The evolutionary status of protostellar clumps hosting class II methanol masers

Jones, B.; Fuller, G. A.; Breen, S. L.; Avison, A.; Green, James; Traficante, A.; Elia, D.; Ellingsen, S. P.; Voronkov, M. A.; Merello, Manuel; Molinari, S.; Schisano, E.

doi:10.1093/mnras/staa233

Cited by 14 publications

(10 citation statements)

References 99 publications

(193 reference statements)

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“…The mean temperature of a maser clump is 23.9 K whereas the mean temperature of an ATLASGAL clump is 19.4 K. We have also tested the samples using a KS test and find that the differences in temperature between the two samples is statistically significant (p 0.0013). This difference has also been noted in another previous study by Jones et al (2020), who examined a sample of 731 MMB sources with compact emission at four Hi-GAL wavelengths, and investigated the association between masers and Hi-GAL sources.…”

Section: Physical Parameterssupporting

confidence: 69%

“…The mean and median luminosities for maser associated clumps are both ∼10 4 L . These values are ∼ 2 times higher than those found by Jones et al (2020), likely due to the differences in the way that the luminosity measurements were conducted. This implies that a certain protostellar luminosity is required, and therefore, protostellar mass in order to drive sufficient Table 5.…”

Section: Physical Parameterscontrasting

confidence: 56%

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ATLASGAL – relationship between dense star-forming clumps and interstellar masers

Billington

Urquhart

König

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We have used catalogues from several Galactic plane surveys and dedicated observations to investigate the relationship between various maser species and Galactic star forming clumps, as identified by the ATLASGAL survey. The maser transitions of interest are the 6.7 & 12.2 GHz methanol masers, 22.2 GHz water masers, and the masers emitting in the four ground-state hyperfine structure transitions of hydroxyl. We find clump association rates for the water, hydroxyl and methanol masers to be 56, 39 and 82 per cent respectively, within the Galactic longitude range of 60○ > ℓ > −60○. We investigate the differences in physical parameters between maser associated clumps and the full ATLASGAL sample, and find that clumps coincident with maser emission are more compact with increased densities and luminosities. However, we find the physical conditions within the clumps are similar for the different maser species. A volume density threshold of n(H2) > 104.1 cm−3 for the 6.7 GHz methanol maser found in our previous study is shown to be consistent across for all maser species investigated. We find limits that are required for the production of maser emission to be 500 L⊙ and 6 M⊙ respectively. The evolutionary phase of maser associated clumps is investigated using the L/M ratio of clumps coincident with maser emission, and these have similar L/M ranges (∼100.2 − 102.7 L⊙/M⊙) regardless of the associated transitions. This implies that the conditions required for the production of maser emission only occur during a relatively narrow period during a star’s evolution. Lower limits of the statistical lifetimes for each maser species are derived, ranging from ∼ 0.4 − 2× 104 yrs and are in good agreement with the “straw man” evolutionary model previously presented.

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Section: Physical Parameterssupporting

confidence: 69%

Section: Physical Parameterscontrasting

confidence: 56%

ATLASGAL – relationship between dense star-forming clumps and interstellar masers

Billington

Urquhart

König

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Section: Physical Parameterscontrasting

confidence: 56%

“…Studies have also investigated the relationship between different maser species (e.g. Forster & Caswell 1989;Menten 1997;Szym-czak et al 2005;Jones et al 2020), and it has been shown that different maser transitions are often spatially associated with one another (within 15 arcsec). Ellingsen et al (2007) presented a "straw man" model for the evolution and relative timescales of different maser species (water, methanol, hydroxyl) within regions of star formation.…”

mentioning

confidence: 99%

ATLASGAL -- Relationship between dense star forming clumps and interstellar masers

