Continuo Infrarosso IR puo’ essere non termico (sincrotrone) o termico. Importante slope del cut off submm Se sincrotrone auto-assorbimento a = -2.5 Il minimo a 1 micro suggerisce termico Variabilita’ (dimensioni) da indicazioni discordanti Recenti dati ISO suggeriscono IR termico in radio quieti QSO mentre flat spectrum radio QSO hanno emissione non termica dominante

Recent result: Baldi et al. arXiv:1010.5277 Usando HST osservazioni di 100 3C sources si ricava che: FR I: The correlation among near IR, optical, and radio nuclear luminosity  non thermal origin (IR) FR II con righe di emissione deboli (low-ionization galaxies LIG): sono indistinguibili da FR I  stesse proprieta’ FR II con righe allargate (BLO): unresolved near IR nucleus + large near IR excess dominant  hot circumnuclear dust (confermato da spettro e SED) FR II con righe strette ma luminose (high-ionization galaxies HIG) simili ma fainter di BLO  substantial obscuration + reflection

What do AGN look like? Mass not well known 10 years ago… Big! So disc peak somewhere in unobservable UV/EUV !! Spectra generally not dominated by the disc – hard tail often carries a large fraction of Lbol and puzzling soft excess also can carry large fraction of Lbol Richards et al 2006, Elvis et al 2004

Effetti con z e/o Luminosita’ Spettri in ottico e UV non mostrano dipendenza da luminosita’ o redshift in QSS ma αox mostra una chiara dipendenza con z o L Intrinseco o effetti di selezione? Piu’ recenti risultati a favore di reale dipendenza da L e non da z anche se difficile separare L da z che si correlano in flux-limited samples. In ogni caso la dispersione e’ molto larga in QSS e probabilmente una fondamentale proprieta’ in parte dovuta anche alla sovrapposizione di star formation effects

Scale di grandezza SMBH ≈ AU Accretion Disk 1 mpc Compact radio VLBI core 0.1 pc BLR 1 pc Toro molecolare 100 pc NLR Host Galaxy Radio Lobi 1 Mpc

Storchi-Bergmann et al. (2003) Disk Signatures A relatively small subset of AGNs have double-peaked profiles that are characteristic of rotation. Disks are not simple; non-axisymmetric. Sometimes also seen in difference or rms spectra. Disks can’t explain everything… NGC 1097 Storchi-Bergmann et al. (2003)

Continuo Banda Radio Importante storicamente e non, ma in Lbolometrica contribuisce poco a causa della sua bassa energia Temperatura di Brillanza: intensita’ di sorgente radio dipende da flusso e diametro angolare da cui proviene. Con Tb intendo la temperatura che dovrebbe avere un CN per irradiare lo stesso flusso. I = F/πθ2 = B = 2kTb/2 F = flusso osservato monocromatico; θ diametro angolare della sorgente. Si ottiene T ≈ 1011 – 1012 K che chiaramente indica una origine non termica

Esiste una Tb massima dell’ordine di 1012 K in quanto densita’ energia del campo magnetico: Umag = B2/8π controlla rate delle perdite di sincrotrone Con densita’ di energia Urad = 4πJ/c Quando Urad e’ al punto che supera Umag inizia ad essere rilevante l’interazione di Compton inverso. Poiche’ non vediamo una intensa radiazione in banda gamma significa che: Urad/Umag < 1 che corrisponde a Tmax ≈ 1012 K (catastrofe Compton) Nuclei radio: sorgenti compatte su risoluzione angolare arcsecond con alta Tb e spettro piatto (piccole dimensioni angolari). Ma spettro piatto + alta variabilita’ indicano presenza di strutture su piccola scala quindi con T tale da dare catastrofe Compton Vedremo la soluzione grazie a alta risoluzione  VLBI

