1. Parent Population intrinsic observed
Low frequency  no beaming effects
Nuclear properties different since are affected
by beaming but in agreement if we compare intrinsic
values.

2. The correlation between the optical and radio nuclear flux density in FR I implies common synchrotron origin and no dust torus
BL Lacs show the same correlation in agreement with Unified Models. The shift is due to the different boosting
BL Lacs
Chiaberge et al. 1999
FR I

3. BL Lacs
Chiaberge et al. 1999
FR I
Our sample
Corrected for the Doppler factor
BL Lacs observed

4. A correlation between X-ray and radio is expected if there is a fundamental
connection between accretion flows and jets. Merloni et al showed that
the sources define a FP in the three-dimensional space: log LR, log LX, log MBH.
They used AGN and X-ray binaries (SMBH and BH) but not BL Lacs because
of beaming

5. observed
intrinsic
FP relation
FP relation
Observed BL Lacs properties do not follow the FP, but if we plot intrinsic
properties we note a general agreement even if the large data dispersion
and the separation between HBL and LBL suggest secondary effects (velocity
structures and/or correlation between jet velocity and source properties)

6. The Chandra view of the 3C/FRI sample. I
X-ray cores are ubiquitous in FR I,
just like the optical cores.

7. The Chandra view of the 3C/FRI sample. II
A very strong correlation emerges between the radio/optical and the
X-ray cores in FRI radio-galaxies.

8. Summarizing:
Chandra observations of FR I radio-galaxies provide further support for the jet scenario and not only based on the strong radio/optical/X-ray correlations.
Spectral indices have values similar to proper counterpart of jet dominated sources (LBL). They also show the evolution expected from beaming and the same luminosity evolution of BL Lac.
Measurements of radio/optical and X-ray nuclei represents a unique
tool to explore the properties of AGN.

9. Tests of radio galaxy/quasar unification
The relative numbers of FR2 RGs and Qs (about 2:1 => half-cone angle of ~45 degrees) should be related to the size of the un-obscured cone angle hence can calculate by what factor the radio sizes of Qs should be smaller than RGs.
The results are mixed but do not rule anything out.
If the quasar nucleus is hidden by dust the intercepted energy should be re-radiated in the FIR. Qs and RGs should have same FIR luminosity.
Seems just about ok

10. Tests continued
Broad lines should be detectable in narrow line RGs – either in scattered polarized light or in the IR.
Some examples of both are seen as well as some UV broad lines (e.g. Cygnus A)
Narrow emission lines well away from the torus should have the same luminosity in RGs and Qs of intrinsically the same power.
[OIII] is stronger in Qs (Jackson and Browne)
[OII] is the same (Hes et al.)
The Q luminosity function should be a “beamed” version of the RG one (Urry and Padovani)

11. Correlations -- Radio
If jets are relativistic, some “unification” is inevitable. What’s the evidence for relativistic jets?
Superluminal motion (rarely measurable in RGs)
Jet asymmetry (X-ray jets seen with Chandra need relativistic motion to give enough IC emission)
Laing– Garrington effect
Even in radio galaxies, the side of the source with the jet is less depolarized
=> Jet asymmetry arises from orientation and hence they are relativistic.
Inserire paper2 bl-lacs

12. Radio map of 3C175

13. CHANDRA X-Ray Jet in Pictor-A

14. Unification across the FR1/FR2 boundary?
There does seem to be a real distinction between FR1s and FR2s:
Radio structure
Radio luminosity
Optical emission line properties
Cosmological evolution
But the non-thermal emission is similar in both
Also FR2s could possibly evolve into FR1s
There is no strong evidence against this (Unification by time?)

