1. EVN imaging of methanol masers towards massive protostars Anna Bartkiewicz Marian Szymczak Huib Jan van Langevelde 8th EVN Symposium Torun 2006

2. The ring G23.657-00.127: Ellipse: e=0.38 133 mas x 123 mas i.e. 1400 AU x 1300 AU at 10.5 kpc or 700 AU x 630 AU at 5.1 kpc

3. A disc at i=67 deg? V lsr =V rot * cos i * cos A A(deg)

4. VLBA observations on November 2005: 12.2 GHz 6.7 GHz ?

5. IRAS 2MASS MSX 540 K and 80 K (Walsh et al. 1999)

6. Arc-like sources: G24.541+00.312 & G23.707-00.198 370 (560) AU 370 (750) AU

7. Model by Moscadelli, Cesaroni & Rioja, 2000

8. Complex distribution:

9. Conclusions: new structures of 6.7 GHz methanol masers were detected at maps with milliarcsecond resolution (esp. ring), the arc-like masers were explained well by the bipolar outflow model, complex structures arose likely through propagation of a few shock fronts driven by protostars. Future work: further investigation of the ring G23.657-00.127 including proper motion studies and measurements of the parallax, high resolution studies of radio continuum and infrared counterparts.