How Compact are Blazar Cores – How Compact are Blazar Cores – AGN studied with micro-AGN studied with micro-

arcsecond/sub-pc scale resolutionarcsecond/sub-pc scale resolution

T.P.Krichbaum T.P.Krichbaum

with contributions from with contributions from U. Bach, S. Lee, U. Bach, S. Lee,

M. Gurwell and A. MarscherM. Gurwell and A. Marscher

Max-Planck-Institut für Radioastronomie, Max-Planck-Institut für Radioastronomie, Bonn, GermanyBonn, Germany

e-mail:tkrichbaum@mpifr-bonn.mpg.dee-mail:tkrichbaum@mpifr-bonn.mpg.de

involved scientists:

IRAM: M. Bremer, P. Cox, S. Sanchez, C. Thum, H. Ungerechts, H. Wiesemeyer, et al.

MPIfR: I. Agudo, W. Alef, U. Bach, D. Graham, T. Krichbaum, S.S. Lee, A. Lobanov, R. Porcas, A. Witzel, A. Zensus, et al.

Onsala/Sest: R. Booth, J. Conway, M. Lindquist, et al.

Metsähovi: A. Mujunen, M. Tornikoski, E. Valtaoja, K. Wiik, et al.

NRAO-VLBA: V. Dhawan, J. Ulvestad, C. Walker, et al.

and for VLBI at 1 & 2mm:

ARO (HHT/KP): A. Apponi, H. Fagg, R. Freund, P. Strittmatter, L. Ziurys, et al.

MIT-Haystack: S. Doeleman, A. Rogers, A. Whitney, et al.

special thanks for providing data, partly prior to publication:

A. Marscher & S. Jorstad (Boston)

J.L. Gomez (IAA Spain)

M. Gurvell (SMA)

M. & H. Aller (UMRAO)

T. Savolainen (Tuorla, now MPIfR)

What does VLBI at short millimeter wavelengths offer ?

• Study compact galactic and extragalactic radio sources with an angular resolution of a few ten micro-arcseconds (size,

structure, kinematics, polarization)

• Image regions which are (self-) absorbed and therefore not observable at longer wavelength (spectrum, radiation/ energy transport, outburst – ejection relations).

• For nearby super-massive Black Holes a chance to study their immediate environment (Sgr A*, M87, etc.) with a spatial resolution of ~10 - 100 gravitational radii (accretion, jet formation and collimation, GR-effects).

Spectral variability of

3C454.3 after May

2005 Flare:

Effelsberg:

1.4 – 32 GHz

Pico Veleta:

90 – 230 GHz

SMA:

230, 350 GHz

combined data:

Krichbaum, Ungerechts, Wiesemeyer, Gurwell et al.

SMA data: M. Gurwell et al.

quasi periodicity during peak !

11days or 1.2as or 95 Rs

T. Krichbaum, et al. 2007

monthly 2004 - 2007

• Europe: Effelsberg (100m), Pico Veleta (30m), Plateau de Bure (35m), Onsala (20m), Metsähovi (14m)

• USA: 8 x VLBA (25m)

The Global Millimeter VLBI Array – VLBI Imaging The Global Millimeter VLBI Array – VLBI Imaging at 86 GHz with ~40 at 86 GHz with ~40 as resolutionas resolution

http://www.mpifr-bonn.mpg.de/div/vlbi/globalmm

Proposal deadlines: February 1st, October 1st

Baseline Sensitivity

in Europe:

50 – 350 mJy50 – 350 mJy

in US:

250 – 350 mJy250 – 350 mJy

transatlantic:

80 – 350 mJy80 – 350 mJy

Array:

2 – 4 mJy / hr2 – 4 mJy / hr

(assume 7, 100sec, 512 Mbps)

common beam 0.25 x 0.1 mas

43 GHz, Oct. 6

86 GHz, Oct. 17

Quasi-simultaneous mm-VLBI observations

of 3C454.3 after outburst

43 GHz: no emission near core

known jet emission at 0.3 -1.4 mas

86 GHz: emission near core clearly visible

jet components at 0.6 & 1.1mas

compare well to 43 GHz image

conclusion:

strong absorption in the 0.1-0.3 mas region,

i.e. on the 1-2 pc scale

spectral index : +1.1 .... + 2.6 (range of uncertainty)

43/86 GHz: - 0.4 (core), - 0.3 (jet)

8.5Jy 0.23 Jy

6.7Jy 0.14Jy 0.18Jy

data: Marscher et al.

