GENJI プログラム :電波銀河3C84のモニター観測結果
1
2
1
2,3
日浦 皓一朗 、永井 洋 、徂徠 和夫 、秋山 和徳 、他 GENJIプログラムメンバー"
1 北海道大学 、2 国立天文台 、3 東京大学!

Abstract
国立天文台VERAを用いたAGN ジェットモニタリングプログラム「GENJI(Gamma-ray Emitting Notable-AGN Monitoring by Japanese VLBI)」では、
現在8天体を1–2 週間に1 回の頻度でVLBIモニター観測を行っている。
今回は、そのうちの一つである電波銀河3C84の解析の途中経過を報告する。3C84は、赤方偏移z=0.0176に位置する非常に明るい電波源であり、母銀河は巨大楕円銀河NGC1275である。3C84はFermi γ線望遠鏡の観測からGeV γ線が1990年代に比べて7倍以上明るくなっていることがわかっており[1]、また特に2005年頃から
電波増光が起こり、その後、中心核から新たに放出された成分が運動する様子が確認されている[2]。長いタイムスケールでγ線増光と電波増光の傾向が良く一致していることから、γ線放射領域と電波増光の発生場所の密接な関係を示唆していると考えられる。
GENJIプログラムが始まった2010年11月以降は、目立ったγ線変動は報告されていないので、今のところγ線変動との関係を明らかにするに至っていない。
しかし、より高エネルギーの電子からの放射が卓越していると思われるサブミリ波帯のデータとの比較から、サブミリ波の変動とVLBIコアの変動には目立った相関は見られないことがわかった。一方、下流側にあるジェット成分の変動はサブミリ波の変動と似ていることがわかった。
また、構造変化の速度を見積もったところ、Nagai et al. 2010 のデータと比べてジェット成分の見かけの速度がさらに減速していることがわかった。

GENJIとは
GENJIプログラムは国立天文台が所有するVERAを用いて、γ線AGNに対して約2週間に１回の高頻度でモニター観測を行い下記のテーマに取り組んでいる。 "(i) VLBIコアフラックスとガンマ線フラックスの変動の関係(ii) ジェットの下流領域あるいは空間的に広がった成分のフレア有無の調査"(e.g.M87におけるHST1)
γ線源の所在とVLBIコアの本質の解明(iii) ジェットの固有速度と、γ線放射から期待されるローレンツ因子の関係
変動が同期
相関はあるが、電波にdelayが見られる
・VLBIコアの中にγ線放射領域があり、	
  γ線放射領域が光学的に薄い	

γ線放射領域	

Sub-mm or Space VLBIによってγ線放射領域の撮像が期待される

解釈②

電波	

電波	

γ線	

電波コア	

厚い
薄い
光学的厚み	
厚い

変動が無相関解釈

γ線放射領域の光学的厚み

γ線	

電波とγ線の放射領域が空間的に異なる	  -­‐-­‐>	
  たとえばJetの多層構造など	

光学的厚み	薄い時間	・VLBIコアはτ=1の光球面。	
  ・γ線放射領域はJetの光球面の中に存在	
  ・放射領域がジェットに沿って移動し、 	
  光学的に薄い領域に出る事で電波で	
  増光が見える。	

観測・観測装置：VERA (右図)
No. 2]VLBI Monitoring of 3C 84 in Early Phase of the 2005 Outburst
・周波数： 22 GHz
・空間分解能： 〜1 mas @22 GHz
・バンド幅： 176 MHz (16 MHz × 11 IF)
観測天体 3C84- 電波銀河 ; z = 0.0176 (75 Mpc)
- 0.35 pc/mas ; 1c = 0.87 mas/yr

・VLBIコアの中にγ線放射領域があるが、	
  γ線放射領域が光学的に厚い	
  ・放射領域自体が光学的に薄くなる事で	  No. 2]VLBI Monitoring of 3C 84 in Early Phase of the 2005 Outburst
電波で増光が見える。	
  	
