J/A+A/461/11 Radio observations of MYSO candidates (Urquhart+, 2007)
The RMS Survey: Radio observations of candidate massive YSOs in the
southern hemisphere.
Urquhart J.S., Busfield A.L., Hoare M.G., Lumsden S.L., Clarke A.J.,
Moore T.J.T., Mottram J.C., Oudmaijer R.D.
<Astron. Astrophys., 461, 11-23 (2007)>
=2007A&A...461...11U 2007A&A...461...11U (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Radio sources ; Radio continuum
Keywords: Radio continuum: stars - Stars: formation - Stars: early-type -
Stars: pre-main sequence
Abstract:
The Red MSX Source (RMS) survey is a multi-wavelength programme of
follow-up observations designed to distinguish between genuine massive
young stellar objects (MYSOs) and other embedded or dusty objects,
such as ultra compact (UC) HII regions, evolved stars and planetary
nebulae (PNe). We have identified nearly 2000 MYSOs candidates by
comparing the colours of MSX and 2MASS point sources to those of known
MYSOs. There are several other types of embedded or dust enshrouded
objects that have similar colours as MYSOs and contaminate our sample.
Two sources of contamination are from UCHII regions and PNe, both of
which can be identified from the radio emission emitted by their
ionised nebulae. In order to identify UCHII regions and PNe that
contaminate our sample we have conducted high resolution radio
continuum observations at 3.6 and 6cm of all southern MYSOs candidates
(235°<l<350°) using the Australia Telescope Compact Array
(ATCA). These observations have a spatial resolution of ∼1-2" and
typical image rms noise values of ∼0.3mJy, sensitive enough to detect
a HII region powered by a B0.5 star at the far side of the Galaxy.
Of the 826 RMS sources observed we found 199 to be associated with
radio emission, ∼25% of the sample. The Galactic distribution,
morphologies and spectral indices of the radio sources associated with
the RMS sources are consistent with these sources being UCHII regions.
Importantly, the 627 RMS sources for which no radio emission was
detected are still potential MYSOs. In addition to the 802 RMS fields
observed we present observations of a further 190 fields. These
observations were made towards MSX sources that passed cuts in earlier
versions of the survey, but were later excluded.
Description:
The electronic version contains
Field names, positions and synthesised beam parameters for all
observations made using the ATCA towards the RMS sample of massive
young stellar object candidates.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 80 802 Summary of the RMS fields observed
table5.dat 108 369 Radio sources associated to RMS sources
table6.dat 80 190 Summary of the additional fields observed
table7.dat 108 67 MSX sources with associated radio emission
table8.dat 114 158 Radio sources without IR counterpart
fig3/* . 704 Maps of RMS sources with associated radio emission
fig7/* . 114 Maps of the radio sources with MSX counterparts
fig8/* . 302 Maps of the radio sources with no MSX counterparts
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See also:
V/114 : MSX6C Infrared Point Source Catalog (Egan+ 2003)
Byte-by-byte Description of file: table3.dat table6.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- RMS RMS (MSX) field name (GLLL.llll+BB.bbbb)
19- 20 I2 h RAh Right Ascension J2000 (hours)
22- 23 I2 min RAm Right Ascension J2000 (minutes)
25- 28 F4.1 s RAs Right Ascension J2000 (seconds)
30 A1 --- DE- Declination J2000 (sign)
31- 32 I2 deg DEd Declination J2000 (degrees)
34- 35 I2 arcmin DEm Declination J2000 (minutes)
37- 38 I2 arcsec DEs [0,60] Declination J2000 (seconds)
40- 42 F3.1 arcsec maj3 3cm (8640MHz) synthesised beam Major Axis
44- 46 F3.1 arcsec min3 3cm (8640MHz) synthesised beam Minor Axis
48- 52 F5.1 deg PA3 [-90,90] 3cm synthesised beam Position Angle
54- 59 F6.2 mJy rms3 3cm Image rms of final restored map (1)
61- 63 F3.1 arcsec maj6 6cm (4800MHz) synthesised beam Major Axis
65- 67 F3.1 arcsec min6 6cm (4800MHz) synthesised beam Minor Axis
69- 73 F5.1 deg PA6 [-90,90] 6cm synthesised beam Position Angle
75- 80 F6.2 mJy rms6 6cm Image rms of final restored map (1)
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Note (1): The image rms have been estimated from an average of standard
deviation taken from several emission free regions near the
centre of each map.
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Byte-by-byte Description of file: table5.dat table7.dat table8.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- RMS RMS (MSX) name (GLLL.llll+BB.bbbb)
18 A1 --- m_RMS Multiplicity flag
20- 24 F5.1 arcsec Offset Source offset from observed centre
26- 29 A4 --- Morph Morphology (1)
31- 33 F3.1 cm wl Observation wavelength (3.6 or 6.0cm)
35- 36 I2 h RAh Right Ascension J2000 (hours)
37 A1 --- --- [:]
38- 39 I2 min RAm Right Ascension J2000 (minutes)
40 A1 --- --- [:]
41- 45 F5.2 s RAs Right Ascension J2000 (seconds)
48 A1 --- DE- Declination J2000 (sign)
49- 50 I2 deg DEd Declination J2000 (degrees)
51 A1 --- --- [:]
52- 53 I2 arcmin DEm Declination J2000 (minutes)
54 A1 --- --- [:]
55- 58 F4.1 arcsec DEs Declination J2000 (seconds)
61- 66 F6.1 mJy Sp Peak flux density (mJy/beam, 8.6 or 4.8GHz)
69- 74 F6.1 mJy Sint Integrated flux density
76- 80 F5.1 arcsec Dmax Source maximal diameter
82- 86 F5.1 arcsec Dmin Source minimal diameter
88-114 A27 --- FileName Name of associated file (2)
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Note (1): Morphology in one of the 5 types defined in the the classification
scheme developed by Wood & Churchwell (1989ApJ...340..265W 1989ApJ...340..265W)
as follows:
S/U = spherical/unresolved
C = cometary
I/MP = irregular/multi-peaked
SH = shell-like
CH = core-halo
Note (2): Files are in the subdirectories: fig3 (table5), fig7 (table7) and
fig8 (table8). Two files exist, in PNG and FITS
(extensions .png and .fits respectively)
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(End) James Urquhart [Leeds University], Francois Ochsenbein [CDS] 24-Jul-2007