J/ApJ/626/195 HI self-absorption (HISA) survey in the CGPS (Gibson+, 2005)
A self-absorption census of cold H I clouds in the Canadian Galactic Plane
Survey.
Gibson S.J., Taylor A.R., Higgs L.A., Brunt C.M., Dewdney P.E.
<Astrophys. J., 626, 195-213 (2005)>
=2005ApJ...626..195G 2005ApJ...626..195G
ADC_Keywords: H I data ; Interstellar medium
Keywords: ISM: clouds - ISM: kinematics and dynamics - ISM: structure -
methods: analytical - surveys - techniques: image processing
Abstract:
We present a 21cm line HI self-absorption (HISA) survey of cold atomic
gas within Galactic longitudes l=75° to 146° and latitudes
b=-3° to +5°. We identify HISA as spatially and spectrally
confined dark HI features and extract it from the surrounding HI
emission in the arcminute-resolution Canadian Galactic Plane Survey
(CGPS). We compile a catalog of the most significant features in our
survey and compare our detections against those in the literature.
Within the parameters of our search, we find nearly all previously
detected features and identify many new ones.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 147 69 Major CGPS HI Self-Absorption (HISA) features
table2.dat 98 28 Prior HISA studies in the CGPS region
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See also:
B/cgps : Log of CGPS exposures (Taylor+, 2003-)
VIII/54 : Atlas of Galactic Neutral Hydrogen (Hartmann+, 1997)
VIII/11 : Berkeley Low-Latitude H I Survey (Weaver+ 1973)
VIII/47 : Galactic 21-cm line Survey (Westerhout+ 1982)
J/ApJ/626/887 : HI clouds in Southern Galactic Plane Survey (Kavars+, 2005)
J/MNRAS/201/495 : HI Survey of Southern Galactic Plane (Strong+ 1982)
http://www.ras.ucalgary.ca/CGPS/ : Canadian Galactic Plane Survey home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [GHISA]
7- 20 A14 --- GHISA Feature designation
( in Simbad)
22- 28 F7.3 deg GLON Galactic longitude (1)
30- 35 F6.3 deg GLAT Galactic latitude (1)
37- 42 F6.2 km/s VLSR Local standard of rest velocity (1)
44- 49 F6.3 deg Dlon Δl box dimension (2)
51- 55 F5.3 deg Dlat Δb box dimension (2)
57- 61 F5.2 km/s Dv Δv box dimension (2)
63- 68 F6.3 deg2.km/s Vol Volume occupied by |ΔT|>0 voxels (3)
70- 75 F6.3 deg2 Area Projected area of feature volume
77- 83 F7.2 K.deg2.km/s IntAbs Three-dimensional integrated absorption of
feature ∫ΔT.dV
85- 90 F6.2 K <dT> [-25/-7] Mean absorption <ΔT>
per voxel (4)
92- 97 F6.2 K dTmin [-81/-27] Maximum absorption in any voxel
(ΔTmin=-|ΔT|max)
99-104 F6.2 K <Tu> [71/108] Mean unabsorbed brightness
temperature TU per voxel
106-109 F4.2 --- phiU [0/1] Fraction φU of detected volume
for which TU≥80K (5)
111-114 F4.2 --- etaV [0.6/1] Fraction of detected volume (6)
116-119 F4.2 --- etaT [0.6/1] Fraction of detected absorption (7)
121-147 A27 --- Ref Prior detections of this feature in the
literature, if any (references in table2)
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Note (1): Average feature coordinates, weighted by ΔT.
Note (2): Dimensions of the (l, b, v) box containing the feature.
Note (3): A voxel is a volume-pixel.
Note (4): ΔT=TON-TU, where TON is the brightness temperature on
the feature and TU the mean unabsorbed brightness temperature.
Note (5): Fraction φU of detected volume for which TU≥80K and
detections are most complete, based on fdet (fraction of input HISA
detected)
Note (6): Fraction ηV of detected volume that is probably reliable,
based on ftrue(l,b,v), the fraction of output HISA that represents
true detections.
Note (7): Fraction ηΔT of detected three-dimensional integrated
absorption that is probably reliable, based on ftrue(l,b,v), the
fraction of output HISA that represents true detections.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref [1/28] Reference number
4- 22 A19 --- Bibcode Bibcode
24- 51 A28 --- Aut Author's name
53- 71 A19 --- Tel Name of radio telescope
72 A1 --- n_Tel Observation of a survey (1)
74- 77 F4.2 deg Beam Angular resolution (FWHM)
79- 87 A9 km/s Dv Velocity channel separation Δv (km/s)
89 A1 --- Map [Yn] Were maps made of HISA features?
91- 92 I2 --- Nc [1/41] Number of features covered (2)
94- 95 I2 --- Nf [0/29] Number of features found (3)
97- 98 I2 --- Nm [0/17] Number of major features (4)
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Note (1): Flag on Tel, defined as follows:
g = Maryland-Green Bank Galactic 21cm Line Survey data
(Westerhout & Wendlandt 1982, Cat. VIII/47)
h = Berkeley Low-Latitude Survey of Neutral Hydrogen data
(Weaver & Williams 1973, Cat. VIII/11)
i = Canadian Galactic Plane Survey data (Taylor et al. 2003, Cat. B/cgps)
Note (2): Features within the CGPS Phase I coverage.
Note (3): Features detected wholly or partially in this HISA search.
Note (4): Features overlapping with major features in this survey.
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History:
From electronic version of the journal
References:
Gibson et al., Paper I 2000ApJ...540..851G 2000ApJ...540..851G
Gibson et al., Paper III 2005ApJ...626..214G 2005ApJ...626..214G
(End) Marianne Brouty [CDS] 06-Sep-2006