15. FR2s evolving into FR1s? Assume:
FR2s are objects with relativistic jets that reach the full extent of the radio source
That the distance that jets can travel at relativistic speeds depends on jet power; high power jets make it further out.
Then young small sources of a given jet power will be FR2s, but as they grow and get older they will become FR1s
Some crossing of the FR boundary with time for lower-power objects.
(N.B. There are some FR2s with weak emission lines which when beamed may become BL Lacs)

16. Apparenza AGN dipende da angolo rispetto a linea di vista
Toro oscurante – nasconde AGN e BLR in type 2 AGN
Jet relativistico: doppler boosting
Esistenza toro:
Ionization cones
BLR polarizzate in oggetti tipo 2
Emissione continua visto da oggetti tipo 2 puo’ non essere
sufficiente a ionizzare NLR
Soft X-ray absorption in oggetti tipo 2
Radio free-free absorption
Non esistenza toro: correlazione Pcore e nucleo ottico in FR I
In accordo con assenza righe Bl-Lacs

17. Wider Unification
Stimulated by the discovery of polarized broad lines in a Seyfert 2 (narrow-line Seyfert) by Antonucci and Miller (1985,ApJ,297,621), in the mid 1980s the optical community realized that AGN were not spherically symmetric and that orientation effects were important.
There emerged the standard model the key ingredient of which is the “obscuring torus” which hides the inner part of all AGN (BLR plus disk emission), both radio-quiet and radio-loud

18. Accretion Disk+Black Hole
The Structure of AGN
Seyfert 1
Narrow Line Region
Torus
Central Engine:
Accretion Disk+Black Hole
Seyfert 2
Broad Line Region

19. Seyfert 1 – Seyfert 2 Intrinsically same except for obscuration ?
So now take only unobscured objects!

20. Seyfert 1 - Quasars Similar spectra and line ratios,
strong UV flux to excite lines,
probably similar L/LEdd ~
Increasing L
Increasing M

21. Evidence for the standard model
More hidden BLR seen in scattered (polarized) light.
Ionization cones.
Though many claimed not many are convincing
Photoionization considerations – some Seyfert 2s do not have enough ionization photons seen to give the NLR luminosity
Molecular disks, particularly NGC4258

22. Ionization cone in NGC 5728
If ionizing photons are blocked by the torus then one expects to see cones delineating the boundary.

28. In S2 vediamo continuo e BLR solo se riflesse, da nubi, materiale
ionizzato o altro S1
BLR riflessa S2

30. X-ray ionization cones
Seyfert 2 galaxy NGC5252
OIII ionization cones
X-ray ionization cones
Tadhunter & Tsvetanov, Nature, 1989
Wilson & Tsvetanov, 1994
Camilla Boschieri, tesi di laurea

31. Young radio sources Powerful in radio band (P1.4 GHz > 1025 W/Hz);
1. Introduction
Young radio sources
Powerful in radio band (P1.4 GHz > 1025 W/Hz);
Compact size (LS < 15 – 20 kpc):
Spectral peak  ~ 100 MHz to a few GHz;
Heavily depolarized;
High fraction in flux-density limited catalogues (15% – 30% )

32. 1. Introduction
The peak frequency
Turnover

33. Linear size - turnover CSS GPS HFP LLS < 15 - 20 kpc
1. Introduction
Linear size - turnover
HFP
GPS
CSS
LLS < kpc
t ~ 50 – 100 MHz
CSS
LLS < 1 kpc
t ~ 1 GHz
GPS
LLS ~ 10 pc
t  4 GHz
HFP
The smaller the source, the higher the turnover frequency

34. Linear size The radio sources completely resides within the
1. Introduction
Linear size
The radio sources completely resides within the
Insterstellar medium (ISM) of the host galaxy
Compact Symmetric Objects (CSO)
LS < 1 kpc (<0.1”), within the NLR;
Medium Symmetric Objects (MSO)
LS < 15 – 20 kpc (<1”)

35. High resolution observations!
1. Introduction
High resolution observations!
MSO: VLA  21 cm; 3.6 cm

36. High resolution observations!
1. Introduction
High resolution observations!
CSO: VLBI  21 cm; 3.6 cm
VLBA
EVN

37. 1. Introduction
Morphology
Scaled-down version of the classical Extended Doubles: they should represent the young stage in radio source evolution
Hot spots
Core
150 kpc
7 pc
350 pc
Core HS HS
Core
4.5 kpc HS
Core

