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Introduction to HyperLeda |
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HyperLEDA is a database and a collection of tools to study the physics of galaxies and 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 literature and modern surveys, 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.
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The search by designation prompts the user for the name of an object or a list of names.
These names are searched for in the designation catalogue, taking into account a range of variants in their spelling
(for example abbreviations or alternatives to the catalogue acronym) and accepting some wildcard characters.
In addition, a specific syntax allows searching for the nearest object to a given position on the sky.
The search can be applied to the LEDA catalogue or to any of the other compilations.
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The cone search takes a position on the sky and a radius to limit the surrounding area.
A variety of images of the field can be displayed with a possible overlay that the database objects use,
for instance, the Aladin applet
(Bonnarel et al. 2000)
from the Centre de Données de Strasbourg.
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The SQL search gives a flexible access to the LEDA catalogue.
The user can define her or his own SQL constraints and retrieve any desired fields or valid SQL expressions involving fields.
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The sample request allows the user to retrieve data for his own or predefined sample of objects.
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
- Philippe Prugniel, Observatoire de Lyon (CRAL, France), Project manager, Software development
- Dmitry Makarov, Special Astrophysical Observatory (SAO, Russia), Project manager, software and catalogues
- Galina Korotkova, Special Astrophysical Observatory (SAO, Russia), catalogues
- Anatoly Zasov, Moscow University (SAI, Russia), Catalogue of Spatially Resolved Kinematics of galaxies
People were involved or associated in the past:
- Georges Paturel, Observatoire de Lyon (CRAL, France), LEDA project manager
- Chantal Petit, Observatoire de Lyon (CRAL), LEDA, catalogues
- Helene Courtois, Observatoire de Lyon (CRAL), homogenization of the astrophysical parameters
- Isabelle Vauglin, Observatoire de Lyon (CRAL), LEDA, catalogues
- Igor Chilingarian, Moscow University (SAI) and Observatoire de Lyon, Software development
- Sofia Mitronova, Special Astrophysical Observatory (SAO, Russia), catalogues
- Natasa Gavrilovic, Astronomical Observatory of Belgrade, catalogues
- Valeri Golev, Sofia University, catalogues
- Gilles Theureau, Observatoire de Paris (GEPI), Software development
- Rumen Bogdanovski, Sofia, Software development
- Nicole Coudreau, Observatoire de Paris (GEPI), catalogue of HI data
- Nicole Hallet, Observatoire de Paris (GEPI), catalogue of HI data
- Ivan Zolotukhin, Moscow University, database structure and Virtual Observatory
- Sergey Koposov, Moscow University, database structure and Virtual Observatory
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
- Cite the paper: Makarov et al. 2014, A&A, 570, A13
- Indicate the URL of the database as a footnote: \footnote{http://leda.univ-lyon1.fr/}
- The following sentence is suggested in the acknowledgments:
We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr).
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.