Foreground: LAB Survey

The data made available through this page have been superseded by the Effelsberg-Bonn HI survey and the GASS HI survey.
The Effelsberg-Bonn northern sky HI map is available here
and the HI4PI all-sky HI map made from a combination of Effelsberg-Bonn and GASS data is available here

LAB_HI_Survey Maps

Coordinate System:
Projection Type:
HEALPix, ring, res 9 (Nside=512)
Original Data Source:
Leiden/Argentine/Bonn (LAB) Galactic HI Survey
Download Links:

These data were used in Land & Slosar, arXiv:0706.1703 and given for public use through LAMBDA.

The LAB survey contains the final data release of observations of 21-cm emission from Galactic neutral hydrogen over the entire sky, merging the Leiden/Dwingeloo Survey (LDS: Hartmann & Burton 1997, Cat. VIII/54) of the sky north of -30° with the Instituto Argentino de Radioastronomia Survey (IAR: Arnal et al. 2000A&AS..142...35A and Bajaja et al. 2005, Cat. VIII/75) of the sky south of -25°. The angular resolution of the combined material is HPBW ~ 0.6°. The LSR velocity coverage spans the interval -450 km/s to +400 km/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 0.07-0.09 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 ηMB>0.99% to achieve the same accuracy. The merged and refined material entering the LAB Survey of Galactic H I 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 H I survey to date, with the most extensive coverage both spatially and kinematically.

The data were resampled on NSIDE=512 HEALPix grid using nearest neighbour pixel. The NSIDE=512 with approx 0.1 sq deg pixels is probably oversampling the original data, which is stored in approximately 0.25 sq deg pixels. The HEALPix map is a two-channel map: the first channel (the TEMPERATURE field) contains the HI brightness temperature in K averaged averaged over velocity channels, while the second channel (the SIMULATION field) is the number of original LAB velocity channels that went into that particular HEALPix pixel. The velocity channel spacing is 1.030571969 km s-1. With exception of thin velocity slices, the sky coverage is pretty uniform.

The naming convention is as follows:

LAB_fullvel.fits - the entire velocity range
LAB_LV.fits -30 .. 30 km/s, low velocity
LAB_MV.fits -100 .. -30 km/s, intermediate velocity
LAB_HV.fits -500 .. -100 km/s, high velocity
LAB-cutXXX.fits XXX .. XXX+10 km/s range.
Note that number is the lower limit not the mean.

Please do not hesitate to contact us if you require any further information.

In addition to the standard HEALPix acknowledgement, you must also cite the original data:

Kalberla P.M.W., Burton W.B., Hartmann D., Arnal E.M., Bajaja E., Morras R., Poeppel W.G.L. Leiden/Argentine/Bonn (LAB) Survey of Galactic HI. Astron. Astrophys., 440, 775 (2005)

Citation of Land and Slosar (2007) is also appreciated:

Land, K. and Slosar, A. Correlation between galactic HI and the Cosmic Microwave Background, arXiv:0706.1703, PRD in print

Anze Slosar & Kate Land

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A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Andrew F. Ptak
LAMBDA Director: Dr. Thomas M. Essinger-Hileman
NASA Official: Dr. Thomas M. Essinger-Hileman
Web Curator: Mr. Michael R. Greason