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Unified Schemes for Radio-Loud Active Galactic Nuclei

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Unified Schemes for Radio-Loud Active Galactic Nuclei Powered By Docstoc
					               The disk-jet link:
  X-ray and radio monitoring of PKS 0558-504

                  Mario Gliozzi (GMU)
 I. Papadakis (Crete)             W. Brinkmann (MPE)
              L. Kedziora-Chudczer (Sidney)


*Disk-jet connection
*AGN-GBH analogy
*PKS 0558-504 in Grand Unification Model

*Results from RXTE & radio monitoring

*Conclusions & future work
                           Disk & Jet

*Basic Ingredients of BH systems:
 Most evident manifestations of BH presence



*Growing evidence (theory, observations, simulations)
 of strong accretion-ejection link:
 No jet without accretion but not vice versa


*Main Goals:
1) Understand the conditions leading to jet formation/quenching
2) Assess jet role in energetics of the system
                   X-ray & Radio monitoring
Previous studies demonstrate crucial role of radio X-ray monitoring:
X-rays track the accretion activity
Radio tracks the jet activity

 Microquasar GRS1915+105              BLRG 3C120
 [Mirabel et al. 1998]                [Marscher et al. 2002]




Same phenomena occur on different scales: analogy GBHs -AGN
                     Grand Unification Model
GBHs scaled down versions of AGN:
AGN classes correspond to GBHs in different spectral states
[e.g., Mc Hardy et al. 2006]

2 main spectral states:
1) Low/Hard State (LS) and 2) High/Soft State (HS)

  LS energy spectrum:                      HS energy spectrum:




               E [keV]                                E [keV]


                                       [Fig from Zdziarski & Gierlinski 2004]
                   Grand Unification Model
GBHs scaled down versions of AGN:
AGN classes correspond to GBHs in different spectral states
[e.g.,Mc Hardy et al. 2006]

2 main spectral states:
1) Low/Hard State (LS) and 2) High/Soft State (HS)

  LS power spectrum:                       HS power spectrum:




                                          [GX 339-4 Homan & Belloni 2004]
                    Grand Unification Model
GBHs scaled down versions of AGN:
AGN classes correspond to GBHs in different spectral states
[e.g.,Mc Hardy et al. 2006]

2 main spectral states:
1) Low/Hard State (LS) and 2) High/Soft State (HS)

  LS radio properties:                        HS radio properties:
Persistent radio emission
                                           Weak/absent radio emission
Correlation with X-rays: LR~LX0.7
                                           Jet quenching
Emission from compact jet



                      [Cyg X-1 Sterling et al. 2001]



                                      [Fender et al. 2004; E. Gallo et al. 2004;]
            GBH Intermediate State

                       HID: model-independent
                            way to describe GBH
                            evolution
                       Existence of Intermediate
                       spectral State (IS)

                       [GX 339-4 Homan & Belloni 2004]




IS energy spectrum:




                        [Fig from Zdziarski & Gierlinski 2004]
            GBH Intermediate State

                       HID: model-independent
                            way to describe GBH
                            evolution
                       Existence of Intermediate
                       spectral State (IS)




IS power spectrum:




                        [Fig from Homan & Belloni 2004]
                   GBH Intermediate State

                                    HID: model-independent
                                         way to describe GBH
                                         evolution
                                    Existence of Intermediate
                                    spectral State (IS)




   IS radio properties:

Transient & strong radio emission
Steep spectrum
Large bulk Lorentz factor
Most powerful jet ejections


                                    [GRS1915+105 Mirabel & Rodriguez 1998]
                  AGN-GBH Correspondence
 LS           LLAGN
 Based on generalization of HID [Koerding et al. 2006]
 Based on “fundamental plane” [Merloni et al. 2003; Falke et al. 2004]

 HS           Seyfert 1
 Based on PSD
 [Uttley et al. 2002; Markowitz et al. 2003; McHardy et al. 2006]

 IS           ?
Importance of finding IS-analog AGN:
frozen look of BH systems during major ejections

IS requirements:
* high accretion rate
* strong radio emission
* steep energy spectrum
* PSD with QPOs
                         PKS 0558-504
In principle any radio-loud NLS1 satisfies basic requirements for IS,
but only few of these objects [Komossa et al. 2005]
only PKS 0558-504 bright enough for RXTE monitoring
(F2-10 keV ~ 2x10-11 erg cm-2 s-1, L2-10 keV ~ 1045 erg s-1)


Radio-loud:       R~30                                 [Siebert et al. 1999]



BH mass: MBH~4x107 Msolar                              [Wang et al. 2001]



