SUMMARY OF PROPOSAL 81601
UNIVERSITY OF TOKYO
HONGO 7-3-1
BUNKYO-KU
TOKYO JAPAN 113-0033
Tel: 03-5841-4202 Fax: 03-5841-4158
Medium: CD ROM
Subject: NORMAL GALAXIES
Ultra-luminous X-ray source in M33
ABSTRACT
Some luminous point-like X-ray sources (ULXs) seen in nearby spiral galaxies are promising blackhole binaries. In recent ASCA observation (AO8), from two ULXs in IC 342, we have detected remarkable transitions between two characteristic spectral states, which provides a strong evidence for the blackhole nature of these ULXs. Furthermore, this indicates the possibility that we can extend our study of blackhole binaries to extra-Galactic sources. One of the nearest spiral galaxies, M33, was observed with ASCA in PV phase, and ten point-like sources were detected. Among them, X-8 is known as the nearest ULX with X-ray luminosity of 1E39 erg/s, and three bright sources of >1E38 erg/s can be blackhole binaries considering their hardness ratio. Together with its size and distance, M33 is the best target to examine the ULXs nature and extra-Galactic blackhole binaries. We therefore propose additional multiple (2 times) observations of M33. By these observations together with the PV phase observation, we can discuss the spectral transition and variation of disk parameters, and we can identify other sources with detailed spectral study.
CO-INVESTIGATORS
| CO-I NAME | INSTITUTE | COUNTRY |
|---|
| KAZUO MAKISHIMA | UNIV OF TOKYO | JAPAN |
| NAOKO IYOMOTO | UNIV OF TOKYO | JAPAN |
| TSUNEFUMI MIZUNO | UNIV OF TOKYO | JAPAN |
| YASUSHI FUKAZAWA | UNIV OF TOKYO | JAPAN |
| YUKIKATSU TERADA | UNIV OF TOKYO | JAPAN |
| KAZUHISA MITSUDA | ISAS | JAPAN |
| YOSHITAKA SAITO | ISAS | JAPAN |
| TATEHIRO MIHARA | RIKEN | JAPAN |
TARGETS
| TARGET NAME | PRI | RA | DEC | TIME | TC | OFF | GIS | SIS CNT | OBS |
|---|
| 1)M33 | A | 23.4621 | 30.6600 | 100 ks | N | N | P | 0.40000 | 2 |