ASCA lightcurves of Source 2 in soft state

1
ASCA Observations of the two Ultra Luminous X-Ray
Sources in the Nearby Spiral Galaxy IC 342 (II)
- Possible Orbital Periods -
Masahiko Sugiho, Jun'ichi Kotoku, Aya Kubota,
Kazuo Makishima(University of Tokyo), Tsunefumi
Mizuno(Hiroshima University) E-mail
sugiho_at_amalthea.phys.s.u-tokyo.ac.jp, Homepage
http//www-utheal.phys.s.u-tokyo.ac.jp/sugiho/ind
ex-j.html
We present temporal analyses of ASCA one week
monitoring observation of ULXs in IC 342. About
their images and spectral analyses, see the
poster I, which reinforces the scenario that ULXs
are 100 solar mass BHBs. To conclusively
establish this scenario, we search for their
orbital periods.
Temporal analyses (2- 10 keV band)
Power spectra
Period diagrams
double periods
Orbital period of satellite
31hr 41hr
GIS
SIS
GIS
ASCA lightcurves of Source 2 in soft state
30hr
SIS
Significant variation one day scale
7bin
? 2 10 keV band ?
Periodic variation of 31hr or 41hr is suggested
GIS
SIS
30h
GIS folded lightcurves
Background level
31hr
41hr
2 10 keV band
a week
Time (s) from 2000/02/24 03000
? 0.7 2 keV band ? No significat variations
0.0-0.5
0.5-1.0
0.8-0.3
0.3-0.8
0.7 2 keV band
SIS
GIS
2
2
?/d.o.f. 1.27
?/d.o.f. 1.12
Phase resolved GIS spectra (background subtracted)
? Source1 ? No significant variations
MCD (N frozen) model fitting
H
What does 31hr or 41hr possible periodicity mean ?
?? Best fit model for the whole spectrum
31hr
41hr
10100 solar mass main sequence star
phase 0.3-0.8
phase 0.5-1.0
semi detouched binary
? orbital period 2050hr
phase 0.8-0.3
phase 0.0-0.5
With elliptic orbit ? ? mass accreting rate
changed ?
100 solar mass black hole
We may detect binary orbital period of ULX as
100 solar mass black hole for the first time
Inner disk temperature T in changed ?