Risoluzione angolare: R = 1.22 lambda/D in radianti Lambda e D stessa unita’ di misura! occhio D= 8 mm R = 17.3” ma retina degrada a 1’ Telescopio 4 m puo’ arrivare a 0.035” ma seeing…. Radio non ha grossi problemi con atmosfera a frequenze fino a 22 GHz per cui R meglio di 1 mas

Accuratezza Specchio  0.1  ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY Il Radiotelescopio Sub-riflettore Simile a telescopio ottico! Il radiotelescopio funziona allo stesso modo di un telescopio ottico. Notare pero’ che in banda radio sono consentite discontinuità dell’ordine del mm e cm mentre in ottico le discontinuita’ devono essere dell’ordine del centesimo di micron. Schema: specchio riflettente + sub-riflettore + ricevitori al fuoco secondario. Esempio di ricevitore a 20 cm. Sostegno Ricevitori Accuratezza Specchio  0.1  RADIOASTRONOMY

Importanti caratteristiche del telescopio ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY Importanti caratteristiche del telescopio Sensibilità  D2 Potere Risolutore  /D D= 30 m 30’ Banda radio:  = 20 cm 10’ D= 80 m D=700 m 1’ Caratteristiche principali dei telescopi. Sensibilita’ e potere risolutivo. I radiotelescopi non riescono a risolvere bene i dettagli. I radio telescopi sono un po’ miopi! Pupilla:  ~ 0.001 mm D = 5 mm 1’ RADIOASTRONOMY

Arecibo 300 m Effelsberg (Bonn) 100 m Parkes (Australia) 64 m Green Bank (WEST VIRGINIA) 100x110 m (Agosto 2000) Arecibo (Portorico) 300 m Effelsberg (Bonn) 100 m Parkes (Australia) 64 m Jodrell Bank (Manchester) 75 m La necessita’ di aumentare il potere risolutivo fa si’ che i radiotelescopi siano molto grandi. Ecco i piu’ grandi del mondo! Parkes: 64 m dal 1961 Jodrell Bank 75 m Effelsberg 100 m (anni 60) Nuovo Green Bank 100x110 25 Agosto 2000 Arecibo 300 m (stesso dettaglio dell’occhio umano)

L’ INTERFEROMETRO d Potere Risolutore: ~ /d Sensibilità: ~ N x D2 ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY L’ INTERFEROMETRO Potere Risolutore: ~ /d (d = distanza antenne) Sensibilità: ~ N x D2 (N=numero antenne) d La radiointerferometria sfrutta un principio dell’ottica che dice che il potere risolutore e’ definito dai 2 punti diametralmente opposti dello specchio. Si puo’ quindi immaginare uno specchio virtuale di diametro d=distanza tra le due antenne, di cui le due antenne sono I due punti diametralmente opposti. RADIOASTRONOMY

Very Large Array (New Mexico) ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY Very Large Array (New Mexico) 27 antenne di 25 m Dmax ~ 30 km Westerbork (Olanda) 14 antenne di 25 m Dmax ~ 3 km Esempi di interferometri: Westerbork (Olanda): 14 antenne di 25 metri. Dmax = 3 km ATCA (Australia): 6 antenne di 22 m. Dmax = 6 km VLA (New Mexico): 27 antenne di 25 m. Dmax = 30 km (1” a 20 cm) ATCA (Australia) 6 antenne di 22 m Dmax ~ 6 km 1” a 20 cm RADIOASTRONOMY

European VLBI Network – EVN ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY European VLBI Network – EVN L’EVN. 18 Antenne di cui 2 in Cina, 1 in Sud Africa e 1 negli Stati Uniti (Arecibo). E’ mostrato anche il correlatore EVN situato Dwingeloo (Olanda). Cl 18 Antenne RADIOASTRONOMY

Very Long Baseline Array (VLBA) ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY Very Long Baseline Array (VLBA) Dal 1993 10 antenne da 25-m sparse tra USA e Canada Correlatore a Socorro RADIOASTRONOMY

