J/A+A/417/421 WSRT wide-field HI survey. II. (Braun+, 2004)
The WSRT wide-field HI survey. II. Local Group features.
Braun R., Thilker D.A.
<Astron. Astrophys., 417, 421-435 (2004)>
=2004A&A...417..421B 2004A&A...417..421B
ADC_Keywords: Molecular clouds ; Radial velocities ; H I data
Keywords: galaxies: Local Group - galaxies: evolution - galaxies: formation -
galaxies: Magellanic Clouds - galaxies: intergalactic medium -
quasars: absorption line
Abstract:
We have used the Westerbork array to carry out an unbiased wide-field
survey for HI emission features, achieving an RMS sensitivity of about
18mJy/Beam at a velocity resolution of 17km/s over 1800deg2 and
between -1000<VHel<+6500km/s. The primary data consists of
auto-correlation spectra with an effective angular resolution of 49'
FWHM. The survey region is centered approximately on the position of
Messier 31 and is Nyquist-sampled over 60x30deg in RAxDE. In this
paper we present our HI detections at negative velocities which could
be distinguished from the Galactic foreground. Fully 29% of the entire
survey area has high velocity HI emission at a column density
exceeding our 3-sigma limit of about 1.5x1017cm-2 over 30km/s. We
tabulate the properties of 95 discrete HVC components in the field,
corresponding to more than an order of magnitude increase in number
over that known previously. The distribution of discrete object number
with flux density has an inflection point near 12Jy.km/s which may
correspond to a characteristic mass and distance for this population.
A complete description of the observations and general methods of data
reduction has already been given in Paper I (Braun et al., Cat.
J/A+A/406/829).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 97 95 Catalog of high velocity HI features
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See also:
J/A+A/406/829 : WSRT wide-field HI survey. I. (Braun+, 2003)
J/A+A/391/159 : A search for Compact High-Velocity Clouds (De Heij+, 2002)
J/AJ/123/873 : HIPASS high-velocity clouds (Putman+, 2002)
J/ApJS/136/463 : Distances and metallicities of HVCs and IVCs (Wakker, 2001)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Running ID number
4- 7 A4 --- Pref Name-prefix (HVC or CHVC) (1)
9- 22 A14 --- Name Name-suffix (LLL.L+BB.B+VVV) (1)
24- 25 I2 h RAh Right ascension (J2000)
27- 28 I2 min RAm Right ascension (J2000)
30- 31 I2 s RAs Right ascension (J2000)
33 A1 --- DE- Declination sign (J2000)
34- 35 I2 deg DEd Declination (J2000)
37- 38 I2 arcmin DEm Declination (J2000)
40- 41 I2 arcsec DEs Declination (J2000)
43- 46 I4 km/s HRV Heliocentric radial velocity
48- 52 F5.1 km/s FWHM Velocity FWHM of the single spectrum with
peak column density
54- 57 F4.2 10+18cm-2 NHI Peak HI column density
59- 62 F4.2 deg Maj Major axis FWHM
64- 67 F4.2 deg Min Minor axis FWHM
69- 71 I3 deg PArd [0,180] Major axis PA, CCW in (RA,DE) coord.
73- 77 F5.1 Jy.km/s FHI Total HI Flux
81- 98 A18 --- IDs Other published IDs (2)
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Note (1): Designation, consisting of a prefix, followed by the Galactic
longitude, Galactic latitude, and Local Standard of Rest velocity.
The prefix is CHVC for the clouds satisfying our isolation criteria;
while HVC is used to indicate clouds connected to more extended
complexes. The longitude and latitude refer to the peak of a spatial
Gaussian fit to the integrated HI. The velocity refers to the peak of
a Gaussian fit to the single spectrum of peak column density.
Note (2): References:
WW: Wakker & van Woerden, 1991A&A...250..509W 1991A&A...250..509W, WV NNN in Simbad
BB: Braun & Burton, 1999A&A...341..437B 1999A&A...341..437B, [BB99] NN in Simbad
DBB: De Heij et al., 2002 Cat. J/A+A/391/159, [DBB2002] NN in Simbad
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Acknowledgements: R. Braun
(End) Patricia Bauer [CDS] 06-Apr-2004