光学的厚みによってはSub-mm VLBIでγ線放射領域の撮像が期待できる。

L13

L13

LETTER

解釈① ジェットの光学的厚み

LETTER

解釈

観測天体 3C84・巨大楕円銀河NGC1275の活動銀河核電波源!p "Fig. 1. (a) JVN image of 3C 84 at 8 GHz. The contours are plotted at the level of 86.2 mJy !
2 (n = "1, 0, 1, 2, 4, : : :, 128). The lowest contour(Seyfart 2, MBH = 3 × 108 M⊙ )corresponds to three-times image noise r.m.s.. The beam size is 3.85 ! 2.14 mas at a position angle of "47 , which is shown in the lower left corner ofthe image. (b)–(o) VERA images of 3C 84 at 22 GHz. All images are shifted in reference to the northern component (component C1). The contours
・1990年代に比べてGeV γ線が7倍以上増光 [1]。
are plotted at levels of 4.18, 8.36, 16.72, 33.44, and 66.88% of the peak intensity (4.989 Jy beam) on 2009 April 24. The restoring beam (1.1 ! 0.7 mas,・ジェット成分の見かけの速度が、中心核
position angle of "60 ) was set to make images uniform.
・2005年頃からVLBI観測により1 pc以内の中心核で長いtime-scaleで電波増光とγ線増光の傾向が良く一致から遠ざかると減速することが判明[2]
電波増光を確認[2]
・Fermi による検出以降、2回のγ線フレアが発生[3]
High-energy γ -ray propertiesof the FR I radio galaxy NGC 1275
2787
n

ı

ABDO ET AL.

COS-B

γ-ray

EGRETによるupper limit

Fermi

radio
Abdo et al.2009

Figure 5. (Upper) Historical γ -ray activity of 3C 84 measured above 100 MeV.
COS-B flux in this energy range was estimated by assuming a differential spectral
index of Γ = 2.0. (Lower) A long-term radio light curve of 3C 84 taken with
the UMRAO at 14.5 GHz between 1974 February and 2008 December. Data
are binned with daily averages. The radio light curve is in a rising state during
the Fermi observations.

Vol. 699

EGRET was observing. This trend appears similar to the opticalactivities of this source (Nesterov et al. 1995; Pronik et al. 1999).
Furthermore, the UMRAO light curve shows a flare (or a risingstate) starting in 2005, which could be interpreted as an ejectionof new jet components.
In fact, the Monitoring Of Jets in Active galactic nuclei with
VLBA Experiments (MOJAVE; Lister et al. 2009) 15 GHz
VLBA observations of 3C 84, taken simultaneously with Fermi
on 2008 August 25, show a significant brightening of the central sub-parsec-scale structure, indicating that a flare is happening in the innermost jet region (Figure 6). This brightening might be connected to the γ -ray activity detected. The
1–22 GHz instantaneous radio spectrum of 3C 84 was also
observed with the 600 meter ring radio telescope RATAN-600
of the Special Astrophysical Observatory, Russian Academyof Sciences, located in Zelenchukskaya, Russia, on 2008
September 11 and 12. The continuum spectrum was measured
on both days quasi-simultaneously (within several minutes) ina transit
sixlight
different
following
centralFigure mode
2. Theat2-yr
curve bandsof 800with
MeV theto 200GeV γ -rayflux fromfrequencies
frequency
bandwidths):
0.95byGHz(0.03 GHz),NGC 1275 (andbinnedin week intervals,
as detected
Fermi-LATwith a ROI
2.3ofGHz1◦ . (0.25 GHz), 4.8 GHz (0.6 GHz), 7.7 GHz (1.0 GHz),
11.2 GHz (1.4 GHz), and 21.7 GHz (2.5 GHz). Details on themethodof observation,data
and×amplitude
calibraa maximum
weekly flux
ofprocessing,(9.03 ± 1.22)
10−8 photon
cm −2 s−1 ,tion are described in Kovalev et al. (1999). An average spectrum
increasing by a factor of 2.3 from the previous week.
is used for the spectral energy distribution (SED).

No. 2]

1pc

1pc

1pc

Fig. 3. Plot of the separation between component C3 and component C1. The error bar is smaller than the size of each symbol. The
blue solid line represents a linear fit to the data from 2007/297
to
!p "n
The
brokenline
represents
thatof 86.2
fromFig. 1. (a) 2009/114.
JVN image of 3C
84 atgreen
8 GHz. The
contours
are plottedat the levelmJy2007/142!
2 (n to= "1, 0, 1, 2, 4, : : :, 128). The lowest contour
corresponds2007/297,
to three-timesassuming
image noise thatr.m.s..component
The beam size C3
is 3.85! 2.14mas at froma positionof "47ı , which is shown in the lower left corner ofwasejectedtheangle
position
the image. of(b)–(o)VERA images
84 at 22 GHz.
Allsubsection
images are shiftedcomponent
C1 ofon3C2007/142(see4.2).in reference to the northern component (component C1). The contours
are plotted at levels of 4.18, 8.36, 16.72, 33.44, and 66.88% of the peak intensity (4.989 Jy beam) on 2009 April 24. The restoring beam (1.1 ! 0.7 mas,position angle of "60ı ) was set to make images uniform.

any residual instrumental background.
4 The test statistic (TS) is defined as twice the difference between the log
likelihood of two different models (2[log L − log L0 ], where L and L0 are
defined as the likelihood when the source is included or not, respectively)(Mattox et al. 1996).

