From the Realm of the Nebulae to Populations of Galaxies by Mauro D’Onofrio Roberto Rampazzo & Simone Zaggia

Author:Mauro D’Onofrio, Roberto Rampazzo & Simone Zaggia
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

5.2 From the Sky to Databases

Questions for George Paturel:

You have contributed to the transition between the preparation of classical catalogs (RC3) and the implementation of first large digital catalogues and galaxy databases, e.g. HYPERCAT. May you trace the history of such transition? What is/will be the impact of surveys in the building of the next generation of galaxy catalogues (LSST will produce parameters for ≈ 109 galaxies at different z)? May you discuss the homogenization strategies of galaxy parameters behind the preparation of large catalogues?

The evolution, from classical catalogues to modern databases can be seen as a series of steps. I’ll describe some of them using my personal experience. I would like to comment on the technique of homogenization within this historical part. In this way, it will be easier to explain how very large catalogues have changed the homogenization step.

In the introduction of his famous Uppsala General Catalogue (UGC), the Swedish astronomer Peter Nilson recalls that Knut Lundmark dreamed, in 1930, of collecting and updating all known data on galaxies. Of course some catalogues existed, such as the Messier catalogue of nebulous objects or the not less famous New General Catalogue (NGC) by Dreyer (actually a compilation of observations by many astronomers, including Herschel’s General Catalogue). Unfortunately these catalogues not only contained galaxies but all kinds of nebulous objects, such as star clusters or gaseous nebulae.

It is regrettable that Lundmark’s dream didn’t come true, because the scientific world was just entering an incredible new era with the discovery of the real nature of our Universe: a Universe of galaxies. How many hours of tedious research of data would have been saved if the project had started that early. How many duplication of efforts would have been avoided. Nevertheless, some catalogues of galaxies were published here and there. They were the seed of our present image databases. The databases themselves will probably be the seed of the future Virtual Observatory .

Let me reproduce part of one of the pioneer works: the first catalogue made by hand by Gérard de Vaucouleurs in 1952 (see Fig. 5.1). In his office, not only did Gérard de Vaucouleurs his handmade catalogue but he also had a long wooden box in which he gathered cards with a detailed description of bright galaxies. Sometimes the description was illustrated by a drawing. This box is the poor ancestor of our present image databases.

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