Malaga, May Matt Lister Department of Physics & Astronomy Purdue University, USA AGN Jet Kinematics on Parsec Scales

Malaga, May 2016 MOJAVE Collaboration M. Lister (P.I.), E. Stanley, M. Hodge (Purdue, USA) T. Arshakian (U. Cologne, Germany) M. and H. Aller (U. Michigan, USA) M. Cohen, J. Richards (Caltech, USA) D. Homan (Denison, USA) M. Kadler, J. Trüstedt (U. Wurzburg, Germany) K. Kellermann (NRAO, USA) Y. Y. Kovalev (ASC Lebedev, Russia) J. A. Zensus (MPIfR, Germany) A. Pushkarev (Crimean Observatory) E. Ros (MPIfR, Germany & U. Valencia, Spain) T. Savolainen, T. Hovatta (Mets ă hovi Obs., Finland) M onitoring O f J ets in A ctive Galaxies with V LBA E xperiments Very Long Baseline Array The MOJAVE Program is supported under NASA Fermi Grant NNX15AU76C

Malaga, May 2016 MOJAVE VLBA Program Milliarcsec-resolution 15 GHz images over 400 AGN jets – continuous time baselines on many jets back to 1994 – full polarization since hr observing session every month – 22 AGN chosen from list of ~100 targets > dec -30°and > 0.1 Jy – cadences tailored to individual jets Results published in series of papers, full list is available at Blazar at 15 GHz Colors: fractional linear polarization

Malaga, May 2016 MOJAVE AGN Samples 1.5 Jy : all 181 AGN above δ = -30  known to have exceeded 1.5 Jy in 15 GHz VLBA flux density ( ; Lister et al. 2015, ApJ 810, L9). 1FM γ -ray : complete 1FGL Fermi-selected sample (116 AGN) above 100 MeV (Lister et al. 2011, ApJ 742,27). Low-luminosity : representative sample of 43 AGN with 15 GHz luminosity < W Hz -1 from the Radio Fundamental Catalog Hard Spectrum : complete sample of 110 hard  -ray spectrum, radio bright AGN from Fermi 2-year catalog

Malaga, May Upcoming MOJAVE VLBA Program Approved at high priority for Sept – 12 sessions per year – 30 AGN per 24 hr long session, 124 AGN in total Goals: – Continue studying long term acceleration & nozzle behavior of 30 jets – Complete the kinematic statistics for MOJAVE radio and γ -ray samples: 43 GHz monitoring of 14 ultra-compact jets to get speeds Increase VLBA time baseline on 5 jets with very slow expansion rates – Support multi-wavelength campaigns with 50 new targets from: Fermi LAT monitored list of flaring AGN RoboPol optical polarization monitoring sample Hard spectrum AGN from 2FHL and 3FGL Fermi catalogs

MOJAVE Kinematics Analysis Gaussian models fit to visibilities at each epoch (at least 5 epochs per AGN). positional rms accuracy: mas Two dimensional sky motion fits made to individual jet features probing jet kinematics at pc (de-projected) from central engine MOJAVE X, XI, XIII studies cover 1295 jet features in 307 AGNs, based on 5837 VLBA epochs from 1994 Sep Aug. most recent paper XIII adds 122 new jets, most are Fermi LAT γ -ray associations: Malaga, May 2016 Lister et al. arXiv

Malaga, May 2016 Speed Dispersion Within the Jet An AGN jet typically contains features with a range of bulk Lorentz factor and/or pattern speed A characteristic median speed exists for each jet Normalized speed distribution within 12 jets each having at least 10 moving features. Lister et al. 2013, AJ 146, 120

Malaga, May 2016 Slow Pattern Speeds Defined as: i. < 20  as/y ii.< 1/10 th of max speed seen in the jet iii.Non-accelerating 6% of all jet features Majority are located close to the base of the jet Present in 15% of quasar and 25% of BL Lac jets

Malaga, May Maximum Jet Speed Distribution (301 AGNs) Peaked at low values – only 6 jets with  app > 30, distribution implies Γ max = 50 – parent population can’t all have the same Lorentz factor (Vermeulen & Cohen 1995) Blazars are not typical jets! – most AGN jets in the parent population have much lower synchrotron power and a Lorentz factor << 10. Lister et al. arXiv

Malaga, May Jet Acceleration Studies (MOJAVE XI, XIII) Proper motion vector direction (  ) Overall jet direction Analyzed 651 features in 295 blazar jets which had at least ten VLBA epochs. Measured accelerations in directions || and  to fitted apparent motion vector on the sky. μμ μ || Non-radial = proper motion vector does not point back to the core feature core

Malaga, May Acceleration of Non-Radial Features Proper motion vector direction (  ) Mean position angle of jet feature over time ( ) Determine main jet axis direction using stacked-epoch image. Most off-axis features have accelerations that are steering them back towards the jet axis. We are seeing jet collimation at scales up to 50 pc jetPA Acceleration MOJAVE XI

