Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-25T15:41:20.476Z Has data issue: false hasContentIssue false
  • English
  • Français

Class I Methanol Masers in the Galactic Center

Published online by Cambridge University Press:  24 July 2012

Loránt O. Sjouwerman  and
Ylva M. Pihlström
Loránt O. Sjouwerman
Affiliation:
National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Rd., Socorro, NM 87801
Ylva M. Pihlström
Affiliation:
Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We report on 36 and 44 GHz Class I methanol (CH3OH) maser emission in the Sagittarius A (Sgr A) region with the Expanded Very Large Array (EVLA). At least three different maser transitions tracing shocked regions in the cm-wave radio regime can be found in Sgr A. 44 GHz masers correlate with the positions and velocities of 36 GHz CH3OH masers, but the methanol masers correlate less with 1720 MHz OH masers. Our results agree with theoretical predictions that the densities and temperatures conducive for 1720 MHz OH masers may also produce 36 and 44 GHz CH3OH maser emission. However, many 44 GHz masers do not overlap with 36 GHz methanol masers, suggesting that 44 GHz masers also arise in regions too hot and too dense for 36 GHz masers to form. This agrees with the non-detection of 1720 MHz OH masers in the same area, which are thought to be excited under cooler or denser conditions. We speculate that the geometry of the bright 36 GHz masers in Sgr A East outlines the location of a SNR shock front.

Keywords

Galaxy: center — Masers — Shock waves — Supernovae: individual(Sgr A East)
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 8 , Symposium S287: Cosmic Masers - from OH to H0 , January 2012 , pp. 449 - 454
Copyright
Copyright © International Astronomical Union 2012

References

Amo-Baladrón, M. A., Martín-Pintado, J., & Martín, S. 2011, A&A, 526, A54Google Scholar
Bachiller, R. & Perez Gutierrez, M., 1997, ApJ, 487 L93Google Scholar
Claussen, M. J., Frail, D. A., Goss, W. M., & Gaume, R. A. 1997, ApJ, 489, 143CrossRefGoogle Scholar
Coil, A. L. & Ho, P. T. P. 2000, ApJ, 533, 245CrossRefGoogle Scholar
Cragg, D. M., Johns, K. P., Godfrey, P. D., & Brown, R. D., 1992, MNRAS, 259, 203Google Scholar
Fish, V. L., Muehlbrad, T. C., Pratap, P., Sjouwerman, L. O., Strelnitski, V., Pihlström, Y. M., & Bourke, T. L., 2011, ApJ, 729, 14Google Scholar
Frail, D. A. & Mitchell, G. F. 1998, ApJ, 508, 690CrossRefGoogle Scholar
Gray, M. D., Doel, R. C., & Field, D. 1991, MNRAS, 262, 30CrossRefGoogle Scholar
Gray, M. D., Field, D., & Doel, R. C. 1992, A&A, 264, 220Google Scholar
Hartquist, T. W., Menten, K. M., Lepp, S., & Dalgarno, A., 1995, MNRAS, 272, 184CrossRefGoogle Scholar
Herrnstein, R. M. & Ho, P. T. P. 2005, ApJ, 620, 287Google Scholar
Hidaka, H., Watanabe, N., Shiraki, T. m, Nagaoka, A., & Kouchi, A., 2004, ApJ, 614, 1124CrossRefGoogle Scholar
Liechti, S. & Wilson, T. L., 1996, A&A, 314, 615Google Scholar
Lockett, P., Gauthier, E., & Elitzur, M. 1999, ApJ (Letters), 511, L235Google Scholar
Menten, K. M., Wilson, R. W., Leurini, S., & Schilke, P., 2009, ApJ, 692, 47Google Scholar
Morimoto, M., Kanzawa, T., & Ohishi, M., 1985, ApJ (Letters), 288, L11Google Scholar
Pedlar, A., Anantharamaiah, K. R., Ekers, R. D., Goss, W. M., van Gorkom, J. H., Schwarz, U. J., & Zhao, J.-H. 1989, ApJ, 342, 769Google Scholar
Pihlström, Y. M., Fish, V. L., Sjouwerman, L. O., Zschaechner, L. K., Lockett, P. B., & Elitzur, M., ApJ, 676, 371Google Scholar
Pratap, P., Shute, P. A., Keane, T. C., Battersby, C., & Sterling, S., 2008, AJ, 135, 1718CrossRefGoogle Scholar
Szczepanski, J. C., Ho, P. T. P., Haschick, A. D., & Baan, W. A., 1989, IAU Symp. 136, 383Google Scholar
Szczepanski, J. C., Ho, P. T. P., & Gusten, R. 1991, ASP Conf. Series, Vol. 16, 143Google Scholar
Sjouwerman, L. O., Pihlström, Y. M., & Fish, V. L. 2010, ApJ (Letters), 710, L111CrossRefGoogle Scholar
Sobolev, A. M., Cragg, D. M., Ellingsen, S. P., Gaylard, M. J., Goedhart, S., Henkel, C., Kirsanova, M. S., Ostrovskii, A. B., Pankratova, N. V., Shelemei, O. V., van der Walt, D. J., Vasyunina, T. S., & Voronkov, M. A., 2007, IAU Symp., 242, Vol. 242, 81Google Scholar
Sobolev, A. M., Ostrovskii, A. B., Kirsanova, M. S., Shelemei, O. V., Voronkov, M. A., & Malyshev, A. V., 2005, IAU Symp. 227, Vol. 227, 174CrossRefGoogle Scholar
Tsuboi, M., Miyazaki, A., & Okumura, S. K. 2009, PASJ, 61, 29CrossRefGoogle Scholar
Voronkov, M. A., Brooks, K. J., Sobolev, A. M., Ellingsen, S. P., Ostrovskii, A. B., & Caswell, J. L., 2006, MNRAS, 373, 411Google Scholar
Wardle, M. 1999, ApJ (Letters), 525, L101Google Scholar
Yusef-Zadeh, F., Braatz, J., Wardle, M., & Roberts, D. 2008, ApJ (Letters), 683, L147Google Scholar
Yusef-Zadeh, F., Wardle, M., Rho, J., & Sakano, M. 2003, ApJ, 585, 319Google Scholar