SUMMARY OF PROPOSAL 53018

DR. JOACHIM SIEBERT
JOS@MPE-GARCHING.MPG.DE

MAX-PLANCK-INSTITUT F\"UR EXTRATERRESTRISCHE PHYSIK
GERMANY GERMANY 85748
GARCHING
GIESSENBACHSTRASSE
Tel: (0)89-3299-3502 Fax: (0)89-3299-3569
Medium: 4GBDAT
Subject: AGN

IS THE POWERFUL RADIO GALAXY HERCULES A IN A CLUSTER OR NOT?


ABSTRACT

The radio galaxy Hercules A (3C 348) is one of the most prominent AGN in the sky. Although intensively studied, many of its striking characteristics, such as the radio morphology and its environment, are still a matter of debate. A ROSAT PSPC observation provides evidence for extended, i.e. thermal, X-ray emission components. With this ASCA observation we intend to determine accurately the shape of the high energy X-ray spectrum of Her A. By doing so we will be able to decide whether its X-ray emission is dominated by thermal or nonthermal processes. If the indications for thermal emission can be substantiated, this would strongly argue for a cluster environment of Her A and thus provide clues for our understanding of many of the puzzling properties of this peculiar radio galaxy.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY
WOLFGANG BRINKMANNMPEGERMANY
NOBUYUKI KAWAIRIKENJAPAN

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)HERCULES A
3
252.7833 4.9928 40 ksN
Y
P
0.18000
1