Astron. Astrophys. Suppl. Ser.
Volume 143, Number 2, April II 2000
|Page(s)||269 - 301|
|Published online||15 April 2000|
A survey of the 6.7 GHz methanol maser emission from IRAS sources*
Toruń Centre for Astronomy, Nicolaus Copernicus University, ul. Gagarina 11, PL–87100 Toruń, Poland
Send offprint request to: M. Szymczak
Accepted: 4 February 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 μm and 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 Toruń 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
Table 2 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsweb.u-strasbg.fr/Abstract.html
© European Southern Observatory (ESO), 2000