J/A+A/594/A116 HI4PI spectra and column density maps (HI4PI team+, 2016)
HI4PI: a full-sky HI survey based on EBHIS and GASS.
HI4PI collaboration, Ben Bekhti N., Floeer L., Keller R., Kerp J., Lenz D.,
Winkel B., Bailin J., Calabretta M.R., Dedes L., Ford H.A., Gibson B.K.,
Haud U., Janowiecki S., Kalberla P. M. W., Lockman F.J.,
McClure-Griffiths N.M., Murphy T., Nakanishi H., Pisano D.J.,
Staveley-Smith L.
<Astron. Astrophys. 594, A116 (2016)>
=2016A&A...594A.116H 2016A&A...594A.116H (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; H I data ; Milky Way; Interstellar medium ; Spectroscopy
Keywords: surveys - ISM: atoms - techniques: spectroscopic
Abstract:
Measurement of the Galactic neutral atomic hydrogen (HI) column
density, NHI, and brightness temperatures, Tb, is of high scientific
value for a broad range of astrophysical disciplines. In the past two
decades, one of the most-used legacy HI datasets has been the
Leiden/Argentine/Bonn Survey (LAB).
We release the HI 4-pi survey (HI4PI), an all-sky database of Galactic
HI, which supersedes the LAB survey.
The HI4PI survey is based on data from the recently completed first
coverage of the Effelsberg-Bonn HI Survey (EBHIS) and from the third
revision of the Galactic All-Sky Survey (GASS). EBHIS and GASS share
similar angular resolution and match well in sensitivity. Combining
both, they are ideally suited to be a successor to LAB.
The new HI4PI survey outperforms the LAB in angular resolution (16.1',
FWHM) and sensitivity (43mK RMS). Moreover, it has full spatial
sampling and thus overcomes a major issue of LAB, which severely
undersamples the sky. We publish all-sky column density maps of the
neutral atomic hydrogen in the Milky Way, along with full
spectroscopic data, in several map projections including HEALPix.
Description:
The HI4PI data release comprises 21-cm neutral atomic hydrogen data of
the Milky Way (-600km/s<vlsr<+600km/s for declination >0°;
-470km/s<vlsr<+470km/s for declination <0°) as observed with
the 100-m radio telescope at Effelsberg and the 64-m radio telescope
at Parkes. HI4PI covers the full 4-pi sky. Spectral data is provided
in three forms:
(1) Standard FITS data cubes, for the full sky in both, Equatorial
(J2000) and Galactic coordinates, each in four different map
projections, AIT, CAR, MOL, and SFL; see world-coordinate-system,
WCS, references: Greisen & Calabretta, 2002A&A...395.1061G 2002A&A...395.1061G,
Calabretta & Greisen, 2002A&A...395.1077C 2002A&A...395.1077C,
Greisen et al., 2006A&A...446..747G 2006A&A...446..747G
(2) Smaller FITS data cubes, each having a size of about 20x20 sq.deg.
For convenience, we provide four different map projections, CAR, SFL,
SIN, and TAN (again see WCS references). Note, size in longitude is
20° in absolute coordinates for CAR projection, and 20°
true-angular size for SFL, SIN, and TAN projections. Again,
Equatorial and Galactic coordinate systems are provided.
(3) FITS binary tables containing lists of spectra sampled on a HealPIX
grid (nside=1024, Galactic coordinates, Ring indexing scheme,
Gorski et al., 2005ApJ...622..759G 2005ApJ...622..759G). To make handling of the data
easier, the table is split into smaller files. Each of these
contains spectra belonging to one of the 192 base/parent pixels of
the nside=4 pixelization. For convenience, the binary tables also
contain EQ2000 and Galactic coordinate positions for each
individual spectrum, as well as the associated HealPIX index.
Furthermore, we provide the full-sky HI column density distribution, both,
in a
(1) HealPIX-grid binary table (nside=1024, Galactic coordinates, Ring
indexing scheme), and
(2) Standard FITS 2D images in four map projections, AIT, CAR, MOL, and
SFL. Various velocity intervals were applied to calculate NHI.
