Astrophysics Multifrequency Programs AGN properties from gammaray radio

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)

66 high-confidence blazars (27 lower confidence) Radiogal. : Cen. A, 3 C 111

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

FSRQ ISP Bl-Lac HSP Bl-Lac

< 100 m. Jy 8 GHz 20 GHz 30 GHz > 100 m. Jy FSRQs 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)

Y-ray color (purple) + optical

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

LAT 2 FGL 68% and 95% confidence ellipses on radio images IC/X-Ray lobes: B 0. 4 micro. G NGC 6251 Takeuchi etal. 2012 B 1. 5 micro. G in Fornax A Feigelson et al. Better sensitivity is necessary

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

Radio and gamma-ray emission in blazars • • • synchrotron radio emission originates from relativistic electrons that can upscatter photons to high energy low energy – some connection between radio and gamma- photon 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. gamma-ray photon relativistic electron Donato et al. (2001)

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

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

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.

Radio (Medicina at 8 GHz) and gamma from 2012 – M. Rossini master thesis Radio at 4 frequencies – from www 3. mpifr-bonn. mpg. de/staff/ubach/bmonit/

M 87 – A well known friend Good resolution Nearby: 16. 7 Mpc Large black hole mass: ~6 X 109 Msun Scale 1 mas = 0. 081 pc = 140 Rs. Well studied at all wavelengths from radio to TEV Krichbaum Walker 86 GHz 43 GHz 5 mas 1 mas

core 500 pc HST-1

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 Te. V 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)

Why HST-1 ? ? Where is the “blazar emission zone” γ-detected AGN? M 87 a confusing case: 2005 Te. V flare with radio, X-Ray and optical flare of HST-1 Harris et al. 2009 in February 2008 M 87 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 Ge. V: MAGIC ATel 2431 Apr. 9 strong flare VERITAS/MAGIC No activity in X-ray, optical, and radio in the Core and in HST-1

March 1998 VLA A config 15 GHz 4 m. Jy/beam June 2003 23 m. Jy/beam

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).

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 Te. V γ-ray activity

all the data are at 1. 7 GHz the span is from 2005 Oct to 2009 Jul, every 2~4 months, 17 epochs. linear interpolation is used between neighboring epochs (by K. Hada)

CORE LOCATION: approaching the SMBH Hada et al. 2012, observed M 87 at different frequencies with VLBA. They estimated the core shift because of different optical depths. The SMBH is at 14 -23 Rs from the 43 GHz core

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

INNER JET PROPERTIES: jet launching region To understand the mechanisms of jet formation it is crucial to know the jet collimation structure. Jet: -- conical structure above about 105 Rs (Asada & Nakamura 2012) -- a parabolic collimation z(r) = Kr 0. 58± 0. 02 between a few 100 s Rs and 105 Rs from the core Note: HST-1 is at 2 x 105 Rs Now we are reaching the stage to explore z(r) within ~ 100 Rs Using Hada et al. data we can investigate the region < 100 Rs (we know the ‘core’ position): -- Conical shape r 0. 76 < 100 Rs

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 R 0. 76 Alma+mm. VLBI + millimetron & Radioastron VLBI satellite Non spinning Max spinning

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!

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/iau 2012 jd 6/Program. html

Thank You Radioastron launch on 18 July 2011 from Baikonur