Disk-Outflow Models as Applied to High Mass Star Forming Regions through Methanol and Water Maser Observations


As the recent publication by Breen et al. (2013) found, Class II methanol masers are exclusively associated with high mass star forming regions. Based on the positions of the Class I and II methanol and H2O masers, UC H II regions and 4.5 μm infrared sources, and the center velocities (vLSR) of the Class I methanol and H2O masers, compared to the vLSR of the Class II methanol masers, we propose three disk-outflow models that may be traced by methanol masers. In all three models, we have located the Class II methanol maser near the protostar, and the Class I methanol maser in the outflow, as is known from observations during the last twenty years. In our first model, the H2O masers trace the linear extent of the outflow. In our second model, the H2O masers are located in a circumstellar disk. In our third model, the H2O masers are located in one or more outflows near the terminating shock where the outflow impacts the ambient interstellar medium. Together, these models reiterate the utility of coordinated high angular resolution observations of high mass star forming regions in maser lines and associated star formation tracers.

Share and Cite:

Farmer, H. (2014) Disk-Outflow Models as Applied to High Mass Star Forming Regions through Methanol and Water Maser Observations. International Journal of Astronomy and Astrophysics, 4, 571-597. doi: 10.4236/ijaa.2014.44053.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Breen, S.L., Ellingsen, S.P., Contreras, Y., et al. (2013) Confirmation of the Exclusive Association between 6.7-GHz Methanol Masers and High-Mass Star Formation Regions. Monthly Notices of the Royal Astronomical Society, 435, 524-530. http://dx.doi.org/10.1093/mnras/stt1315
[2] Farmer, H.F. (2013) Insights into High Mass Star Formation from Methanol Maser Observations. Master’s Thesis, DePaul University, Chicago. http://via.library.depaul.edu/csh_etd/45
[3] McKee, C.F. and Ostriker, E.C. (2007) Theory of Star Formation. Annual Review of Astronomy and Astrophysics, 45, 565-687. http://dx.doi.org/10.1146/annurev.astro.45.051806.110602
[4] Loinard, L., Torres, R.M., Mioduszewski, A.J. and Rodri′guez, L.F. (2008) A Preliminary VLBA Distance to the Core of Ophiuchus, with an Accuracy of 4%. The Astrophysical Journal, 675, L29-L32.
[5] Genzel, R., Reid, M.J., Moran, J.M. and Downes, D. (1981) Proper Motions and Distances of H2O Maser Sources. I—The Outflow in Orion-KL. Astrophysical Journal, 244, 884-902.
[6] Zinnecker, H. and Yorke, H.W. (2007) Toward Understanding Massive Star Formation. Annual Review of Astronomy and Astrophysics, 45, 481-563.
[7] Menten, K. (1991) Methanol Masers and Submillimeter Wavelength Water Masers in Star-Forming Regions. In: Haschick, A.D. and Ho, P.T.P., Eds., Atoms, Ions and Molecules: New Results in Spectral Line Astrophysics, Astronomical Society of the Pacific, San Francisco, 119.
[8] Sobolev, A.M., Ostrovskii, A.B., Kirsanova, M.S., Shelemei, O.V., Voronkov, M.A. and Malyshev, A.V. (2006) Methanol Masers and Star Formation. arXiv:astro-ph/0601260.
[9] Cragg, D.M., Johns, K.P., Godfrey, P.D. and Brown, R.D. (1992) Pumping the Interstellar Methanol Masers. Monthly Notices of the Royal Astronomical Society, 259, 203-208.
[10] Voronkov, M. (2013) Australia Telescope National Facility.
[11] Val’tts, I.E. and Larionov, G.M. (2007) A General Catalog of Class I Methanol Masers. Astronomy Reports, 51, 519-530. http://dx.doi.org/10.1134/S1063772907070013
[12] Cyganowski, C.J., Brogan, C.L., Hunter, T.R. and Churchwell, E. (2011) Deep Very Large Array Radio Continuum Surveys of GLIMPSE Extended Green Objects (EGOs). The Astrophysical Journal, 743, 56. http://dx.doi.org/10.1088/0004-637X/743/1/56
[13] Kurtz, S., Hofner, P. and Alvarez, C.V. (2004) A Catalog of CH3OH 70-61 A+ Maser Sources in Massive Star-Forming Regions. The Astrophysical Journal Supplement, 155, 149.
