Paper detail

Preparing old and recent radio source tables for the VO age: Current status

Independent of established data centers, and partly for my own research, I have been collecting the tabular data from nearly 1500 articles concerned with radio sources. Optical character recognition (OCR) was used to recover tables from nearly 600 of these. Tables from only 44 percent of these articles are available in the CDS or CATS catalog collections. This fraction is 62 percent for articles with over 100 sources. Surprisingly, these fractions are not better for articles published electronically since 2001, perhaps partly due to the fact that often tabular data are published in formats not useful for direct machine reading. The databases Simbad and NED recognize only about 60 percent of the bibliographic references corresponding to the existing electronic radio source lists, and the number of objects associated with these references is much smaller still. Both, object databases like NED and Simbad, as well as catalog browsers (VizieR, CATS) need to be consulted to obtain the most complete information on radio sources. More human resources at the data centers and better collaboration between authors, referees, editors, publishers, and data centers are required to improve the flow of tabular data from journals to public databases. Current efforts within the Virtual Observatory (VO) project, to provide retrieval and analysis tools for different types of published and archival data stored at various sites, should be balanced by an equal effort to recover and include large amounts of published data not currently available in this way. If human resources can be found, the data sets collected by the author will be made available for the preparation of metadata necessary for their ingression into catalog browsers.