38. Why are they so compact? Youth scenario: Frustration scenario: Compact
1. Introduction
Why are they so compact?
Youth scenario:
Frustration scenario:
Compact
Young
Baldwin 82, Fanti+ 95, Readhead+ 96, Snellen+ 00…..
Compact
Frustrated
van Breugel+ 84, Baum+ 90

39. Youth: Proper motion B0710+439 LS tkin ~ ~ 103 yr!! vsep vsep= 0.3c
1. Introduction
Youth: Proper motion B
Polatidis&Conway 03
vsep= 0.3c
Young
Hot spots
Core LS
vsep
~ 103 yr!!
tkin ~

40. Youth: Proper motion B2352+495 vsep = 0.12c tkin ~ 3·103 yr
1. Introduction
Youth: Proper motion B
Core
Hot-Spot
vsep = 0.12c
tkin ~ 3·103 yr
Owsianik et al. 1998

41. Kinematic age Polatidis&Conway 03
1. Introduction
Kinematic age
Polatidis&Conway 03
The kinematic ages derived for a dozen of the most compact (≤100 pc) CSOs are in the range of 103 – 104 yr, much shorter than the ages estimated for the largest (up to a few Mpc) radio galaxies.

42. Youth: Spectral analysis
1. Introduction
Youth: Spectral analysis
B , Murgia 2003
From the break frequency br we can derive the radiative age, once the magnetic field is known!
trad  br-1/2 H-3/2
From br in the lobes:
trad ~ 103 yr

43. Youth: spectral analysis
1. Introduction
Youth: spectral analysis B

44. 1. Introduction
Youth: radiative age
trad ~ 103 yr

45. The “frustration” scenario
1. Introduction
The “frustration” scenario
Compact
Frustrated
Observations from IR to X-ray searching for an excess of dust,
and cold, warm and hot gas did not provide evidence of a
particularly dense environment.
Fanti+ 00, Siemiginowska+ 05
Indirect support to the youth scenario

46. 1. Introduction
Sample selection
The selection of young sources cannot be based on the morphological properties.
Samples are selected on the basis of the spectral shape and the peak frequency
This implies the selection of both galaxies and quasars, with different proportion depending on the peak frequency and luminosity.

47. Sample selection High frequency/luminosity selected sample
1. Introduction
Sample selection
High frequency/luminosity selected sample
Higher fraction of quasars
Low frequency/luminosity selected sample
Higher fraction of galaxies

48. 2. Radio properties Introduction 3. Source evolution
4. Physical properties
5. The ambient medium

49. Radio properties Flux density and spectral variability;
Radio morphology;
Polarization.

50. 2. Radio properties
Variability
Young radio sources should not possess significant amount of variability because they should be intrinsically compact.
No beaming effects!!

51. Variability…..galaxies
2. Radio properties
Variability…..galaxies
Simultaneous multifrequency observations at various epochs do not show remarkable changes in young radio sources identified with GALAXIES

52. Variability…..galaxies
2. Radio properties
Variability…..galaxies
Simultaneous multifrequency observations at various epochs do not show remarkable changes in young radio sources identified with GALAXIES

53. 2. Radio properties
Variability….quasars
A significant fraction of compact sources identified with QUASARS high level of variability are present.

54. 2. Radio properties
Variability….quasars
A significant fraction of compact sources identified with QUASARS high level of variability are present.

55. 2. Radio properties
Morphology…galaxies
GALAXIES have a “symmetric” structure, where symmetric means “two-sided”
500 pc
Core HS

56. 2. Radio properties
Morphology…quasars
A large fraction of QUASARS have a Core-Jet or a Complex structure.
Complex
Core-Jet
Rossetti et al. 2005

57. Polarization properties
2. Radio properties
Polarization properties
LS < 6 kpc
Fanti et al. 2004
Unpolarized at 1.4 GHz
Cotton et al. 2003
LS < 3 kpc
Unpolarized at 8.4 GHz

58. 2. Radio properties
Faraday screen

59. 2. Radio properties
Rotation Measure
CSS with LLS > 5 kpc are polarized with H // to the jet axis
CSS with LLS < 5 kpc have high RM
GPS and HFP galaxies are usually unpolarized
HFP quasars are strongly polarized