C2

C1

C3

100 MeV to 102.4 GeV spectrum was also fitted with an exponential cut-off power law [dN /dE ∝ E −# × exp(−E/Ecut-off )], withthe best fit shown in Fig. 3. However, it should be noted that theχ 2 and the resultant fit probability is similar for both the powerlaw and exponential cut-off power-law fit. As such, it is not possible to differentiate
betweentheforthe averaged
2-yr
0
1
2
3 two models
456Jy / beam
spectrum.
2
0-2
2

light curve of component C1. Open squares: The light curve of component C2. Filled squares: The light curve of component C3.

2

1pc

Relative R.A. (mas)
4 DISCUSSION

each component quantitatively from the interferometric datathat independently.
reduced-! to be unity. Finally,
positional
error ofin each epoch
Wethethus
employeda methodeach data point was estimated to be 0.013 mas. This error is
C3 as a function of time. The positiondescribedof components C1
two-times
larger(2001).
than that estimatedthe signal- set the uncerin typicallyHoman
et al.
Wefrominitially
and C3 was derived from a two-dimensional Gaussian fit in to-noise ratio (SNR), such that "=SNR, where "
for
data
equal
to unity,
andspeedthenthe interferometric (u; v)-plane using thetainty“modelfit”
taskeachin is thebeampointsize. Thisfit results
in an apparentof we performed
Difmap. It is difficult to measure the positional error of 0.20˙0.01 mas yr (projected speed of 0.23˙0.01c) towards
linear fitdatato thethedataassuming
motionconstant speed toeach component quantitatively from the ainterferometricsouth.
This isapproximately consistent
withwiththe jet speedsin each epoch independently. We thus employed a method in the # -ray quiet2phase (Dhawan et al. 1998). The direction
obtain a preliminary ! . Taking this preliminary !2 , we thendescribed in Homan et al. (2001). We initially set the uncer- of movement of the new component differs from the aligntainty for each data point equal to unity, andthen we performedrescaled
ment of the components
C1 and C2 by # 40
the projected
uniformly
the uncertainty
ofoneachdata point, sucha linear fit to the data assuming motion with constant speed to plane. We note that we did not include the data on 2007/258 to

1pc
0

-2

Relative R.A. (mas)

beam

ı

obtain a preliminary !2 . Taking this preliminary !2 , we thenuniformly rescaled the uncertainty of each data point, such

4.1 Flux variability

To investigate the major flare further, we rebinned the 800 MeV <E < 200 GeV flux for 2010 June–August with daily resolution, theresults of which can be seen in Fig. 4. The most rapid flux variationis seen at 55373 < MJD < 55376, where the flux increased by afactor of ∼8 over a 3-d period.
To characterize the time-scales of this flare event, we evaluate thetime for an exponential flux increase or decrease, referred to as thee-folding time, which is defined by
F (t) = F (to )exp[τ −1 (t − to )],(3)

where τ is the characteristic e-folding time-scale and F(t) and F(to )are the fluxes at time t and to , respectively. The variability observed
during 55372 < MJD < 55380 equates to an e-folding rise time,&C 2011 The Authors, MNRAS 413, 2785–2790

C 2011 RASMonthly Notices of the Royal Astronomical Society &1.55

βapp � 0.17

1.5

1.45

1.4

1.35
2010.6

2010.82011

Time (year)

Reference

2011.2

2011.4beam"1◀ C1 と C3 の中心位置間の相対距離の時間変化
・線形膨張を仮定して速度を概算
見かけの速度は約 0.17c
2007/297以後(0.23c [2])よりもさらに減速している。

1.6

Fig. 3. Plot of the separation between component C3 and compo- (C3)の中心核 (C1) に対する、増光に伴って出現した成分
nent C1. The error bar is smaller than the size of each symbol. The
距離の時間変化[2]line represents a linear fit to the data from 2007/297 toblue solid