Malaga, May AGN Jets Accelerate 82% of well-monitored jets either have at least one accelerating or non- radially-moving feature. Half of all individual jet features show evidence of acceleration. – ejection times can be reliably estimated for only ¼ of all moving features. Parallel accelerations are of larger magnitude and more prevalent than perpendicular accelerations. Similar results seen at 8 GHz in AGN sample of Piner et al ApJ 758, 84 Outward a || Inward a || Average a || No measurable accel. MOJAVE XI Projected Distance From Core [pc]

Malaga, May Evidence for changing Lorentz factors Overall statistics show that observed accelerations cannot be solely due to bending – most features have a high || /  acceleration ratio. Positive parallel accelerations are most common within 10 pc of the core Features tend to speed up near the core, and slow down at ~ 100 pc (deprojected) farther downstream. Changes in Lorentz factor must be the primary cause of the observed accelerations. Outward a || Inward a || Projected Distance From Core [pc] Average a || No measurable accel.

Malaga, May 2016 Half of best monitored MOJAVE jets show show changes in innermost jet position angle, at rate of ~1- 3°per yr NRAO 150 OJ 287 3C ± 1 º/y Changes in Inner Jet Direction

Malaga, May 2016 Sinusoid-like jet position angle variations seen in a few jets Variations are too slow (decade-long) to claim periodicity

16 TeV-detected Quasar at z = pc Max speed = 27 c Viewing angle < 4° Deprojected opening angle < 1.6°

17 18 yr time lapse of Quasar at z = pc Max speed 11 c Viewing angle < 11° Deprojected opening angle at 100 pc is < 2°

18 3C 273 at z = pc Max speed 15 c

Malaga, May Narrow-Line Seyfert I Jets 3 of 5 NLSY1 in MOJAVE have v app > 6 c (MOJAVE XIII) Jets are much weaker than quasars, similar to BL Lacs v/c = 9.0 ± 0.3 1H Have low black hole mass and near-Eddington accretion rate Likely hosted in spirals Rare sub-population (< 7%) are radio loud, and a scarcer few are γ -ray loud 3 rd class of γ -ray AGN Low detection #s may indicate young jets (Foschini et al. 2014)

Malaga, May Investigating Fermi  -ray blazar jets Fermi is an excellent AGN survey instrument: – broadband coverage, sees jet flux only, no contamination from host galaxy Quasars (red points) have low- spectral peaked SEDs IC scattering of broad line region photons quenches high energy electron population in the jet Highest spectral peaked (HSP) jets are of the less powerful BL Lac class (no broad line region) HSP LSP ISP X-ray Radio Fermi LAT Collab, 2012, ApJ 743, 171

Malaga, May 2016 The Role of Doppler Boosting External IC model predicts higher effective flux boosting in gamma-rays than radio, due to blueshifting of external seed photons in jet frame. Fermi LAT is biased against low-spectral peaked, low Doppler factor blazars 21 All of the fastest jets in the 1.5 Jy sample have Fermi-LAT detections. Lister et al. 2015, ApJ L., 810, 1

Malaga, May Jet Speed vs. Synchrotron Peak Frequency More AGN speed data yet to come TeV discovery region

Malaga, May Jet Speed vs. Cosmic Distance TeV discovery region

Malaga, May Jet Speed vs. 15 GHz Luminosity 150 mJy, 3 mas/y Only the most luminous jets attain high bulk Lorentz factors

Malaga, May 2016 Summary The MOJAVE program has revealed important aspects of AGN jets: – the most powerful blazar jets have a wide range of bulk Lorentz factors up to ~50, while typical AGN jets have Lorentz factors of ~a few. – jet features speed up within ~50 pc of the jet base where jet is still collimating, and decelerate further out – VLBI images trace out only the currently energized emission regions, which don’t fill the entire jet cross-section. – Gamma ray surveys are biased against low-spectral peaked, low-Doppler factor AGN jets. Still to come: kinematics of lower-luminosity, hard-spectrum gamma-ray jets, and investigations of long term jet accelerations and nozzle variations.

Malaga, May 2016 Backup slides

Malaga, May 2016 Apparent Inward Motions Statistics: – Rare: only 3% of all moving features – Seen in 2% of quasar and 19% of BL Lac jets Likely causes: – Accelerated motion across the line of sight – Inward pattern speed (e.g., reverse shock) – Misidentification of true core feature Core

Krakow, April The HSP Doppler Beaming Crisis Extreme variability of TeV Ɣ -rays imply very small emission regions Ɣ -rays suffer huge pair losses unless HSP jets have very high beaming factors 40 min. Possible explanations: – Fast spine / slow sheath structure (e.g., Tavecchio et al. 2008) – Reconnection regions or misaligned ‘mini-jets’ (Giannios et al. 2010,2013) – Fast leading edges of intermittent outflows (Lyutikov & Lister 2010)

Krakow, April  Lower VLBI brightness temp. and variability of HSP radio cores are indicative of low radio relativistic beaming factors Relativistic Beaming Levels

