Polarisation of Class II Methanol Masers
P. D. Stack A and S. P. Ellingsen A BA School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, Tasmania 7001, Australia
B Corresponding author. Email: Simon.Ellingsen@utas.edu.au
Publications of the Astronomical Society of Australia 28(4) 338-356 https://doi.org/10.1071/AS11029
Submitted: 17 June 2011 Accepted: 12 September 2011 Published: 26 October 2011
Journal Compilation © Astronomical Society of Australia JYEAR
Abstract
We have used the University of Tasmania Mt Pleasant 26-m radio telescope to investigate the polarisation characteristics of a sample of strong 6.7 GHz methanol masers, the first spectral line polarisation observations to be undertaken with this instrument. As part of this process we have developed a new technique for calibrating linear polarisation spectral line observations. This calibration method gives results consistent with more traditional techniques, but requires much less observing time on the telescope. We have made the first polarisation measurements of a number of 6.7 GHz methanol masers and find linear polarisation at levels from a few to 10% in most of the sources we observed, consistent with previous results. We also investigated the circular polarisation produced by Zeeman splitting in the 6.7 GHz methanol maser G9.62+0.20 to get an estimate of the line of sight magnetic field strength of 35 ± 7 mG.
Additional keywords: masers — polarisation
References
Breen, S. L., Ellingsen, S. P., Caswell, J. L. and Lewis, B. E., 2010, MNRAS, 401, 2219| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXitFKgtr8%3D&md5=8764b0e6a0e38e0f1a7c3c3ff3882fb2CAS |
Breen S. L. & Ellingsen S. P. , 2011 , MNRAS (in press astro-ph arXiv:1105.1318)
Caswell, J. L., 1997, MNRAS, 289, 203
| 1:CAS:528:DyaK2sXlsVKlu7c%3D&md5=6b318d910d99cd5f02461cd24587f53fCAS |
Caswell, J. L., 2004, MNRAS, 349, 99
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXjslGjt78%3D&md5=8ad064f0226cb7d12de338e02b7c3bb0CAS |
Caswell, J. L., 2009, PASA, 26, 454
| Crossref | GoogleScholarGoogle Scholar |
Caswell, J. L. et al., 2010, MNRAS, 404, 1029
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXns1Chtb4%3D&md5=1db507fa49ff18096bf09de2d8040827CAS |
Cenacchi, E., Kraus, A., Orfei, A. and Mack, K.-H., 2009, A&A, 498, 591
Cragg, D. M., Sobolev, A. M. and Godfrey, P. D., 2002, MNRAS, 331, 521
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XjsFWhtr8%3D&md5=05f47f14ca85ef9ccc49647edddb1013CAS |
Cragg, D. M., Sobolev, A. M. and Godfrey, P. D., 2005, MNRAS, 360, 533
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXmtl2nsrY%3D&md5=9707d3f5fdfbb0dbf104b2b0399afa4aCAS |
Dodson, R., 2008, A&A, 480, 767
| 1:CAS:528:DC%2BD1cXlsVeltr4%3D&md5=86d0b15327fe862f0fe03d580ea617a4CAS |
Ellingsen, S. P., Norris, R. P. and McCulloch, P. M., 1996, MNRAS, 279, 101
| 1:CAS:528:DyaK28XitlKns70%3D&md5=c47a31a894c2c546085ece3a6db495c9CAS |
