Exploring the FRI/FRII radio dichotomy with the Fermi satellite - - PowerPoint PPT Presentation

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Exploring the FRI/FRII radio dichotomy with the Fermi satellite - - PowerPoint PPT Presentation

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Exploring the FRI/FRII radio dichotomy with the Fermi satellite Fermi and Jansky: Our Evolving Understanding of AGN PAOLA GRANDI INAF/IASF BOLOGNA, ITALY Fermi-LAT Collaboration E. Torresi (IASF, Italy) November 10-12, 2011 Harbour towne

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PAOLA GRANDI

INAF/IASF BOLOGNA, ITALY

Fermi-LAT Collaboration

  • E. Torresi (IASF, Italy)

Exploring the FRI/FRII radio dichotomy with the Fermi satellite

November 10-12, 2011

Harbourtowne Conference Center

St Michaels, MD, USA Fermi and Jansky: Our Evolving Understanding of AGN

Friday, November 11, 2011

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BL LACs FSRQs Other Extragalactic Sources

Abdo, A. A., et al. 2010a, ApJ, 715, 429 (1LAC); Abdo, A. A., et al. 2010b, ApJS, 188, 405 (1FGL)

In the Second Catalog of AGN (2LAC-ApJ in press) , the number of detected AGNs is increased by more than 40% (877 sources). The clean sample of the First Catalog

  • f AGN (1LAC) contains 599 sources

1 year 2 years

The Fermi sky

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δ =1/Γ(1-β cosθ) Γ

The Doppler factor relates intrinsic and observed flux for a moving source at relativistic speed v= c. For an intrinsic power law spectrum: F’(’) = K (v’)-a the observed flux density is F()= p F’’ () p=n+

Blazar

The majority of Extragalactic Sources are BL LAC and FSRQs

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  • 1. ¡SNR as particle accelerator -- SNR expanding shocks -> CR acceleration -> -rays

Narrow Line Seyfert 1 Sources Misaligned AGNs

¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡

  • 2. ¡AGN ¡as ¡par0cle ¡accelerator ¡ ¡-­‑> ¡Jets

Starburst Galaxies The “other” Extragalactic Sources belongs to two broad classes of

  • bjects reflecting two different particles acceleration processes:

h9p://wwwmagic.mppmu.mpg.de/magic/index.html

However ~3% of the -sources are not Blazars

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After 24 months of sky survey

Blazars Non-Blazars

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  • 2. ¡AGN ¡as ¡par0cle ¡accelerator: ¡Misaligned ¡AGN ¡(MAGN)

With MAGNs we intend Radio Sources with the jet not directly pointed towards the

  • bserver.

Blazars MAGNs NLRG BLRG ¡ ¡ ¡ SSRQs

BL ¡LACs FSRQS

MAGNs

Γ

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and/or MAGNs show: Steep Radio Spectra  >0.5 Resolved and possibly symmetrical structures in radio map

FRI are considered the PARENT POPULATION of BL LACs FRII are considered the PARENT POPULATION of FSRQs (SSRQs are in between) However the picture could be more complex (see Kharb, Lister and Cooper ApJ 2010)

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FIRST SAMPLE of MAGNS (15 MONTH-DATA)

Abdo, A. A., et al. 2010, ApJ, 720, 912 (MAGN)

FR I Radio Galaxy FRII SSRQ MAGNs are generally faint and soft sources F(>0.1 GeV)~10-8 Phot. cm-1 s-2   2.4

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T ext

The association of MAGNs to -ray LAT sources has raised some questions: First question Are we really missing FRII radio galaxies?

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3CRR sample  =178 MHz F> 10.9 Jy 173 sources 2Jy sample  =2.7 GHz F> 2 Jy 88 sources Molonglo Southern 4Jy sample MS4  =408 MHz F> 4 Jy 228 sources 3CR sample  =178 MHz F> 9 Jy 113 sources

Number of sources Radio Sources of 3CRR+3CR+2Jy+MS4 catalogs Radio Sources of 3CRR+3CR+2Jy+MS4 catalogs with LAT association

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Rate of Detections for each class

Source with TS >25

15 and 24 months of sky survey

FRII are the less detected objects

The -ray elusiveness of FRIIs has been also confirmed by a dedicated study of Broad Line Radio Galaxies (Kataoka et al. 2011)

