Presentation is loading. Please wait.

Presentation is loading. Please wait.

Continuo Infrarosso IR puo essere non termico (sincrotrone) o termico. Importante slope del cut off submm Se sincrotrone auto-assorbimento a = -2.5 Il.

Similar presentations


Presentation on theme: "Continuo Infrarosso IR puo essere non termico (sincrotrone) o termico. Importante slope del cut off submm Se sincrotrone auto-assorbimento a = -2.5 Il."— Presentation transcript:

1 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

2 Recent result: Baldi et al. arXiv: 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

3 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

4 Effetti con z e/o Luminosita Spettri in ottico e UV non mostrano dipendenza da luminosita o redshift in QSS ma α ox 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

5 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

6 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 cant explain everything… NGC 1097 Storchi-Bergmann et al. (2003)

7 Continuo Banda Radio Importante storicamente e non, ma in L bolometrica 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 T b intendo la temperatura che dovrebbe avere un CN per irradiare lo stesso flusso. I = F /πθ 2 = B = 2kT b / 2 F = flusso osservato monocromatico; θ diametro angolare della sorgente. Si ottiene T – K che chiaramente indica una origine non termica

8 Esiste una T b massima dellordine di K in quanto densita energia del campo magnetico: U mag = B 2 /8π controlla rate delle perdite di sincrotrone Con densita di energia U rad = 4πJ/c Quando U rad e al punto che supera U mag inizia ad essere rilevante linterazione di Compton inverso. Poiche non vediamo una intensa radiazione in banda gamma significa che: U rad /U mag < 1 che corrisponde a T max K (catastrofe Compton) Nuclei radio: sorgenti compatte su risoluzione angolare arcsecond con alta T b 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

9 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 ma seeing…. Radio non ha grossi problemi con atmosfera a frequenze fino a 22 GHz per cui R meglio di 1 mas

10 Accuratezza Specchio 0.1 RADIOASTRONOMY ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY Il Radiotelescopio Simile a telescopio ottico! Sub- riflettore Sostegno Ricevitori

11 Importanti caratteristiche del telescopio Sensibilità D 2 Potere Risolutore /D RADIOASTRONOMY ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY Banda radio: = 20 cm D= 80 m 10 D= 30 m 30 D=700 m 1 Pupilla: ~ mm D = 5 mm 1

12 Parkes ( Australia ) 64 m Jodrell Bank ( Manchester ) 75 m Effelsberg ( Bonn ) 100 m Green Bank ( WEST VIRGINIA ) 100x110 m ( Agosto 2000) Arecibo (Portorico) 300 m

13 RADIOASTRONOMY ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY L INTERFEROMETRO Potere Risolutore: ~ /d (d = distanza antenne) Sensibilità: ~ N x D 2 (N=numero antenne) d

14 Westerbork (Olanda) 14 antenne di 25 m D max ~ 3 km RADIOASTRONOMY ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY ATCA (Australia) 6 antenne di 22 m D max ~ 6 km Very Large Array (New Mexico) 27 antenne di 25 m D max ~ 30 km 1 a 20 cm

15 RADIOASTRONOMY ISTITUTO DI RADIOASTRONOMIA, INAF - ITALY European VLBI Network – EVN 18 Antenne

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

17 Very Long Baseline Interferometry : VLBI VLBAVLBA VLBAVLBA Spatial VLBI EVN

18

19

20 3C 264

21 z1 1 mas kpc 1.6 pc kpc 3.6 pc kpc 7.1 pc Cyg A 3C 273 3C 48 Resolving Power radians = 20 cm, D = 1000 km = 0.04

22 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 Expansion of about 6 pc in 3.5 years: velocity 6c

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

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

25 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 : 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 : The apparent velocity as seen by the observer is The apparent velocity as seen by the observer is SUPERLUMINAL MOTION For example : = 10 o and v = 0.999c then : v(OBS) = 10.7 c For example : = 10 o and v = 0.999c then : v(OBS) = 10.7 c

26 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

27 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-βcosθ o )) = e D Dove e il fattore di Lorentz e D = 1/( (1-βcosθ o )) e il Doppler factor (velocita positiva in avvicinamento D > 1 quando β > 0 e o > e Se velocita bassa 1 e D (1 + β cosθ o ) Doppler classico Consideriamo sorgente con Luminosita totale L e e luminosita monocromatica L( e ) La potenza irradiata in banda e sara ricevuta in banda o = e D