Ellingsen S. P. , 2002 , in Proceedings of IAU Symposium 206 ed. V. Mignes & M. Reid, Astron. Soc of the Pacific, 151
Ellingsen S. P. , Voronkov M. A. , Cragg D. M. , Sobolev A. M. , Breen S. L. & Godfrey P. D. , 2007 , in Proceedings of IAU Symposium 242, ed. J. M. Chapman & W. A. Baan, Cambridge University Press, 213
Fish, V. L., Muehlbrad, T. C., Pratap, P., Sjouwerman, L. O., Strelnitski, V., Pihlström, Y. M. and Bourke, T. L., 2011, ApJ, 729, 14
| Crossref | GoogleScholarGoogle Scholar |
Green, J. A. et al., 2010, MNRAS, 409, 913
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXjsFCrtA%3D%3D&md5=cd0a561324f40e3ecd95d44139e668c4CAS |
Hamaker, J. P. and Bregman, J. D., 1996, A&A Sup., 117, 161
Hamaker, J. P., Bregman, J. D. and Sault, R. J., 1996, A&A Sup., 117, 137
Hamaker, J. P., 2000, A&A Sup., 143, 515
Heiles, C. et al., 2001, PASP, 113, 1274
| Crossref | GoogleScholarGoogle Scholar |
Jen, C. K., 1951, PhRv, 81, 197
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaG3MXhsFOisQ%3D%3D&md5=92a080d36e431044ab5cef44e6938f84CAS |
Johnston, S., 2002, PASA, 19, 277
| Crossref | GoogleScholarGoogle Scholar |
Menten, K. M., Reid, M. J., Pratap, P., Moran, J. M. and Wilson, T. L., 1992, ApJ, 401, L39
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3sXivFCmtQ%3D%3D&md5=fcc37476d5f9eb7c8c0e6a287471935dCAS |
Minier, V., Booth, R. S. and Conway, J. E., 2000, A&A, 362, 1093
| 1:CAS:528:DC%2BD3cXovVKlsbc%3D&md5=d410f80d600250c664a0a4ed7c7ffbacCAS |
Minier, V., Ellingsen, S. P., Norris, R. P. and Booth, R. S., 2003, A&A, 403, 1095
| 1:CAS:528:DC%2BD3sXls1Cksbg%3D&md5=1d4bb1fdb3be413e22a3e8cc0d0ec1f1CAS |
Modjaz, M., Moran, J. M., Kondratko, P. T. and Greenhill, L. J., 2005, APJ, 626, 104
| Crossref | GoogleScholarGoogle Scholar |
Mouschovias T. C. & Ciolek G. E. , 1999 , in The Origin of Stars and Planetary Systems, NATO ASIC Proc. 504, 305
Norris, R. P. et al., 1998, ApJ, 508, 275
| Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXit1Om&md5=4f05fdbccc485c5ea86215ded5a838b0CAS |
van Straten, W., 2004, ApJ Sup., 152, 129
| Crossref | GoogleScholarGoogle Scholar |
Surcis, G., Vlemmings, W. H. T., Curiel, S., Hutawarakorn Kramer, B., Torrelles, J. M. and Sarma, A. P., 2011, A&A, 527, 48
Vlemmings, W. H. T., Diamond, P. J. and van Langevelde, H. J., 2002, A&A, 394, 589
Vlemmings, W. H. T., 2008, A&A, 484, 773
| 1:CAS:528:DC%2BD1cXpt1ajtL4%3D&md5=49ebdb67ab28494bf115be87a8f2a41aCAS |
Vlemmings, W. H. T., Goedhart, S. and Gaylard, M. J., 2009, A&A, 500, L9
| 1:CAS:528:DC%2BD1MXhtFSqtbrE&md5=1fa90b20c0c83984bc4f5f92c1ddfaf4CAS |
Vlemmings, W. H. T., Surcis, G., Torstensson, K. J. E. and van Langevelde, H. J., 2010, MNRAS, 404, 134
| 1:CAS:528:DC%2BC3cXntlOhu7g%3D&md5=f0744edd4ce59d7745b46ebf0fca6dd7CAS |
Vlemmings, W. H. T., Torres, R. M. and Dodson, R., 2011, A&A, 529, 95
Xu, Y., Li, J. J., Hachisuka, K., Pandian, J. D., Menten, K. M. and Henkel, C., 2008, A&A, 485, 729
| 1:CAS:528:DC%2BD1cXhtF2jsLrL&md5=dbd62ea0e127c95c0febea9276b4312bCAS |
