scholarly journals Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. III. Optical Variability and X‐Ray/UV/Optical Correlations

2006 ◽  
Vol 650 (1) ◽  
pp. 88-101 ◽  
Author(s):  
Louis‐Benoit Desroches ◽  
Alexei V. Filippenko ◽  
Shai Kaspi ◽  
Ari Laor ◽  
Dan Maoz ◽  
...  
Keyword(s):  
Optical Variability ◽  
X Ray ◽  
Ngc 4395

scholarly journals Correlated X-ray/ultraviolet/optical variability in the very low mass AGN NGC 4395

2012 ◽  
Vol 422 (1) ◽  
pp. 902-912 ◽  
Author(s):  
D. T. Cameron ◽  
I. McHardy ◽  
T. Dwelly ◽  
E. Breedt ◽  
P. Uttley ◽  
...  
Keyword(s):  
Optical Variability ◽  
X Ray ◽  
Low Mass ◽  
Ngc 4395

scholarly journals X-ray/UV/optical variability of NGC 4593 with Swift: reprocessing of X-rays by an extended reprocessor

2018 ◽  
Vol 480 (3) ◽  
pp. 2881-2897 ◽  
Author(s):  
I M McHardy ◽  
S D Connolly ◽  
K Horne ◽  
E M Cackett ◽  
J Gelbord ◽  
...  
Keyword(s):  
Optical Variability ◽  
X Rays ◽  
X Ray

scholarly journals Correlated X-ray/optical variability in the quasar MR 2251−178

2008 ◽  
Vol 389 (3) ◽  
pp. 1479-1488 ◽  
Author(s):  
P. Arévalo ◽  
P. Uttley ◽  
S. Kaspi ◽  
E. Breedt ◽  
P. Lira ◽  
...  
Keyword(s):  
Optical Variability ◽  
X Ray

Rapid X-ray and optical variability in the X-ray selected BL Lacertae object IE 1402.3 + 0416

1986 ◽  
Vol 303 ◽  
pp. 596 ◽  
Author(s):  
Paolo Giommi ◽  
Paul Barr ◽  
Isabella M. Gioia ◽  
Tommaso Maccacaro ◽  
Rudolph Schild ◽  
...  
Keyword(s):  
Optical Variability ◽  
X Ray ◽  
Bl Lacertae

scholarly journals 2.13. Optical and X-ray variability in NGC 4395

1998 ◽  
Vol 184 ◽  
pp. 83-84 ◽  
Author(s):  
P. Lira ◽  
A. Lawrence
Keyword(s):  
Emission Lines ◽  
X Ray ◽  
High Ionization ◽  
Ngc 4395 ◽  
Narrow Emission

The spectrum of the dwarf Seyfert 1 nucleus in NGC 4395 was first reported about a decade ago (Filippenko & Sargent 1989), showing high ionization narrow emission lines and broad permitted lines. The later detection of radio and X-ray compact nuclear sources and of a featureless UV continuum gave support to the idea that NGC 4395 is a genuine low luminosity AGN (Sramek 1992; Filippenko, Ho & Sargent 1993). However, it has been claimed that, unlike classic Seyferts, NGC 4395 does not vary at all (Shields & Filippenko 1992).

scholarly journals Using AGN Variability Surveys to explore the AGN-Galaxy Connection

2013 ◽  
Vol 9 (S304) ◽  
pp. 385-390
Author(s):  
Vicki L. Sarajedini
Keyword(s):  
Conference Proceedings ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Optical Variability ◽  
Host Galaxies ◽  
X Ray ◽  
Galaxy Surveys ◽  
Successful Technique

AbstractVariability is a successful technique used to identify active galactic nuclei in both ground and space-based galaxy surveys. Optical variability surveys using HST have uncovered a number of AGN in deep extragalactic fields extending to z ~ 3 and probing intrinsically faint sources. Mid-IR variability surveys using Spitzer have identified a significant number of AGN and are particularly sensitive to obscured sources. Many variability-detected AGN are not strong X-ray sources or lack the characteristic colors of AGN and would thus be unidentified using other selection techniques. In this conference proceedings, I discuss the nature of the variable sources and their host galaxies identified in deep extragalactic optical and mid-IR surveys.

scholarly journals X-ray and optical variability in the low-mass burst source X1735 – 444

1986 ◽  
Vol 223 (2) ◽  
pp. 207-217 ◽  
Author(s):  
A. P. Smale ◽  
R. H. D. Corbet ◽  
P. A. Charles ◽  
J. W. Menzies ◽  
P. Mack
Keyword(s):  
Optical Variability ◽  
Burst Source ◽  
X Ray ◽  
Low Mass

scholarly journals X-ray absorption and rapid variability of the dwarf Seyfert nucleus of NGC 4395

2000 ◽  
Vol 318 (3) ◽  
pp. 879-888 ◽  
Author(s):  
K. Iwasawa ◽  
A. C. Fabian ◽  
O. Almaini ◽  
P. Lira ◽  
A. Lawrence ◽  
...  
Keyword(s):  
Rapid Variability ◽  
X Ray ◽  
Ngc 4395 ◽  
Seyfert Nucleus ◽  
X Ray Absorption

scholarly journals Optical and X-ray variability in the least luminous active galactic nucleus, NGC 4395

1999 ◽  
Vol 305 (1) ◽  
pp. 109-124 ◽  
Author(s):  
P. Lira ◽  
A. Lawrence ◽  
P. O'Brien ◽  
R. A. Johnson ◽  
R. Terlevich ◽  
...  
Keyword(s):  
Active Galactic Nucleus ◽  
X Ray ◽  
Ngc 4395

New Data on Sources of Obsidian Artifacts from Tikal, Guatemala

1990 ◽  
Vol 1 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Hattula Moholy-Nagy ◽  
Fred W. Nelson
Keyword(s):  
Optical Characteristics ◽  
Optical Variability ◽  
X Ray ◽  
Xrf Analysis ◽  
Artifact Type ◽  
Lowland Maya

AbstractIn 1984, 29 obsidian artifacts and an unworked nodule from Tikal were attributed to source by visual means and then analyzed by X-ray fluorescence (XRF). We conclude that the considerable within-source optical variability of gray Mesoamerican obsidians makes visual sourcing unreliable at present, although a corpus of descriptions of the optical characteristics of obsidian may eventually provide a way to exclude possible sources. The XRF analysis identified two additional central Mexican sources, bringing to six the number of Mexican obsidian sources represented at Tikal; failed to provide a secure identification for the nodule; supported the succession of Guatemalan obsidian sources utilized by the Southern Lowland Maya previously proposed by Nelson; and suggested other correlations between source, artifact type, and archaeological context.

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