Astron. Astrophys. Suppl. Ser. 134, 115-128

The Medicina survey of methanol masers at 6.7 GHz

V.I. Slysh ¹ - I.E. Val'tts ¹ - S.V. Kalenskii ¹ - M.A. Voronkov ^1,2 - F. Palagi ³ - G. Tofani ⁴ - M. Catarzi ^4,

Send offprint request: F. Palagi

1 - Astro Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
2 - Moscow State University, Physical Faculty, Astronomical Department, Universitetskii pr. 13, 119899 Moscow, Russia
3 - C.A.I.S.M.I., C.N.R., Largo E. Fermi 5, 50125 Firenze, Italy
4 - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy

Received May 19; accepted July 23, 1998

Abstract:

A survey of Class II methanol masers at 6.7 GHz was made in the Northern hemisphere with the 32-m Medicina radio telescope. 42 objects were detected, 20 of them are new detections at 6.7 GHz. Our results show that the detection rate of 6.7 GHz masers toward the inner part of the Galaxy is higher than in other directions. It is confirmed that most of the methanol masers are associated with faint compact HII regions. The 6.7 GHz methanol masers show large velocity dispersion and large velocity offset from the velocity of parent molecular clouds.

Key words: masers -- ISM: molecules; HII regions -- radio lines: ISM