J/ApJ/653/1226 Physical properties of galactic HII regions (Quireza+, 2006)
The electron temperature gradient in the Galactic disk.
Quireza C., Rood R.T., Bania T.M., Balser D.S., Maciel W.J.
<Astrophys. J., 653, 1226-1240 (2006)>
=2006ApJ...653.1226Q 2006ApJ...653.1226Q
ADC_Keywords: H II regions ; Abundances
Keywords: H II regions - ISM: abundances - ISM: clouds - ISM: evolution -
ISM: lines and bands - ISM: structure -
nuclear reactions, nucleosynthesis, abundances - radio lines: ISM
Abstract:
We derive the electron temperature gradient in the Galactic disk,
using a sample of HII regions that spans Galactocentric distances of
0-17kpc. The electron temperature was calculated using high-precision
radio recombination line and continuum observations for more than 100
HII regions. Nebular Galactocentric distances were calculated in a
consistent manner, using the radial velocities measured by our radio
recombination line survey. The large number of nebulae widely
distributed over the Galactic disk, together with the uniformity of
our data, provide a secure estimate of the present electron
temperature gradient in the Milky Way.
Description:
Our HII region sample data are described by Quireza et al. (2006,
Cat. J/ApJS/165/338 and references therein).
All observations were made near 8.6GHz (3.5cm) with the National
Radio Astronomy Observatory (NRAO)6 140ft (43m) telescope in Green
Bank, WV, which has a half-power beam width (HPBW) of 3.20' at this
frequency. Our sample has 106 sources: 47 nebulae from the 3He
survey and 66 from the CII survey. (There are seven objects in
common.)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 106 119 Physical properties of Galactic HII regions
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See also:
J/ApJS/165/338 : Radio recombination lines in HII regions (Quireza+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Source Source designation (GLLL.ll+BBB.bb)
14- 16 A3 --- n_Source [d,e ] Observational notes (1)
18- 30 A13 --- Name Other name
32- 35 F4.1 kpc RGal Galactocentric distance
37- 40 F4.1 kpc dSun ?=- Heliocentric distance
42- 45 F4.1 arcmin theta ?=- Angular diameter
47- 50 F4.1 pc Diam ?=- Linear diameter
52- 56 F5.3 --- He+/H+ Ionic abundance ratio N(He+)/N(H+)
58- 62 F5.3 --- e_He+/H+ rms uncertainty on He+/H+
64- 68 F5.1 Jy Snu ?=- Flux density at 8.6GHz
70- 74 F5.1 K TBC ?=- Continuum brightness Temperature
76- 81 F6.1 cm-3 ne ?=- Electron density
83- 87 I5 K Te ?=- Electron temperature (2)
89- 93 I5 K e_Te ?=- rms uncertainty on Te
95- 96 A2 --- Mode Continuum observing mode (3)
98 A1 --- Qc [A-E] Continuum quality factors (4)
100 A1 --- Ql [A-E] Line quality factors (4)
102-106 A5 --- Survey Survey (CII or 3He)
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Note (1): Notes as follows:
d = M16, M17, NGC 6334, Rosette, and S209 were observed at different
positions in the 3He survey
e = Observed in both CII and 3He surveys
Note (2): The electron temperatures were rounded off to the nearest 10K.
Note (3): Mode refers to the continuum observing mode as follows:
TP = total power observations
SP = denotes switched power observations
Note (4): Quality flag: A best to E worst
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Aug-2008