The DFBS Spectroscopic Database and the Armenian Virtual Observatory
The Digitized First Byurakan Survey (DFBS) is the digitized version of the famous Markarian Survey. It is the largest low-dispersion spectroscopic survey of the sky, covering 17,000 square degrees at galactic latitudes |b|>15. DFBS provides images and extracted spectra for all objects present in the FBS plates. Programs were developed to compute astrometric solution, extract spectra, and apply wavelength and photometric calibration for objects. A DFBS database and catalog has been assembled containing data for nearly 20,000,000 objects. A classification scheme for the DFBS spectra is being developed. The Armenian Virtual Observatory is based on the DFBS database and other large-area surveys and catalogue data.
Surveys, Catalogues, Databases, and Archives of Astronomical Data
Abstract This chapter traces the development of astronomical observational methods from visual, for decades tracking the behavior of individual objects, to modern space missions that produce data simultaneously for several hundred thousand objects in different spectral ranges. Thanks to this, astronomy has moved from the study of individual objects to the study of the universe as a whole and has become the science of Big Data. The chapter describes briefly visual, photographic, and CCD surveys of stars, galaxies and the intergalactic medium, spectral photographic and spectral CCD surveys, and multiwavelength ground-based and space-born databases and archives, which made it possible to create a high-precision coordinate system, to discover new properties of celestial bodies, and, as a result, to construct three-dimensional models of the visible parts of the universe. We mention also the “conserved” data of photographic astroplates accumulated over the centuries, which have been actively digitized during the last decades and provide a new knowledge from the comparative analysis of old and new observational material. Astronomy research is changing from being hypothesis-driven to being data-driven to being data-intensive. To cope with the various challenges and opportunities offered by the exponential growth of astronomical data volumes, rates, and complexity, the new disciplines of astrostatistics and astroinformatics have emerged.
Geomagnetic Polarity Epochs: Sierra Nevada Data, 3
Available paleomagnetic and radiometric results for about 60 igneous rocks 3.6 m.y. old or less are consistent with the following geomagnetic polarity epoch time scale: Brunhes normal polarity epoch, 0.0 to 0.85±0.15 million years; Matuyama reversed polarity epoch, 0.85±0.15 to 2.4±0.1 million years; Gauss normal polarity epoch, 2.4±0.1 to 3.35±0.1 million years; Gilbert reversed polarity epoch, 3.35±0.1 million years to (?). A brief interval of normal polarity (the Olduvai event) occurs within the Matuyama reversed epoch at about 1.9 m.y., and a brief interval of reversed polarity (the Mammoth event) occurs within the Gauss normal epoch at about 3.06 m.y. Data for twelve units from eastern California and Nevada, reported here for the first time, are particularly useful in defining the Gauss-Gilbert boundary and for recognizing the Mammoth event.