2. Pluses:
Effelesberg
that reduced-!2 to be unity.Fig.
Finally,
the positional
errorlightof curve of 3C 84 at 22 GHz. Crosses:
total
fluxThisof VERAobservation at 22.2 GHz. Asterisks: The
each data point was estimatedto CLEANed
be 0.013 mas.
error isC3 as a function of time. The position of components C1 typically two-times larger thanthatcurve
estimatedfrom the C1.
signallightof component
Open squares: The light curve of compoFigure 3. The 2-yr-averaged LAT spectrum, E > 100 MeV, of NGC 1275.
anddefined
C3 wasderivedto-noise ratio (SNR), such nentthat C2.
"beam
=SNR,
whereThe"beam
Filledsquares:light curve of component C3.
The solid line represents the power-law function
in equation(1),from a two-dimensional Gaussian fit inthecut-off
interferometric(u; v)-plane using the “modelfit” task in is the beam size. This fit results in an apparent speed ofwith the dashed line representing the exponential
power-law fit. With2
similar χ fits, it is not possible to differentiateDifmap.
between the twomodels.
It isdifficult to measure the positional error of 0.20˙0.01 mas yr"1 (projected speed of 0.23˙0.01c) towards
モデルフィットマップ
2011/138
each component quantitatively from the interferometric data the south. This is approximately consistent with the jet speeds0.04) from four months of observations and= (2.13± 0.02)fromin#eachepoch
independently.
We thus employed a method in the # -ray quiet phase (Dhawan et al. 1998). The direction
1 yr of observations (Kataoka et al. 2010).described in Homan et al. (2001). We initially set the uncer- of movement of the new
C3
as a functionof thetime.
component
differs fromalign- The position of components C1
Fig.
3.
Plot
of
the
separation
between component C3 and compoı
The best-fitting power-law function, given
byforequation(1), cantaintyeach data
point equal to unity, and then we performed ment of the components andC1 andC2 wasby # 40
projected
nentonC1.the
The error
bar is smaller
than the size of each symbol. The Gaussian fit inC3
derivedfromatwo-dimensionalbe seen in Fig. 3, where the data pointsa in
Fig. fit
3 wasobtainedblue onsolid 2007/258
line represents atolinear fit to the data from 2007/297 tolinearto thedata assuming motion with constant speed to plane. We note that we did not include the data
2009/114. (u;The greenbroken line represents
that from2007/142
toby applying GTLIKE separately to 10 logarithmic energy bands in 2
theC3 interferometricv)-planeusingthe“modelfit”
task inobtain a preliminary ! . Taking this preliminary !2 , we thenFig. 2.thisfitEffelesberg
becausecomponent
mighthave moved
2007/297,fasterassumingbefore
that component C3 was ejected from the position
Pluses:
light
curve
of
3C
84
at
22
GHz.
Crosses:the range 100 MeV to 102.4 GeV. In an attempt to account for theof component
C1 on 2007/142
subsection 4.2). the positional error offlux of (seeVERA observation
22.2Difmap.
GHz. Asterisks: The It isdifficultto (seemeasureuniformly rescaled the uncertainty of each data point, suchtotal CLEANed
2007/297
sectionat4).
small deviation between the model and data above E = 20 GeV, the▲ 全 4エポックのイメージとモデルフィットマップ
・C1 は中心核成分で、C3 は2005年の電波フレアに起因して放出されたジェット成分
・C1 – C3 間の距離は約1.5 (mas) で、見かけの速度は約0.17c (下図参照)
・C2 は2005年のフレアが起こる前から存在。ほぼ動かず定在。

Relative distance from C1 to C3 (mas)Relative Decl. (mas)

結果

L13

電波光度変動 (左) と、増光に伴って出現した成分 (C3) の様子 (右) [2]

Fig. 2. Pluses: Effelesberg light curve of 3C 84 at 22 GHz. Crosses:
total CLEANed flux of VERA observation at 22.2 GHz. Asterisks: The
light curve of component C1. Open squares: The light curve of component C2. Filled squares: The light curve of component C3.