Percentage of radio sources with -ray emission

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Are FRIIs elusive GeV sources because too far? Maybe not!

a b r P_r

TOT TOT TS>25 MAGN TS>25 5.1 (1.0) 0.7 (0.1) 0.74 >99.9% 6.2 (1.6) 0.6 (0.2) 0.65 99.9% 7.9 (1.2) 0.4 (0.1) 0.66 97.4%

The Radio ray fluxes are correlated

Log (f )1GeV = a + b x Log(f )5GHz

see also: Ghilranda et al. 2011, Ackermann et al. 2011 ApJ in press Friday, November 11, 2011

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Predicted fluxes @ 1 GeV of the 3CR+3CRR+MS4+2Jy sources Log (f )1GeV = a + b x Log(f )5GHz

Predicted Observed

correlation based on the MAGN sample

FRI: observed sources FRI: expected sources FRII: expected sources FRII: observed sources

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Predicted fluxes @ 1 GeV of the 3CR+3CRR+MS4+2Jy sources

A large number of FRIIs should cross over the LAT sensitivity threshold. In spite of this, only a handful of FRIIs is seen at GeV energies ( see also Dermer & Benoit 2011)

Log (f )1GeV = a + b x Log(f )5GHz

Predicted Observed

correlation based on the total sample

FRII: expected sources FRII: observed sources FRI: observed sources FRI: expected sources

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Radio Flux indicates that the “core” of FRIIs is bright enough to be visible at very high energies Second question Why does Fermi-LAT preferentially catch FRIs and lose FRIIs ?

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SED studies of FRI Radio galaxies indicate that a pure, one-zone homogeneous, synchrotron self-Compton model is problematic Model Parameters: =25° =2.4 R~1017 cm B~0.04 G N=K-p p1=2.76 p2=4.04 K~2×106 cm-3 break=2×104 min=250 max=2×105 NGC6251: an example (Migliori et al. 2011)

The one-zone homogeneous SSC model applied to MAGNs needs too slow jets BL > MAGN

Possible conflict with Unified Models

Slow SSC jets are also required in other MAGNs (M87:Abdo et al. 2009; NGC1275: Abdo et al. 2009)

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Possible solutions to the problems (not the only ones) v Decelerating jet (Georganopoulos & Kazanas 2003) v Structured (spine +slower layers) jet (Ghisellini, Tavecchio & Chiaberge 2005) vColliding shells (Bottcher & Dermer 2010)

T h e h y p o t h e s i s o f homogeneity is relaxed and more regions at different velocities are assumed. These models can generally fit pretty well the SEDs of FRI radio galaxies.

The jet is structured

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The jet is decelerated

Γ2

Possible solutions to the problems (not the only ones) v Decelerating jet (Georganopoulos & Kazanas 2003) v Structured (spine +slower layers) jet (Ghisellini, Tavecchio & Chiaberge 2005) vColliding shells (Bottcher & Dermer 2010)

T h e h y p o t h e s i s o f homogeneity is relaxed and more regions at different velocities are assumed. These models can generally fit pretty well the SEDs of FRI radio galaxies.

Γ1

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The jet is decelerated

Γ2

Possible solutions to the problems (not the only ones) v Decelerating jet (Georganopoulos & Kazanas 2003) v Structured (spine +slower layers) jet (Ghisellini, Tavecchio & Chiaberge 2005) vColliding shells (Bottcher & Dermer 2010)

T h e h y p o t h e s i s o f homogeneity is relaxed and more regions at different velocities are assumed. These models can generally fit pretty well the SEDs of FRI radio galaxies.

Γ1 The jet is structurated Possible solutions to the problems (not the only ones) v Decelerating jet (Georganopoulos & Kazanas 2003) v Structured (spine +slower layers) jet (Ghisellini, Tavecchio & Chiaberge 2005) vColliding shells (Bo”ttcher & Dermer 2010)

T h e h y p o t h e s i s o f homogeneity is relaxed and more regions at different velocities are assumed. These models can generally fit pretty well the SEDs of FRI radio galaxies.

