Texas in Florence

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VLBI Observations of a Complete Sample of
Radiogalaxies
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In collaboration with L. Lara and E. Arbizzani
S. Baum J. Biretta M. Bondi W. Cotton J.E.
Conway P.G. Edwards L. Feretti F.D. Macchetto
J.M. Marcaide H. Hirabayashi M. Giroletti A.P.
Marscher C.P. ODea B.G. Piner M. Rioja S.R.
Spangler G.B. Taylor T. Venturi A.E. Wehrle
First paper in collaboration with Lucas in
1993 44 papers or contribution to international
conferences have been published on this topic
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New Results
Relativistic jets also in faint cores of low
power radio sources.
Complex morphologies singular sources
here only a few of them
MKN501, 3C264, 4C31.04
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Jet morphology
The complete sample B2 and 3CR radio sources
with z lt 0.1 Being selected at low frequency it
is not affected by observational biases related
to orientation effects. Nearby sources good
linear resolution low power
The large scale morphology of observed sources
is 37 FR I rg 11 FR II rg 8 compact flat
spectrum sources Other 2 Bl_Lacs, 1 CSO, 1 CSS
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• Important result is that two-sided sources on the
  pc scale are 18
• corresponding to 30.2 to be compared with 11 in
  PR sample
• and 4.6 in Caltech survey.
• All FR II two-sided are NLR.
• 
  
• Two-sided sources show low power radio cores.
• In most sources there is a good agreement
  between the pc-kpc
• scale jet orientation in agreement with the
  suggestion that
• large distortions seen in BL-Lac sources are
  due to small
• intrinsic bends amplified by projection effects

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3C192 z 0.0597 arcsecond core 8 mJy at 5
GHz
VLBI phase reference mode Peak 1.7 mJy/b
noise 0.05 mJy/b
VLA BC at 1.4 GHz
10 pc
LS 200 kpc
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3C 382 a BL FR II radio galaxy
3C 66B a FR I radio galaxy
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Radio jet of the FR I radio galaxy 3C264 at
different angular resolutions (Lara et al. 1999)
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B2 and 3Cr sources Rg and QSS No selection effect
on ?
The comparison of the expected intrinsic and
observed core radio power will constrain ß and
?. A large dispersion of the core radio power is
expected because of the dependance of the
observed core radio power with ?. From the data
dispersion we derive that ? has to be lt 10 and gt 3
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Results
From our study on 60/95 sources from the B2 and
3CR catalogues and from literature data we found
that - In all sources pc scale jets move at
high velocity. No correlation has been found
with core or total radio power - We used the jet
velocity and the corresponding orientation to
derive the Doppler factor for each source
and the corresponding intrinsic core radio
power
? 0
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M87
3C192
The line is the general correlation between the
core and total radio power. Points in the left
side (observed data) show the expected
dispersion because of different orientation. Note
that we started to observe sources with brighter
core. In the right figure we plotted the derived
intrinsic core radio power. We have here a small
dispersion since we removed the spread due to
different orientation angles.
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Sources with a faint radio core more
complex structures -- restarted activity --
different orientation angle between pc and kpc
structure -- complex pc scale structure with no
evident core or multiple core? A
statistical problem or we are starting to study
sources with different properties?
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4C 26.42 134626 central cD in A1795 z 0.0633
VLBI 6 cm peak flux 5.9 mJy/b noise 0.1 mJy/b
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10 pc
VLBI 20 cm Phase ref. Mode Peak 24 mJy/b Noise
0.07 mJy/b
5 pc
VLBI 6cm
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3C 310 VLA BC Linear size ? 300 kpc
1.4 GHz
1.7 GHz
In agreement with Gizani and Garrett (2002) 6th
EVN Symp.
5 GHz
5 pc
Peak flux 1.3 mJy/b Noise 0.07 mJy/b
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Markarian 501
This low redshift (0.034) BL_Lac object is well
known for its emission at high frequency. We
studied its radio properties on the pc scale
using data at 14 different epochs and at
mas resolution (high frequency VLBI and space
VLBI) Giroletti et al. 2004 ApJ Despite of
the large number of different high quality
images no proper motion has been found.
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The jet shows a complex and continuous morphology
with many sharp bends before undergoing a last
turn in the PA of the kpc scale structure. The
jet is clearly limb brightened at lt 1 mas
from the core (lt 4 pc deprojected).
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Physical parameters
Magnetic field core region (0.03 to 0.15 pc)
0.03 gauss
(self-absorption) Jet region 0.015 0.010
gauss (equipartition) Relativistic jet up to 300
pc Symmetric non relativistic structure on the
kpc scale To observe the intermediate region we
need the extended VLA (or SKA).
New observations December 2004 at 18 cm with the
High Sensitive Array VLBAY27
GBTBonn
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4C31.04 a CSO

• z 0.06
• S1.4 GHz 2.5 Jy
• P1.4 GHz 2.4 x 1025 W/Hz
• MH-23.6 (Perlman et al. 2001)

1 mas/yr 5.4 c (H0 50 km sec-1 Mpc-1)
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VLBA _at_ 5 GHz, epoch July 2000 (10 mas 15 pc)
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Expansion... results.

