X-RAY EMITTING STARS IN THE NGC-1333 STAR-FORMING REGION

We present the results of a very deep ROSAT HRI X-ray observation of t he highly active star forming region NGC 1333. In total we could detec t 20 X-ray sources, 16 of which we assume to be members to the cluster of pre main sequence stars. Since most of the stars in NGC 1333 are s till deeply embedded in the molecular cloud (A(V) less than or similar to 5-30 mag), we use near infrared data to estimate individual extinc tions for the calculation of X-ray luminosities.One of the X-ray sourc es is identified with the optically invisible, very deeply embedded(A( V) approximate to 28 mag) infrared class I source SVS16, for which we find an extremely high X-ray luminosity of 2.8 x 10(32) erg/sec, makin g this object one of the most X-ray luminous pre main sequence stars k nown to date. Since we have already performed similar sensitive ROSAT observations of the young cluster IC 348 (the second active star formi ng region in the Perseus molecular cloud complex), we compare the X-ra y properties of the young stars in NGC 1333 to those in IC 348. We fin d no evidence for a significant change of the X-ray luminosity functio n during the first few million years in the life of the pre main seque nce stars.