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

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) • 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 Zhao et al. 2015 1

3C 66A • 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 • 3C 66A is used as reference source of 3C 66B 3C 66A in multi-epoch relative astrometry observations (Sudou et al. 2003) Sudou et al. 2003 1-yr core wandering 3C 66B 5 in 3C 66B 1 6 2 4 Binary SMBH in 3C 66B 3 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) • Relative dec [mas] The Gaussian components distributed wiggly. • Inner jet PA: ~190 deg | Outer jet PA: ~160 deg 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 Blazar monitoring program - comparing the peak flux density of the image convolved with the same beam 2008-2017 | 56 epochs | Q band 6

Analysis ➢ Position angle of inner jet Arbitrary circular bin: 0.15 – 0.4 mas 1. 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] YEAR 8

Preliminary Results 1. P.A. of inner jet 3C 66A • from BU archive data (2008/10/22 – 2017/11/06) Inner jet PA [deg] • Least square fit (Model = Amp*sin(w*t+phase)+offset) Period: 11.48 ± 0.85 yr 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] YEAR Extrapolation line is well matched with P.A. of innermost jet component of previous studies. “Periodicity is real and have been existed.” 9

Preliminary Results 2. Variability of peak flux density 3C 66A • Strong variability with time Peak flux density • Bright : late 2009 – late 2011 Faint : early 2012 – late 2016 [Jy/beam] Bright : early 2017 – • The peak flux density of 3C 66A become higher in recent YEAR 10

Discussion & next plan 3C 66A (EVPA value is came from BU-blazar program homepage) EVPA • 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. Inner jet PA • For detailed interpretation, kinematic analysis is needed. YEAR 11

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

Discussion & next plan 3C 66A Peak flux density Inner jet PA Peak flux density Inner jet PA 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) YEAR 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 • Include big antenna -> higher sensitivity • K/Q simultaneous observation -> efficient phase-transfer 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

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