The Astrogeo VLBI FITS image database


The Astrogeo VLBI FITS image database contains 50,696 brightness distributions of 9049 compact radio sources, mainly active galaxy nuclea (AGN), generated by analyzing very long baseline interferometry (VLBI ) surveys — dedicated radioastronomy observations of large lists of radio sources on networks of radio telescopes spread at distances of thousand kilometers. The primary database contents is not pictures, but brightness distribution in a digital form, specifically in FITS format, and calibrated visibility data, which makes it possible to use this database for scientific work. Derived quantities, such as visualization of images and estimates of the correlated flux density are also available. The images were contributed by courtesy of many authors.

The database can be searched using one of these methods:

In addition to brightness distribution, estimates of the correlated flux density from VLBI experiments for a number of sources are available. Currently, they are not included in the database and are not searched.

The contents of the database can also accessible as

Each image is represented with six files:

  1. the calibrated and edited set of visibility (i.e. cross-correlation function) points in FITS format;
  2. the set of clean components that models the source brightness distribution in FITS format;
  3. the picture of the source image in Postscript format;
  4. the plot of dependence of the correlated flux density on the baseline length in Postscript format;
  5. the plot of the uv-coverage;
  6. the table with the total correlated flux density; the median correlated flux density at baseline lengths less than 900 km, the median correlated density at baseline lengths greater than 5000 km. For many sources images at more than one epoch, at more than one frequency bands are available.

The images in FITS format submitted by authors were pre-processed to a standardized form. The process of standardization involved: a) assignment of new names to each file; b) adding 14 new keywords in the FITS headers; c) removal of lengthy history records; d) generating the pictures and plots in Postscript format; e) generating the table with estimates of the correlated flux density.

Authors who contributed images (in alphabetic order)

How to submit images

If you have images that you would like to be incorporated in the database, you are welcome to submit them. At minimum, two files per source should be available for submission: 1) a map in FITS format; 2) calibrated visibilities in FITS format. Images are grouped in campaigns that usually correspond to individual observing projects. Each submission for a given campaign should be accompanied with an ascii file with meta-data and an cross-reference table between sources names embedded in the FITS-file header and 10-character long IAU J2000 source names. Just send the link to the tar-files with data and the metadata to the database maintainer, Leonid Petrov.

Usage policy

The contents of this database is protected by the GNU Public License. You can download and use the contents of this database for your personal work. If you would like to reproduce images from this database in any sort of publications, please ask permission of the image's author. The author will instruct you how to acknowledge properly his contribution. You can put a reference to this database or any file from this database in any electronic or printed document. You are not allowed to make available at your web site or to distribute by other means derived products, for instance postscript or gif pictures of any source, without 1) providing valid links to brightness distributions and calibrated visibilities in FITS-format, 2) without providing the link to this web-document and proper acknowledgment of the Astrogeo Center Database of Brightness Distributions, Correlated Flux Densities, and Images of Compact Radio Sources Produced with VLBI. In a similar way, you cannot distribute compiled executable software program protected by the GNU Public License without providing its source code. If you would like to make available at your Web the entire copy of this database you must ask prior permission from the maintainer.
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This web page was prepared by Leonid Petrov ()
Last update: 2016.10.25_21:50:45