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   PR # 41257
   We propose the observation of the unknown, new type of object called
   "failed clu ster" of galaxies. It is characterized to be a large
   cloud of hot gas with no vi sible galaxies. At first, the exsistence
   of this type of object was suggested by a survey of EINSTEIN/IPC
   field. From the initial screening of 1435 IPC field, a t last only
   ONE possible candidate was found. If the candidate is really the fai
   led cluster, that will constrain the cosmological models for the
   large scale str uctures. The existence of failed cluster will be a
   difficulty for so called "bot tom up model" of hierarchcal
   clustering. Our aim is to identify thecandidate as failed cluster by
   detailed spectroscopy with ASCA.
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