28 Consideriamo come varia luminosita – essendo radiazione per unita di tempo teniamo conto trasformazione energia fotoni o = e x D Trasformazione dei tempi dt o = dt e - dt e v cosθ/c = dt e (1 – β cosθ) = dt e /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 /D 2 si ottiene da aberrazione relativistica ricordando che d o π dθ o 2

29 In conclusione L o = L e x D 4 Boosting relativistico o Doppler boosting o relativistic beaming Se lavoriamo con luminosita monocromatiche L o ( o )d o = L e ( e )d e x D 4 da cui L o ( o ) = L e ( e ) x D 3 Se lo spettro e di sincrotrone L( ) - possiamo scrivere L o ( o ) = L e ( o ) x D 3+ = L e ( o ) x D 4 D -(1- ) Il termine D -(1- ) e noto come correzione K

30

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

32 JET SIDEDNESS RATIO From the ratio between the approaching and the receding jet, the jet velocity and orientation can be constrained From the ratio between the approaching and the receding jet, the jet velocity and orientation can be constrained 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:

33 Jet sidedness Se = 5 (β = 0.98) e = 0.7 e θ = 0 risulta B a /B r = R = 2 x 10 4 Ne consegue che dati 2 getti intrinsecamente uguali vedo solo quello che si muove verso di me e non laltro 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 0.62

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

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

36 This giant elliptical (E1) galaxy is ~100 Kpc across. It has a jet of material coming from the nucleus. Visible image of the core-halo (FR I) radio galaxy M87. 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.

37 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.

38 BL Lac BL Lac MK 501 Radio Galaxy Quasar

39 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. Radio core dominance P c = observed core radio power at 5 GHz P tot = 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

40 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 Alta e bassa Potenza: Relativistici Su scala piccola

41 Pc = Pi D (2+ ) P best-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 !!!!

42 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 t a, osservatore riceve segnale a t 2 = t a +(d – vt a cosθ)/c Osservatore vede 2 segnali a t = t 2 – t 1 = t a (1 – v/c cosθ) = t a (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 t a = t /(1-β cosθ) t r = t /(1+β cosθ) Essendo L a = L a sinθ = vt a sinθ e L r = L r sinθ = vt r sinθ L = Lunghezza (size)

43 By comparison of the size of the approaching (L a ) and receding (L r ) jet we derive: Arm length ratio risulta che: o anche L a /L r = L a /L r = θ a /θ r = D a /D r

44 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 S a /S r = (θ a /θ r ) 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

45 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) THE MEASUREMENT OF THE JET VELOCITY

46 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 Cotton et al for NGC 315 Giovannini et al for However in the same source we can have different pattern velocities as well as standing and high velocity moving structures

47 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) β amax = β per v c Il massimo si ha per cos θ = β ossia sen θ = 1/ (θ 1/ per grandi)

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

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

50 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: β app = 2.7 constant All components constant velocity cj side β app = 0.3 Superluminal motion

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

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

53 Shear-layer δ = 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. If the external region started with the same velocity of the inner spine, its velocity decreased from to 0.88c in less than 100 pc. This suggest a velocity structure already present at the jet beginning. core

54 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 Results

55 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. M87 3C192

56 Struttura dei nuclei radio Strutture compatte auto assorbite Non vediamo core ma base del getto Autoassorbimento: T b 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 S max la frequenza dove lo spettro raggiunge il massimo e con S max il flusso corrispondente abbiamo H(gauss) (θ(mas)) 4 ( max (GHz)) 5 (S max (Jy)) -2 D/(1+z) con D = fattore Doppler

57 3C 452 a NL FR II radio galaxy 3C 338 a FR I radio galaxy 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

58 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 < cT v dove T v e il tempo della variabilita, ne derivano dimensioni angolari < arcsec

59 Da dimensioni angolari cosi piccole risulta che I = F /πθ 2 = B = 2kT b / 2 Se e θ piccolo e/o e grande possiamo ottenere T b ( ) > 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 T bo = T bi x D

60 AGN Unification History The present status

61 Whats 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

62 The AGN Paradigm

63 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

64 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.

