Wiggly Jet Distribution and Jet Wobbling with Strong Flux - - PowerPoint PPT Presentation

Wiggly Jet Distribution and Jet Wobbling with Strong Flux Variability in 3C 66A

Jeonguk Kim (Yonsei Univ. / KASI)

Guang-Yao Zhao, Bong Won Sohn, Zhi-Qiang Shen, Yong-Jun Chen, Hiroshi Sudou, Pablo de Vincente, Taehyun Jung, Maria Rioja, Richard Dodson, and Suk-Jin Yoon

EAVN Workshop 2018, PyeongChang, September 4-7

• Intermediate-frequency-peaked BL Lac object (IBL)

(Schlegel et al. 1998; Perri et al. 2003; Abdo et al. 2010)

• TeV object (Acciari et al. 2009; Aliu et al. 2009)
• Redshift = 0.34 (Torres-Zafra et al. 2018; Uncertain)
• Variable at various bands (e.g. Bottcher et al. 2005)
• One-sided jet with P.A. of ~180 deg

3C 66A

1

Zhao et al. 2015

• 6-arcmin separated from 3C 66B (radio galaxy at z=0.0215; Matthews et al. 1964)
• > Ideal source pair for relative astrometry (Sudou et al. 2003)
• Note that both sources are not physically related

2 Red : radio / Blue : optical

Image credit : NRAO/AUE 1999

3C 66B 3C 66A

• 3C 66A is used as reference source of 3C 66B

in multi-epoch relative astrometry observations

(Sudou et al. 2003)

1 2 3 4 5 6

Sudou et al. 2003

1-yr core wandering in 3C 66B Binary SMBH in 3C 66B

3C 66A

(Jenet et al. 2004)

• Gravitational wave not detected
• > another reason for the 1-yr motion

Non-detection

Image Credit : R. Hurt/Caltech-JPL

3

✓ Annual parallax ✓ Episodic core-wandering

(e.g. Mrk 421, Niinuma et al. 2015)

✓ Non-stationarity of reference point

3C 66B : binary SMBH ?

(Jenet et al. 2004)

• Gravitational wave not detected
• > another reason for the 1-yr motion

Non-detection

Image Credit : R. Hurt/Caltech-JPL

3

✓ Annual parallax ✓ Episodic core-wandering

(e.g. Mrk 421, Niinuma et al. 2015)

✓ Non-stationarity of reference point

3C 66B : binary SMBH ?

• The innermost jet component of 3C 66A moved inward.

(Lister et al. 2013; Zhao et al. 2015)

• We should take into account the effect from reference

source, 3C 66A.

Zhao et al. 2015

22 GHz

KaVA

2014 | 3 epochs | K,Q bands

4

Data reduction

• Prior calibration in AIPS package
• Hybrid mapping (Clean + selfcal)

in difmap package

• Circular Gaussian components modeling

in difmap package

Observation &

Relative RA [mas] Relative dec [mas]

• 22 GHz KaVA image

(2014-09-30)

• The Gaussian components distributed wiggly.
• Inner jet PA: ~190 deg

| Outer jet PA: ~160 deg

Hint for something happening when jet ejected.

KaVA image of 3C 66A

5

6

VLBA

2008-2017 | 56 epochs | Q band

Boston University Blazar monitoring program

Analysis

• Position angle of inner jet
• using distribution of clean components
• Flux variability
• comparing the peak flux density of the

image convolved with the same beam

Archive data

➢Position angle of inner jet

1. Arbitrary circular bin: 0.15 – 0.4 mas 2. Find the flux-weighted position angle 3. Error = uncertainty of weighted mean value 7

Analysis

Results 1. P.A. of inner jet

• from BU archive data

(2008/10/22 – 2017/11/06)

YEAR Inner jet PA [deg]

8

Preliminary 3C 66A

• from BU archive data

(2008/10/22 – 2017/11/06)

• Least square fit

(Model = Amp*sin(w*t+phase)+offset)

Period: 11.48 ± 0.85 yr Amp: 11.90 ± 0.80 deg Offset: 189.49 ± 0.76 deg Phase: 3.19 ± 1.42

Results

Results 1. P.A. of inner jet

YEAR Inner jet PA [deg]

8

Preliminary 3C 66A

Results 1. P.A. of inner jet

YEAR Inner jet PA [deg]

9

Preliminary

Extrapolation line is well matched with P.A. of innermost jet component of previous studies.

Previous study list

3C 66A

Note that the red curve is fitted by only BU data (red points).

“Periodicity is real and have been existed.”

Peak flux density [Jy/beam] YEAR

• Strong variability with time
• Bright : late 2009 – late 2011

Faint : early 2012 – late 2016 Bright : early 2017 –

• The peak flux density of 3C 66A

become higher in recent

10

Results 2. Variability of peak flux density

Preliminary 3C 66A

YEAR EVPA Inner jet PA (EVPA value is came from BU-blazar program homepage)

• Decrease of EVPA and inner jet PA in 2014.
• From Zhao et al. (2015), the innermost component

would be approach to the core at 2014.

• For detailed interpretation, kinematic analysis is

needed.

11

Discussion & next plan

3C 66A

Peak flux density Inner jet PA

High flux density – increasing phase in inner jet PA Low flux density – decreasing phase in inner jet PA

12

Discussion & next plan

YEAR

3C 66A

Peak flux density Inner jet PA

12

Simply explained by geometrical effect

• Precession (e.g. BL Lac, Caproni et al. 2013;

3C 120, Caproni et al. 2004)

• Helical jet (e.g. Mrk 501, Villata et al. 1999)

Discussion & next plan

YEAR Peak flux density Inner jet PA

3C 66A

• To check whether the observational properties of 3C 66A affect the astrometry

results, and if then, to see how much it will affect, we proposed new observations. KVN Yebes EAVN For precise SFPR astrometry For high-quality imaging

Image Credit: An, Sohn, & Imai 2018, Nature Astronomy, 2, 118

• Long baseline -> higher resolution
• K/Q simultaneous observation -> efficient phase-transfer
• Include big antenna -> higher sensitivity

13

New astrometry + imaging observations

• In relative astrometry, the reference source should be stationary.
• There are some evidences that 3C 66A which is reference source of 3C 66B is not

stationary. (e.g. Lister et al. 2013; Zhao et al. 2015)

• We found wiggle jet and jet wobbling with strong variability in 3C 66A.
• explained by geometrical effect?
• related with non-stationary of the core?
• New astrometric & imaging observations can support the detailed analysis.

14

Summary

Thank YOU

for listening