Very Long Baseline Interferometry : VLBI EVN Spatial VLBI

1144+35

3C 264

z 1” 1 mas 0.06 1.6 kpc 1.6 pc 0.16 3.6 kpc 3.6 pc 0.5 7.1 kpc 7.1 pc Cyg A 3C 273 3C 48 Resolving Power radians  = 20 cm, D = 1000 km   = 0.04”

VLBI studies of radio galaxy nuclei : one of the most important results is the detection of proper superluminal motion Expansion of about 6 pc in 3.5 years:  velocity  6c

QUASAR 1642+690 z = 0.75 The southernmost feature is moving at about 9c (Venturi et al. 1997)

Observation performed with the space VLBI at 5 GHz QUASAR 1928+738 z = 0.302 Aug 97 Sep 01 Observation performed with the space VLBI at 5 GHz (Murphy et al. 2003)

For example :  = 10o and v = 0.999c then : v(OBS) = 10.7 c By the time that light leaves from position (2), light emitted from position (1) will have travelled a distance AC The difference in arrival time for the observer is : SUPERLUMINAL MOTION The apparent velocity as seen by the observer is For example :  = 10o and v = 0.999c then : v(OBS) = 10.7 c

The detection of superluminal motions and of one-sided jets in the majority of both low power and high power radio galaxies indicates that the jets at their basis are all strongly relativistic

Effetto Doppler e boosting relativistico Se una sorgente si muove con v = βc in una direzione che forma angolo θ con la linea di vista abbiamo o = e/((1-βcosθo)) = e D Dove  e’ il fattore di Lorentz e D = 1/((1-βcosθo)) e’ il Doppler factor (velocita’ positiva in avvicinamento D > 1 quando β > 0 e o > e Se velocita’ bassa  ≈ 1 e D  (1 + β cosθo) Doppler classico Consideriamo sorgente con Luminosita’ totale Le e luminosita’ monocromatica L(e) La potenza irradiata in banda e sara’ ricevuta in banda o = e D

Consideriamo come varia luminosita’ – essendo radiazione per unita’ di tempo teniamo conto trasformazione energia fotoni o = e x D Trasformazione dei tempi dto = dte - dte  v cosθ/c = dte(1 – β cosθ) = dte/D sorgente si e’ avvicinata tra tempo emissione 2 fotoni La radiazione ricevuta in superficie unitaria compresa in cono angolo solido do che sara’ diverso da de do = de/D2 si ottiene da aberrazione relativistica ricordando che do ≈ π dθo2

In conclusione Lo = Le x D4 Boosting relativistico o Doppler boosting o relativistic beaming Se lavoriamo con luminosita’ monocromatiche Lo(o)do = Le(e)de x D4 da cui Lo(o) = Le(e) x D3 Se lo spettro e’ di sincrotrone L()  - possiamo scrivere Lo(o) = Le(o) x D3+ = Le(o) x D4 D-(1-) Il termine D-(1-) e’ noto come correzione K

JET RELATIVISTIC EFFECTS (DOPPLER BOOSTING) : Doppler factor Jet pointing toward the observer is AMPLIFIED

From the ratio between the approaching and the receding jet, the jet velocity and orientation can be constrained JET SIDEDNESS RATIO Ma se parliamo di getti o plasmoidi quasi continui si parla di brillanza: la lunghezza della struttura nella direzione del moto e’ influenzato da D ma lo spessore della struttura no (moto unidimensionale) ne segue che:

Jet sidedness Se  = 5 (β = 0.98) e  = 0.7 e θ = 0 risulta Ba/Br = R = 2 x 104 Ne consegue che dati 2 getti intrinsecamente uguali vedo solo quello che si muove verso di me e non l’altro From the jet to cj brightness ratio R we derive: Main problem: low luminosity radio jets do not give strong constraints: in 3C264 the highest j/cj ratio is > 37 corresponding to θ < 52o and β > 0.62

FR I - 3C 449 FR II - 3C 47

Radio image of the FR II radio galaxy Cygnus A. ~1 Mpc This galaxy also has HUGE radio lobes. The thin line through the galaxy is a jet ejected from the nucleus. The lobes occur where the jets plow into intracluster gas.

