1. Gabriele Giovannini Dipartimento di Astronomia, Bologna University Istituto di Radioastronomia - INAF The jet and core in M 87 In collaboration with : K. Hada, M. Giroletti, M. Orienti – IRA-INAF Bologna C.C. Cheung, A. Doi, M. Kino, N.P. Lee, H. Nagai – Japan C. Casadio – Inst. de Astrof. de Andalucia M. Beilicke & H. Krawczynski - Phys. Dept. – Washington, MO A. Cesarini - School of Physics, Univ. of Ireland Galway

2. 1 mas 5 mas Krichbaum 43 GHz 86 GHz M87 – A well known friend Good resolution –Nearby: 16.7 Mpc –Large black hole mass: ~6X10 9 M sun –Scale 1 mas = 0.081pc = 140 Rs. Well studied at all wavelengths from radio to TEV Walker

3. core HST-1 500 pc

4. SUMMARY: HST-1: an interesting jet structure CORE LOCATION: approaching the SMBH INNER JET PROPERTIES: jet launching region

5. Why HST-1 ?? 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

6. 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°

7. 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)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

8. 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

9. 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 R s from the 43GHz core

10. Large scale jet direction 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

11. INNER JET PROPERTIES: jet launching region To understand the mechanisms of jet formation it is crucial to know the jet collimation structure. Asada et al (2011) found a parabolic collimation z(r) = Kr 0.58±0.02 between a few 100s R s and 10 5 R s from the core Now we are reaching the stage to explore z(r) within ~ 100 R s Waiting new 86 GHz data, we used archive data

12. INNER JET PROPERTIES: jet launching region R 0.56±0.03 parabolic Conical shape Non spinning Max spinning

13. Thank You

14. Where is the “blazar emission zone” γ-detected AGNs? M87 a confusing case: 2005 TeV flare with radio X-Ray and optical flare of HST-1 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) Core in its highest state since 2000 (Acciari et al. 2009) 2010 TeV flare, no enhanced radio flux in the core and in HST-1 (Abramowski et al. 2012)