65

66 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 thats 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.

67 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).

68 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

69 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.

70 The AGN Paradigm

71

72 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)

73 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)

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

75 Evidence for superluminal motion in M87

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

77 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

78 Optical nuclei are very common.

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

80 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 FR I BL Lacs Chiaberge et al. 1999

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

82 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 L R, log L X, log M BH. They used AGN and X-ray binaries (SMBH and BH) but not BL Lacs because of beaming

83 observed intrinsic 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)

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

85 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.

86 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.

87 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

88 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)

89 Correlations -- Radio If jets are relativistic, some unification is inevitable. Whats 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.

90 Radio map of 3C175

91 CHANDRA X-Ray Jet in Pictor-A

92 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?)

93 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)

94 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

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

96 Apparenza AGN dipende da angolo rispetto a linea di vista 1)Toro oscurante – nasconde AGN e BLR in type 2 AGN 2) 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 P core e nucleo ottico in FR I In accordo con assenza righe Bl-Lacs

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

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

99 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

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

101

102

103

104

105

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

107

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

109 Young radio sources ();Powerful in radio band (P 1.4 GHz > 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% ) 1. Introduction

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

111 Turnover frequency versus linear size Implica campi magn. simili

112 The peak frequency Turnover 1. Introduction

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

114 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) 1. Introduction

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

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

117 Morphology Hot spots Core150 kpc 4.5 kpc HS Core HS Core HS Scaled-down version of the classical Extended Doubles: they should represent the young stage in radio source evolution 7 pc350 pc 1. Introduction

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

119 Youth: Proper motion Young Hot spots Core B Polatidis&Conway 03 v sep = 0.3c t kin ~ LS v sep ~ 10 3 yr!! 1. Introduction

120 Youth: Proper motion Core Hot-Spot v sep = 0.12c B t kin ~ 3·10 3 yr Owsianik et al Introduction

121 Kinematic age The kinematic ages derived for a dozen of the most compact (100 pc) CSOs are in the range of 10 3 – 10 4 yr, much shorter than the ages estimated for the largest (up to a few Mpc) radio galaxies. Polatidis&Conway Introduction

122 Youth: Spectral analysis From the break frequency br we can derive the radiative age, once the magnetic field is known! t rad br -1/2 H -3/2 From br in the lobes: t rad ~ 10 3 yr B , Murgia Introduction

123 Youth: spectral analysis B Introduction

124 Youth: radiative age t rad ~ 10 3 yr 1. Introduction

125 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

126 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. 1. Introduction

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

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

129 Radio properties Flux density and spectral variability; Radio morphology; Polarization. 2. Radio properties

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

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

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

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

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

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

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

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

138 Faraday screen 2. Radio properties

139 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 2. Radio properties

140 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 2. Radio properties

141 …with some exceptions J Quasar z=0.45 v sep = 0.39c±0.18c t kin = 360±170 yr 2. Radio properties

142 The quasar J From the source expansion: From the flux density ratio: v i =0.43c±0.04c 12 < θ < Radio properties

143 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 2. Radio properties

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

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

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

147 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 yr yr ~~ 0.01% 3. Source evolution

148 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) 3. Source evolution

149 Luminosity evolution… If the thrust of each relativistic jet is balanced by the ram-pressure of the surrounding medium: v PjPjPjPj n ext m p cA 1/2 u Pj tPj tPj tPj tV Velocity: Energy density: luminosity Assuming equipartition, the luminosity is: L P j t V 3/7 7/4 3. Source evolution

150 …in a King-like density profile n ext n ext n0n0n0n0 1 + r2r2r2r2 r02r02r02r02 - /2 r < r 0 (like CSO) r < r 0 (like CSO) r > r 0 (like MSO) r > r 0 (like MSO) v t -1/2 L t 5/8 v t L t Source evolution

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

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

153 A survey of low luminosity compact sources and its implication for the evolution of radio loud active galactic nuclei – I. Radio data Monthly Notices of the Royal Astronomical Society Volume 408, Issue 4, pages , 30 SEP 2010 DOI: /j x Volume 408, Issue 4,

154 A survey of low luminosity compact sources and its implication for the evolution of radio loud active galactic nuclei – I. Radio data Monthly Notices of the Royal Astronomical Society Volume 408, Issue 4, pages , 30 SEP 2010 DOI: /j x Volume 408, Issue 4,