60. Galaxies vs quasars The different characteristics shown by GPS/HFP
2. Radio properties
Galaxies vs quasars
The different characteristics shown by GPS/HFP
with different optical identification are consistent
with the idea that GPS/HFP galaxies and quasars
represent two different radio source populations:
Galaxies Compact sources
Quasars Beamed objects

61. …with some exceptions J0650+6001 Quasar z=0.45 vsep = 0.39c±0.18c
2. Radio properties
…with some exceptions J
Quasar z=0.45
vsep = 0.39c±0.18c
tkin = 360±170 yr

62. The quasar J0650+6001 vi=0.43c±0.04c 12 < θ < 28
2. Radio properties
The quasar J
From the source expansion:
From the flux density ratio:
vi=0.43c±0.04c
12 < θ < 28

63. The quasar J1459+3337 t ~ 50 yr Rapid evolution of radio emission
2. Radio properties
The quasar J
Rapid evolution of radio emission
peak moves to low frequency
- from 24 to 12 GHz in 7 yr
variability of the spectrum
- in the optically-thick part of the spectrum the flux density increases as the source expands
t ~ 50 yr

64. 3. Source evolution Introduction 2. Radio properties
4. Physical properties
5. The ambient medium

65. Evolutionary stages Higher peak frequency Smaller linear size
3. Source evolution
Evolutionary stages
Murgia 2003
Higher peak frequency
Smaller linear size
Younger the source

66. ? Evolutionary stages HFP GPS CSS FR I/II HFP GPS CSS
3. Source evolution
Evolutionary stages
HFP
GPS
CSS ?
HFP
GPS
CSS
FR I/II

67. Too many young radio sources!
3. Source evolution
Too many young radio sources!
Young radio sources represent 15% - 30% of the
objects in flux density-limited catalogues.
The fraction expected on the basis of the source
age is much smaller!!
Young
Old
103-4 yr
107-8 yr ~
0.01%

68. 3. Source evolution
Luminosity evolution
The radio sources should decrease in luminosity by an order of magnitude as they evolve (Fanti et al. 1995).
The ambient medium enshrouding the radio source should play a role in the source evolution (Baldwin 1982)

69. Luminosity evolution…
3. Source evolution
Luminosity evolution…
If the thrust of each relativistic jet is balanced by the ram-pressure of the surrounding medium:
Velocity:
Assuming equipartition, the luminosity is:
1/2 Pj
v 
nextmpcA
L 
Pj t
V3/7
7/4
Energy density:
u 
Pj t V

70. …in a King-like density profile
3. Source evolution
…in a King-like density profile
- /2 r2
next  n0
1 +
r02
r < r0 (like CSO)
r > r0 (like MSO)
v  t
2 - 
4 - 
v 
t-1/2
2 + 
L 
t5/8
L  t
16 - 4

71. 3. Source evolution
Luminosity evolution
L  t 5/8
L  t -1/2

72. CSS evolvono in radio sorgenti piu’ deboli, questo risolve
il problema del loro numero apparentemente troppo elevato
FR II
FR I
limite osserv. per giganti

73. A survey of low‐luminosity compact sources and its implication for the evolution of radio‐loud active galactic nuclei – I. Radio data
(a) Luminosity–size diagram for AGNs. (b) Luminosity–redshift diagram for AGNs. Squares indicate CSS sources from the samples: grey squares, Fanti et al. (2001); black squares, Marecki et al. (2003a); empty squares, Laing et al. (1983). The diamonds indicate GPS objects and small black squares indicate HFP objects from the sample of Labiano et al. (2007). The filled circles indicate FR I objects and open circles indicate FR IIs from the sample of Laing et al. (1983). The crosses indicate the current sample of LLC sources, except for the source with the redshift indicated as ‘d’.
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74. A survey of low‐luminosity compact sources and its implication for the evolution of radio‐loud active galactic nuclei – I. Radio data
Evolutionary scheme of radio‐loud AGNs.
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75. Fading radio sources Young but fading objects?
3. Source evolution
Fading radio sources
Despite the luminosity evolution, young objects are still too many
Gugliucci et al. 2005
The age distribution sharply peaks below 500 yr
Young but fading objects?

