The 6-GHz Multibeam Maser Survey – III. Comparison between the MMB and HOPS

Breen, S. L.; Contreras, Y.; Ellingsen, S. P.; Green, James; Walsh, A. J.; Avison, A.; Longmore, S. N.; Fuller, G. A.; Voronkov, M. A.; Horton, Janice; Kroon, A

doi:10.1093/mnras/stx3051

Cited by 15 publications

(24 citation statements)

References 60 publications

(132 reference statements)

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“…An ex-OH maser is taken to be associated with a 6.7 GHz source if the on-sky separation is less than 2.0 . Breen et al (2018) also identified associations between the 6.7 GHz MMB masers and the water masers from the HOPS data, with positional association a more complex task due to the less localised nature of water maser emission. The authors take this into account, and 6.7 GHz methanol maser is associated with a water maser if a HOPS maser spot falls within 2.0 arcsec.…”

Section: Identification Of Counterpart Masersmentioning

confidence: 80%

“…These were used to group detected masers into sites, 435 of which are associated with star formation. For this work, we use the association of these masers with MMB masers given in Breen et al (2018).…”

Section: Additional Maser Studiesmentioning

confidence: 99%

“…Also making use of the Hi-GAL data, Guzmán et al (2015) find an average temperature of 18.6 K for protostellar objects, and the study of Breen et al (2018) also makes use of these temperature maps to derive a temperature of ∼24 K towards 6.7 GHz methanol masers. Both of these are significantly warmer than the respective temperatures of 15.3 K and 19.5 K for the protostellar and maser objects considered Figure 4.…”

Section: Temperature and Mass Surface Densitymentioning

confidence: 99%

“…The authors take this into account, and 6.7 GHz methanol maser is associated with a water maser if a HOPS maser spot falls within 2.0 arcsec. A full analysis of maser associations and their number statistics over the full Galactic Plane is presented in Breen et al (2018). For this work, we are only concerned with investigating population differences in FIR-derived properties of protostellar clumps hosting 6.7 GHz class II methanol masers based on the presence of additional maser emission, i.e.…”

Section: Identification Of Counterpart Masersmentioning

confidence: 99%

“…An untargeted survey of the 22 GHz maser line of water has also been observed by the H 2 O Southern Galactic Plane Survey (HOPS, Walsh et al 2011) for the inner Galactic Plane, giving a large sample of water maser detections to supplement the higher sensitivity follow-up towards a small number of MMB sources by Titmarsh et al (2014Titmarsh et al ( , 2016. Breen et al (2018) recently investigated the Galactic populations of these masers and the associations between them, finding further evidence to support an evolutionary sequence for the common maser species found in the vicinity of young stars.…”

Section: Introductionmentioning

confidence: 99%

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The evolutionary status of protostellar clumps hosting class II methanol masers

Jones

Fuller

Breen

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The Methanol MultiBeam survey (MMB) provides the most complete sample of Galactic massive young stellar objects (MYSOs) hosting 6.7 GHz class II methanol masers. We characterise the properties of these maser sources using dust emission detected by the Herschel Infrared Galactic Plane Survey (Hi-GAL) to assess their evolutionary state. Associating 731 (73%) of MMB sources with compact emission at four Hi-GAL wavelengths, we derive clump properties and define the requirements of a MYSO to host a 6.7 GHz maser. The median far-infrared (FIR) mass and luminosity are 630 M and 2500 L for sources on the near side of Galactic centre and 3200 M and 10000 L for more distant sources. The median luminosity-to-mass ratio is similar for both at ∼4.2 L / M . We identify an apparent minimum 70 µm luminosity required to sustain a methanol maser of a given luminosity (with L 70 ∝ L 6.7 0.6 ). The maser host clumps have higher mass and higher FIR luminosities than the general Galactic population of protostellar MYSOs. Using principal component analysis, we find 896 protostellar clumps satisfy the requirements to host a methanol maser but lack a detection in the MMB. Finding a 70 µm flux density deficiency in these objects, we favour the scenario in which these objects are evolved beyond the age where a luminous 6.7 GHz maser can be sustained. Finally, segregation by association with secondary maser species identifies evolutionary differences within the population of 6.7GHz sources.

