ERRATIC JET WOBBLING IN THE BL LACERTAE OBJECT OJ287 REVEALED BY SIXTEEN YEARS OF 7 mm VLBA OBSERVATIONS

We present the results from an ultra-high-resolution 7 mm Very Long Baseline Array study of the relativistic jet in the BL Lacertae object OJ287 from 1995 to 2011 containing 136 total intensity images. Analysis of the image sequence reveals a sharp jet-position-angle swing by >100° during [2004,2006], as viewed in the plane of the sky, which we interpret as the crossing of the jet from one side of the line of sight to the other during a softer- and longer-term swing of the inner jet. Modulating such long-term swing, our images also show for the first time a prominent erratic wobbling behavior of the innermost ∼0.4 mas of the jet with fluctuations in position angle of up to ∼40° over timescales ∼2 yr. This is accompanied by highly superluminal motions along non-radial trajectories, which reflect the remarkable non-ballistic nature of the jet plasma on these scales. The erratic nature and short timescales of the observed behavior rule out scenarios such as binary black hole systems, accretion disk precession, and interaction with the ambient medium as possible origins of the phenomenon on the scales probed by our observations, although such processes may cause longer-term modulation of the jet direction. We propose that variable asymmetric injection of the jet flow, perhaps related to turbulence in the accretion disk, coupled with hydrodynamic instabilities leads to the non-ballistic dynamics that causes the observed non-periodic changes in the direction of the inner jet.

[1]  Paul S. Smith,et al.  ON THE LOCATION OF THE γ-RAY OUTBURST EMISSION IN THE BL LACERTAE OBJECT AO 0235+164 THROUGH OBSERVATIONS ACROSS THE ELECTROMAGNETIC SPECTRUM , 2011, 1105.0549.

[2]  P. Hardee,et al.  USING TWISTED FILAMENTS TO MODEL THE INNER JET IN M 87 , 2011, 1104.4480.

[3]  Richard E. Rothschild,et al.  CONNECTION BETWEEN THE ACCRETION DISK AND JET IN THE RADIO GALAXY 3C 111 , 2011, 1104.0663.

[4]  O. Titov,et al.  ON THE CONNECTION OF THE APPARENT PROPER MOTION AND THE VLBI STRUCTURE OF COMPACT RADIO SOURCES , 2011, 1103.3963.

[5]  A. Marscher,et al.  ON THE SOURCE OF FARADAY ROTATION IN THE JET OF THE RADIO GALAXY 3C 120 , 2011, 1102.1943.

[6]  A. Marscher,et al.  THE MEGAPARSEC-SCALE X-RAY JET OF THE BL Lac OBJECT OJ287 , 2010, 1008.5178.

[7]  Paul S. Smith,et al.  LOCATION OF γ-RAY FLARE EMISSION IN THE JET OF THE BL LACERTAE OBJECT OJ287 MORE THAN 14 pc FROM THE CENTRAL ENGINE , 2010, 1011.6454.

[8]  J. Cela,et al.  Stability of three-dimensional relativistic jets: implications for jet collimation , 2010, 1005.4332.

[9]  Paul S. Smith,et al.  FLARING BEHAVIOR OF THE QUASAR 3C 454.3 ACROSS THE ELECTROMAGNETIC SPECTRUM , 2010, 1003.4293.

[10]  Paul S. Smith,et al.  PROBING THE INNER JET OF THE QUASAR PKS 1510−089 WITH MULTI-WAVEBAND MONITORING DURING STRONG GAMMA-RAY ACTIVITY , 2010, 1001.2574.

[11]  J. Prieto,et al.  Variability and stability in blazar jets on time-scales of years: optical polarization monitoring of OJ 287 in 2005–2009 , 2009, 0912.0005.

[12]  E. Fomalont,et al.  Approaching Micro-Arcsecond Resolution with VSOP-2: Astrophysics and Technologies , 2009 .

[13]  Paul S. Smith,et al.  SYNCHRONOUS OPTICAL AND RADIO POLARIZATION VARIABILITY IN THE BLAZAR OJ287 , 2009, 0903.3934.

[14]  R. Blandford,et al.  Stability of relativistic jets from rotating, accreting black holes via fully three-dimensional magnetohydrodynamic simulations , 2008, 0812.1060.

[15]  P. Giommi,et al.  Results of WEBT, VLBA and RXTE monitoring of 3C 279 during 2006-2007 ⋆ , 2008, 0810.4261.

[16]  B. Gong.  The non‐ballistic superluminal motion in the plane of the sky , 2008, 0806.2708.

[17]  A. Marscher,et al.  Faraday Rotation and Polarization Gradients in the Jet of 3C 120: Interaction with the External Medium and a Helical Magnetic Field? , 2008, 0805.4797.

[18]  M. Kidger,et al.  A massive binary black-hole system in OJ 287 and a test of general relativity , 2008, Nature.

[19]  E. Ros,et al.  The Trails of Superluminal Jet Components in 3C 111 , 2008, 0801.0617.

[20]  M. Bremer,et al.  Superluminal non-ballistic jet swing in the quasar NRAO 150 revealed by mm-VLBI , 2007, 0710.5435.

