J/MNRAS/490/2779 Dust clumps associated with methanol masers (Billington+, 2019)
ATLASGAL - physical parameters of dust clumps associated with 6.7GHz methanol
masers.
Billington S.J., Urquhart J.S., Konig C., Moore T.J.T., Eden D.J.,
Breen S.L., Kim W.-J., Thompson M.A., Ellingsen S.P., Menten K.M.,
Wyrowski F., Leurini S.
<Mon. Not. R. Astron. Soc., 490, 2779-2798 (2019)>
=2019MNRAS.490.2779B 2019MNRAS.490.2779B (SIMBAD/NED BibCode)
ADC_Keywords: Masers ; Millimetric/submm sources ; Radio sources ;
Star Forming Region ; Milky Way
Keywords: stars: formation - stars: massive - ISM: molecules -
submillimetre: ISM
Abstract:
We have constructed the largest sample of dust-associated class II
6.7GHz methanol masers yet obtained. New measurements from the
Methanol Multibeam (MMB) survey were combined with the 870µm APEX
Telescope Large Area Survey of the Galaxy (ATLASGAL) and the 850µm
JCMT Plane Survey (JPS). Together with two previous studies we have
now identified the host clumps for 958 methanol masers across the
Galactic Plane, covering approximately 99 per cent of the MMB
catalogue and increasing the known sample of dust-associated masers by
over 30 per cent. We investigate correlations between the physical
properties of the clumps and masers using distances and luminosities
drawn from the literature. Clumps hosting methanol masers are
significantly more compact and have higher volume densities than the
general population of clumps. We determine a minimum volume density
threshold of n(H2)≥104cm-3 for the efficient formation of
intermediate- and high-mass stars. We find 6.7GHz methanol masers are
associated with a distinct part of the evolutionary process
(Lbol/Mfwmh ratios of between 100.6 and 102.2) and have
well-defined turning on and termination points. We estimate the lower
limit for the mass of embedded objects to be ≥6M☉ and the
statistical lifetime of the methanol maser stage to be ∼3.3x104yr.
This suggests that methanol masers are indeed reliable tracers of
high-mass star formation, and indicates that the evolutionary period
traced by this marker is relatively rapid.
Description:
The MMB survey (Green et al. 2009MNRAS.392..783G 2009MNRAS.392..783G) has surveyed
60°≥l≥186° and |b|<2° of the Galactic plane in search of
the 6.7GHz methanol masers using the Parkes 64m radio telescope.
In order to determine the dust properties of associated dense clumps
we have opted to use both the JPS (Moore et al. 2015MNRAS.453.4264M 2015MNRAS.453.4264M,
Cat. J/MNRAS/453/4264) and ATLASGAL (Schuller et al.
2009A&A...504..415S 2009A&A...504..415S) surveys. ATLASGAL has produced a complete sample
of clump properties across the inner Galactic plane, however, we use
JPS to help refine these properties for a select number of clumps.
The APEX Telescope Large Area Survey of the GALaxy (ATLASGAL; Schuller
et al. 2009A&A...504..415S 2009A&A...504..415S) is the largest, most sensitive
ground-based submillimetre wavelength survey to date. It traces dust
emission at 870µm across the Galactic plane. Approximately 10000
dense clumps have been identified from the ATLASGAL maps.
The JCMT Plane Survey (JPS; Moore et al. 2015MNRAS.453.4264M 2015MNRAS.453.4264M, Cat.
J/MNRAS/453/4264) is an 850µm continuum survey of six fields in the
northern inner Galactic plane. The JPS survey has produced a source
catalogue of ∼8000 sources that has a completeness of 95 per cent at
0.04Jy/beam and 0.3Jy for the peak and integrated fluxes respectively.
We have attempted to associate each of the 265 masers listed in the
latest methanol maser catalogue published by the MMB survey (Breen et
al. 2015MNRAS.450.4109B 2015MNRAS.450.4109B) with either an ATLASGAL or JPS detection from
their respective catalogues. These matches can be found in Table 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 95 265 Matched MMB sources with the ATLASGAL and JPS
catalogues
table4.dat 79 265 Matches between MMB and ATLASGAL for the newest
addition to the MMB survey
table5.dat 88 896 Matches between MMB and ATLASGAL for the entire
MMB catalogue
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See also:
J/MNRAS/453/4264 : JCMT Plane Survey: l=30° field (Moore+, 2015)
VIII/96 : 6-GHz methanol multibeam maser catalogue (Caswell+, 2010-12)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name MMB source name (Glll.ll+bb.bbba)
18 A1 --- f_Name [*] Flag on Name (1)
20- 37 A18 --- CSCName ATLASGAL name (AGALlll.lll+bb.bbb)
39- 44 F6.2 arcsec AMoffset ? Offset between MMB emission and ATLASGAL
peak emission
46- 50 F5.2 Jy/beam FpeakA ? ATLASGAL 870µm peak flux density
52- 57 F6.2 Jy S870A ? ATLASGAL 870µm integrated flux density
59- 76 A18 --- JPSName JPS name (JPSGlll.lll+bb.bbb)
78- 82 F5.2 arcsec JMoffset ? Offset between MMB emission and JPS peak
emission
84- 88 F5.2 Jy/beam FpeakJ ? JPS 850µm peak flux density
90- 95 F6.2 Jy S850J ? JPS 850µm integrated flux density
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Note (1): Flag as follows:
* = Maser for which we have opted to use the measured JPS flux (8/265)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- Name MMB source name (Glll.ll+bb.bbba)
18- 35 A18 --- CSCName ATLASGAL name (AGALlll.lll+bb.bbb)
37- 41 F5.1 Jy FpeakM ? MMB peak flux density
43- 47 F5.1 Jy.km/s SMMB MMB integrated flux density
49- 53 F5.1 km/s vLSR ? Molecular line velocity
55- 59 F5.1 km/s vpeak MMB peak velocity
61- 66 F6.2 km/s vmedian MMB median velocity
68- 72 F5.2 km/s vrange MMB velocity range
74- 79 F6.2 arcsec AMoffset ? Offset between MMB emission and ATLASGAL
peak emission
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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- 17 A17 --- Name MMB source name (Glll.ll+bb.bbba)
19- 36 A18 --- Clump Clump name
38 A1 --- f_Clump [*] Flag on Clump (1)
40- 44 F5.2 K Tdust ? Dust temperature
46- 49 F4.1 kpc Dist ? Distance to source
51- 54 F4.2 pc Radius ? Radius of source
56- 60 F5.2 Lsun Lum ? Associated maser luminosity
62- 65 F4.2 [Msun/pc2] Sdens ? Surface density of source
67- 70 F4.2 [cm-3] Vdens ? Volume density of source
72- 76 F5.2 [Lsun] logL ? Logarithm of the clump's bolometric
luminosity
78- 82 F5.2 [Msun] logMass ? Logarithm of the FWHM mass of the clump
84- 88 F5.2 [Lsun/Msun] logL/M ? Logarithm of the clump's luminosity-mass
ratio
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Note (1): The initial matches were identified using a search radius of 50arcsec
and this was sufficient to match ∼90 per cent of the methanol masers.
Visual inspection of the submm emission maps identified another four
masers that are located within the boundary of extended ATLASGAL
clumps; these matched masers lie further away from the peak of the
thermal dust emission.
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 30-Jan-2023