We present results of ASCA deep exposure observations of the hardest X-ray source discovered in the ASCA Large Sky Survey ( LSS ) project , designated as AX J131501 + 3141 .
We extract its accurate X-ray spectrum , taking account of the contamination from a nearby soft source ( AX J131502 + 3142 ) , separated only by 1 ^ { \prime } .
AX J131501 + 3141 exhibits a large absorption of N _ { H } = ( 6 ^ { +4 } _ { -2 } ) \times 10 ^ { 22 } { H } { cm } ^ { -2 } with a photon index \Gamma = 1.5 ^ { +0.7 } _ { -0.6 } .
The 2–10 keV flux was about 5 \times 10 ^ { -13 } { erg } { cm } ^ { -2 } { s } ^ { -1 } and was time variable by a factor of 30 % in 0.5 year .
From the highly absorbed X-ray spectrum and the time variability , as well as the results of the optical follow-up observations ( [ Akiyama et al .
1998 ] ) , we conclude that AX J131501 + 3141 is a type 2 Seyfert galaxy .
Discovery of such a low flux and highly absorbed X-ray source could have a significant impact on the origin of the cosmic X-ray background .