J/other/PASA/26.454 Precise positions of methanol masers (Caswell, 2009)
Precise positions of methanol masers.
Caswell J.L.
<Publ. Astron. Soc. Australia, 26, 454-467 (2009)>
=2009PASA...26..454C 2009PASA...26..454C
ADC_Keywords: Masers ; Radio sources
Keywords: ISM: molecules - masers - methanol - stars: formation
Abstract:
The Australia Telescope Compact Array (ATCA) has been used to
determine positions for many southern methanol maser sites, with
accuracy better than 1 arcsec. The results are presented here as a
catalogue of more than 350 distinct sites, some of them new
discoveries, and many others with positional precision 10-times
better than existing published values. Clusters of 2 or 3 sites are
occasionally found to account for single previously listed sources.
This in turn reveals that the velocity range for each individual site
is sometimes smaller than that of the originally tabulated (blended)
source. Only a handful of examples then remain with a velocity range
of more than 16km/s at a single compact (less than 2 arcsec)
site. The precise methanol positions now allow apparent coincidences
with OH masers to be confidently accepted or rejected; this has led to
the important conclusion that, where a 1665-MHz OH maser lies in a
massive star formation region, at more than 80 percent of the OH sites
there is a precisely coincident methanol maser. The methanol precision
achieved here will also allow clear comparisons with likely associated
IR sources when the next generation of far-IR surveys produce precise
positions.
Description:
The methanol maser observations described here were obtained with the
ATCA in many sessions since 1993 February, chiefly in any of the four
standard '6-km' configurations (instantaneously yielding 15
baselines ranging from 76 to 6000m).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 375 Positions of methanol masers
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See also:
VIII/96 : 6-GHz methanol multibeam maser catalogue (Caswell+, 2010-12)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Galactic name (LLL.lll+BB.bbbAA)
17- 18 I2 h RAh Right ascension (J2000)
20- 21 I2 min RAm Right ascension (J2000)
23- 27 F5.2 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 39 F4.1 arcsec DEs Declination (J2000)
41- 47 F7.2 Jy Fpk Peak intensity of 6668MHz transition
49- 54 F6.1 km/s Vpk [-126/121] Peak velocity of 6668MHz transition
56- 59 I4 km/s Vl [-127/121] Lower value of velocity range
60 A1 --- --- [,]
62- 65 I4 km/s Vu [-118/122] Upper value of velocity range
67- 70 A4 --- OH? Reference to the OH maser data (1)
72- 83 A12 --- Ref References and epoch (abbreviated as year
and month) (1)
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Note (1): References as follows:
CVF95 = Caswell, Vaile & Forster (1995MNRAS.277..210C 1995MNRAS.277..210C)
C96a = Caswell (1996MNRAS.279...79C 1996MNRAS.279...79C)
C96b = Caswell (1996MNRAS.283..606C 1996MNRAS.283..606C)
C97 = Caswell (1997MNRAS.289..203C 1997MNRAS.289..203C)
c98 = Caswell (1998MNRAS.297..215C 1998MNRAS.297..215C)
c01 = Caswell (2001MNRAS.326..805C 2001MNRAS.326..805C)
c03 = Caswell (2003MNRAS.341..551C 2003MNRAS.341..551C)
c04 = Caswell (2004MNRAS.351..279C 2004MNRAS.351..279C, 2004MNRAS.349...99C 2004MNRAS.349...99C, 2004MNRAS.352..101C 2004MNRAS.352..101C)
C04 = Caswell (2004MNRAS.351..279C 2004MNRAS.351..279C, 2004MNRAS.349...99C 2004MNRAS.349...99C, 2004MNRAS.352..101C 2004MNRAS.352..101C)
text = refers to notes in section 4. of the paper
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 14-May-2014