Astron. Astrophys. Suppl. Ser. 143, 269-301
A survey of the 6.7 GHz methanol maser emission from IRAS sources
M. Szymczak - G. Hrynek - A.J. Kus
Send offprint request: M. Szymczak
Torun Centre for Astronomy, Nicolaus Copernicus University,
ul. Gagarina 11, PL-87100 Torun, Poland
Received December 17, 1999; accepted February 4, 2000
We report the first results of a search for 6.7 GHz methanol masers
in the direction of 1399 IRAS objects north of declination
with the flux densities greater than 100 Jy at 60
the flux density ratio
Observations were made with the sensitivity of 1.7 Jy and the velocity resolution of 0.04 km s-1
using the 32-m Torun radio telescope.
Maser emission was found in 182 sources, including 70 new detections.
32 new sources were identified with objects of radio emission associated
with star-forming regions.
Comparison of the present data set with other observations suggests that about
65% of methanol masers exhibit moderate or strong variations on time-scales
of about 4 and 8 years.
Key words: masers -- surveys -- stars: formation -- ISM: molecules -- radio
lines: ISM -- HII regions
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