A search for water masers associated with class II methanol masers – II. Longitude range 341° to 6°

Titmarsh, Anita; Ellingsen, S. P.; Breen, S. L.; Caswell, J. L.; Voronkov, Maxim

doi:10.1093/mnras/stw636

Cited by 31 publications

(54 citation statements)

References 76 publications

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“…The fraction of solitary methanol maser sites is higher than solitary OH maser sites (21%) and solitary water maser sites (39%). A sensitive 22 GHz water maser survey toward the MMB masers found that ∼48% of 6.7 GHz methanol masers have a 22 GHz water maser counterpart (Titmarsh et al 2014(Titmarsh et al , 2016, which is higher than our result (38/112, 34%). Moreover, Breen et al (2010b) made a targeted search for 22 GHz water masers toward star formation OH maser sites and concluded about 79% of OH masers sites show coincident water maser emission.…”

Section: Star Formation Sitescontrasting

confidence: 94%

Accurate Oh Maser Positions From the Splash Pilot Region

Qiao¹,

Walsh²,

Green³

et al. 2016

ApJS

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We report on high spatial resolution observations, using the Australia Telescope Compact Array (ATCA), of ground-state OH masers. These observations were carried out toward 196 pointing centers previously identified in the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) pilot region, between Galactic longitudes of 334°a nd 344°and Galactic latitudes of −2°and +2°. Supplementing our data with data from the MAGMO (Mapping the Galactic Magnetic field through OH masers) survey, we find maser emission toward 175 of the 196 target fields. We conclude that about half of the 21 nondetections were due to intrinsic variability. Due to the superior sensitivity of the followup ATCA observations, and the ability to resolve nearby sources into separate sites, we have identified 215 OH maser sites toward the 175 fields with detections. Among these 215 OH maser sites, 111 are new detections. After comparing the positions of these 215 maser sites to the literature, we identify 122 (57%) sites associated with evolved stars (one of which is a planetary nebula), 64 (30%) with star formation, two sites with supernova remnants, and 27 (13%) of unknown origin. The infrared colors of evolved star sites with symmetric maser profiles tend to be redder than those of evolved star sites with asymmetric maser profiles, which may indicate that symmetric sources are generally at an earlier evolutionary stage.

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Section: Star Formation Sitescontrasting

confidence: 94%

Accurate Oh Maser Positions From the Splash Pilot Region

Qiao¹,

Walsh²,

Green³

et al. 2016

ApJS

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“…through outflows) than the 6.7-and 12.2-GHz masers that are more directly related to the evolution of the protostar. Recently, Titmarsh et al (2016) compared the occurrence of 6.7-and 12.2-GHz methanol masers and water masers in the 341 • -6 • longitude range and arrived at a similar conclusion.…”

Section: Discussionmentioning

confidence: 70%

12.2-GHz methanol maser MMB follow-up catalogue – IV. Longitude range 20°–60°

Breen

Ellingsen

Caswell

et al. 2016

Mon. Not. R. Astron. Soc.

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This is the fourth and final instalment of a series of catalogues presenting 12.2-GHz methanol maser observations made towards each of the 6.7-GHz methanol masers detected in the Methanol Multibeam (MMB) survey. This final portion of the survey covers the 20 • -60 • longitude range, increasing the 12.2-GHz follow-up range to the full MMB coverage of 186 • ≥ l ≤ 60 • and |b| ≤ 2 • . Towards a total of 260 6.7-GHz MMB methanol masers (we were unable to observe five of the MMB sources in this longitude range) we detect 116 12.2-GHz masers counterparts, 64 of which were discovered in this survey. Including data from the literature, we find that there are 12.2-GHz methanol masers towards 47.1 per cent of the 6.7-GHz methanol masers in this portion of the Galaxy. Across the entire MMB survey range, we find a detection rate of 45.3 per cent. We find that the detection rate of 12.2-GHz methanol masers as a function of Galactic longitude is not uniform and there is an excess of masers with broad velocity ranges at longitudes near 30 • and 330 • . Comparing the occurrence of 12.2-GHz methanol masers with MMB-targeted CO observations has shown that those outflows associated with a 12.2-GHz source have a larger average dynamical time-scale than those associated with only 6.7-GHz methanol masers, supporting the notion that the 12.2-GHz masers are associated with a later phase of high-mass star formation.

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“…Across the full MMB range, the median velocity of 6.7-GHz methanol masers is 6 km s −1 (Green et al 2017) and the median of 12.2-GHz sources is 1.7 km s −1 and therefore are consistent with the sub-sample we consider here. The fact that the water masers show the largest velocity range is expected, particularly because of their tendency to trace high-velocity outflow, but the median velocity of the HOPS sources is significantly lower than either of the Breen et al (2010b) or Titmarsh et al (2014Titmarsh et al ( , 2016 targeted water maser observations which have medians of 15 and 17 km s −1 , respectively. A part of this difference can be accounted for by the fact that the Walsh et al (2014) quoted peak velocities of spots and therefore results in an underestimation of the velocity ranges of sites, but some of the difference is due to the unbiased nature of HOPS.…”

Section: Basic Properties Of the Different Maser Populationsmentioning

confidence: 88%

“…The consistency with the Titmarsh et al (2016) sample is probably reflective of the fact that they also use a portion of the complete sample of MMB masers, but it is interesting that the percentage of sources remains constant with the much more sensitive Titmarsh et al (2016) sample, suggesting that the distribution holds to lower water maser peak flux densities.…”

Section: Comparing Methanol Maser Velocities To Water and Excited-stamentioning

confidence: 96%

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

Breen

Contreras

Ellingsen

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We have compared the occurrence of 6.7-GHz and 12.2-GHz methanol masers with 22-GHz water masers and 6035-MHz excited-state OH masers in the 100 square degree region of the southern Galactic plane common to the Methanol Multibeam (MMB) and H 2 O southern Galactic Plane surveys (HOPS). We find the most populous star formation species to be 6.7-GHz methanol, followed by water, then 12.2-GHz and, finally, excited-state OH masers. We present association statistics, flux density (and luminosity where appropriate) and velocity range distributions across the largest, fully surveyed portion of the Galactic plane for four of the most common types of masers found in the vicinity of star formation regions.Comparison of the occurrence of the four maser types with far-infrared dust temperatures shows that sources exhibiting excited-state OH maser emission are warmer than sources showing any of the other three maser types. We further find that sources exhibiting both 6.7-GHz and 12.2-GHz methanol masers are warmer than sources exhibiting just 6.7-GHz methanol maser emission. These findings are consistent with previously made suggestions that both OH and 12.2-GHz methanol masers generally trace a later stage of star formation compared to other common maser types.

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A search for water masers associated with class II methanol masers – II. Longitude range 341° to 6°

Cited by 31 publications

References 76 publications

Accurate Oh Maser Positions From the Splash Pilot Region

Accurate Oh Maser Positions From the Splash Pilot Region

12.2-GHz methanol maser MMB follow-up catalogue – IV. Longitude range 20°–60°

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

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