76. PKS 1518+047: a study case tsyn = 2700±600 yr
3. Source evolution
PKS : a study case
tsyn = 2700±600 yr
Neither injection nor acceleration of new particles!
tOFF = 550±100 yr

77. Recurrent activity? Low accretion rate: 103 yr
3. Source evolution
Recurrent activity?
The large fraction of young radio sources may be explained assuming the existence of short-lived objects with intermittent activity.
Recurrent activity may be caused by radiation pressure instability within the accretion disk (Czerny et al. 2009).
Low accretion rate: 103 yr
Eddington accretion rate: 108 yr

78. FIRST 33Myr 0836+29B 4C29.30 100Myr A galaxy merger >200Myr
Jamrozy et al.
2007
FIRST
33Myr
25 kpc
Van Breugel et al. 1986
VLA A+B at 20cm
B 4C29.30
A galaxy merger
100Myr
Jamrozy et al. 2007

79. only flat spectrum component
Core – most compact
only flat spectrum component 4
10 yrs
1 kpc
VLA – A array at 6 cm

80. core 15 yrs 70 yrs Strong outburst after 1990 Jamrozy et al. 2007
2005.8
core
15 yrs
5 pc
1 kpc
70 yrs
Strong outburst after 1990
Jamrozy et al. 2007

81. Fossils from the past On kpc scales: J0111+3906: 128 kpc
3. Source evolution
Fossils from the past
On kpc scales:
J : 128 kpc
trelic ~ 107–108 yr
On pc-scales:
J : 50 pc
OQ208: 43 pc
trelic ~ 103 – 104 yr

82. 4. Physical properties Introduction 2. Radio properties
3. Source evolution
4. Physical properties
5. The ambient medium

83. Physical properties The knowledge of the physical properties
occurring during the first stages of the radio
emission is fundamental in order to determine
the initial conditions to be used in the
development of the evolutionary models!!

84. Spectral peak SSA in a homogeneous component: β = 2.5
4. Physical properties
Spectral peak
Optically thin
Optically
thick


Radiative
losses
Log 
Log S()
SSA in a homogeneous component:
β = 2.5
SSA is present BY DEFAULT!

85. Magnetic field In the presence of SSA from homogeneous component:
4. Physical properties
Magnetic field
In the presence of SSA from homogeneous component:
Vm = FB1/5Sm2/5θ-4/5(1+z)1/5 GHz
F funzione dipende da indice
spettrale energia

86. Are young objects in equipartition?
4. Physical properties
Are young objects in equipartition?
In case of equipartition:
Heq  (1+k)2/7 -2/7 P2/7 V-2/7
Pacholczyk 1970
Heq  HSSA
Orienti&Dallacasa 08

87. Are young objects in equipartition?
4. Physical properties
Are young objects in equipartition?
In case of equipartition:
Heq  (1+k)2/7 -2/7 P2/7 V-2/7
Pacholczyk 1970
Heq  HSSA
Orienti&Dallacasa 08
with some exceptions…

88. SSA or Free-Free Absorption?
4. Physical properties
SSA or Free-Free Absorption?
Optically-thick part of the spectrum is too steep to be described by SSA only. Addition of FFA is needed!!!
HSSA cannot be derived

89. Inhonogeneous ambient medium!
4. Physical properties
SSA or FFA?
FFA
SSA
Inhonogeneous ambient medium!

90. 5. The ambient medium Introduction 2. Radio properties
3. Source evolution
4. Physical properties
5. The ambient medium

91. The ambient medium The onset of radio 4C 31.04 activity is currently
thought to be related to
merger/accretion
events occurring in the
host galaxy and which
fill the central region of
fuel for the AGN
4C 31.04

92. 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)

