X-ray observation of the Lynds 1157 dark cloud region with ASCA

An ASCA observation of a region containing a Class 0 protostar IRAS 20386 6751 in the Lynds 1157 dark cloud, has been carried out. The protostar was not detected, and the 95% upper limit to the luminosity depends on the ass umed N-H: L-X(0.5-10 keV) < 1.1 x 10(31) erg s(-1) for N-H = 1 x 10(23) cm( -2). A Class I protostar in Lynds 1152, IRAS 20353 + 6742, in the same fiel d was also undetected with an upper limit about three-times as much as the Lynds 1157 level. Besides these non detections, nine new X-ray sources were detected and a spectral analysis was performed for 4 sources. One object ( AX J2038 + 6801) shows a hard spectrum with a temperature of kT similar to 8 keV or a power-law photon index of similar to 2.0 and absorbed with N-H s imilar to 2 x 10(22) cm(-2). Another fainter one (AX J2036 + 6800) has a so ft spectrum with most of the emission falling below 2 keV. We examine the p ossible nature of these new X-ray sources based on their spectral propertie s.