The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections

TL;DR

The LAB Survey provides a comprehensive, high-resolution map of Galactic neutral hydrogen by merging and refining two major surveys, offering a valuable resource for interstellar medium studies.

Contribution

This paper presents the final data release of the LAB Survey, combining LDS and IAR data with improved stray-radiation corrections for the first time.

Findings

Most data have residual stray-radiation errors below 40 mK.

The survey achieves an rms noise level of 0.07-0.09 K.

It is the most sensitive and extensive Galactic 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.