[21]  J. Martí,et al.  Resonant Kelvin-Helmholtz modes in sheared relativistic flows. , 2007, Physical review. E, Statistical, nonlinear, and soft matter physics.

[22]  Heidelberg,et al.  Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71 II. A search for intra-day variability at millimetre wavelengths with the IRAM 30 m telescope , 2006, astro-ph/0606049.

[23]  Bonn,et al.  Structure and flux variability in the VLBI jet of BL Lacertae during the WEBT campaigns (1995-2004) , 2006, astro-ph/0606050.

[24]  Bonn,et al.  The milliarcsecond-scale jet of PKS 0735+178 during quiescence , 2006, astro-ph/0604543.

[25]  D. Jones,et al.  The Fastest Relativistic Jets: VLBA Observations of Blazars with Apparent Speeds Exceeding 25c , 2005, astro-ph/0511664.

[26]  M. Perucho,et al.  Nonlinear stability of relativistic sheared planar jets , 2005, astro-ph/0510426.

[27]  Helsinki University of Technology,et al.  Multifrequency VLBA monitoring of 3C 273 during the INTEGRAL Campaign in 2003 - I. Kinematics of the parsec scale jet from 43 GHz data , 2005, astro-ph/0509623.

[28]  M. Cohen,et al.  MOJAVE: MONITORING OF JETS IN ACTIVE GALACTIC NUCLEI WITH VLBA EXPERIMENTS. XI. SPECTRAL DISTRIBUTIONS , 2014, 1404.0014.

[29]  Paul S. Smith,et al.  Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Jet Kinematics from Bimonthly Monitoring with the Very Long Baseline Array , 2005, astro-ph/0502501.

[30]  G. Denn,et al.  IS THE RADIO CORE OF BL LACERTAE PRECESSING , 2004, astro-ph/0412496.

[31]  A. Lobanov,et al.  A supermassive binary black hole in the quasar 3C 345 , 2004, astro-ph/0411417.

[32]  R. Walker,et al.  Modeling the 3C 120 Radio Jet from 1 to 30 Milliarcseconds , 2004, astro-ph/0410720.

[33]  A. Caproni,et al.  Observational Evidence of Spin-induced Precession in Active Galactic Nuclei , 2004, astro-ph/0410450.

[34]  J. Martí,et al.  Stability of hydrodynamical relativistic planar jets - II. Long-term nonlinear evolution , 2004, astro-ph/0407574.

[35]  J. Martí,et al.  Stability of hydrodynamical relativistic planar jets. I. Linear evolution and saturation of Kelvin-Helmholtz modes , 2004, astro-ph/0407548.

[36]  K. Kingham,et al.  Structure of OJ 287 from Geodetic VLBA Data , 2004 .

[37]  Heidelberg,et al.  Kinematic Study of the Blazar S5 0716+714 , 2003, astro-ph/0412406.

[38]  Paul S. Smith,et al.  Discovery of a precessing jet nozzle in BL Lacertae , 2003 .

[39]  M. Cohen,et al.  Jet Collimation in Action: Realignment on Kiloparsec Scales in 3C 279 , 2003, astro-ph/0304132.

[40]  M. Aloy,et al.  Three-dimensional Simulations of Relativistic Precessing Jets Probing the Structure of Superluminal Sources , 2003, astro-ph/0302123.

[41]  M. Cohen,et al.  4C +12.50: A Superluminal Precessing Jet in the Recent Merger System IRAS 13451+1232 , 2002, astro-ph/0210372.

[42]  F. Tavecchio.  Jets at all scales , 2002, astro-ph/0212254.

[43]  A. Marscher,et al.  Monthly 43 GHz VLBA Polarimetric Monitoring of 3C 120 over 16 Epochs: Evidence for Trailing Shocks in a Relativistic Jet , 2001, astro-ph/0110133.

[44]  A. V. Yurchenko,et al.  Multiepoch Very Long Baseline Array Observations of EGRET-detected Quasars and BL Lacertae Objects: Superluminal Motion of Gamma-Ray Bright Blazars , 2001, astro-ph/0101570.

[45]  M. Aloy,et al.  Jet Stability and the Generation of Superluminal and Stationary Components , 2001, astro-ph/0101188.

[46]  Jorstad,et al.  Flashing superluminal components in the jet of the radio galaxy 3C120 , 2000, Science.

[47]  Jianjun Xu,et al.  The Stability of Radiatively Cooled Jets in Three Dimensions , 2000, astro-ph/0007446.

[48]  V. Dhawan,et al.  Kinematics of the Nucleus of NGC 1275 (3C 84) , 1998 .

[49]  M. Rees,et al.  Massive black hole binaries in active galactic nuclei , 1980, Nature.

[50]  R. Mushotzky,et al.  Search for X-ray emission from bursting radio sources , 1979 .

[51]  R. Blandford,et al.  Electromagnetic extraction of energy from Kerr black holes , 1977 .

[52]  J. Bardeen,et al.  The Lense-Thirring Effect and Accretion Disks around Kerr Black Holes , 1975 .