FR I radio galaxy: most of the energy comes from a small nucleus with a halo of weaker emission in a halo around the nucleus. Visible image of the core-halo (FR I) radio galaxy M87. This giant elliptical (E1) galaxy is ~100 Kpc across. It has a “jet” of material coming from the nucleus.

Close-up view of the jet in M87 at radio wavelengths. ~2 kpc galaxy nucleus, i.e. the radio core The jet is apparently a series of distinct “blobs”, ejected by the galaxy nucleus, and moving at up to half the speed of light. The jet and nucleus are clearly non-stellar.

Quasar BL Lac MK 501 Radio Galaxy 1144+35 BL Lac 0521-365

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. Pc = observed core radio power at 5 GHz Ptot = observed total radio power at 408 MHz La potenza del core e’ legata alla presenza del jet relativistico la potenza totale NO – a bassa frequenza cosi core non pesa essendo auto-assorbito

Alta e bassa Potenza: Relativistici Su scala piccola The comparison of the expected intrinsic and observed core radio power will constrain β and θ. A large dispersion of the core radio power is expected because of the dependance of the observed core radio power with θ. From the data dispersion we derive that Г has to be > 2 and < 10

Pc = Pi D(2+ ) Pbest-fit = P(60) = Pi D(2+ ) = Pi/2+(1-β cosθ)2+ = con θ = 60 Pi/2+(1-β/2)2+ Pi = P(60)/D(2+ ) da cui Pi = P(60) 2+(1-β/2)2+ e Pc = P(60) (1-β/2)2+ / (1-β cosθ)2+ Assumendo  = 0 (nucleo) Pc = P(60) (1-β/2)2 / (1-β cosθ)2 (Pc/P(60))0.5 = (1-β/2)/ (1-β cosθ) Pc da osservazioni P(60) da Ptot e best fit Possiamo assumere tutti i getti circa stessa velocita  posizione punti solo legati a orientazione MA dispersione dipende da velocita’ dei getti Problema: variabilita’ !!!!

Conseguenze di tempi diversi Getto relativistico in avvicinamento insegue suoi fotoni per cui intervalli di tempo non si conservano Se emesso segnale a tempo t=0 e segnale successivo a intervallo tempo ta, osservatore riceve segnale a t2 = ta+(d – vta cosθ)/c Osservatore vede 2 segnali a t = t2 – t1 = ta(1 – v/c cosθ) = ta(1 – β cosθ) Se 2 getti o lobi intrinsecamente simmetrici si muovono relativist. appariranno diversi perche li vediamo a t intrinseco diverso a = approaching ed r receading ta = t /(1-β cosθ) tr = t /(1+β cosθ) Essendo L’a = La sinθ = vta sinθ e L’r = Lr sinθ = vtr sinθ L = Lunghezza (size)

Arm length ratio risulta che: By comparison of the size of the approaching (La) and receding (Lr) jet we derive: o anche La/Lr = L’a/L’r = θa/θr = Da/Dr

Lobi radio: Mediano asimmetria flussi = 1.6 se dovuto a moto relativistico ne derivo β cosθ ≈ 0.06 da cui β < 0.1 Inoltre risulta che Sa/Sr = (θa/θr)3+ da cui lobo piu’ lontano dal nucleo dovrebbe essere piu’ luminoso, ma cio’ non verificato anzi contrario Tutto porta a derivare velocita’ espansione lobi < 0.1c Tale velocita’ e’ anche in accordo con diametro e stima eta’ della radio sorgente

THE MEASUREMENT OF THE JET VELOCITY Proper Motion In some sources proper motion has been detected allowing a direct measure of the jet apparent pattern velocity. The observed distribution of the apparent velocity shows a large range (e.g. Kellerman et al. 2000)