• DE 0.4 mas
• DW 0.5 mas
• DT 5 yr

• v 0.5 c
• age 500 yr

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Lara et al. 1997 Lara et al. 1999 Lara et al. 2004
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• Different jet structures
• Brightness decrease and change in polarization
  after the crossing of the optical ring
• Initial jet velocity 0.99c
• The spectrum between radio and optical bands is
  consistent with a synchrotron spectra
• with a break frequency in the infrared

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CONCLUSIONS

• The parsec scale jet morphology is the same in
  high (FR II) and low (FR I) power sources
• The pc scale morphology is in agreement with
  expectations from unified models
• There is a good agreement between the pc and kpc
  scale orientation
• The pc scale jet velocity is highly relativistic
  in FR II and FR I sources. It is not related to
  the total or core radio power of the source. No
  correlation with the kpc scale structure.

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In some sources with a low power nuclear source
we find a peculiar morphology restarted activity
and a complex mas scale structure not yet
understood, misaligned with the kpc scale
structure. We need to add more pieces to solve
the puzzle of the physical properties of AGN
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Thanks and
C i a o
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(No Transcript)
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Giant radio galaxy, core dominated at z 0.0630
114435
counterjet
flat spectrum core
main jet
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A1
B2
B1
B
A
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We started to observe this source with VLBI in
1990. The pc scale jet shows a well defined
structure moving with a constant velocity and
direction.
We have an apparent jet velocity 1.92c and a
counter jet motion with an apparent velocity
0.23c.
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Assuming a symmetry in the jet/counter jet
velocity, according to Mirabel and Rodriguez
(1994) we can derive the intrinsic jet velocity
and orientation
We derive ? 30o and ß 0.95 These
values are in agreement with the measured arm
ratio the jet/cj length ratio is ?10 ? ß
cos(?) 0.82 ? ß 0.95 and

? 30o .
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The arcsecond core shows a clear flux density
variability. Observations are available from 1972
at different frequencies. From a comparison of
multi-epoch data it is clear that the flux
density variability is not due to a core
activity but to jet substructures (mainly the A
component).
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In the last period 2002 to 2006 1) The VLBI
core is slightly increasing its flux density at
8.4 GHz In 2006 for the first time the VLBI core
is the dominat mas structure 2) The arcsecond
core flux density at frequencies gt 8.4 GHz has
stopped its flux density decrease. Since A
component is still decreasing the change is due
to the VLBI core Possible explanation After
2002 and before 2006 the core is in an active
phase and a new component is coming out. This
new component is not yet visible in our images
and is still self absorbed at frequencies lower
than 8.4 GHz
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We can estimate its size from the selfabsorption
frequency assuming equipartition magnetic
field The estimated size of this new
component is ? 0.03 mas ? not yet visible
(VLBA HPBW is 0.17 mas at 7 mm) If it is
moving with ßa 1.92 (as the main jet) we
should start to resolve it in about 2 yrs (X
band)
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JET KINEMATICS
Proper Motion
But are bulk and pattern velocity
correlated???? In a few cases where proper
motion is well defined there is a general
agreement between the highest pattern velocity
and the bulk velocity Ghisellini et al.
1993 Cotton et al. 1999 for NGC 315 Giovannini et
al. for 114435
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However in the same source we can have different
pattern velocities as well as standing and high
velocity moving structures
In some well studied sources the jets show a
smooth and uniform surface brightness ? no
proper motion visible e.g. Mkn
501 (Giroletti et al. 2004) poster
Assuming that the jets are intrinsically
symmetric we can use relativistic effects to
constrain the jet bulk velocity ßc
and orientation with respect to the line of sight
(?) as following
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Jet sidedness From
the jet to cj brightness ratio R we derive
Radio core dominance
Given the existence of a general correlation
between the core and total radio power we can
derive the expected intrinsic core radio power
from the unboosted total radio power at low
frequency.
Arm length ratio

By comparison of the size of the approaching (La)
and receding (Lr)
and more