A new and comprehensive 86 GHz VLBI Survey:

Comparison with previous surveys at 86 GHz

VLBI Surveys at 86 GHz

1. Beasley et al. (1996) (N=45, 16% detect)

2. Lonsdale et al. (1998) (N=79, 14% detect)

3. Rantakyro et al. (1998) (N=67, 24% detect)

4. Lobanov et al. (2000) (N=28, 93% detect)

5. Lee et al. (2006, 2007)

- 3~4 times better sensitivity (Scorr >0.3 Jy)

- larger sample (127sources)

taken from surveys at lower frequencies

- 121 (95%) sources were detected and

- 109 (86%) sources could be imaged This Survey

S.S. Lee et al. 2006

86 GHz VLBI Survey: Some preliminary statistics

distribution of core flux densities distribution of measured core sizes

BL Lacs are more compact and more core dominated than QSOs. QSOs are more compact and core dominated than Radio-Galaxies.

Lee, Lobanov, Krichbaum et al. 2006

Lee et al. 2007, in prep.

normalized visibilities vs. uv-distance

M87 with the VLBA at 43 GHz

Ly et al. 2004, & 2007

counter-jet or self-absorbed jet base ?

234 x 59 as = 25 x 6 light days = 82 x 21 Rs9

transverse width of jet at 1mas: ~250 – 300 Rs

assume size of VLBI core = size of jet base:

300 Rs

1 mas = 0.09 pc

April 2002

96 light days

The Mini – Spiral

VLA 2cm

Krichbaum et al. 1993

VLBI 86 GHz

19 Rs size

Krichbaum et al. 1998 & 2006

From VLBI at 1.3mm:

50 as < FWHM < 190 as

or

5 RS < size < 19 RS

(for a SMBH with 4 x106 M)

best estimate: 110 ± 60 as

or : 11 ± 6 RS

3mm VLBI of M87 with the participation of PdBure

Peak: approx. 1.5 Jy

One year later:completely different visbility functions →the source structure must vary !

Mode: 512-8-2-LU

Peak: approx 0.7 Jy

Variability in the inner jet of M87 detected : 0.2 mas/yr 18000 km/s (0.06c)

(but: 3 – 6 c seen further downstream)

53 light days

counter-jet or new jet component ?April 2002 April 2003

new global 3mm map of M87 observed with the GMVA in April 2004:

now with better sensitivity, data rate: 512 Mbit/s (MK5 hard disk recording)

The size of the jet base (uniform weighting):

197 x 54 as = 21 x 6 light days = 69 x 19 Rs

transverse width of jet at 0.5 mas: ~174 Rs

M87 at 86 GHz

Krichbaum et al. 2006

174 Rs

The diameter of the light-cylinder

determines the jet width:

Camenzind, 1990jet width Rs for Kerr

BH)

> 40 Rs

Casse & Keppens 2004

Bach et al. 2006 and in prep.

The two-sided Jets of Cygnus AThe two-sided Jets of Cygnus A

Jet-to-counter-jet ratio modified by free-free absorption

apparent jet speed

Magnetic acceleration

Vlahakis & Königl, 2003

intrinsic jet acceleration from 0.1c – 0.7c

Enhance 3mm VLBI sensitivity by including the 3 largest European mm-telescopes:

Effelsberg 100 m (MPIfR)

Pico Veleta 30 m (IRAM, Spain)

Plateau de Bure, 6 x 15 m (IRAM, France)

Baseline lengths (km):

PdB PVEB 658 1700Pdb 1146

fringe spacing: 0.4 – 1.1 mas,

sensitivity > 40 -70 mJy (7512 Mbps)

plus the GBT, asap :

SEFD[Jy]

150GBT

590Plateau de Bure

710Pico Veleta

950 Effelsberg

Global mm-VLBI at 150 - 230 GHzGlobal mm-VLBI at 150 - 230 GHzKitt Peak, 12m

HHT, 10m

Metsähovi, 14m

Pico Veleta, 30mAPEX, 10m

angular resolutions: for 230 GHz

Plateau de Bure, 6x15m

near future

ALMA 50x12m

20 as

60 a

s

first detection of 2 first detection of 2 QSOs with VLBI QSOs with VLBI at 230 GHz !at 230 GHz !

Model of Sgr A*image distorted by gravitational light bending

Reconstructed Clean Image

Simulation of future 230 GHz VLBI of Sgr A* with IRAM (Pico Veleta, Plateau de Bure), HHT, CSO/SMA, CARMA, APEX

weighted mean: 3mm =0.18 ± 0.02 mas, range: 0.10 – 0.36 mas

weighted mean: 7mm =0.55 ± 0.03 mas, range: 0.43 – 0.70 mas

Does the observed 3mm size of Sgr A* vary ?

