Seimei telescope usersʼ meeting @ Kyoto University (2023/9/12̶13)

可視光・X線高速同時観測で探る、
超強重力場下の降着現象

発表者：木邑 真理子 (金沢大学)
共同研究者：酒向重行 (東京大学)、山田真也 (立教大学)、根來均 (日本大学)、磯貝桂介、野上大作、榎戸輝揚 (京都大学)、前原裕之、大澤亮 (国立天文台)、植村誠 (広島大学)、藤沢健太 (山口大学)

11. X線連星・矮新星のアウト ースト中における、秒スケールの可視光変動（2022B—） TriCCSのモニタリン
2.

ンマ線 ーストの即時放射・早期残光の可視光高速観測と残光の長期モニター（2023B—） TriCCS
The black-hole X-ray binary Swift J1727.8-1613 is now outbursting !

Today’s topic• Introduction• X-ray & optical high-speed observations of MAXI J1820＋070 (NICER & Tomo-eGozen)• Future observations & advantages by Seimei telescope

バグ2バガOur Seimei proposals

Low-mass X-ray binaries• Easy to be observed (bright, many objects)• Outbursts = sudden brightening of the disk
• Multi-wavelength emission• Triggered by the thermal-viscous instability

X-raysThermal equilibrium curveṀacc (Te↵ )Hot state

OpticalṀcrit(Low-mass X-ray binaries)
Cool state

050

100

150

200

250

300Days(Mineshige & Wheeler 1990; Kimura & Done 2019)3Millisecond ares in black-hole binaries
The black-hole binary shows millisecond
optical ares during outburst.
Inherent to black-hole systems• Magnetic activities ?
• Relativistic jets ?
• Disk instabilities ?

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Multi-wavelength observations of ares
Jet ejection

Correlation & time lags between
optical & X-ray variations• Radiation mechanism• Geometry of X-ray emitting
plasma & disk

Physical mechanism• Correlated & optical delay → X-ray reprocessing• Correlated & zero lag → Synchrotron emission• Anti-correlated → Synchrotron self-Compton emission(Gandhi et al. 2010, 2016; Veledina et al. 2011)

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Quasi-periodic oscillations (QPOs)
L̲x

X-ray

gʼ-bandrʼ-band• Do optical and X-ray QPOs have the same origin ?
• Lense-Thirring precession of the inner accretionow ? Instability ? (For Type-C QPOs)(Veledina et al. 2015; Motta 2016; Motta et al. 2017)6

Our goals & high-speed observations
We propose TriCCS observations during outbursts in X-ray binaries to understand themechanism of milli-second ares & QPOs. + NICER, Kanata telescope, Yamaguchiinterferometer
X-raysNICER＠ISS (2018~)• Soft X-rays (0.2-12 keV)
• Large e ective area
• High time resolution

Flexible DDT !

(accuracy <0.1ms)

OpticalTomo-e Gozen（2019~）

DDT for particular targets
within 15 min x 2 / night• CMOS camera• Wide- eld survey• High-speed observations

flfffi(~160 fps at maximum)X-ray & optical high-speed
observations of the black-holebinary MAXI J1820+070

8Millisecond ares in the low/hard state(Shidatsu et al. 2019)

Low/hard state

High/soft state• The low/hard state continued for ~110 days
• Millisecond ares were observed during the long-lasting low/hard state• We failed simultaneous observations : (flfl9

X-ray shot analyses
1. Subtract the overall trend of the light curveand normalize it (per date)
2. Extract shots from the light curve (-10 s < t_p< +10 s)yra

3. Superimpose shots

4. Average shot pro lesnimile↓ Cyg X-1

rP

0.3—7 keV

2–7 keV / 0.3—2 keV
-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

(Negoro et al. 1994; Negoro et al. 2001)

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Time evolution of X-ray shotsyranimile• Shot pro le & hardness ratio were changing with time.
• Asymmetry of the pro le was growing.

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2 components ? (Flares + QPOs)

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• Fitting of each shot by the following equation<latexit sha1_base64="ACRHgZEbWEfvRgOzZtrWkVwSrqI=">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</latexit>f (t) = a exp( |t|/b) + c cos

Normalized ux

areyranimiler
P✓

2⇡(tdQPOux• Violent variations during rst 2 weeks• After ~110 d, the rapid variability was fading.

correlated.

12fi◆e) + f• Phase shift was always minus.
• Flare duration and QPO period wereflflflTime evolution of X-ray shots

Comparison with optical shots

yranimile• Optical shots were always narrower than X-ray shots.
• Always symmetric pro le to the light maximumrP

The optical shot is 1 component, while the X-ray shot has 2 components ?
The optical shot is just narrower ?

