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OH MASERS TOWARDS THE W49A STAR-FORMING REGION WITH MERLIN AND e-MERLN OBSERVATIONS

  • ASANOK, KITIYANEE (Department of Physics, Faculty of Science, Khon Kaen University) ;
  • ETOKA, SANDRA (Hamburger Sternwarte) ;
  • GRAY, MALCOLM D. (The University of Manchester, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy) ;
  • RICHARDS, ANITA M.S. (The University of Manchester, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy) ;
  • KRAMER, BUSABA H. (Max-Planck-Institut fur Radioastronomie) ;
  • GASIPRONG, NIPON (Department of Physics, Faculty of Science, Ubon Ratchathani University)
  • Received : 2014.11.30
  • Accepted : 2015.06.30
  • Published : 2015.09.30
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Abstract

We present preliminary results from OH ground state phase referenced observations carried out with the Multi Element Radio Linked Interferometer Network (MERLIN) and e-MERLIN towards the massive star forming region W49A. There are three active SFRs within this complex: W49 North (W49 N), W49 South (W49 S) and W49 South West (W49 SW). The first epoch of observations was obtained in 2005 with MERLIN while the second epoch was obtained in 2013 with the e-MERLIN upgraded system. In this paper, we present 1665 and 1720 MHz maser emission towards W49 S and W49 SW. Overall, both epochs show good agreement with the previous observations of Argon et al. (2000) carried out with the Very Large Array (VLA). The better sensitivity and wider velocity coverage of the MERLIN/e-MERLIN observations allowed us to discover a new 1720 MHz OH maser site in W49 S.

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References

  1. Argon, A. L., Reid, M. J., & Menten, K. M., 2000, Interstellar Hydroxyl Masers in the Galaxy. I. The VLA Survey, ApJS, 129, 159 https://doi.org/10.1086/313406
  2. Cohen, R. J., 1989, Compact maser sources, Reports on Progress in Physics, 52, 881 https://doi.org/10.1088/0034-4885/52/8/001
  3. De Pree, C. G., Mehringer, D. M., & Goss, W. M., 1997, Multifrequency, High-Resolution Radio Recombination Line Observations of the Massive Star-forming Region W49A, ApJ, 482, 307 https://doi.org/10.1086/304119
  4. Galvan-Madrid, R., Liu, H. B., & Zhang, Z.-Y., et al., 2013, MUSCLE W49: A Multi-Scale Continuum and Line Exploration of the Most Luminous Star Formation Region in the Milky Way. I. Data and the Mass Structure of the Giant Molecular Cloud, ApJ, 779, 121 https://doi.org/10.1088/0004-637X/779/2/121
  5. Harvey, P. M., Campbell, M. F., & Hoffmann, W. F., 1977, High-resolution Far-infrared Observations of H II Regions - Sagittarius B2, W49, DR 21-W75, ApJ, 211, 786 https://doi.org/10.1086/154988
  6. Zhang, B., Reid, M. J., Menten, K. M., Zheng, X. W., Brunthaler, A., Dame, T. M., & Xu, Y., 2013, Parallaxes for W49N and G048.60+0.02: Distant Star Forming Regions in the Perseus Spiral Arm, ApJ, 775, 79 https://doi.org/10.1088/0004-637X/775/1/79