Equatorial and Galactic coordinate systems are provided.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
nhi_eq.dat 31 44 List of all-sky NHI FITS images, Equatorial
NHI/EQ2000/* . 44 All-sky NHI FITS images, Equatorial (1.4G)
nhi_gal.dat 31 44 List of all-sky NHI FITS images, Galactic
NHI/GAL/* . 44 All-sky NHI FITS images, Galactic (1.4G)
allsky_eq.dat 12 4 List of all-sky FITS data cubes, Equatorial
ALLSKY/EQ2000/* . 4 All-sky FITS data cubes, Equatorial (120G)
allsky_gal.dat 12 4 List of all-sky FITS data cubes, Galactic
ALLSKY/GAL/* . 4 All-sky FITS data cubes, Galactic (120G)
cubes_eq.dat 28 534 List of 20dx20d FITS data cubes, Equatorial
CUBES/EQ2000/* . 534 20dx20d FITS data cubes, Equatorial (132G)
cubes_gal.dat 28 534 List of 20dx20d FITS data cubes, Galactic
CUBES/GAL/* . 534 20dx20d FITS data cubes, Galactic (132G)
nhi_hpx.dat 71 12582912 HI column densities
NHI_HPX.fits 2880 209720 HI column densities (HPX-grid FITS binary table)
hpxspec.dat 52 192 List of HPX-grid FITS binary tables
HPX/* . 192 Individual HPX-grid FITS binary tables (45G)
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Byte-by-byte Description of file: nhi_eq.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- WCSproj WCS projection code
5- 8 I4 km/s b_RVel Lower radial velocity limit (LSR, Radio)
10- 13 I4 km/s B_RVel Upper radial velocity limit (LSR, Radio)
15- 31 A17 --- FileName Name of FITS file in subdirectory NHI/EQ2000
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Byte-by-byte Description of file: nhi_gal.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- WCSproj WCS projection code
5- 8 I4 km/s b_RVel Lower radial velocity limit (LSR, Radio)
10- 13 I4 km/s B_RVel Upper radial velocity limit (LSR, Radio)
15- 31 A17 --- FileName Name of FITS file in subdirectory NHI/GAL
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Byte-by-byte Description of file: allsky_eq.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- WCSproj WCS projection code
5- 12 A8 --- FileName Name of FITS file in subdirectory ALLSKY/EQ2000
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Byte-by-byte Description of file: allsky_gal.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- WCSproj WCS projection code
5- 12 A8 --- FileName Name of FITS file in subdirectory ALLSKY/GAL
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Byte-by-byte Description of file: cubes_eq.dat
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Bytes Format Units Label Explanations
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1- 5 F5.1 deg RAdeg Right ascension (J2000) of data cube center
7- 11 F5.1 deg DEdeg Declination (J2000) of data cube center
13- 15 A3 --- WCSproj WCS projection code
17- 28 A12 --- FileName Name of FITS file in subdirectory CUBES/EQ2000
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Byte-by-byte Description of file: cubes_gal.dat
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Bytes Format Units Label Explanations
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1- 5 F5.1 deg GLON Galactic longitude of data cube center
7- 11 F5.1 deg GLAT Galactic latitude of data cube center
13- 15 A3 --- WCSproj WCS projection code
17- 28 A12 --- FileName Name of FITS file in subdirectory CUBES/GAL
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Byte-by-byte Description of file: nhi_hpx.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- HPX HPX index (HPXINDEX)
10- 18 F9.5 deg RAdeg Right ascension (J2000)
20- 28 F9.5 deg DEdeg Declination (J2000)
30- 38 F9.5 deg GLON Galactic longitude (J2000)
40- 48 F9.5 deg GLAT Galactic latitude (J2000)
50- 71 E22.15 cm-2 NHI HI column density
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Byte-by-byte Description of file: hpxspec.dat
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Bytes Format Units Label Explanations
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1- 8 F8.4 deg GLON Galactic longitude
10- 17 F8.4 deg GLAT Galactic latitude
19- 26 F8.4 deg RAdeg Right ascension (J2000)
28- 35 F8.4 deg DEdeg Declination (J2000)
37- 39 I3 --- HPXidx HealPIX index (nside=4, RING scheme,0-based)
41- 52 A12 --- FileName Name of the FITS file in subdirectory HPX
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Acknowledgements:
Benjamin Winkel, bwinkel(at)mpifr.de
References:
McClure-Griffiths et al., 2009ApJS..181..398M 2009ApJS..181..398M
Kalberla et al., 2010A&A...521A..17K 2010A&A...521A..17K
Winkel et al., 2010ApJS..188..488W 2010ApJS..188..488W
Kerp et al., 2011AN....332..637K 2011AN....332..637K
Kalberla & Haud, 2015A&A...578A..78K 2015A&A...578A..78K
Winkel et al., 2016A&A...585A..41W 2016A&A...585A..41W
(End) Patricia Vannier [CDS] 22-Sep-2016