From the measure of the apparent velocity we can derive constraints on β and θ: 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. 1999 for 1144+35 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. 2003, ApJ) βamax = β ≈  per v ≈ c Il massimo si ha per cos θ = β ossia sen θ = 1/ (θ ≈ 1/ per  grandi)

Se il redshift e’ molto elevato occorre inserire correzione relativistica perche’ tutto si sta allontanando da noi con moto relativistico Sempre: v = βc e’ la velocita’ del blob rispetto al nucleo della sorgente Vedi astro-ph/0407478, 9-9-04

On the parsec scale it shows a core, a strong extended jet and a short cj counterjet flat spectrum core main jet

Superluminal motion Well defined components – 11 epochs from 1991 to 2002 Only high quality data: jet: 5 and 8.4 GHz data cj 8.4 GHz only Jet: βapp = 2.7 constant All components constant velocity cj side βapp = 0.3

Since we know the j and cj proper motion according to Mirabel et al. 1994 we can derive the jet orientation: μa = β senθ/(1 – β cosθ) c/D μr = β senθ/(1 + β cosθ) c/D che diventano β cosθ = (μa – μr) /(μa + μr) = 0.8 cgs e moti propri in radianti s-1 Da cui D <= c/(μaμr)0.5 (velocita’ massima e’ c) (distance of the superluminal galactic source) .

From the j-cj arm ratio ( about 10) we derive β cosθ = 0.8 in agreement with the measured pattern velocity

Shear-layer δ = 2.4 - boosted If the inner spine is moving with e.g. Г = 15 the corresponding Doppler factor is 0.7 – deboosted. A fast spine and a lower velocity shear layer can explain the limb brightened structure. core If the external region started with the same velocity of the inner spine, its velocity decreased from 0.998 to 0.88c in less than 100 pc. This suggest a velocity structure already present at the jet beginning.

Results From our study on 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

The line is the general correlation between the core and total 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.

Struttura dei nuclei radio Strutture compatte auto assorbite Non vediamo ‘core’ ma base del getto Autoassorbimento: Tb simile a temperatura cinetica elettroni relativistici Spettro a campana radiosorgente opaca a se stessa in regime opaco flusso cresce come 2.5, dove la sorgente e’ trasparente flusso cala come - Indicando con max ed Smax la frequenza dove lo spettro raggiunge il massimo e con Smax il flusso corrispondente abbiamo H(gauss) ≈ 3.2 10-5(θ(mas))4(max(GHz))5(Smax(Jy))-2 D/(1+z) con D = fattore Doppler

Dove θ e’ il diametro angolare nella zona di transizione quindi abbiamo stima del campo magnetico viceversa assumendo il campo magnetico di equipartizione possiamo stimare diametro angolare della rs Spettro = somma spettri di singole componenti da cui spettro piatto 3C 338 a FR I radio galaxy 3C 452 a NL FR II radio galaxy

Variabilita’ Compatte mostrano variabilita’ piu’ o meno marcata in tutte le bande A frequenze < 1 GHz scintillazione interstellare Variabilita’ a lungo periodo ad alta frequenza intrinseco: modello nube inizialmente opaco che espande e diventa trasparente a frequenze sempre piu’ basse e con flussi sempre minori (perdite adiabatiche) La variabilita’ avviene a tempi diversi a diverse frequenze Variabilita’ a corto periodo Assumendo che dimensioni lineari sorgente siano < cTv dove Tv e’ il tempo della variabilita’, ne derivano dimensioni angolari < 10-4 10-5 arcsec

Tbo = Tbi x D Da dimensioni angolari cosi piccole risulta che I = F/πθ2 = B = 2kTb/2 Se e’ θ piccolo e/o  e’ grande possiamo ottenere Tb() > 1012 K Per cui 1) emissione coerente – difficile per regioni cosi grandi 2) diametri sottostimati Infatti T alta implica radiazione alta energia non osservata e vita breve della rs Possibile soluzione nube in espansione in moto relativistico verso di noi Tbo = Tbi x D