γ線と電波の長期変動の様子 (左:[1]) とFermi による検出以降の光度曲線 (右:[3])of NGC 1275 may decrease gradually over four months, andthere are some hints of spectral evolution as well. However, thehypothesis of constancy cannot be rejected, with χ 2 = 12.2
4. DISCUSSION AND INTERPRETATION
and 12.4 for 16 degrees of freedom, for flux and photon index
3.3 Spectrum
In the previous sections, we have reported the detection ofvariations, respectively.68 We checked that the contaminantTo
NGCfrom1275’saverage-ray spectrum
the 2 yr ofγ -raystudy
emission
NGC
1275 γduring
the initialduring
sky survey
src_A does not vary. We independently checked the light curvewithFermi, andhistoricaland contemporaneousradio
GTLIKE
was applied
to the 100 MeV< Eobserva< 200 GeV
observation
using gtexposure, taking a small ROI radius of r = 2◦ to
tions
with
UMRAO,RATAN,andMOJAVE.
Although2010/332
2011/034
2011/111
continuum, assuming a power-law source model withexcess
additional
reduce the contamination from diffuse background and nearbyγ-rayemissionaround the position
this galaxycomponents.
had been preGalacticand extragalactic
diffuse of
background
Takingsources. We assumed the spectral photon index of Γ = 2.2, and◦ with COS B, the association of the latter withviouslyfoundbackgroundwassubtracted
fromnearbyregion
of
the
same
ROI
a ROI of 8 , we utilized the most recent Galactic (gll_iem_v02.fit)
2
NGC
was ambiguous,
due to the relatively poor
angular3
radius. The results were consistent with what has been obtainedwith theand 1275
extragalactic
diffuse (isotropic_iem_v02.txt)
models,resolution
andlowphotonstatistics(Strong&
Bignami1983;
with gtlike. Further long-term monitoring of this source isnormalization of these models free to vary.
see Section 1). The Fermi observations, with much improved
important. Since the source is apparently variable on longer
We obtain
the following
best-fitting
function for
sensitivity
and angularresolution,
allow uspower-law
to more precisely
timescale, year-scale variability is naturally expected as we will
NGC 1275:
determine
the localization of the γ -ray source and its possible
0discuss below.
! intriguing"−2.09±0.02
association
with NGC 1275. Moreis that the source
EdN−9=detected(2.43 ± during0.09) ×CGRO/EGRET
10
was
not
observations
over 10
3. RADIO OBSERVATIONSdE periods (Reimer et al. 2003).
100 MeVviewing
The 2σ EGRET upper−2 −1
limit to the fluxphoton
is Fγ <
10−8−1
ph(>100 MeV) cm−2 s−1 , (1)In the radio, the University of Michigan Radio Astronomy
cm3.72s × MeVwhich is about a factor of seven lower than the flux measured
Observatory (UMRAO) have monitored 3C 84 since 1965. The
equatesand
to morean integrated
flux, ofin magnitude
the 100 MeV
to than
200 GeV-2UMRAO variability program utilizes a 26 meter prime focus
bywhichFermi/LAT,
than an orderlower
range,of Figure 2). This means the source varies on
theenergy
COS B
flux (seeparaboloid equipped with transistor-based radiometers whichtimescales shorter than years to−7
decades, so −2that the emission
operate at the central frequencies 4.8, 8.0, and 14.5 GHz;
photon cm s−1(2)
FE>100
MeV = (2.2 ± 0.1) × 10
regionsize
R ! ctvar ≈ 0.3 pc.
the bandwidths are 560, 760, and 1600 MHz, respectively. A
Withthis simple
estimate,
provideusefultypical observationconsists
measurements
2
0 of 8–16 individual-2
20taking-2 errorswe
2 From0 law, the -2
onlystatistical
intocanaccount.
thisconstraints
power
onpredicted
whether theγ-rayemissionoriginates
fromaclusteror AGN.
4
obtained over a 20–40 minute time interval. The flux scaleofR.A.
TS (mas)
=
γ
-ray
count
was
6844.1,withatest
statistic
Relative
R.A.
(mas)
Relative
R.A.
(mas)
Relative
Although
the
LAT
error
circle
is
still
large
enoughtoincludeis set by observations of Cassiopeia A (e.g., see Baars et al.
9459.9, corresponding to a ∼97σ detection. The Galactic diffuse
both nonthermal AGN and nonthermal cluster emission, a large1977). Further details of the UMRAO calibration and data
backgroundfound
to havea normalizationof 1.07± 0.01
fractionof the was
γ -rayemissionmeasuredwith the Fermi
LAT
analysis procedures are given in Aller et al. (1985). Figure 5
andapredicted
countof
94496,
while
theextragalactic
diffusemust originate from within a few light years of an active region,shows a long-term light curve of 3C 84 measured at 14.5 GHz,
backgroundfound
to havea normalizationof 0.77 ±0.02 andmostlikely thewas
cluster
center,on thebasis of the EGRET
upper
taken by the UMRAO from 1974 February to 2008 December.
◦ backgroundapredicted
count
of
22
118.5.
The
predicted
diffuselimit. Since the Perseus cluster is extended over "0. 5 (or βInterestingly, the radio flux density reached a maximum between◦
countscalculated
from 1),the corresponding
2-yr data set areconsistentofwith
radius∼ 0.
3; see Section
to hundreds
kpc,these
1980 and 1985 (the COS B era), and then substantially faded
if previous
the emission
were
extendedon this index
size scale,it 1275
wouldcalculated
notout after 1990 (O’Dea et al. 1984; Teräsranta et al. 2004) whenworks.
However,the photonof NGChave
beenvariable
and
could
have
been
detected
asanextended
over the 2-yr data set # = (2.09 ± 0.02) appears to be slightly hardersourcewith previously
the LAT above
1 GeV,
where
the(2009a),
PSF becomes
68 NGC 1275 is flagged as a variable source in the Fermi LAT bright γ -raythan thosepublishedin Abdoet al.
# = (2.17 ±smaller than ≈0.◦ 5. As seen in Figure 2, however, the observed
source list (Table 6 of Abdo et al. 2009). This is because they have fixed thespectral index of each source to the best-fit value over the full interval to avoid
count distribution is consistent with a point source.
large error bars in the flux estimates, while both flux and photon index are free
limits the γ -ray flux from the cluster formed by3This
to vary in the fit of this paper. Further long-term monitoring is thus important
It should be noted that the isotropic_iem_v02.txt model file also models(1)p–pinteractionsof high-energy cosmic rays or by (2) particle
to confirm the variability of this source.

