Gabriele Giovannini

Dipartimento di Astronomia, Bologna UniversityIstituto di Radioastronomia - INAF

The jet and core in M 87

In collaboration with :K. Hada, M. Giroletti, M. Orienti – IRA-INAF BolognaC.C. Cheung, A. Doi, M. Kino, N.P. Lee, H. Nagai – JapanC. Casadio – Inst. de Astrof. de AndaluciaM. Beilicke & H. Krawczynski - Phys. Dept. – Washington, MO A. Cesarini - School of Physics, Univ. of Ireland Galway

1 mas5 mas

Krichbaum

43 GHz86 GHz

M87 – A well known friend• 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

Walker

core

HST-1

500 pc

SUMMARY:

HST-1: an interesting jet structure

CORE LOCATION: approaching the SMBH

INNER JET PROPERTIES: jet launching region

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 radioCore 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/MAGICNo activity in X-ray, optical, and radio in the Core and in HST-1

HST-1 is detected at all epochsThe 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°

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

all the data are at 1.7GHzthe span is from 2005 Oct to 2009 Jul, every 2~4 months, 17epochs. linear interpolation is used between neighboring epochs

CORE LOCATION: approaching the SMBH

Hada et al. 2012, observedM87 at different frequencieswith VLBA. They estimated the core shift because ofdifferent optical depths.

The SMBH is at 14-23 Rs fromthe 43GHz core

Large scale jet direction

New observations with VLBAand the GBT have been obtainedbut not yet scheduled to observeat 86 GHz and to obtain images in the accretion region

INNER JET PROPERTIES: jet launching region

To understand the mechanisms of jet formation it is crucial toknow the jet collimation structure.Asada et al (2011) found a parabolic collimation z(r) = Kr0.58±0.02

between a few 100s Rs and 105 Rs from the core

Now we are reaching the stage to explore z(r) within ~ 100 Rs

Waiting new 86 GHz data, we used archive data

INNER JET PROPERTIES: jet launching region

R 0.56±0.03

parabolic

Conical shape

Non spinningMax spinning

Thank You

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)