Non-detections (or upper limits) are not stored in the database, therefore galaxies with no HI measurements available may either be too faint or not have been observed.
The m21 magnitude is available for 13984 galaxies (May 2003 version of the database).
Flux at other wavelengths are given in the parameters: bt, it, mfir. The corrected m21 is m21c.
HyperLeda | Questions: prugniel@obs.univ-lyon1.fr |