J/ApJ/699/186 VLA observations of the Galactic center (Zhao+, 2009)
Dynamics of ionized gas at the galactic center: very large array observations of
the three-dimensional velocity field and location of the ionized streams in
Sagittarius A West.
Zhao J.-H., Morris M.R., Goss W.M., An T.
<Astrophys. J., 699, 186-214 (2009)>
=2009ApJ...699..186Z 2009ApJ...699..186Z
ADC_Keywords: H II regions ; Proper motions ; Interstellar medium ; Radio lines
Keywords: Galaxy: center - H II regions - ISM: individual (Sagittarius A West) -
ISM: kinematics and dynamics - radio lines: ISM
Abstract:
We present new results based on high-resolution observations of Sgr A
West at the Galactic center with the Very Large Array (VLA) at 1.3cm.
By combining recent observations with those made at earlier epochs
with the VLA at wavelengths of 1.3 and 3.6cm, we measured proper
motions for 71 compact HII components in the central 80" (3pc,
assuming D=8pc). Using VLA archival data for the H92α radio
recombination line, we also investigated radial velocities in the LSR
velocity range from +200 to -415km/s. Combining proper motion and
radial velocity measurements, we have determined the three-dimensional
velocity distribution in Sgr A West.
Description:
The new observations of Sgr A* and its vicinity were made at 1.3cm on
2004 December 23 and 2005 April 26 with the VLA with an angular
resolution of 0.1".
At 3.6cm, a total of nine observations was acquired from the VLA
archive. All the observations were made in the spectral line mode for
the H92α line with angular and velocity resolutions of 1.25" and
15km/s, respectively. Table 1 summarizes the observations and data
that are used in this paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 78 15 Log of data and observations
table2.dat 96 71 Measurements of proper motion and radial velocity
table3.dat 26 51 Radial velocities from three mini-spiral arms
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See also:
J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010)
J/A+A/502/91 : Proper motions of stars near SgrA* (Schoedel+, 2009)
J/ApJS/177/515 : 6cm and 20cm survey of Galactic Center (Law+, 2008)
J/ApJ/670/1115 : IRS spectra at 38 positions in Galactic center (Simpson+,
2007)
J/ApJS/155/421 : Survey of Galactic Center region at 20cm (Yusef-Zadeh+, 2004)
J/AJ/128/1646 : The Galactic Center region at 330MHz (Nord+, 2004)
J/A+A/426/81 : Kinematic analysis of the Minispiral (Paumard+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 F3.1 cm Obs [1.3/3.5] Observation wavelength (1)
5- 14 A10 "YYYY/MM/DD" Date Date of observation
16- 17 I2 h RAh Hour of right ascension (B1950)
19- 20 I2 min RAm Minute of right ascension (B1950)
22- 28 F7.4 s RAs Second of right ascension (B1950)
30 A1 --- DE- Sign of declination (B1950)
31- 32 I2 deg DEd Degree of declination (B1950)
34- 35 I2 arcmin DEm Arcminute of declination (B1950)
37- 42 F6.3 arcsec DEs Arcsecond of declination (B1950)
43 A1 --- f_pos [a] J2000 position (2)
45- 51 F7.4 GHz nu Observed frequency
53- 58 F6.4 GHz nu0 ? Effective frequency
60- 63 I4 km/s Vlsr ? LSR velocity
65- 71 F7.4 MHz Delnu Frequency interval
73- 74 I2 --- Nch Channel number
76- 78 A3 --- Arr Array configuration
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Note (1): Continuum observations at 1.3cm
or H92α line observations at 3.5cm
Note (2): The J2000 equinox was used for the observations at:
17 45 40.0848 -29 00 27.779
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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- 3 A3 --- ID Source (1)
4 A1 --- n_ID [d-h] Source located in IRS region (2)
6- 31 A26 --- IRs Infrared identification (3)
33- 39 F7.3 arcsec RAoff Right ascension offset with respect to Sgr A*
(G1)
41- 45 F5.3 arcsec e_RAoff RAoff uncertainty
47- 53 F7.3 arcsec DEoff Declination offset with respect to Sgr A* (G1)
55- 59 F5.3 arcsec e_DEoff DEoff uncertainty
61 A1 --- n_amaj [U] U: unresolved
62- 65 F4.2 arcsec amaj ? Deconvolved source major axis size
67- 70 F4.2 arcsec bmin ? Deconvolved source minor axis size
72- 74 I3 deg PA ? Deconvolved source position angle
76- 81 F6.2 mas/yr mua Proper motion along right ascension
83- 86 F4.2 mas/yr e_mua mua uncertainty
88- 92 F5.1 mas/yr mud Proper motion along declination
94- 96 F3.1 mas/yr e_mud mud uncertainty
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Note (1): KNN for sources measured from 1.3cm observations or XNN for sources
measured from 3.5cm observations. <[ZMG2009] ANN> in Simbad.
Note (2): Flag as follows:
d = The radio component is located in the IRS 6/34 region.
e = The radio component is located in the IRS 13N region.
f = The radio component is located in the IRS 13E region.
g = The radio component is located in the IRS 2L region.
h = The radio component is located in the VISIR 51 region.
Note (3): XJ174540.0290031 (and CXOGC J174540.029003 in section 4.2)
is a misprint for CXOGC J174540.0-290031; corrected at CDS.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- IDs IDs of locations in the mini-spiral arms (1)
5- 10 F6.2 arcsec RAoff Right ascension offset from Sgr A* (G1)
12- 17 F6.2 arcsec DEoff Declination offset from Sgr A* (G1)
19- 22 I4 km/s Vlsr LSR velocity width of the spectral features
24- 26 I3 km/s VFWHM FWHM velocity width of the spectral features
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Note (1): NNN for northern arm, ENN for eastern arm and WNN for western arm
sources. <[ZMG2009] WNN> in Simbad.
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Global notes:
Note (G1): Position for Sgr A* used to calculate offsets from table 1, 2005
observation, at J2000: 17:45:40.0490-29:00:27.980
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 11-Aug-2011