Brightness temperatures of galactic masers observed in the RadioAstron project

We present estimates of brightness temperature for 5 galactic masers in star-forming regions detected at space baselines. Very compact features with angular sizes of about 23-60 micro arcsec were detected in these regions with corresponding linear sizes of about 4-10 million km. Brightness temperatures range from 1e+14 up to 1e+16 K.