VLBI Monitoring of 3C 84 in Early Phase of the 2005 Outburst

Flux Density

36

LETTER!p "nFig. 1. (a) JVN image of 3C 84 at 8 GHz. The contours are plotted at the level of 86.2 mJy !
2 (n = "1, 0, 1, 2, 4, : : :, 128). The lowest contour
corresponds to three-times image noise r.m.s.. The beam size is 3.85 ! 2.14 mas at a position angle of "47ı , which is shown in the lower leftıcorner ofthe image. (b)–(o) VERA images of 3C 84 at 22 GHz. All images are shifted in reference to the northern component (component C1). The contours
are plotted at levels of 4.18, 8.36, 16.72, 33.44, and 66.88% of the peak intensity (4.989 Jy beam) on 2009 April 24. The restoring beam (1.1 ! 0.7 mas,position angle of "60ı ) was set to make images uniform.

2009/114. The green broken line represents that from 2007/142 to
2007/297, assuming that component C3 was ejected from the positionof component C1 on 2007/142 (see subsection 4.2).

that reduced-!2 to be unity. Finally, the positional error ofeach data point was estimated to be 0.013 mas. This error istypically two-times larger than that estimated from the signalto-noise ratio (SNR), such that "beam =SNR, where "beamis the beam size. This fit results in an apparent speed of
0.20˙0.01 mas yr"1 (projected speed of 0.23˙0.01c) towards
the south. This is approximately consistent with the jet speedsin the # -ray quiet phase (Dhawan et al. 1998). The directionof movement of the new component differs from the alignment of the components C1 and C2 by # 40ı on the projected
plane. We note that we did not include the data on 2007/258 tothis fit because component C3 might have moved faster before
2007/297 (see section 4).

this fit because component C3 might have moved faster before
2007/297 (see section 4).

▲ 成分毎の光度曲線とサブミリ波データとの比較
・C1 は変動なし、C2・C3 でわずかに変動している。
・GENJI 開始後、目立ったγ線変動が報告されていないので、より高エネルギー領域をトレースできるサブミリ波データ(SMA@1mm [4])との比較を行った。
サブミリ波の振る舞いは C2・C3 と似ている？

まとめ：・サブミリ波データとの比較により、サブミリ波のわずかな時間変動に対応して、ジェット成分(C2,C3)の変動が見られた。
一方、VLBIコア(C1)は変動が見られなかった。
・C3のC1に対する見かけの速度が文献[2]のデータよりもさらに減速していることがわかった。
・高エネルギー放射領域への、より厳しい制限を課すためにも、さらなるデータの蓄積および解析を行っていきたい。

[1] Abdo et al, 2009, ApJ, 699, 31[2] Nagai et al, 2010,PASJ, 62, L11[3] Brown & Adams, 2011, MNRAS, 413, 2785

[4] SMA Calibrator List