SUMMARY OF PROPOSAL 52151

DR. GREG M. MADEJSKI
MADEJSKI@LHEAVX.GSFC.NASA.GOV

NASA/GODDARD
GREENBELT RD.
GREENBELT
MD USA 20771
Tel: (301) 286-8099 Fax:
Medium: 4GBDAT
Subject: AGN

ASCA AND HST OBSERVATIONS OF BL LAC 0235+164 AND THE INTERVENING SYSTEM


ABSTRACT

AO 0235+164 (z = 0.9) is a unique BL Lac object as it is located behind an intervening galaxy half way between us and the BL Lac, yet is is sufficiently bright in X--rays to provide a "white light source" to study the elemental composition in that galaxy. Our previous ROSAT and Asca observations of this highly variable source yielded excess absorption in the intervening system implying abundances of about 0.5 Solar, but the limited statistics precluded any measurement of edges due to individual elements. We propose to reobserve it for 20 ks simultaneously with STIS, to measure the elemental abundances as well as the dust content of the intervening system.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY
MARGARET BURBIDGEUCSDUSA
ROSS COHENUCSDUSA

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)AO 0235+164
2
 39.6583 16.6167 20 ksN
Y
P
0.50000
1

TARGET 1

THIS OBSERVATION WILL BE CONDUCTED SIMULTANEOUSLY WITH STIS