Correlated X-Ray and Optical Variability in the O-type Supergiant ζ Puppis

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.

Download Full-text

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/223.2.207 ◽

1986 ◽

Vol 223 (2) ◽

pp. 207-217 ◽

Cited By ~ 6

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

Download Full-text

New Data on Sources of Obsidian Artifacts from Tikal, Guatemala

Ancient Mesoamerica ◽

10.1017/s0956536100000080 ◽

1990 ◽

Vol 1 (1) ◽

pp. 71-80 ◽

Cited By ~ 21

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.

Download Full-text

AGN in the GOODS Fields: Variability and Multiwavelength Detection

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310006009 ◽

2009 ◽

Vol 5 (S267) ◽

pp. 139-139

Author(s):

Vicki L. Sarajedini ◽

David C. Koo ◽

Alison J. Klesman

Keyword(s):

Active Galactic Nuclei ◽

Selection Criteria ◽

Galactic Nuclei ◽

Optical Variability ◽

Complete Sample ◽

X Ray

AbstractActive galactic nuclei can be identified in deep HST surveys using different selection techniques and multiwavelength data. We aim to produce a complete sample of AGN in the GOODS South and North fields by combining X-ray, optical and mid-IR selection criteria, including galaxies displaying nuclear optical variability.

Download Full-text