leda Introduction to HyperLeda site

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HyperLEDA is a database and collection of tools to study the physics of galaxies and the cosmology. The project, started in 1983, is currently maintained by a collaboration between Observatoire de Lyon (France) and the Special Astrophysical Observatory (Russia).

The principle behind HyperLEDA is to collect measurements published in the literature, and to combine them into a unique homogeneous description of the astronomical objects. This enables the researcher to compare objects located at very different distances. This approach is a continuation of the famous series of Bright Galaxy Catalogues (RC1, RC2, RC3) by de Vaucouleurs and co-workers. The result of the homogenization is the Leda catalogue.

HyperLeda is not only used by researchers, but also by sky lovers or amateur astronomers interested to learn more about galaxies, by students, and by professors. HyperLeda is developed in the frame of the Virtual Observatory, an initiative intended to facilitate the exchange and usage of the data at the global scale. All the data and the software is publicly available in open-source for non-commercial purposes.

Compilations

The compilations of data from the astronomical literature are maintained on a regular basis (see the additions over the past year). The maintenance of these catalogues involves efforts to provide accurate cross-identifications of the celestial sources, a clear description of each series of measurements (including a documentation on the precision and systematic errors), and a flagging of doubtful or erroneous data. The compilations are processed to produce the mean homogenized parameters of the Leda catalogue.

The following table gives the list of compilations, together with statistics on their content:

Homogenization

The Leda catalogue provides homogenized description of observable and physical properties of galaxies. For this purpose the raw measurements are combined into the same scale taking into account systematic shifts and data scatter. The precise definition of each parameter and the homogenization recipes are described in the documentation of each parameter. For more information, please, see the list of astrophysical parameters in the Leda catalogue.

History

HyperLEDA (Makarov et al. 2014) takes its roots in the Lyon-Meudon Extragalactic database (Paturel et al. 1988, LEDA), which was created in 1983, and in Hypercat, which started as the observational catalogue on kinematics of early-type galaxies (Prugniel & Simien 1996). These databases were joined toghether in 2000. Historically, the LEDA database was used for preparation of the Third Reference Catalogue of Bright Galaxies (de Vaucouleurs et al. 1991, RC3).

Interface

The web interface gives access to a number of tools. The principal ones are the searches by designation, near a position (also called cone searches), and by parameters using Structure Query Language (SQL)-like commands.

In some cases it is useful to access HyperLEDA with scripts or to customize the output (to fit the needs of a particular application). The advanced user's guide provides informations about these possibilities

Mirrors

The public mirrors of HyperLEDA are operated with the pleinpot software. Both the software and data are available as a free packages for a Unix/Linux system, which enables installing a private mirror of the system. The list of the mirrors:

Team

People were involved or associated in the past:

Acknowlegments

The acknowlegments are crucial in order to continue to provide public access to the database. If you use HyperLeda to prepare observations, define a sample, or for any other purpose, please

Bibliography

The main publications describing PGC/LEDA/HyperLeda (from the NASA Astrophysics Data System - ADS).

See a list of papers which used HyperLeda.

Special thanks

This database has been developed with the help of many people: Andernach H., Becker M., Bottinelli L., Buta R.J., Corwin H.G.Jr., Davoust E., de Vaucouleurs A., de Vaucouleurs G., Courtois H., Durand N., Fouqué P., Garnier R., Kogoshvili N., Gouguenheim L., Hallet N., Lanoix P., Mamon G., Marthinet M.C., Miyauchi-Isobe N., Rouaix S., Rousseau J., Simien F., Odewahn S., Takase B., Vauglin I., Watson, C., Winner R.. and the following Institutions : MENST, INSU, PNG, PNC, CNRS, DRED, Conseil Régional Rhône-Alpes, Observatoire de Lyon, Observatoire de Paris-Meudon, Centre de Données de Strasbourg (CDS).

HyperLeda makes use of AladinLite produced by the Centre de Données de Strasbourg.


HyperLeda Questions: leda@univ-lyon1.fr