93. VLBA @ 5 GHz, epoch July 2000 (10 mas = 15 pc)

94. Expansion... results. DE ~ 0.4 mas DW ~ 0.5 mas DT = 5 yr v ~ 0.5 c
age ~ 500 yr

95. Rich environment High incidence of ionized gas (FFA);
5. The ambient medium
Rich environment
As a consequence of the merger, the medium
enshrouding the radio source should be rich
and dense of gas
High incidence of ionized gas (FFA);
Highly depolarized sources;
High detection rate (~40%)of molecular gas (CO) in emission (Mack+ 09);

96. 5. The ambient medium
The ambient medium
The jet is piercing its way through the dense medium left by the merger
4C 31.04, Conway 03

97. The HI in young radio sources
5. The ambient medium
The HI in young radio sources
Larger incidence than what found in extended galaxies (~10%, Morganti et al. 2001)

98. The HI in young radio sources
5. The ambient medium
The HI in young radio sources
Anti-correlation between linear size LS and the column density NHI (Pihlström et al. 2003, Gupta et al. 2006)

99. The HI in young radio sources
5. The ambient medium
The HI in young radio sources
Circumnuclear disk/torus with a radiaclly decreasing density profile
Mundell et al. 2003

100. The molecular gas Disk structure Symmetric Doubled-peak profile
5. The ambient medium
The molecular gas
Symmetric Doubled-peak profile
Disk structure
Mdisk ~ 1.4·1010 M○
Ocaña-Flaquer et al 2010

101. The molecular gas HCO+ (1-0) CO (2-1) Unsettled disk?
5. The ambient medium
The molecular gas
HCO+ (1-0)
CO (2-1)
Asymmetric doubled-peak profiles
Unsettled disk?
Mdisk ~ 5·109 M○
…and the absorption?
Garcia-Burillo+ 08

102. VLBI observations Central disk HI detected against the whole source
5. The ambient medium
VLBI observations
, Peck+ 99
HI detected against the whole source
Central disk
v = 350 km/s
NH  2x1023 cm –2 (Ts = 8000 K)

103. VLBI observations Off-nuclear cloud
5. The ambient medium
VLBI observations
, Maness+04
HI detected only against the southern hot spot
Off-nuclear cloud
v = 540 km/s
NH  2x1020 cm –2 (Ts = 100 K)

104. VLBI observations Off-nuclear cloud
5. The ambient medium
VLBI observations
4C 12.50
HI located ~100 pc from the core, where the jet bends
Morganti+ 04
Off-nuclear cloud
v = 150 km/s
NH  1022 cm –2 (Ts = 100 K)
Mcl ~ 106 M○

105. Jet-cloud interaction?
5. The ambient medium
Jet-cloud interaction?
Jet-cloud interaction may influence the source growth, for example slowing down the jet expansion and enhancing its luminosity!
Labiano+ 06

106. Jet-cloud interaction
5. The ambient medium
Jet-cloud interaction
4C 12.50
Shallow, broad and blue-shifted component
Morganti+ 04
Outflow!
v  2000 km/s
NH  2.6x1021 cm –2 (Ts = 1000 K)

107. Outflows Δv ~ 2000 km/s τ ~ 0.005 NHI ~ 8·1020 cm-2
5. The ambient medium
Outflows
OQ 208, Orienti+ 06
Δv ~ 2000 km/s
τ ~ 0.005
NHI ~ 8·1020 cm-2
Amounts of gas are expelled from the host galaxy!!

108. Fast outflows of atomic gas
5. The ambient medium
Fast outflows of atomic gas
Large receiver WSRT
7 CSOs detected
Mrate ~50 M○/yr
Morganti+05

109. Fast outflows of ionized gas
5. The ambient medium
Fast outflows of ionized gas
Giant outflows of ionized gas detected only in galaxies hosting a young radio source
Complex line profile O[III]
v ~ 2000 km/s
Blueshift
Holt+ 08

110. 5. The ambient medium
Outflows
Jet-cloud interaction may influence both the source growth and the properties of the ISM.
Outflows of ionized and atomic gas found only in galaxies hosting a young radio sources, implying a higher probability that jet-ISM interaction takes place in such objects!!