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 3C 66A

• 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)

• = 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

Zhao et al. 2015

1 3C 66A

• 6-arcmin separated from (radio 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

3C 66A • 3C 66A is used as reference source of 3C 66B in multi-epoch relative astrometry observations (Sudou et al. 2003)

Sudou et al. 2003 1-yr core wandering 3C 66B 5 1 in 3C 66B 2 6 4 3 Binary SMBH in 3C 66B Red : radio / Blue : optical Image credit : NRAO/AUE 1999

2 3C 66B : binary SMBH ?

Non-detection (Jenet et al. 2004) • Gravitational wave not detected -> another reason for the 1-yr motion

✓ Annual parallax

Image Credit : R. Hurt/Caltech-JPL ✓ Episodic core-wandering (e.g. Mrk 421, Niinuma et al. 2015)

✓ Non-stationarity of reference point

3 3C 66B : binary SMBH ?

Non-detection (Jenet et al. 2004) • Gravitational wave not detected -> another reason for the 1-yr motion

✓ Annual parallax

Image Credit : R. Hurt/Caltech-JPL ✓ Episodic core-wandering (e.g. Mrk 421, Niinuma et al. 2015) 22 GHz Zhao et al. 2015 ✓ Non-stationarity of reference point

- 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.

3 Observation & Data reduction

KaVA • Prior calibration in AIPS package

• Hybrid mapping (Clean + selfcal) in difmap package

• Circular Gaussian components modeling in difmap package

2014 | 3 epochs | K,Q bands

4 KaVA image of 3C 66A

• 22 GHz KaVA image (2014-09-30)

• The Gaussian components distributed wiggly. [mas]

dec

• Inner jet PA: ~190 deg | Outer jet PA: ~160 deg Relative Relative

Hint for something happening when jet ejected.

Relative RA [mas]

5 Archive data

VLBA Analysis

• Position angle of inner jet - using distribution of clean components

• Flux variability Boston University monitoring program - comparing the peak flux density of the 2008-2017 | 56 epochs | Q band image convolved with the same beam

6 Analysis ➢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 Preliminary Results 1. P.A. of inner jet

3C 66A • from BU archive data

(2008/10/22 – 2017/11/06) Inner jet PA [deg] PA jet Inner

YEAR

8 Preliminary Results 1. P.A. of inner jet

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 Inner jet PA [deg] PA jet Inner Amp: 11.90 ± 0.80 deg Results Offset: 189.49 ± 0.76 deg Phase: 3.19 ± 1.42 YEAR

8 Preliminary Results 1. P.A. of inner jet

Note that the red curve is fitted by only BU data (red points). 3C 66A

Previous study list Inner jet PA [deg] PA jet Inner

YEAR

Extrapolation line is well matched with P.A. of innermost jet component of previous studies. “Periodicity is real and have been existed.”

9 Results 2. Preliminary

Peak flux density [Jy/beam] Variability of peakfluxdensity 3C 66A YEAR • • • become higher in recenthigher become densityflux of peak The 3C 66A Bright Faint Bright Strongvariability with time : early 2012 : early : early 2017 : early : late2009 – – – late 2016 late 2011 10 Discussion & next plan

3C 66A

(EVPA value is came from BU-blazar program homepage)

• Decrease of EVPA and inner jet PA in 2014. EVPA • From Zhao et al. (2015), the innermost component would be approach to the core at 2014.

• For detailed interpretation, kinematic analysis is

Inner jet PA jet Inner needed.

YEAR

11 Discussion& next plan

Peak flux density Inner jet PA 3C 66A YEAR Low flux density High flux density decreasing phase in inner jet PA increasing phase in inner jetPA – – 12 Discussion& next plan

Peak flux density Inner jet PA 3C 66A YEAR

- - explainedSimply by geometrical effect Peak flux density Helical Helical jet Precession Inner Inner jet PA (e.g. (e.g. BL Lac, Mrk 3C 120, 3C 501, Caproni Villata Caproni et et al. 1999) et et al. 2004) et et al. 2013; 12 New astrometry + imaging observations

• 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.

For precise SFPR astrometry For high-quality imaging

EAVN

KVN

Yebes

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 Summary

• 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 Thank YOU for listening