光赤外大学間連携
参加望遠鏡による
low mass X-ray binaryの追観測
村田勝寛(東工大)
東工大MITSuMEチーム!1

Low-mass X-ray binaries
Artist’s impression of a X-ray binary• X-ray binary (XRB):

system where one of thecomponent is either a blackhole or neutron star (compactstar).

• Low-mass X-ray binary(LMXB): XRB whose
companion star has a masssimilar to or less than the Sun.

Credit: NASA/R. Hynes!2

Optical/near-IR radiation from Low-mass X-ray binaries
Artist’s impression of a X-ray binary• Thermal emission from the Xray irradiated accretion diskand/or the companion• Synchrotron emission from thejet—>

optical/near-IR

Optical/near-IR observation may
provide information on
accretion disk and radiation
process.
This is motivation of our follow-up
observation.

Credit: NASA/R. Hynes!3

The low-mass X-ray binaries of our follow-up observations aremainly those discovered by MAXI (Monitor of All-sky X-ray Image).

ISS (International Space Station)

Kibo
Japanese Science module• Mission started 2009.
• a few - several new lowmass X-ray binaries /year直近２年の観測
detection• MAXI J1535-571 (near-IR) <— IRSF• MAXI J1820+070 (optical & near-IR) <— OISTER ToO 3月• Swift J1858.6-081 (optical & near-IR) <— OISTER ToO 先月• MAXI J1727-203 (optical & near-IR) <— MITSuME、IRSF• MAXI J1621-501 (near-IR, upper limit) <— IRSF

… 他

検出できたX線連星は継続した観測を実施した!5今日のお話• MAXI J1820+070 <̶ OISTER ToO• 現状の報告• MAXI J1535-571 <̶ IRSF観測• preliminary result•.SA41

•

;25J

8,XD

E41;25;064 21

以下の図のベースはShidatsu et al. ApJ、河合さんGROWTHミーティングスライドより

JetSynchrotronEmi ssion

 OISTER (3/24)+ MAXI/GSC (3/24)+ Swift/BAT (3/24)
optical + radio (3/18; ATel #11439, 11458)
 mid-IR + radio (4/8; ATel #11420, 11533)

onitcrecAdneot
itiaadzian kTin = 0.35 keVIrr skot
p
5 Rg
Di om
Rout=10+Cfout = 0.005

Radio
Infrared OpticalDisk+ corona
jet8,

IRSF1.4m望遠鏡による
MAXI J1535-571の近赤外線観測

MAXI J1535-571: Low-mass X-ray binary
MAXI X-ray light curve

MAXI X-ray all sky image, 2017 Sep 19

total X-ray
2-20 keV
2-4 keV••MAXI J1535-571• discovered by MAXI on 2017 Sep 2• almost simultaneously andindependently discovered by Swift• on the Galactic plane
Bright X-ray binary• peak X-ray flux ~ 5 Crab (T ~ 17days)• the brightest X-ray binary in thiscentury
94-10 keV

10–20 keV

20 days

Discovery of the optical/near-IR counterpartof MAXI J1535 by other groups (T=1, 3 days)
The optical counterpart was detected
next day after the X-ray discovery.
i’-band image by 0.61m B&C telescope
Atel #10702, Scaringi et al. 2017

• T=1 day: Discovery of optical iʼband counterpart, but no detection
in g and r band(Atel #10702, Scaringi et al.)
̶> Extinction by interstellar dust on
the galactic plane is large.
̶> Obs. with longer wavelength suchas near-IR is important.

• T=3 days: Identiﬁcation of the nearinfrared counterpart(Atel #10716, Dincer et al.)!10

Observation with IRSF 1.4 m telescope
Observation• 2017 Sep 6 — Oct 2:• ~3 hours continuous

observation for several nights• Oct 2 - now• monitoring observation

almost once every month• observe J (1.2μm), H (1.6μm),
Ks (2.3μm) simultaneously

Sutherland observatory in SouthAfrica• Southern Hemisphere• MAXI J1535-571 is notobservable from Japan.

Our near-IR observation
This is the ﬁrst night of our follow-up observation.
Before the X-ray outburst
After the X-ray outburst
2MASS archive image in J band IRSF 1.4m telescope J-band image

J > 16.4 mag

MAXI J1535
J ~ 15 mag

We detected the near-IR uncatalogued source
reported by Atel #10716 (Dincer et al. 2017).
!12

Our near-IR observation
We detected MAXI J1535 with J, H and Ks band.
J band (1.2micron)

MAXI J1535

H band (1.6micron)

MAXI J1535!13

Ks band (2.1micron)

MAXI J1535

Our near-IR observation is on-goingnear-IR peak flux (Sep.9)

Jan. 2Mar. 24
May 31~ 270 days!14•

Since this night, we have
performed near-IR
monitoring observation.

•At least up to 2018 Sep, we
detected MAXI J1535.

•We are now reducing andanalyzing all the data.

•

In this talk, we focus on 2017
Sep 17 observation when
intranight short-term variation
is clearly detected.

Summary• MAXI J1820+070, MAXI J1535-571など小質量X線連星の追観測をしている• MAXI J1820+070• OISTER可視光、近赤外線、X線でSEDをかいて放射成分を制限（Shidatsu et al. 2018, ApJ）

• 短時間変動の解析を現在進めている• MAXI J1535-571• IRSFで発見から270日以上観測をおこなった!15