History The present status AGN Unification History The present status

What’s all this Unification? Historically it is attempt to explain as much as the spread of observational properties as possible in terms of orientation effects. Assume some axis; i.e. rotation More generally, it is an attempt to explain the diversity of observational properties in terms of a simple model

The AGN Paradigm

Introduction AGN are not spherically symmetric and thus what you see depends on from where you view them. This is the basis of most unification models. It was the discovery of superluminal motion and the interpretation in terms of bulk relativistic motion of the emitter that first made people realize that orientation in AGN was important. I will outline the consequences of Doppler boosting, describe the historical development of schemes and then review the modern evidence. N.B. Relativistic beaming is not the only mechanism that can make AGN emission anisotropic

Doppler boosting When an emitting body is moving relativistically the radiation received by an observer is a very strong function of the angle between the line of sight and the direction of motion. The Doppler effect changes the energy and frequency of arrival of the photons. Relativistic aberration changes the angular distribution of the radiation.

Parent populations To every beamed source there will be many unbeamed sources – the parent population. How to identify the parent population? Look at some emission that’s isotropic; e.g. radio lobe emission, far infrared emission, narrow-line emission, etc in the beamed population and look for another population having the same luminosity function for the isotropic emission.

History of Unification Rowan-Robinson (1976, ApJ, 213,635) tried to unify Seyfert galaxies and radio sources. Mostly wrong – no beaming But the importance of dust and IR emission correct. Blandford and Rees (Pittsburgh BL Lac meeting 1978) laid the foundations for beaming unification. (Radio loud only).

History continued Scheuer and Readhead (1979, Nature,277,182) proposed that radio core-dominated quasars and radio quiet quasars could be unified – the former being beamed versions of the latter. Orr and Browne (1982,MNRAS,200,1067 ) realized that the Scheuer and Readhead scheme could not work because MERLIN and VLA had shown that most of the core-dominated quasars had extended (isotropic) radio emission and thus their parent population could not be radio quiet. We looked for a non-radio quiet parent population Proposed core-dominated/lobe-dominated unification for quasars

Radio Galaxy/Quasar Unification (Both are FR2s) Widely discussed before, but first published by Barthel (1989, ApJ, 336,606) – an extension of core-dominated/lobe-dominated quasar unification. Quasars have strong continuum and broad lines and radio galaxies (FR2s) have little continuum (other than starlight) and no broad lines. How could they be the same thing? Only if one could hide the quasar nucleus with something optically thick (a molecular torus). N.B. In a parallel line of development Antonucci and Miller had discovered polarized broad lines in the Seyfert 2 NGC1068 which they interpreted as being scattered nuclear radiation from a hidden BLR.

The AGN Paradigm

BL Lacs and FR1 RGs Similar arguments apply to these intrinsically lower luminosity objects; BL Lacs are the beamed cores of FR1 RGs. (Note FR1 RGs generally have only weak and narrow emission lines and BLLacs are almost lineless.) Blandford and Rees (1978) Browne (1983, MNRAS,204,23) Antonucci and Ulvestad (1985,ApJ,294,158) Padovani and Urry (1991, ApJ,368,373)

Evidence for BL Lac/FR1 unification The statistics look ok (Browne; Padovani and Urry) for reasonable Lorentz factors The required relativistic jets are seen in a few FR1s, most notably in M87 (Biretta AJ,520,621). The strength of optical cores in FR1s seems to correlate with the strength of the radio core consistent with both being beamed (Capetti &Celotti,1999,MNRAS,303,434, Chiaberge et al. 2000,A&A,358,104) => No hidden BLR in FR1s (but BL Lac itself has a broad line)

HST Image of jet in M87 M87 is an FR1 radio galaxy Superluminal motion has been detected in both radio and optical

Evidence for superluminal motion in M87

Correlation between optical nuclear and radio core luminosities (Chiaberge et al,A&A,358,104)

NGC6251 HST image of the optical core. Despite dust lane (dark band) the core is clearly visible The strength of cores correlated with that of radio core

Optical nuclei are very common.

