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This interface allows you to extract HI profiles from the Leiden/Argentine/Bonn (LAB) survey. The profiles are generated on your request from the same database that is used by professional astronomers. The LAB survey took several years for the observations and in addition some more years of processing until all instrumental problems were eliminated. This interface allows you to simulate perfect observations with a 25m telescope - or if you like, with a smaller telescope. Below you find also plots for the rotation velocity of the HI gas. The velocity curve below the brightness temperature profile is calculated for each position along the line of sight and shows the radial velocity as function of distance from the observer. The lower plot shows velocities as function of the distance from the Galactic center, hence the galactocentric Radius. Use this information to find spiral arms in the Milky Way! The velocities refer to the local standard of rest (LSR). Peculiar motions of the earth and the Sun are removed, the observer follows the mean motion of material in the Milky Way! You can check where you are, the Sun is at R = 8.5 kpc and there v = 0 km/s.
For positions you may select between Galactic and Equatorial coordinates
Galactic coordinates should be given in degrees. For Equatorial coordinates enter Right Ascension (RA) in hours minutes seconds and Declination (DEC) in in degree minutes seconds.
Observations were made with the Dutch 25m telescope in Dwingeloo and the Argentinean 30m telescope in Villa Elisa. The full width half maximum(FWHM) beamsize is 0.6° but you may choose a beam width for a smaller telescope (e.g. 5° for a 3m telescope). Please use this option with care, large FWHM values demand excessive calculations. This may fail if the calculations take too much CPU time or if the Internet data transfer is too slow.
If you use data products in your research or publications, please reference the EU-HOU project, the Comenius grant, our web page and the following publiction:
Kalberla, P.M.W., Burton, W.B., Hartmann, Dap, Arnal, E.M., Bajaja, E., Morras, R., & Pöppel, W.G.L. (2005), A&A, 440, 775 (Kalberla et al. (2005))
Rotation velocities are calculated according to Fich et al. (1989). Please note that this is an approximation. Velocities in the inner part of the Milky Way for longitudes |l| < 20 ° (or for R < 3.5 kpc) are very uncertain. Don't use such data.
Webinterface created by Peter Kalberla