J/A+A/391/159 A search for Compact High-Velocity Clouds (De Heij+, 2002)
An automated search for compact high-velocity clouds in
the Leiden/Dwingeloo Survey
De Heij V., Braun R., Burton W.B.
<Astron. Astrophys. 391, 159 (2002)>
=2002A&A...391..159D 2002A&A...391..159D
ADC_Keywords: Interstellar medium ; H I data
Keywords: ISM: clouds - ISM: kinematics and dynamics - Galaxy: evolution -
Galaxies: dwarf - Galaxies: evolution - Galaxies: Local Group
Description:
An automated search is applied to the Leiden/Dwingeloo HI Survey (LDS)
for high-velocity clouds north of Dec.=-28°. From the general
catalog we extract a sample of relatively small (less than about
8°) and isolated high-velocity clouds, CHVCs: anomalous-velocity
HI clouds which are sharply bounded in angular extent with no
kinematic or spatial connection to other HI features down to a
limiting column density of 1.5x1018cm-2. Unambiguously isolated
objects are given the "CHVC" designation, while those with some degree
of ambiguity in this classification or designated "CHVC:" or "CHVC?".
The vast majority of features show diffuse connections at low column
densities with the extended HVC complexes and are simply designated as
"HVC" features. The automated search algorithm has been applied to the
HIPASS and to the Leiden/Dwingeloo data sets. The results from the LDS
are described here; Putman et al. (2002, Cat. J/AJ/123/873) describe
application of this algorithm to the HIPASS material. Only those
catalog entries which have and additional ID listed have been
confirmed in independent data.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 130 917 Catalog of high velocity HI features in the LDS
--------------------------------------------------------------------------------
See also:
J/AJ/123/873 : HIPASS high-velocity clouds (Putman+, 2002)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 4 I3 --- Seq Running ID number
7- 11 A5 --- Pref *Name-prefix (one of HVC, CHVC, CHVC:, CHVC?)
13- 26 A14 --- Suff Name-suffix (LLL.L+BB.B+VVV)
30- 31 I2 h RAh Right ascension (J2000)
33- 36 F4.1 min RAm Right ascension (J2000)
39 A1 --- DE- Declination sign (J2000)
40- 41 I2 deg DEd Declination (J2000)
43- 44 I2 arcmin DEm Declination (J2000)
48- 51 I4 km/s LRV LSR (Local Standard of Rest) radial velocity
54- 57 I4 km/s GRV *GSR (Galactic Standard of Rest) velocity
60- 63 I4 km/s LGRV *LGSR (Local Group Standard of Rest) velocity
66- 68 I3 km/s FWHM Velocity FWHM
71- 75 F5.1 deg Maj Major axis FWHM
78- 81 F4.1 deg Min Minor axis FWHM
84- 86 I3 deg PAlb *[-90,90] Major axis PA
90- 93 F4.2 K PTB Peak HI brightness temperature
96- 99 F4.2 10+20cm-2 NHI Peak HI column density in units of 1020cm-2
103-107 I5 Jy.km/s Flux Total HI Flux
111-130 A20 --- IDs *? Other published IDs
--------------------------------------------------------------------------------
Note on Pref:
The prefix is CHVC for the clouds satisfying both of our isolation
criteria; the prefix is CHVC: for clouds for which the isolation is
less clear; the prefix is CHVC? for clouds which have some other
shortcoming in their isolation designation; while HVC is
used to indicate clouds connected to extended complexes
Note on GRV: the velocity is defined by
V(GSR) = V(LSR) + 220 cos(b) sin(l)
Note on LGRV: the velocity is defined by
V(LGRV) = V(GSR)) -62 cos(b) cos(l) + 40 cos(b) sin(l) - 35 sin(b)
Note on PAlb:
The position angle is positive in the direction of increasing Galactic
longitude, with a value of zero when the cloud is aligned pointing toward
the Galactic north pole.
Note on IDs:
WW: Wakker B.P., van Woerden H., 1991A&A...250..509W 1991A&A...250..509W
BB: Braun R., Burton W.B., 1999A&A...341..437B 1999A&A...341..437B
HP: Putman M., et al., 2002AJ....123..873P 2002AJ....123..873P, Cat. J/AJ/123/873
DBB: De Heij V., Braun R., Burton W.B., 2002A&A...391..159D 2002A&A...391..159D, this work
--------------------------------------------------------------------------------
Acknowledgements: Robert Braun
History:
* 03-Mar-2003: In table1, Sequential number 999 corrected into 899
(End) Robert Braun [Astron] 21-Aug-2002