The jet is shocked

Colliding shells

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Structured Jet =25°

Layer =2.4 Spine =15

(Migliori et al. 2011)

SSC Layer SSC Spine IC Layer

In the spine-layer and decelerating models there is an efficient (radiative) feedback between different regions in the jet that increases the IC emission. Models can fit the Spectral Energy Distributions of FRIs.

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The jet of FRIIs could be less structured (spine dominated) or/and less decelerated

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In FRII the jet propagates through a photon rich environment (see Torresi’s talk) => EC dominant mechanism . EC emission is narrower in the beaming direction than the SSC radiation (Dermer 1995, ApJ, 446, L63)

EC SSC

=15

and/or

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Third question Where do the -rays originate in radio galaxies ?

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Where are the -ray produced in Radio Galaxies?

in large extended regions (kpc-scale structures) Cen A Lobes Abdo et al. 2010, Science, 328, 725 in/near the radio core (sub-pc/pc scales)? NGC1275 Abdo et al. 2010 (MAGN) Brown&Adams 2011

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Some inspiring Results on BLazars presented at the HEPROIII Meeting in Barcellona last summer

mm

B A Amm B

1 2 3 4 5 F (10-7 phot/cm2/s)

2009 2010 Gregorian Date [years] 0.1-200 GeV

2 4 6 8 10 12 14 F (10-12 erg/cm2/s)

0.3-10 keV 2 4 6 8 10 12 S [mJy] V 2 4 6 8 10 12 S [mJy] R 2 4 6 8 10 S [Jy] 850µm 1mm 3mm 54600.0 54800.0 55000.0 55200.0 RJD [days] 5 10 15 S [Jy] 8mm 7mm C1 7mm C0 7mm VLBA

Agudo et al. 2011(ApJL 2011) -ray flare more than 14 pc from the central engine BL Lac OJ287 FSRQ PKS 1510-089 Marscher et al. 2010 (ApJL 2010) complex -ray emission different/regions-mechanisms as a single disturbance propagates along the jet

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In general it is difficult to detect -ray variability in MAGNs (Abdo et al. 2010 MAGN)

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3C111 FRII BLRG -ray coming from the radio core

x-ray, optical radio data from Chatterjee et al. 2011 http://www.bu.edu/blazars/VLBA_GLAST/3c111.html

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3C111 FRII BLRG -ray coming from the radio core

x-ray, optical radio data from Chatterjee et al. 2011 http://www.bu.edu/blazars/VLBA_GLAST/3c111.html

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3C111 FRII BLRG -ray coming from the radio core

x-ray, optical radio data from Chatterjee et al. 2011 http://www.bu.edu/blazars/VLBA_GLAST/3c111.html

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3C111 FRII BLRG -ray coming from the radio core

x-ray, optical radio data from Chatterjee et al. 2011 http://www.bu.edu/blazars/VLBA_GLAST/3c111.html

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97% of the Fermi sources are BL LACs and FSRQs. 3% are other kind of objects: NLSy1, SB and MAGNs. The MAGN class is mainly populated by FRI radio galaxies. The presence of inhomogeneous jets in these sources seems to favor their detection. Paucity of FRIIs FRIIs are difficult to detect in gamma. The study of all the gamma-counterparts of 4 complete radio catalogs weakens the hypothesis that the FRIIs are missed because too far. Two effects could be contribute to reduce the number of FRIIs observed by Fermi: i) the absence/reduction of feedback between different jet layers (particularly efficient mechanism in FRI with large inclination angles) ; ii) the -ray narrower beaming cone of External Compton scattering (EC) when compared to that of the synchrotron-self processes (SSC). -ray origin in MAGns It is attested that both extended (kpc scales) and compact (sub-pc/pc scales) regions can emit high-energy photons in FRIs. No spatial identification of -ray source in FRIIs has been provided up to now. A multiwavelength study comparing X-ray, optical, radio (Chattarjee et al 2011) and Fermi-LAT data (Abdo et al. 2010) allows to localize for the first time the -ray region in a FRII radio galaxy. In 3C111 the base of the jet (core) is the probable site (BLR) of MeV-GeV photon production.

Conclusions

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M87: first attempts to localize high energy emission-region in a MAGN Raue et al.

Hepro III-meeting Hepro III-meeting 29

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3C111 NGC6251

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