Krakow, April Ramifications of a Very Fast-TeV Jet Spine

Krakow, April 2015 “The fast spine is invisible since it is beamed away from you”  works only if jet viewing angle > 10º or spine δ >> 100 Γ spine δ spine δ sheath

Krakow, April Radio Jets of HSPs in Fast Spine Scenario

Krakow, April LAS = 90 kpc Mrk 421 LAS = 50 kpc Mrk 501 >500 kpc is considered a ‘giant’ radio galaxy (see Machalski et al. ApJ 679, 149 and poster upstairs) Machalski & Condon 1985 Cassaro et al. 1999

Malaga, May Radio Jet Luminosity vs. Cosmic Distance HSP AGN lie at faint end of blazar radio luminosity function

Krakow, April MOJAVE Kpc-Imaging Campaigns VLA imaging of 300 MOJAVE AGN in A and B configurations at 1.4 and 5 GHz (Ethan Stanley, Ph.D. thesis) LOFAR imaging of MOJAVE 1.5 Jy sample (Jonas Trüstedt, Ph.D. thesis) – using international baselines to achieve 1 arcsec resolution at 140 MHz – 610 MHz GMRT observations have also been proposed LOFAR image of giant radio halo of ISP BL Lac courtesy Jonas Tr ϋ stedt LAS = 240 kpc

Blazar Flavors: Quasars and BL Lacs Quasars: – broad optical emission lines – high power jets seen end-on – synchrotron peak in infrared BL Lacertae objects: –weak/absent broad emission lines –low power jets seen end-on –synchrotron peaks range from infrared to optical/UV FR II jet FR I jet Palma et al. AUI/NRAO AGN Hotspot (low power) (high power)

Malaga, May 2016 Current BL Lac Paradigm Lower jet power implies low accretion rate onto black hole:  inflow radiates inefficiently, thus no optically thick accretion disk or broad line region No broad line photons are available for external Compton scattering  less Compton cooling of synchrotron electrons  synchrotron can peak up to optical/UV regime 37

Krakow, April Are these trends solely due to jet bending? Predictions: a)no inward/outward acceleration trend expected with distance b)parallel accelerations should be ~60% magnitude of  accelerations c)features with large parallel accelerations should also show large perpendicular accelerations Most features have a high || /  acceleration ratio. Speed increase/decrease trend is more evident in these features.

Krakow, April Acceleration Down the Jet Features tend to speed up near the core, and slow down at ~ 100 pc (deprojected) farther downstream. Outward parallel accelerations Inward parallel accelerations

Malaga, May No perpendicular acceleration is expected in cases of changes in speed along a straight trajectory. If jet features are moving with constant speed on a curved trajectory, should expect to see accelerations both parallel and perpendicular to mean velocity vector. = velocity vector

NRAO-AOC, March 6, Do the observed motions reflect the underlying jet flow? Any intrinsic shock speeds are added relativistically to the flow speed. Broad statistical trends in MOJAVE jets are impossible to reproduce with a random collection of inward & outward moving shocks. Red: inward acceleration Blue: outward acceleration Black: no significant acceleration

Malaga, May Inner Jet Collimation Proper motion vector directions within ~50 pc (deprojected) of jet core indicate collimation. No apparent collimation seen further out. (Major exception: 3C 279 in 1999 ; Homan et al. 2003)

Krakow, April Rate of Jet Speed Changes Cygnus A BL Lacertae

Malaga, May

Malaga, May 2016 Some of the best-sampled features, however, show variable acceleration

Krakow, April Prior Coverage of radio/ γ- ray flux plane γ -ray Radio

Malaga, May 2016 Max. Fractional Linear Polarization Mean Projected Distance from Core [pc] Evolution of Magnetic Field Order

Malaga, May 2016 No examples of fast features with low-synchrotron luminosity. Only the most luminous jets can attain high Lorentz factors  = 30, L = W Hz -1

Malaga, May 2016 BL Lacs and radio galaxies show clear trend of increasing speed down the jet. Situation unclear for quasars, but we can directly measure the accelerations.

Malaga, May Jet speed versus redshift Lister et al. arXiv

Malaga, May Jet Feature Statistics All AGN Jet Features Quasar Jet Features BL Lac Jet Features Accelerating38%39% Accelerating or non-radial 52%54%52% Non-radial 35%34%40% Inward motion 3% 1% 8% Slow pattern speed 6% 9% 1295 robust features 1016 have >3 sigma speeds 211 have ejection epochs 691 features examined for acceleration

Malaga, May MOJAVE Kinematics Statistics All AGN (295)Quasars (212)BL Lacs (53) Accelerating65%64%71% Non-radial 59%58%60% Accelerating or non-radial 82%81%80% Inward motion 6% 2%19% Slow pattern speed 16% 15%25%

Malaga, May At any given time, typically only a portion of the full (conical) outflow is energized/visible in a VLBA image Stacked image: Quasar jet image: 2008 Energized Jet Channels