2005A&A...440..775K

We present the final data release of observations of λ21-cm emission from Galactic neutral hydrogen over the entire sky, merging the Leiden/Dwingeloo Survey (LDS: Hartmann & Burton, 1997, Atlas of Galactic Neutral Hydrogen) of the sky north of δ=-30° with the Instituto Argentino de Radioastronomia Survey (IAR: Arnal et al., 2000A&AS..142...35A; and Bajaja et al., 2005A&A...440..767B) of the sky south of δ=-25°. The angular resolution of the combined material is HPBW∼0.6deg. The LSR velocity coverage spans the interval -450km/s to +400km/s, at a resolution of 1.3km/s. The data were corrected for stray radiation at the Institute for Radioastronomy of the University of Bonn, refining the original correction applied to the LDS. The rms brightness-temperature noise of the merged database is 0.07-0.09K. Residual errors in the profile wings due to defects in the correction for stray radiation are for most of the data below a level of 20-40mK. It would be necessary to construct a telescope with a main beam efficiency of η_MB>99% to achieve the same accuracy. The merged and refined material entering the LAB Survey of Galactic HI is intended to be a general resource useful to a wide range of studies of the physical and structural characteristices of the Galactic interstellar environment. The LAB Survey is the most sensitive Milky Way HI survey to date, with the most extensive coverage both spatially and kinematically.