SUMMARY OF PROPOSAL 42159
DR. TAHIR YAQOOB
NASA/GSFC/USRA
MD USA 20771
GREENBELT
CODE 666

  E-mail: LHEAVX::YAQOOB	Tel: 301-286-5015	Fax: 301-286-1684
  Medium: 2GBDAT

Subject: AGN                                                         
  Title: HARD X-RAY OBSERVATION OF THE ULTRA-SOFT VARIABLE NARROW LINE QSO TON S 180     


Abstract:
 Recent ROSAT observations of Narrow Line Seyfert 1s find a very steep soft spectrum
 and rapid variability. It has been suggested that these properties result from an
 extreme value of a yet unknown physical parameter; a high accretion rate or low
 black hole mass have been suggested. We propose a 50ks ASCA observation of one of
 the brightest NLS1s TonS180. Coordinated EUVE and optical observations are also
 being proposed. TonS180 is bright enough that excellent spectral and variability
 constraints are possible, allowing direct tests of models for the hard X-ray
 emission and optical-UV-soft X-ray excess. Comparison with results from ordinary
 Seyfert 1s will help us understand how and why they are different and contribute to our understanding of the Seyfert 1 phenomenon.

 Co-Is:
   1  KAREN LEIGHLY       	RIKEN                         JAPAN     
      (No Co-I contact data)
   2  ANDREA COMASTRI     	BOLOGNA ASTRON OBS            ITALY     
   3  HERMAN MARSHALL     	EUREKA SCIENTIFIC             USA       


Target Name           PRI RA        Dec        Time TC  Off GIS SIS_Cts  Obs
-------------------   --- --------  --------   ---- --  --- --- -------  ---
TON S 180              0   14.3292  -22.3797    50   N   Y   P  0.90000   1 

REMARKS:  PLEASE SCHEDULE DURING SUMMER WINDOW (1996 JUNE 24 - 1996 JULY 24). EUVE
          AND OPTICAL OBSERVATIONS WILL BE COORDINATED.