HYPERLEDA - II. The homogenized HI data

After a compilation of HI data from 611 references and new observations made in Nancay, we produce a catalog of homogenized HI data for 16781 galaxies. The homogenization is made using the EPIDEMIC method from which all data are progressively converted into the adopted standard. The result is a catalog giving: 1) the logarithm of twice the maximum rotation velocity, log 2V(M)(sini) M, converted to the system of Mathewson et al. (1996). This quantity is given without correction for inclination; 2) the HI magnitude, m(21), ( area of the 21-cm line width expressed in magnitude) converted to the flux system of Theureau et al. (1998); 3) the HI velocity, V-HI, expressed with the optical definition (i.e., using wavelengths instead frequencies). The typical uncertainties are: 0.04 for log 2V(M)(sin i) 0.25 mag for m(21) and 9 km s(-1) for V-HI.