SUMMARY OF PROPOSAL 41178
DR TORU YAMADA
THE INSTITUTE OF PHYSICAL AND CHEMICAL RESEARCH (RIKEN)
SAITAMA JAPAN 351-01
WAKO-SHI
2-1 HIROSAWA

  E-mail: YAMADA@CRICKET.RIKEN.GO.JP	Tel: 048-462-1111 EXT. 3227	Fax: 048-462-4640
  Medium: 4GBDAT

Subject: AGN                                                         
  Title: X-RAY SPECTRUM OF THE Z                                                         


Abstract:
 It has been recently reported (Mathur & Elvis 1995) that the newly discovered
 radio-loud quasar GB1508+5714, with z=4.3, was observed serendipitously with the
 Einstein observatory. The source has a (0.3-3.5 keV) flux of about 10**-12
 erg/cm2/s, more than 10 times brighter than the other two X-ray detected z>4
 quasars. A hardness-ratio analysis indicates that the source is remarkably hard, or
 absorbed, but no spectral fitting is possible with the Einstein data. With a 40 Ks
 ASCA observation, we anticipate the determination of the spectral parameters (Nh,
 absorption, FeK) of this very distant quasar. These values, combined with previous
 results from high-z quasars (Cappi et al. 1995), will be compared to low-z quasars
 and radio-quiet quasars to study the evolution of quasars.

 Co-Is:
   1  TATEHIRO MIHARA     	RIKEN                         JAPAN     
      (No Co-I contact data)
   2  MASSIMO CAPPI       	RIKEN                         JAPAN     
   3  KAREN LEIGHLY       	RIKEN                         JAPAN     
   4  CHIKO OTANI         	RIKEN                         JAPAN     
   5  MASARU MATSUOKA     	RIKEN                         JAPAN     


Target Name           PRI RA        Dec        Time TC  Off GIS SIS_Cts  Obs
-------------------   --- --------  --------   ---- --  --- --- -------  ---
GB1508+5714            3  227.5121   57.0454    40   N   N   P  0.05000   1