G.Giovannini Department of Physics and Astronomy – Bologna University & IRA/INAF

1. Astrophysics Multifrequency Programs: AGN properties from gamma-ray & radio observations G.Giovannini Department of Physics and Astronomy – Bologna University & IRA/INAF with the collaboration of M. Giroletti, K. Hada and M. Orienti (IRA/INAF)

2. 66 high-confidence blazars (27 lower confidence) Radiogal.: CenA, 3C111

3. Now about 1000 gamma-ray AGN AGN -non BLAZARS include radio galaxies

4. FSRQ ISP Bl-Lac HSP Bl-Lac

5. < 100 mJy > 100 mJy • 8 GHz 20 GHz 30 GHz FSRQs FSRQs BL Lacs BL Lacs • Significant correlation between radio and gamma-ray (e.g., Ackermann et al. 2011, • Ghirlanda et al. 2010, Lister et al. 2011, Lindford et al. 2011) FSRQs on average brighter and apparently more luminous in radio than BL Lacs (but severe redshift incompleteness)

7. Y-ray color (purple) + optical

8. Over ½ of the total >100 MeV observed LAT flux in the lobes WMAP 20GHz LAT >200 MeV • Background & point sources subtracted From Nils Odegard (GSFC) Abdo et al. 2010 Science, 328, 725

9. LAT 2FGL 68% and 95% confidence ellipses on radio images IC/X-Ray lobes: B 0.4 microG NGC6251 Takeuchi etal.2012 B 1.5 microG in Fornax A Feigelson et al. Better sensitivity is necessary

10. See e.g. Meng Su et al. 2012 IAU-GA, JD-6

13. gamma-ray photon low energy photon relativistic electron Radio and gamma-ray emission in blazars • synchrotron radio emission originates from relativistic electrons that can upscatter photons to high energy • some connection between radio and gamma-ray properties is expected! • observationally, all EGRET AGNs are radio loud, differently from most X-ray QSOs • the blazar sequence was originally devised on the basis of the radio luminosity • evidence or not of flux-flux, Lum-Lum correlations is a debated issue • Stecker et al. (1993), Mücke et al. (1997), Bloom (2008), etc. • bias, variability, number of sources, etc. Donato et al. (2001)

14. Radio/gamma-ray connection in the Fermi era • Big questions • is there a correlation between radio and gamma-ray flux in AGNs? YES • is it also significant? YES • does it depend on simultaneity? YES • does it depend on blazar type? May be • does it depend on energy band? May be

15. Many useful resources are available to study the connection between the Gamma-ray and radio emission VLBI for milliarcsecond scale resolution imaging, e.g. through MOJAVE or dedicated monitoring experiment: https://www.physics.purdue.edu/astro/mojave/ - single dish studies, e.g. with the Medicina (5, 8, and 22 GHz) and Noto (43 GHz) radio telescopes

16. Blazar monitoring at Medicina/Noto • People involved: C. Raiteri, M. Villata, U. Bach, P. Leto, M. Giroletti, M. Orienti, M. Rossini • 34 blazars are monitored about once per month at four frequency (up to 43 GHz) since december 2004. • The new Enhanced Single-dish Control System is in use since late 2011 in Medicina, granting improved sensitivity • Comparison of radio vs gamma-ray light curve is possible, to assess correlation, time delays etc.

17. Radio (Medicina at 8 GHz) and gamma from 2012 – M. Rossini master thesis Radio at 4 frequencies – from www3.mpifr-bonn.mpg.de/staff/ubach/bmonit/

18. Good resolution Nearby: 16.7 Mpc Large black hole mass: ~6X109 Msun Scale 1 mas = 0.081pc = 140 Rs. Well studied at all wavelengths from radio to TEV M87 – A well known friend Krichbaum Walker 86 GHz 43 GHz 5 mas 1 mas

