SUMMARY OF PROPOSAL 41286
DR. ATSUMASA YOSHIDA
THE INSTITUTE OF PHYSICAL AND CHEMICAL RESEARCH (RIKEN)
SAITAMA JAPAN 351-01
WAKO
HIROSAWA 2-1

  E-mail: AYOSHIDA@POSTMAN.RIKEN.GO.JP	Tel: 048-462-1111(EXT.3226)	Fax: 048-462-4640
  Medium: 4GBDAT

Subject: COSMIC X-RAY BACKGROUND AND DEEP SURVEYS AND OTHER          
  Title: A SEARCH FOR X-RAY COUNTERPARTS OF THE MOST INTESE GAMMA-RAY BURSTS             


Abstract:
 We propose an ASCA search for X-ray counterparts of the two very intense gamma-ray
 bursts, GRB930131 and GRB940217. GRB930131 displayed very strong peak intensity of
 168 photons/cm2/sec which was the brightest one detected before with BATSE/CGRO.
 GRB940217 showed surprising characteristics; it lasted for more than 5,000 seconds
 in a band from several tens of MeV to about 18 GeV after the cessation of the lower
 energy busting activity < MeV. This is the most intense burst in a GeV range ever
 seen before. These two bursts, therefore, should be regarded as belonging to the
 nearest GRBs. Furthermore, they have both localized in small error regions. From
 these reasons, they should be the best targets for an X-ray counterpart search.

 Co-Is:
   1  TOSHIO MURAKAMI     	ISAS                          JAPAN     
      MURAKAMI@ASTRO.ISAS.AC.JP	0427-51-3911
   2  FUYUKI TOKANAI      	RIKEN                         JAPAN     
   3  NOBUYUKI KAWAI      	RIKEN                         JAPAN     
   4  YASUSHI OGASAKA     	ISAS                          JAPAN     
   5  RYO SHIBATA         	ISAS                          JAPAN     


Target Name           PRI RA        Dec        Time TC  Off GIS SIS_Cts  Obs
-------------------   --- --------  --------   ---- --  --- --- -------  ---
GRB930131              1  183.7750  -10.2000    40   N   N   P  0.01000   1 
          
GRB940217              1   29.7500    3.9500    40   N   N   P  0.01000   1