SUMMARY OF PROPOSAL 61190

MS NAOMI OTA
OTA@astro.isas.jaxa.jp

ISAS
KANAGAWA JAPAN 229
SAGAMIHARA
3-1-1 YOSHINODAI
Tel: +81-427-3911 EX 2617 Fax: +81-427-59-4253
Medium: 4GBDAT
Subject: CLUSTERS OF GALAXIES AND SUPERCLUSTERS

THE DISTANT RADIO GALAXY WITH A GIANT LUMINOUS ARC; 3C220.1


ABSTRACT

3C220.1 is a radio galaxy located at z=0.62, and revealed to have a "giant luminous arc". Such arcs are known to be images of background galaxies produced by the gravitational lensing effect. The arc radius of 3C220.1(= 9") implies "minimum" velocity dispersion of 720km/sec, which means that the lens potential is provided by a cluster of galaxies rather than a galaxy. Then it's very puzzling that the galaxy population of the fictitious cluster is apprerently very poor. We have analyzed the public archival data of ROSAT HRI to find an extended X-ray emission from the 3C220.1. We propose ASCA observations to determine the temperature and the redshift of the hot gas in the cluster. It will be a strong test to confirm the existence of deep cluster potentical well at z=0.62.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY
KAZUHISA MITSUDAISASJAPAN
YASUSHI FUKAZAWAUNIVERSITY OF TOKYOJAPAN

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)3C220.1
2
143.1654 79.1088 40 ksN
Y
P
0.02800
1