽  
T. Ohashi ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
High Luminosity ◽  
X Ray
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