Billington,

Urquhart,

König

et al. 2020

Preprint

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We have used catalogues from several Galactic plane surveys and dedicated observations to investigate the relationship between various maser species and Galactic star forming clumps, as identified by the ATLASGAL survey. The maser transitions of interest are the 6.7 & 12.2 GHz methanol masers, 22.2 GHz water masers, and the masers emitting in the four ground-state hyperfine structure transitions of hydroxyl. We find clump association rates for the water, hydroxyl and methanol masers to be 56, 39 and 82 per cent respectively, within the Galactic longitude range of 60 • > > −60 • . We investigate the differences in physical parameters between maser associated clumps and the full ATLASGAL sample, and find that clumps coincident with maser emission are more compact with increased densities and luminosities. However, we find the physical conditions within the clumps are similar for the different maser species. A volume density threshold of n(H 2 ) > 10 4.1 cm −3 for the 6.7 GHz methanol maser found in our previous study is shown to be consistent across for all maser species investigated. We find limits that are required for the production of maser emission to be 500 L and 6 M respectively. The evolutionary phase of maser associated clumps is investigated using the L/M ratio of clumps coincident with maser emission, and these have similar L/M ranges (∼ 10 0.2 − 10 2.7 L /M ) regardless of the associated transitions. This implies that the conditions required for the production of maser emission only occur during a relatively narrow period during a star's evolution. Lower limits of the statistical lifetimes for each maser species are derived, ranging from ∼ 0.4 − 2×10 4 yrs and are in good agreement with the "straw man" evolutionary model previously presented.

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“…EGOs are also strongly associated both with radiatively-pumped 6.7 GHz Class II CH 3 OH masers, which are known to exclusively trace high-mass star formation (e.g. Cragg et al 2005;Billington et al 2019;Jones et al 2020), and with collisionally-pumped 44 and 25 GHz Class I CH 3 OH masers (e.g. Cyganowski et al 2008Cyganowski et al , 2009Towner et al 2017).…”

Section: Introductionmentioning

confidence: 99%

ALMA observations of the Extended Green Object G19.01−0.03 – I. A Keplerian disc in a massive protostellar system

Williams

Cyganowski

Brogan

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Using the Atacama Large Millimetre/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA), we observed the Extended Green Object (EGO) G19.01–0.03 with sub-arcsecond resolution from 1.05 mm to 5.01 cm wavelengths. Our ∼0.4″ ∼ 1600 AU angular resolution ALMA observations reveal a velocity gradient across the millimetre core MM1, oriented perpendicular to the previously known bipolar molecular outflow, that is consistently traced by 20 lines of 8 molecular species with a range of excitation temperatures, including complex organic molecules (COMs). Kinematic modelling shows the data are well described by models that include a disc in Keplerian rotation and infall, with an enclosed mass of 40 − 70 M⊙ (within a 2000 AU outer radius) for a disc inclination angle of i = 40○, of which 5.4 − 7.2 M⊙ is attributed to the disc. Our new VLA observations show that the 6.7 GHz Class II methanol masers associated with MM1 form a partial ellipse, consistent with an inclined ring, with a velocity gradient consistent with that of the thermal gas. The disc-to-star mass ratio suggests the disc is likely to be unstable and may be fragmenting into as-yet-undetected low mass stellar companions. Modelling the centimetre–millimetre spectral energy distribution of MM1 shows the ALMA 1.05 mm continuum emission is dominated by dust, whilst a free–free component, interpreted as a hypercompact H ii region, is required to explain the VLA ∼5 cm emission. The high enclosed mass derived for a source with a moderate bolometric luminosity (∼104 L⊙) suggests that the MM1 disc may feed an unresolved high-mass binary system.

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The evolutionary status of protostellar clumps hosting class II methanol masers

Cited by 14 publications

References 99 publications

ATLASGAL – relationship between dense star-forming clumps and interstellar masers

ATLASGAL – relationship between dense star-forming clumps and interstellar masers

ATLASGAL -- Relationship between dense star forming clumps and interstellar masers

ALMA observations of the Extended Green Object G19.01−0.03 – I. A Keplerian disc in a massive protostellar system

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