ConclusionsConclusions• The Global 3mm VLBI Array (GMVA) provides up to 40 as resolution and 50 –

250 mJy baseline sensitivity. USE IT !

• misalignement of jets between 86 GHz and longer wavelengths indicates transverse jet stratification (3C120, 3C273, 3C454.3, ...).

• M87 and SgrA* can be imaged with nearly the same spatial resolution of a few 10 Schwarzschild radii (M87 has a jet, SgrA* not).

• The small diameter (~20 RS) and high brightness temperature of the M87 jet base points towards MHD driven jet formation (Kerr metric, BH rotation acc. jet?)

• SgrA* is smaller than 11±6 RS; need global 1mm VLBI (+ SMA, CARMA, HHT, APEX, ALMA,...) to image GR effects near a SMBH.

• Global VLBI at 2mm & 1.3mm is technical feasible. The further increase of bandwith (2-4 Gbit/s), will facilitate imaging of compact sources with a resolution of 10 - 20 micro-arcseconds at Restz) ! (e.g. for z=3 and 345 GHz, RestHz ).

• mm-VLBI monitoring is needed in support of GLAST, Herschel and Planck. The GMVA provides good sensitivity and the smallest observing beam in Astronomy.

Station CountryDiamete

r Zenith Tsys Gain App.Eff. SEFD    [m] [K] [K/Jy] % [Jy]Effelsberg Germany 80 130 0.14 8 930Plateau de Bure France 35 120 0.21 60 570Pico Veleta Spain 30 120 0.14 55 715Onsala Sweden 20 300 0.049 43 6100Metsähovi Finland 14 400 0.017 30 23500VLBA(8) USA 25 100 0.036 20 2800             Hopefully soon:            GBT Va, USA 100 150 1.0 35 150Noto Italy 32 150 0.05 20 3000Yebes Spain 40 150 0.22 50 680Nobeyama Japan 45 150 0.17 30 880             Future:            CARMA Ca ,USA 35 150 0.14 50 1070LMT Mexico 50 150 0.43 60 350ALMA Chile 64x12 100 1.8 70 55

Global VLBI at 3mm: Existing and possible future antennas

• need more sensitivity

• need more stations to allow better self –calibration

• need southern antennas for low declinatioin sources

What does the GMVA offer ?

• a global 13 station VLBI array allowing high dynamic range imaging with angular resolution of up to 40 as at 86 GHz

• 3 – 4 times higher sensitivity than stand-alone VLBA (512 Mbps is standard, max. 7 baseline sensitivity is ~ 50 mJy)

• 2 epochs/year, each session ~ 3 – 5 days long (limitation by proposal pressure)

• open to cummunity by usual proposal procedures (deadlines Feb. 1st, Oct. 1st)

• AIPS ready FITS files after correlation

3C120 with the full GMVA at 86 GHz, Oct. 12, 2004

1.3 pc

east-west resolution: 54 light days

present sensitivity limit on long baselines ~ 0.2 – 0.3 Jy (512 Mbps)

quasi-simultaneous VLBI maps (within 16 days) allow spectral index determination of inner jet

3C120 at 43 GHz (data: A. Marscher et al.)

misalignement possibly due to transverse opacity effects orthogonal to jet axis jet stratification

1.3 pc

43 GHz

86 GHz

-1.0-0.7-0.3-0.443/86 :

3C120 : Structural differences at 43 and 86 GHz within 14 days

43 GHz, Oct. 28

A B C D

86 GHz, Oct. 12

A B C D

radial distances agree well, p.a.'s differ

spectral index near position A: -0.4; B: 0.0; C: -1.4 (error: +/- 0.3)

0.13 pc

mm-VLBI resolves jet transversely:

A double rail structure

in the jet of 3C273 –

decollimation at 3 pc ?

3.2 pc

3.

5 pc

z = 0.158

1 mas 2.7 pc

MHD simulation of a confining B-field anchored in a rotating disk

The central engine – a MHD dynamo ?

Source PdBI - PV HHT - PVNRAO150 10.73C120 8.20420-014 24.90736+017 7.10716+714 6.8 6.4 ?OJ287 10.41055+0183C273 8.23C279 9.6NRAO530SgrA*3C3451633+3821749+0962013+370BL Lac 9.02145+067CTA1023C454.3 7.3

Signal-to-Noise ratios for the

230 GHz detections in 2003

(PV –PdB – HHT baselines):

short baselines: SNR : 25long baseline: SNR : 6 – 7

Two sources detected at 6.4 G:

3C454.3 and 0716+714

for 3C454.3 (z = 0.859)

´ = 428 GHz , life time B 2 = 3.6 105 ,

16 as = 0.1 pc = 1050 RS9 ,

SSA: B 1 G 600