[14] Pestalozzi, M.R., Minier, V. and Booth, R.S. (2005) A General Catalogue of 6.7-GHz Methanol Masers. I. Data. Astronomy & Astrophysics, 432, 737-742. http://dx.doi.org/10.1051/0004-6361:20035855
[15] Caswell, J.L., Vaile, R.A., Ellingsen, S.P., Whiteoak, J.B. and Norris, R.P. (1995) Galactic Methanol Masers at 6.6 GHz. Monthly Notices of the Royal Astronomical Society, 272, 96-138.
[16] Pandian, J.D., Momjian, E., Xu, Y., Menten, K.M. and Goldsmith, P.F. (2011) The Arecibo Methanol Maser Galactic Plane Survey. IV. Accurate Astrometry and Source Morphologies. The Astrophysical Journal, 730, Article ID: 55. http://dx.doi.org/10.1088/0004-637X/730/1/55
[17] Cyganowski, C.J., Brogan, C.L., Hunter, T.R. and Churchwell, E. (2009) A Class I and Class II CH3OH Maser Survey of EGOs from the GLIMPSE Survey. The Astrophysical Journal, 702, 1615. http://dx.doi.org/10.1088/0004-637X/702/2/1615
[18] Hofner, P. and Churchwell, E. (1996) A Survey of Water Maser Emission toward Ultracompact HII Regions. Astronomy and Astrophysics Supplement Series, 120, 283.
[19] Wood, D.O.S. and Churchwell, E. (1989) The Morphologies and Physical Properties of Ultracompact H II Regions. Astronomy and Astrophysics Supplement Series, 69, 831-895.
[20] Urquhart, J.S., Hoare, M.G., Purcell, C.R., et al. (2009) The RMS Survey: 6 cm Continuum VLA Observations towards Candidate Massive YSOs in the Northern Hemisphere. Astronomy & Astrophysics, 501, 539-551. http://dx.doi.org/10.1051/0004-6361/200912108
[21] Churchwell, E., Babler, B.L., Meade, M.R., et al. (2009) The Spitzer/GLIMPSE Surveys: A New View of the Milky Way. Publications of the Astronomical Society of the Pacific, 121, 213-230.
[22] Cyganowski, C.J., Whitney, B.A., Holden, E., et al. (2008) A Catalog of Extended Green Objects in the GLIMPSE Survey: A New Sample of Massive Young Stellar Object Outflow Candidates. The Astrophysical Journal, 136, 2391. http://dx.doi.org/10.1088/0004-6256/136/6/2391
[23] Sanna, A., Reid, M.J., Moscadelli, L., Dame, T.M., Menten, K.M. and Brunthaler, A. (2009) Trigonometric Parallaxes of Massive Star-Forming Regions. VII. G9.62 + 0.20 and the Expanding 3 kpc ARM. The Astrophysical Journal, 706, 464. http://dx.doi.org/10.1088/0004-637X/706/1/464
[24] Forster, J.R. and Caswell, J.L. (2000) Radio Continuum Emission at OH and H2O Maser Sites. The Astrophysical Journal, 530, 371. http://dx.doi.org/10.1086/308347
[25] Minier, V., Conway, J.E. and Booth, R.S. (2001) VLBI Observations of 6.7 and 12.2 GHz Methanol Masers toward High Mass Star-Forming Regions. II. Tracing Massive Protostars. Astronomy & Astrophysics, 369, 278-290. http://dx.doi.org/10.1051/0004-6361:20010124
[26] Caswell, J.L., Vaile, R.A. and Forster, J.R. (1995) Methanol and Hydroxyl Maser Positions. Monthly Notices of the Royal Astronomical Society, 277, 210-216.
[27] Voronkov, M.A., Caswell, J.L., Ellingsen, S.P. and Sobolev, A.M. (2010) New 9.9-GHz Methanol Masers. Monthly Notices of the Royal Astronomical Society, 405, 2471-2484.
[28] Arce, H.G., Shepherd, D., Gueth, F., Lee, C.-F., Bachiller, R., Rosen, A. and Beuther, H. (2007) Molecular Outflows in Low- and High-Mass Star-forming Regions. In: Protostars & Planets, University of Arizona Press, Tucson, 245-260.
[29] Beuther, H. (2005) X-Ray and Radio Connections. In: Sjouwerman, L.O. and Dyer, K. K., Electronically Published by NRAO. http://www.aoc.nrao.edu/events/xraydio/[meetingcont/1.1_kirk.pdf
[30] Torrelles, J.M., Gomez, J.F., Rodriguez, L.F., et al. (1996) The Thermal Radio Jet of Cepheus A HW2 and the Water Maser Distribution at 0"08 Scale (60 AU). Astrophysical Journal Letters, 457, L107. http://dx.doi.org/10.1086/309903
[31] Titmarsh, A.M., Ellingsen, S.P., Breen, S.L., Caswell, J.L. and Voronkov, M.A. (2013) G 10.472 + 0.027: An Extreme Water Maser Outflow Associated with a Massive Protostellar Cluster. Astrophysical Journal Letters, 775, L12. http://dx.doi.org/10.1088/2041-8205/775/1/L12

Copyright © 2022 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.