X-rays: Bright, Steep PL (Г~2.2), Variable             [Gliozzi et al. 2007]
        Extremely variable: 67% flux variation in 3’   [Remillard et al. 1991]
                       Requirements for IS
High accretion rate?                     Yes
                       Lbol ~ LEdd
 Even considering MBH~ 5 Mvirial [Marconi et al. 2008]
 and different bolometric corrections [Vasudevan & Fabian 2007]


Jet radio emission?                       Maybe (wait and see)


PSD with QPO?                             No (at least not yet)
                                          Answer after XMM AO7
                                          5 orbits (660ks PI Papadakis)

Energy spectrum match?                    Maybe (but spectral degeneracy)

 Comptonization [O’Brien et al. 2001; Brinkmann et al. 2004]
 Ionized Reflection [Ballantyne et al. 2001; Crummy et al. 2006]
 SLIM disk [Haba et al. 2008]
 Beamed emission [Remillard et al. 1991; Gliozzi et al. 2001]
              Additional diagnostics for IS

 From model-independent studies of spectral variability:

1) Fractional variability flattens in IS from LS to HS
     [Gierlinski & Zdziarski 2005]

         LS                              IS                HS




                                     E [keV]




2) Short-term variability Cyg X-1 during IS characterized
   large flux changes without spectral variations
  [Malzac et al. 2006]
RXTE monitoring of PKS 0558-504
               Campaign:
               Started in March 2005;
               monitoring campaign under way

               Sampling:
               1 observation every 2 days
               + 3 periods of denser coverage
                (2 observations per day)
               [Gliozzi et al. 2007]

                  Soft [2.5-5 keV] and
                  Hard [5-15 keV] fluxes
                  highly variable on day-month
                  timescales.

                  Flux variability accompanied
                  by weak spectral variability.
                              Flux-Flux Plot
Plot Hard [5-15 keV] versus Soft [2.5-5 keV] count rate
to characterize the spectral variability
[e.g., Churazov et al. 2001; Taylor et al. 2003] .
Two possible scenarios:
1) If power-law trend:
   Spectral variability explained by pivoting.

2) If linear trend:
   Constant spectral shape with 2 components
   [Zdziarski et al. 2002]



                                 Linear trend        no spectral pivoting

                                 Intercept = 0       no contribution from
                                                     hard component



                Common physical origin for Soft & Hard
                         Fvar- E Plot
Plot Fractional variability Fvar vs energy

 Fvar=√(S2- <σerr2>)/<x>



                            Constant trend reminiscent
                            of GBHs in IS
                            [Gierlinski & Zdziarski 2005]




 Different from typical                        Mrk 501

 jet-dominated behavior:
     Fvar α E
 [Gliozzi et al. 2006]
                        HR-ct Plot

                        Plot of hardness ratio
                        HR=[5-15 keV]/[2.5-5 keV] vs. count rate
                        Constant trend reminiscent of Cyg X-1
                        in IS
                        [Malzac et al. 2006]




Different from typical
jet-dominated behavior:
   HR α ct
[Gliozzi et al. 2006]

                                               Mrk 501
                Radio Observations

                ATCA Imaging:18 GHz




F.O.V= 9”x13”

beam=0.5”

(1”=2.4 kpc)




Source
unresolved
                 Radio Observations

                 ATCA Imaging: 8.6 GHz




F.O.V= 18”x27”

beam=1”


(1”=2.4 kpc)




2 symmetric
lobes resolved
(d=14 kpc)
                 Radio Observations

                 ATCA Imaging: 4.8 GHz




F.O.V= 38”x58”

beam=2”

(1”=2.4 kpc)




2 symmetric
lobes resolved
(d=14 kpc)
               Radio Observations

               VLBI Imaging [S. Tingay]




jet resolved
(R~100 pc)
Radio Monitoring



       Radio emission highly variable



       Timescales longer compared
       to X-rays


       No trivial correlation with X-rays
       but longer baseline needed
               PKS 0558-504 IS-analog ?

High accretion rate?                Yes


Jet radio emission?                 Yes


Typical Spectral variability?       Yes



Energy spectrum match?              Maybe: no evidence for reflection




      PKS 0558-504 extraordinary object:
      high accretion rate AGN with strong radio jet,
      very bright, highly variable on all timescales.
                          Future Work


- From September 2008 PKS 0558-504 weekly
  monitored with SWIFT in Optical, UV, and soft X-ray
  to complement hard X-rays (RXTE) and hopefully
  radio monitoring.

-5 XMM-Newton orbits in AO7 for deep investigation
 of PSD (QPOs) and breaking spectral degeneracy
 via time-resolved spectroscopy.

- Further VLBI observations to investigate
  possible changes in the inner jet structure.

				
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posted:12/4/2011
language:English
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