19. core 500 pc HST-1

20. A VHE у-ray emitting: 2003-2006 by HESS – variability on time scale of days in high state data (Aharonian et al. 2006)  promising possibility of TeV production it is the nucleus However HST-1: in the X-ray increased by more than a factor 50 2001-2006 with a major flare on 2005 Harris et al. 2009 Superluminal motions of radio features in HST-1 (Cheung et al. 2007)

21. Why HST-1 ?? Where is the “blazar emission zone” γ-detected AGN? M87 a confusing case: 2005 TeV flare with radio, X-Ray and optical flare of HST-1 Harris et al. 2009 in February 2008 M87 showed a strong VHE у-ray activity: multiple flares, short term variability. HST-1 was in a low state (in X-ray) , decreasing in radio Core in its highest state since 2000 (Acciari et al. 2009) 2010 Feb 10 high flux level at > 100 GeV: MAGIC ATel 2431 Apr. 9 strong flare VERITAS/MAGIC No activity in X-ray, optical, and radio in the Core and in HST-1

22. March 1998 VLA A config 15 GHz 4 mJy/beam June 2003 23 mJy/beam

23. HST-1 is detected at all epochs The two outermost regions move at ~4 c. The motion of a third feature that is detected upstream is more difficult to characterize. The overall position angle of HST-1 has changed during the time of our observations from −65° to −90° (Giroletti et al. 2012).

24. Our results on the component’s evolution suggest that structural changes at the upstream edge of HST-1 can be related to the VHE events. Giovannini et al. (2011) noted a change in the velocity in HST-1 at the epoch ~2005.5, coincident with the TeV γ-ray activity

25. all the data are at 1.7GHz the span is from 2005 Oct to 2009 Jul, every 2~4 months, 17epochs. linear interpolation is used between neighboring epochs(by K. Hada)

26. CORE LOCATION: approaching the SMBH Hada et al. 2012, observed M87 at different frequencies with VLBA. They estimated the core shift because of different optical depths. The SMBH is at 14-23 Rs from the 43GHz core

27. New observations with VLBA and the GBT have been obtained but not yet scheduled to observe at 86 GHz and to obtain images in the accretion region Large scale jet direction

28. INNER JET PROPERTIES: jet launching region Tounderstand the mechanismsof jet formationitiscrucialto know the jet collimationstructure. Jet: --conicalstructureaboveabout 105Rs (Asada & Nakamura 2012) -- a paraboliccollimation z(r) = Kr0.58±0.02between a few 100s Rs and 105Rsfrom the core Note: HST-1 is at 2 x 105Rs Nowwe are reaching the stage toexplore z(r) within ~ 100 Rs UsingHadaet al. data we can investigate the region < 100 Rs (weknow the ‘core’ position): --Conicalshape r0.76 < 100 Rs

29. INNER JET PROPERTIES: jet launching region conical R 0.56±0.03 parabolic + 230 GHz VLBI Doeleman et al. 2012, circular Gaussian core Conical shape R0.76 + Alma+mmVLBI + millimetron & Radioastron VLBI satellite Non spinning Max spinning

30. Thanks to space VLBI with Radioastron and in the near future to a mm VLBI including ALMA (and millimetron) we will be able to obtain images like these but to do real physics we will need VHE information: spectral and short time variability!

31. Fermi observations show that the maximum Jet power in blazars is emitted at high energy. The high variability implies that emitting regions are very small, however we do not know if these regions are at the jet beginning very near to the SMBH, or are compact jet sub-structures at large distance from the SMBH (> BLR). To understand physical properties of these regions is crucial to investigate the connection between radio properties and high energy emission: -- time variability comparison -- flux density variability comparison -- high resolution VLBI images of the SMBH in comparison with VHE data. JD-6 at the IAU GA in Bejing (2012): The Connection between Radio Properties and High Energy Emission in AGN. Presentations in: www.ira.inaf.it/meetings/iau2012jd6/Program.html

32. Radioastron launch on 18 July 2011 from Baikonur Thank You