The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI

TLDR

The LAB Survey of Galactic HI provides a final, all‑sky 21‑cm emission data release, merging the Leiden/Dwingeloo and Instituto Argentino de Radioastronomia surveys, and serves as a comprehensive resource for studies of the Milky Way’s interstellar medium. The combined survey achieves an angular resolution of ~0.6°, velocity coverage from –450 to +400 km s⁻¹ at 1.3 km s⁻¹ resolution, and applies refined stray‑radiation corrections. The merged database attains rms brightness‑temperature noise of 0.07–0.09 K, residual stray‑radiation errors below 20–40 mK, and represents the most sensitive, spatially and kinematically extensive Milky Way HI survey to date.

Abstract

We present the final data release of observations of lambda 21-cm emission from Galactic neutral hydrogen over the entire sky, merging the Leiden/Dwingeloo Survey (LDS: Hartmann & Burton, 1997) of the sky north of delta = -30 deg with the Instituto Argentino de Radioastronomia Survey (IAR: Arnal et al., 2000, and Bajaja et al., 2005) of the sky south of delta = -25 deg. The angular resolution of the combined material is HPBW ~ 0.6 deg. The LSR velocity coverage spans the interval -450 km/s to +400 km/s, at a resolution of 1.3 km/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 - 0.09 K. 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 - 40 mK. It would be necessary to construct a telescope with a main beam efficiency of eta_{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.