155 Fading radio sources Despite the luminosity evolution, young objects are still too many The age distribution sharply peaks below 500 yr Young but fading objects? Gugliucci et al Source evolution

156 PKS : a study case t syn = 2700±600 yr t OFF = 550±100 yr Neither injection nor acceleration of new particles! 3. Source evolution

157 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: 10 3 yr Eddington accretion rate: 10 8 yr 3. Source evolution

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

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

160 1 kpc 5 pc core 15 yrs 70 yrs Strong outburst after 1990 Jamrozy et al

161 Fossils from the past On kpc scales: J : 128 kpc t relic ~ 10 7 –10 8 yr On pc-scales: J : 50 pc OQ208: 43 pc t relic ~ 10 3 – 10 4 yr 3. Source evolution

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

163 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!!

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

165 Magnetic field In the presence of SSA from homogeneous component: H SSA = f( ) 5 S 2 p (1+z) max min 5 p Kellermann&Pauliny-Toth Physical properties

166 Are young objects in equipartition? In case of equipartition: H eq (1+k) 2/7 -2/7 P 2/7 V -2/7 H eq H SSA Pacholczyk 1970 Orienti&Dallacasa Physical properties

167 Are young objects in equipartition? In case of equipartition: H eq (1+k) 2/7 -2/7 P 2/7 V -2/7 Pacholczyk 1970 H eq H SSA Orienti&Dallacasa 08 with some exceptions… 4. Physical properties

168 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!!! H SSA cannot be derived 4. Physical properties

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

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

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

172 4C31.04: a CSO z = 0.06 S 1.4 GHz = 2.5 Jy P 1.4 GHz = 2.4 x W/Hz M H =-23.6 (Perlman et al. 2001) 1 mas/yr = 5.4 c (H 0 = 50 km sec -1 Mpc -1 )

173 5 GHz, epoch July 2000 (10 mas = 15 pc)

174 Expansion... results. E ~ 0.4 mas W ~ 0.5 mas T = 5 yr v ~ 0.5 c age ~ 500 yr

175 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); High detection rate (~40%)of molecular gas (CO) in emission (Mack+ 09); Highly depolarized sources; Highly depolarized sources; 5. The ambient medium

176 The ambient medium The jet is piercing its way through the dense medium left by the merger 4C 31.04, Conway The ambient medium

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

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

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

180 The molecular gas Symmetric Doubled- peak profile Disk structure Ocaña-Flaquer et al 2010 M disk ~ 1.4·10 10 M M disk ~ 1.4·10 10 M 5. The ambient medium

181 The molecular gas HCO + (1-0) CO (2-1) Asymmetric doubled- peak profiles Unsettled disk? M disk ~ 5·10 9 M M disk ~ 5·10 9 M Garcia-Burillo+ 08 …and the absorption? 5. The ambient medium

182 VLBI observations , Peck+ 99 v = 350 km/s N H 2x10 23 cm –2 (T s = 8000 K) HI detected against the whole source Central disk 5. The ambient medium

183 VLBI observations v = 540 km/s N H 2x10 20 cm –2 (T s = 100 K) , Maness+04 HI detected only against the southern hot spot Off-nuclear cloud 5. The ambient medium

184 VLBI observations 4C Morganti+ 04 v = 150 km/s N H cm –2 (T s = 100 K) HI located ~100 pc from the core, where the jet bends Off-nuclear cloud M cl ~ 10 6 M M cl ~ 10 6 M 5. The ambient medium

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

186 Jet-cloud interaction v 2000 km/s N H 2.6x10 21 cm –2 (T s = 1000 K) Shallow, broad and blue-shifted component Outflow! Morganti+ 04 4C The ambient medium

187 Outflows OQ 208, Orienti+ 06 Δv ~ 2000 km/s τ ~ N HI ~ 8·10 20 cm -2 Amounts of gas are expelled from the host galaxy!! 5. The ambient medium

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

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

190 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!! 5. The ambient medium


Download ppt "Continuo Infrarosso IR puo essere non termico (sincrotrone) o termico. Importante slope del cut off submm Se sincrotrone auto-assorbimento a = -2.5 Il."

Similar presentations


Ads by Google