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Time evolution of X-ray shots• Fitting of each shot by the following equation<latexit sha1_base64="ACRHgZEbWEfvRgOzZtrWkVwSrqI=">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</latexit>f (t) = a exp( |t|/b) + c cos✓2⇡(tdyra◆e) + f• Amplitude of optical ares and QPOs weresmaller.

nimile• Duration of optical ares were shorter.
• QPO period was synchronized ?

rP• Phase shift was around zero !

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Consistency with past works• Several papers described the QPO properties of MAXI J1820+070.
• Our shot pro le was too short todetect long-period QPOs.

• If the period is shorter than ~5 sec,yraour tting results are consistent withthe QPO frequency detected by pastworks.

nimileWe need PSDs and long-duration
shot pro les.

r
P

Shot analyses visualize QPOs.

(Wei et al. 2023; Thomas et al. 2022)

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The physical origin of ares ?
• Shot duration: 0.1—0.8 sec
Kepler period at 1—3 x 108 cm (~30—100 rg). Here, MBH = 10 M_sun
Accretion time at ~106 cm ~107 cm
Sudden accretion event is unlikely ..

yraThe spectral analysis suggested that Rin > ~5e6 cm(Shidatsu et al. 2019; Omama et al. 2023).

nimileMagnetic ares at <100 rg ?

Hot corona

Expected duration is ~1—30 ms → can explain optical aresrP

Spectral hardening is expected → consistent with our results(Poutanen & Fabian 1999)
The shot pro le could be symmetric ?
Shock ? Particle acceleration ?

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The physical origin of ares ?
• The optical shot was narrower than the X-ray shot.
X-ray reprocessing is unlikely.

• If the X-ray ares delayed against

optical ares, accretion propagation issupported.

yraBut, inconsistent with spectral
hardening

nimileSynchrotron self-Compton emission in the hot corona can produce narrower
optical ares (Veledina et al. 2011; Shahbaz et al. 2023)

rPThen, anti-correlation between optical & X-ray ares should be observed

The main source of sub-second ares is the hot corona inside of the disk.

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Future observation plan by using
Seimei / TriCCS

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Multi-wavelength observational network
X-rays

OpticalNIR & RadioNICER＠ISS (2018~)

Tomo-e Gozen（2019~）

Kanata telescope

XRISM (2023~)
TriCCS＠Seimei（2021~）

Yamaguchi interferometer• Realize completely simultaneous observations of multi-wavelength ares !
• Plus broadband multi-wavelength spectra Swift J1727.8-1613 is in outburst !
fl19Advantage of Seimei / TriCCS
TriCCS＠Seimei（2021~）• CMOS camera• 3 bands (g,r,i or g,r,z) & spectrograph (R~700)• High-speed observations (~1000 fps at maximum)
0a1,1@a2,10<latexit sha1_base64="QBe4H3VdpFSKbKgFQ4DUK2yde3Y=">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</latexit>Jet ejection(Fg, Fr, Fi)• Faint targets are observable• Decompose the optical variation into a few components• Investigate the fast variability in disk winds
20

a1,2
a2,2
a3,2

100 A

a3,3

Out ows from the accretion disk
• P-Cyg pro le of He I & broad wings ofHα lines
Low-temperature wind (neutral gas
are blowing ?

How do these pro les change in subsecond ares ?

(Munoz-Darias et al. 2016, 2019)fififlfl

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Observations of Swift J1727.8-1613 ?

Can we try observations by DDT
as soon as possible ?

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Automatic follow-up observations
with Seimei ?

23Immediate automatic observations
Transient alerts by MAXI, Swift,
KOYOH
Ground-based telescopes

Start multi-wavelength follow-up
observations

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Immediate automatic observations
Information of the object’s position, (brightness), (type)

Queue system developed by Maehara-san

9 pointings → catalog matching → detect a transient

Instant photometry → estimate ux → determine exposures

Classi cation of transients by KOYOH data

Type of continuous observations• Immediate goal: open the dome and perform photometry if it’s not rainy.

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Summary• It is unclear what causes millisecond ares and QPOs in X-ray binaries and cataclysmic
variables.

Multi-wavelength observations are useful.

• We analyzed the data obtained by NICER (X-ray) & Tomo-e Gozen (optical) of MAXI
J1820+070.

Shots with ~100-ms duration → Possible magnetic ares
Narrower optical shots → Synchrotron self-Compton emission ?

Millisecond ares would originate from the hot accretion ow.

• We are planning to use TriCCS for completely simultaneous observations of sub-second

variability, and extract information of the disk geometry. Also, we want to investigate timevarying disk winds.

• Automatic observation system is desirable in the future.
Thank you very much for sta s in Okayama Observatory.

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