J/ApJ/615/702 IC 133 water vapor maser (Argon+, 2004)
The IC 133 water vapor maser in the galaxy M33: a geometric distance.
Argon A.L., Greenhill L.J., Moran J.M., Reid M.J., Menten K.M., Inoue M.
<Astrophys. J., 615, 702-719 (2004)>
=2004ApJ...615..702A 2004ApJ...615..702A
ADC_Keywords: Masers ; Radio sources ; VLBI ; Proper motions
Keywords: galaxies: individual (M33) - ISM: individual (IC 133) - masers
Abstract:
We report on the results of a 14yr long VLBI study of proper motions
in the IC 133 H2O maser source in the galaxy M33.
Description:
Observations of the H2O maser in IC 133 were made using the US VLBI
network and its successor, the Very Long Baseline Array (VLBA),
operated by the National Radio Astronomy Observatory (NRAO). The maser
was observed on eight different occasions between 1987 and 2001.
Objects:
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RA (2000) DE Designation(s)
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01 33 15.9 +30 53 02 IC 133
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 67 8 Observed bandpasses
table4.dat 58 106 IC 133 maser feature positions
table5.dat 102 167 IC 133 maser spot positions and proper motions
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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- 14 A14 --- ObsDate Date of Observation
16 A1 --- Epoch Epoch number
18- 24 F7.2 km/s VLSR1 First LSR velocity of band center
26- 32 F7.2 km/s VLSR2 ? Second LSR velocity of band center
34- 40 F7.2 km/s VLSR3 ? Third LSR velocity of band center
42- 47 F6.4 km/s Sep Channel separation
49- 52 I4 km/s BW1l Bandwidth 1 - Lower value of the interval
54- 57 I4 km/s BW1h Bandwidth 1 - Upper value of the interval
59- 62 I4 km/s BW2l ? Bandwidth 2 - Lower value of the interval
64- 67 I4 km/s BW2h ? Bandwidth 2 - Upper value of the interval
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Loc The IC 133 location (Main or West)
6- 12 F7.2 km/s VLSR Average channel LSR velocity
14- 17 F4.2 Jy Speak Peak flux density (22GHz)
19- 26 F8.3 mas offX East-West offset (1)
28- 32 F5.3 mas e_offX Uncertainty in offX
34- 40 F7.3 mas offY North-South offset (1)
42- 46 F5.3 mas e_offY Uncertainty in offY
48- 55 A8 --- Obs Epochs observed (in table3.dat)
57 A1 --- f_Obs [c] Indicates proper motions listed in
table5.dat
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Note (1): Measured with respect to the reference maser feature at the
epoch of observation or at epoch 4 if the feature was observed for
more than one epoch. If a multi epoch feature was not observed in
epoch 4, it was still referred to epoch 4.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Loc The IC 133 location
6- 7 I2 --- Fnum Maser feature number
9- 15 F7.2 km/s VLSR1 ? First LSR velocity for given
spectral channel (1)
17- 23 F7.2 km/s VLSR2 ? Second LSR velocity for given
spectral channel (1)
25- 31 F7.2 km/s VLSR3 ? Third LSR velocity for given
spectral channel (1)
33- 39 A7 --- Ep1 Epoch(s) of first LSR velocity (in table3.dat)
41- 42 A2 --- Ep2 Epoch(s) of second LSR velocity (in table3.dat)
44 A1 --- Ep3 Epoch(s) of third LSR velocity (in table3.dat)
46 A1 --- f_Fnum [W] Indicates all values are
weighted averages (3)
48- 55 F8.3 mas offX East-West offset (4)
57- 61 F5.3 mas e_offX Uncertainty in offX
63- 69 F7.3 mas offY North-South offset (4)
71- 75 F5.3 mas e_offY Uncertainty in offY
77- 82 F6.2 uas/yr pmX East-West proper motion (5)
84- 88 F5.2 uas/yr e_pmX Uncertainty in pmX
90- 95 F6.2 uas/yr pmY North-South proper motion (5)
97-101 F5.2 uas/yr e_pmY Uncertainty in pmY
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Note (1): Each row corresponds to a single spectral channel. Since there
are three different spectral resolutions (see table3.dat), up
to three different entries may appear.
Note (3): Weighted averages account for the fact that the channels listed
are not always statistically independent. See text for details.
Note (4): Offsets from the reference feature at epoch 4.
Note (5): Motions with respect to the reference feature.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 19-May-2005