1. The MOJAVE AGN Program Dept. of Physics Purdue University (currently on sabbatical at Univ. College Cork, Ireland) Matthew Lister VLBA Fermi UMRAOOVRO Chandra

2. MOJAVE Collaborators  M. Lister (P.I.), N. Cooper, B. Hogan, S. Kuchibhotla, T. Hovatta (Purdue)  T. Arshakian, C.S. Chang, L. Fuhrmann, Y. Kovalev, A. Lobanov, A. Pushkarev, T. Savolainen, J. A. Zensus (Max Planck Inst. for Radioastronomy, Germany)  M. and H. Aller (Michigan)  M. Cohen, A. Readhead (Caltech)  D. Homan (Denison)  M. Kadler, M. Boeck (U. Erlangen-Bamberg, Germany)  K. Kellermann (NRAO)  Y. Kovalev (ASC Lebedev, Russia)  E. Ros (Valencia, Spain)  N. Gehrels, J. McEnery, J. Tueller (NASAGSFC) 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 NNX08AV67G and NSF grant 0807860-AST. Fermi

3. Outline  The MOJAVE program: present and future  Kinematics of highly beamed AGN jets –parsec-scale radio imaging –connections with gamma-ray emission  Case study: Impact of 8 antenna VLBA array on jet studies

4. The MOJAVE Program Regularly taking VLBA images of the ~300 brightest jets in the northern sky Jet kinematics on decadal timescales  full polarization images provide additional information on jet magnetic fields Concurrent multiwavelength studies of the sample Currently funded by the National Science Foundation and NASA M onitoring O f J ets in A ctive Galaxies with V LBA E xperiments http://www.physics.purdue.edu/MOJAVE Lister et al., 2009, AJ, 137, 3718

5. Scientific Highlights: Jet Kinematics  Motions of superluminal bright features are related to true flow speed –some near-stationary features are seen (6%), more common in lower power BL Lac jets  Most AGN jets are only mildly relativistic (Γ ~ few) –extended tail to speed distribution –some exceedingly rare jets (blazars) have Γ ~ 50  Fastest jets all have very high synchrotron and gamma-ray luminosity (not likely a beaming effect) Lister et al., 2009, AJ, 138, 1874 Lister et al., 2009, ApJ 696, L22

6. Scientific Highlights: Accelerations  Accelerations of features are common (at least 50%) in both speed and direction –sudden events: collimation of 3C279 jet –continuous: curved motions around stationary bends –unpredictable: different accelerations/non-accelerations seen in the same jet  Positive (speeding up) accelerations more prevalent close to the base of the jet  jet flows are still becoming organized on parsec scales Homan et al., 2003, ApJ, 589, L9 Homan et al., 2009, ApJ, 706, 1253

8. Image from March 1996 Recent image: June 2009 Jet Activity States  At any given time, only the energized portion of a broader jet is visible  Activity states of jets evolve over time –long quiescent periods of no jet ejections are seen –new features ejected at new position angles (precession?)  Fermi is preferentially detecting currently active jets (brighter than their historical average radio level) (Kovalev et al. 2009, ApJL 696, L17) Stacked image: 1995-2009 Lister et al., 2009, AJ, 137, 3718 1308+326

9. What makes a jet gamma–ray bright? 1.Light output peaked at high energy (more important at fainter gamma-ray levels) 2.Preferred viewing angle (aimed toward us) 3.Fast intrinsic jet speed (highly beamed) 4.High current activity state Complex combination of:  Blazar gamma-ray emission is directly related to pc- scale radio jet properties

10. –more Doppler boosting in gamma-rays than radio (Lister et al. in prep) –Gamma-ray emission may be intrinsically anisotropic (Savolainen et al. 2010) Preliminary

11. Other MOJAVE Studies  Intraday variability (Kuchibhotla, Ph.D. Thesis 2010)  rapid flux variations common in quasars, rare in BL Lacs  origin is likely galactic ISM scattering, but requires compact, highly beamed emitting regions  Chandra survey (Hogan et al. 2010, ApJ in press)  X-ray jets are ubiquitous in blazars with extended radio emission  IC-CMB model requires relativisic jet speeds on kpc-scales  Deep VLA imaging survey (Cooper, Ph.D. Thesis 2010, Kharb et al. 2010, ApJ)  low-energy peaked BL Lacs can have FR I or II jet morphologies

12. MOJAVE: What’s in store  Kinematics of complete set of gamma-ray blazars  Circular and linear polarization jet evolution  SED and optical spectroscopy analysis  Extension of sample down to 1.5 Jy and dec > -30º  Extended Chandra and EVLA surveys

13. Case Study: Science Impact of Dropping Two Inner VLBA Antennas Image quality o total intensity and linear polarization Model fitting o positions and flux densities of Gaussian fits

14. Observational Dataset BL149CP: MOJAVE Program o 24 hour run on Sept 17, 2010 o 15 GHz, 512 Mbps, continuum, dual pol. o 30 compact AGN jets, 0.2 to 16 Jy o scans interleaved to optimize u,v coverage o ~35 min total integration time per source o excellent weather at all 10 sites, minimal downtime Data were reduced twice: 1. with all antennas 2. with two inner antennas (KP and LA) completely flagged

15. Image comparison: compact jets 8 antennas 10 antennas 8 antennas

16. Image comparison: extended jets 8 antennas 10 antennas 8 antennas 10 antennas

17. Image rms noise slightly higher than theoretical 2 antenna loss Extended jets suffer higher image rms loss than compact jets Most of extended jet emission lost

18. Gaussian model fitting Evolutionary changes in jets are most simply tracked by modeling emission as discrete Gaussians Positional accuracy: typically ~1/5 beamwidth (0.2 mas)

19. Comparison: Gaussian component flux densities Negligible difference for strongest components (> 300 mJy) Strong difference between 8 and 10 ants. for weaker components

20. Comparison: Astrometry (con’t) Typical offset from 10 antenna-fitted position is 0.1 mas Positional error strongly dependent on flux density of feature Nominal positional accuracy

21. Recording sensitivity versus u,v coverage What would 2X improved VLBA sensitivity look like for AGN jets? Image using all 10 antennas, flagging 3/4 of all the IFs (10 antennas ¼ of IFs) Full array, low recording bandwidth Colorscale = fractional linear polarization

22. Recording sensitivity versus u,v coverage What would 2X improved VLBA sensitivity look like for AGN jets? Image using all 10 antennas, flagging no IFs 10 antennas all IFs Full array, high recording bandwidth Colorscale = fractional linear polarization

23. Recording sensitivity versus u,v coverage What would 2X improved VLBA sensitivity look like for AGN jets? Image using all 8 antennas, flagging no IFs (8 antennas all IFs) Reduced array, high recording bandwidth Colorscale = fractional linear polarization

24. Summary: Loss of 2 inner VLBA antennas = 38% loss in available baselines o but higher rise in image noise o 10 antenna VLBA is already a ‘minimum array’ for imaging Improving recording bandwidth cannot make up for loss of short interferometric baselines o emission on scales > 3 mas becomes invisible to the VLBA (at 15 GHz) o flux and positional measurements significantly degraded for 45% of jet features in MOJAVE survey o strongly affects imaging science capabilities, and will affect astrometry of weaker, less compact features MOJAVE is a comprehensive program aiming to understand the physics of highly relativistic jets from black holes o - Lorentz factors up to at least 50 o - sudden/smooth, parallel and perpendicular accelerations MOJAVE+Fermi combination is a providing a huge leap forward in our understanding of AGN outflows, emission and particle acceleration MOJAVE project webpage and data archive: www.physics.purdue.edu/MOJAVE