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.

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

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

A correlation between X-ray and radio is expected if there is a fundamental connection between accretion flows and jets. Merloni et al. 2003 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

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)

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

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.

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.

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

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)

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.

Radio map of 3C175

CHANDRA X-Ray Jet in Pictor-A

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?)

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)

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

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

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 -------------------------------------------------------------------------

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

Seyfert 1 - Quasars Similar spectra and line ratios, strong UV flux to excite lines, probably similar L/LEdd ~ 0.1-0.3 Increasing L Increasing M

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

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

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

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

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% )

The spectral peak Their main property is the optically-thin 1. Introduction The spectral peak Optically thin Optically thick nb n-a Log  Log S() Their main property is the optically-thin steep spectrum that turns over at low frequencies. (D=1!)

Turnover frequency versus linear size Implica campi magn. simili

1. Introduction The peak frequency Turnover

Linear size - turnover CSS GPS HFP LLS < 15 - 20 kpc 1. Introduction Linear size - turnover HFP GPS CSS LLS < 15 - 20 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

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”)

High resolution observations! 1. Introduction High resolution observations! MSO: VLA  1” @ 21 cm; 0.1” @ 3.6 cm

High resolution observations! 1. Introduction High resolution observations! CSO: VLBI  0.01” @ 21 cm; 0.001” @ 3.6 cm VLBA EVN

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

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

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

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

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.

Youth: Spectral analysis 1. Introduction Youth: Spectral analysis B1943+546, 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

Youth: spectral analysis 1. Introduction Youth: spectral analysis B0147+400

1. Introduction Youth: radiative age trad ~ 103 yr

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

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.

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

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

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

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

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

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

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

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

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

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

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

2. Radio properties Faraday screen

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

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

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

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

The quasar J1459+3337 t ~ 50 yr Rapid evolution of radio emission 2. Radio properties The quasar J1459+3337 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

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

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

? 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

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%

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)

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

…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

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

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

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’. © This slide is made available for non-commercial use only. Please note that permission may be required for re-use of images in which the copyright is owned by a third party. Monthly Notices of the Royal Astronomical Society Volume 408, Issue 4, pages 2261-2278, 30 SEP 2010 DOI: 10.1111/j.1365-2966.2010.17271.x http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2010.17271.x/full#f4 153

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. © This slide is made available for non-commercial use only. Please note that permission may be required for re-use of images in which the copyright is owned by a third party. Monthly Notices of the Royal Astronomical Society Volume 408, Issue 4, pages 2261-2278, 30 SEP 2010 DOI: 10.1111/j.1365-2966.2010.17271.x http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2010.17271.x/full#f5 154

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?

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

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

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 0836+29B 4C29.30 A galaxy merger 100Myr Jamrozy et al. 2007

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

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

Fossils from the past On kpc scales: J0111+3906: 128 kpc 3. Source evolution Fossils from the past On kpc scales: J0111+3906: 128 kpc trelic ~ 107–108 yr On pc-scales: J1511+0518: 50 pc OQ208: 43 pc trelic ~ 103 – 104 yr

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

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!!

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!

Magnetic field In the presence of SSA from homogeneous component: 4. Physical properties Magnetic field In the presence of SSA from homogeneous component: HSSA = f()5 S2p (1+z) max min 5p Kellermann&Pauliny-Toth 81

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

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…

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

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

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

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

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)

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

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

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);

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

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)

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)

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

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

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

VLBI observations Central disk HI detected against the whole source 5. The ambient medium VLBI observations 1946+708, Peck+ 99 HI detected against the whole source Central disk v = 350 km/s NH  2x1023 cm –2 (Ts = 8000 K)

VLBI observations Off-nuclear cloud 5. The ambient medium VLBI observations 0402+379, Maness+04 HI detected only against the southern hot spot Off-nuclear cloud v = 540 km/s NH  2x1020 cm –2 (Ts = 100 K)

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○

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

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)

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!!

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

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

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!!