1 / 16

The Extended Methanol Maser Emission in W51

The Extended Methanol Maser Emission in W51. Chris Phillips ATNF CSIRO. Chris.Phillips@csiro.au. Methanol Masers. Methanol has rich microwave spectrum Many masing transitions Strongest emission at 6.7 GHz Only seen towards regions of massive star formation

vevay
Download Presentation

The Extended Methanol Maser Emission in W51

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Extended Methanol Maser Emission in W51 Chris Phillips ATNF CSIRO Chris.Phillips@csiro.au

  2. Methanol Masers • Methanol has rich microwave spectrum • Many masing transitions • Strongest emission at 6.7 GHz • Only seen towards regions of massive star formation • Many sources have linear structure with velocity gradients – Discs? • May be a good tracer of massive protostars

  3. W51 • One of most luminous regions of massive star formation in the galaxy • Distance of 7 kpc (1” == 0.03pc) • Many distinct components • Strongest “d” and “e” in 1 arcminute region

  4. ATCA Observations FWHM of Effelsberg at 6.7 GHz ATCA Observations • Observed 6.7-GHz methanol maser emission towards ~20 northern methanol maser sources • ATCA only connected element interferometer which can observe 6.7 GHz

  5. EVN Observations • Observed Feb 2002 • 4 stations only: Effelsberg, Torun, Jodrell Bank and Onsala • Two fields of view • Phase referenced with a 3-6-6 minute duty cycle • Correlated at JIVE with a single pass and a 2 second integration time • Dual polarisation with 1024 spectral points per pol

  6. EVN Observations • EVN • ATCA

  7. • Greyscale Methanol Masers VLA 3.6 GHz continuum Mehringer etal 1994, ApJSS, 91 713 60” / 2pc

  8. • • • Methanol OH Water 3.6 cm VLA continuum (0.2”) W51 IRS 2 W51 Main Gaume etal, 1993 ApJ 417 645 Argon etal, 2000, ApJSS, 129, 159 Imai etal, 2002, PASJ, 54, 741

  9. • • • - Methanol OH Water NH3 (1,1) W51 Main e2 e4 Zhang etal, 1997 ApJ 488, 241 e1 e3

  10. M = 90 M

  11. • • • - Methanol OH Water NH3 (1,1) W51 Main: e2 2” 0.06 pc

  12. • • • • - Methanol OH Water SiO NH3 (1,1) W51 d/IRS 2 Eisner etal, 2002, ApJ, 569, 334

  13. + + NH3(9,8) maser

  14. Spectral Type B0.5 Size <300 AU EM = 5.9x109  = 2.1

  15. Conclusions • We have made phased referenced, wide field spectral line observations of the 6.7 GHz methanol maser emission in W51 • The methanol traces a number of previously unreported regions of star formation • The linear maser emission in W51-main probably traces edge of HII rather than disc • The methanol in W51-d2 is associated with a very compact, very young HII region

  16. Ralph Gaume David Mehringer Alice Argon Josh Eisner Qizhou Zhang Hiroshi Imai Paolo Persi Antonio Chrysostom Acknowledgments With many thanks to: Overlays made using the package formally known as aips++

More Related