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Section: Identification Of Counterpart Masersmentioning

confidence: 80%

Section: Additional Maser Studiesmentioning

confidence: 99%

Section: Temperature and Mass Surface Densitymentioning

confidence: 99%

Section: Identification Of Counterpart Masersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The evolutionary status of protostellar clumps hosting class II methanol masers

Jones

Fuller

Breen

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Evolutionary Trends in Star Formation

Urquhart

2022

Proc. IAU

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Over the past 20 years, the Galactic plane has been surveyed at high resolution at wavelengths from 1 micron through to 20 cm. The combination of these surveys has produced large samples of deeply embedded young stars located across the Galactic disc. These continuum surveys are complemented by spectral line surveys of thermal, radio recombination, and molecular maser (OH, H2O, CH3OH) lines. The identified sources cover the whole range of evolutionary stages in the star formation process, allowing the physical properties of these stages to be measured. This information has been used to calculate the star formation efficiency and star formation rate of the Milky Way and to evaluate the impact of environment and location within the disc. This review provides an overview of some of the most significant studies in recent years and discusses how the evolutionary sequence has been used to investigate the correlation of other star formation tracers and maser associations.

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OH maser emission in the THOR survey of the northern Milky Way

Beuther

Walsh

Wang

et al. 2019

A&A

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Context. OH masers trace diverse physical processes, from the expanding envelopes around evolved stars to star-forming regions or supernovae remnants. Providing a survey of the ground-state OH maser transitions in the northern hemisphere inner Milky Way facilitates the study of a broad range of scientific topics. Aims. We want to identify the ground-state OH masers at ∼18 cm wavelength in the area covered by "The HI/OH/Recombination line survey of the Milky Way (THOR)". We will present a catalogue of all OH maser features and their possible associated environments. Methods. The THOR survey covers longitude and latitude ranges of 14. • 3 < l < 66. • 8 and b < ±1. • 25. All OH ground state lines 2 Π 3/2 (J=3/2) at 1612 (F=1-2), 1665 (F=1-1), 1667 (F=2-2) and 1720 MHz (F=2-1) have been observed, employing the Very Large Array (VLA) in its C configuration. The spatial resolution of the data varies between 12.5 and 19 , the spectral resolution is 1.5 km s −1 , and the rms sensitivity of the data is ∼10 mJy beam −1 per channel. Results. We identify 1585 individual maser spots (corresponding to single spectral features) distributed over 807 maser sites (regions of size ∼ 10 3 − 10 4 AU). Based on different criteria from spectral profiles to literature comparison, we try to associate the maser sites with astrophysical source types. Approximately 51% of the sites exhibit the double-horned 1612 MHz spectra typically emitted from the expanding shells of evolved stars. The separations of the two main velocity features of the expanding shells typically vary between 22 and 38 km s −1 . In addition to this, at least 20% of the maser sites are associated with star-forming regions. While the largest fraction of 1720 MHz maser spots (21 out of 53) is associated with supernova remnants, a significant fraction of the 1720 MHz maser spots (17) are also associated with star-forming regions. We present comparisons to the thermal 13 CO(1-0) emission as well as to other surveys of class II CH 3 OH and H 2 O maser emission. The catalogue attempts to present associations to astrophysical sources where available, and the full catalogue is available in electronic form.Conclusions. This OH maser catalogue presents a unique resource of stellar and interstellar masers in the northern hemisphere. It provides the basis for a diverse range of follow-up studies from envelopes around evolved stars to star-forming regions and Supernova remnants.

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The 6-GHz Multibeam Maser Survey – III. Comparison between the MMB and HOPS

Cited by 15 publications

References 60 publications

The evolutionary status of protostellar clumps hosting class II methanol masers

The evolutionary status of protostellar clumps hosting class II methanol masers

Evolutionary Trends in Star Formation

OH maser emission in the THOR survey of the northern Milky Way

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