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The Chandra/SWIRE Survey: Radio Properties Of X-Ray Selected AGN. Manuela Molina INAF/IASF Milano. In collaboration with: M. Polletta, L. Chiappetti, L. Paioro (INAF/IASF-Mi), G.Trinchieri (OA Brera), F. Owen (NRAO) and Chandra/SWIRE Team. . AGN9 – Ferrara, 24/27 May 2010. Talk Outline.

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slide1

The Chandra/SWIRE

Survey: Radio Properties

Of X-Ray Selected AGN

Manuela Molina

INAF/IASF Milano

In collaboration with: M. Polletta, L. Chiappetti, L. Paioro (INAF/IASF-Mi), G.Trinchieri (OA Brera), F. Owen (NRAO) and Chandra/SWIRE Team.

AGN9 – Ferrara, 24/27 May 2010

slide2

Talk Outline

THE DATASET

  • The XMM-Chandra/SWIRE Survey
  • Description of the XMM Sample

RADIO PROPERTIES OF THE XMM SAMPLE

  • Criteria for identifying AGN-driven radio activity
  • Some examples of peculiar sources

X-RAY PROPERTIES OF THE XMM SAMPLE

  • X-Ray Variability (Chandra vs. XMM)
  • X-Ray Variability vs. Obscuration and X-Ray Absorption

SUMMARY & CONCLUSIONS

slide3

Open Questions & Objectives

AGN FEEDBACK

AGN

Host Galaxy

AGN

Star Formation

  • AGN driven emission from sources close to Eddington limit
  • X-ray bright sources

QUASAR or BRIGHT MODE

(e.g. Di Matteo+05)

  • Mechanical Origin
  • Jets on small/large scales
  • Outflows and winds

RADIO MODE

(e.g. Croton+06)

Signatures of AGN feedback

Identify efficiently radiating AGN and radio-active AGN

Study and comparison of their properties

GOALS:

Study of Radio and X-Ray Properties of an X-Ray Selected AGN Sample with deep multi-frequency radio coverage

STRATEGY:

AGN9 – Ferrara, 24/27 May 2010

the xmm chandra swire survey in the deep swire field
The XMM-Chandra/SWIRE Survey in the Deep SWIRE Field
  • The Deep SWIRE Field
  • Lockman Hole North
  • RA = 10h45m, DEC = 58o58′
  • Area: 0.2 deg2

XMM-Newton

  • The Multi-l Data
  • VLA @ 90 and 20 cm (12mJy@5s)
  • GMRT @ 50 cm
  • MIPS @ 24, 70 and 160 mm
  • IRAC @ 3.6, 4.5, 5.8 and 8.0 mm
  • UH/UKIRT J, H, K
  • KPNO Ugriz
  • GALEX @ FUV (1500Å) and NUV (2500Å)
  • Chandra @ 0.3-8 keV (3 bands)
  • XMM @ 0.3-10 keV (5 bands)

RED 0.5-2 keV

GREEN 2-4.5 keV

BLUE 4.5-10 keV

AGN9 – Ferrara, 24/27 May 2010

slide5

The Sample

Selection: XMM Detected AGN (95)

38% UNOBSCURED

58% OBSCURED

  • 93 sources with Chandra counterpart
  • 71 with spectroscopic z
  • 24 with photometric z
  • All detected in Optical and/or Infrared (IR)
  • Count rates and fluxes in 5 bands
  • 3 Hardness Ratios
  • NH estimated from Xspec or HR

FUV-Mid IR Spectral Energy Distribution (SED)

AGN9 – Ferrara, 24/27 May 2010

slide6

Criteria for identifying AGN–driven radio activity

q24 parameter

  • q24<0.21: Radio Loud (RL)/ Radio Intermediate (RI)
  • 0.21<q24<1.45: Radio Quiet (RQ)
  • q24>1.45: Radio Weak (RW)

q24=Log(F24μm/F20cm)

<q24>=0.83±0.31 for RQ and SFGs (Appleton+04)

Radio Spectral Index

-1

inverted

  • α20,50<0.15: Inverted
  • 0.15≤α20,50≤0.5: Flat
  • 0.5<α20,50<1.1: Steep
  • α20,50≥1.1: Ultra Steep

α20,50 (Sν∝ν-α)

1

ultra-steep

2

AGN9 – Ferrara, 24/27 May 2010

(Prandoni+09)

slide7

Radio Properties of the X-Ray Sources

  • RW/RL with typical α (0.2-1)
  • Steep/Ultra-Steep are mostly RW and AGN1
  • Flat spectrum are generally RQ/RI
  • Inverted spectrum are RQ
  • Inverted spectrum sources tend to be absorbed and obscured.
  • Steep/ultra-steep spectrum sources tend to be unabsorbed and unobscured.

Opposite to UM expectations

AGN9 – Ferrara, 24/27 May 2010

slide8

Radio Semimajor Axis and z Distributions

Semimajor Axis Distribution

Redshift Distribution

AGN9 – Ferrara, 24/27 May 2010

slide9

A RW, Steep Spectrum Source

AGN1 (Unobscured)

  • Radio: synchrotron
  • b=2.2 arcsec
  • Lobes/host?
  • Radio Weak: no SF?

Absorbed

α20,50=0.7

Central engine and SF can no longer accelerate electrons

Fossil Synchrotron Emission?

(e.g. Barvainis&Lonsdale 98)

AGN9 – Ferrara, 24/27 May 2010

slide10

Ultra Steep Spectrum Sources

  • Compact Source
  • Lobes/jets?
  • Radio Weak

Unabsorbed

α20,50=1.51

Synchrotron emission from electrons which are cooling down due to the lack of a reacceleration mechanism.

(e.g. Barvainis&Lonsdale 98)

AGN9 – Ferrara, 24/27 May 2010

slide11

Inverted Spectrum Sources

  • Extended Source
  • AGN driven radio emission
  • Radio Weak

SFG

(Obscured)

Absorbed

α20,50=-0.07

Free-Free Absorption responsible for inverted spectrum?

AGN9 – Ferrara, 24/27 May 2010

slide12

A RL, Flat Spectrum Source

  • RL
  • Compact
  • Beamed QSO?
  • Obscuration from host galaxy?

AGN2 (Obscured)

α20,50=0.31

Absorbed

Radio emission indicative of Synchro-Self Absorption

slide13

X-Ray Absorption vs Dust Obscuration

  • UNOBSCURED: 52%
  • OBSCURED: 45%

Almost half of the unabsorbed sources are obscured

  • UNOBSCURED: 27%
  • OBSCURED: 67%

Most of the absorbed sources are also obscured (e.g. Tajer+08)

AGN9 – Ferrara, 24/27 May 2010

slide14

X-Ray Variability (Chandra vs XMM)

Chandra (Sep. 2004) vs XMM (Oct. 2008/Apr. 2009)

A source is variable if

|FCXO-FXMM|>2x(ΔFCXO+ΔFXMM)

i.e., more than 2σ flux variation in any band.

35% of the sources show variability, either in FLUX, SPECTRAL SHAPE or BOTH.

AGN9 – Ferrara, 24/27 May 2010

slide15

X-Ray Variability vs Obscuration and Absorption

The fraction of unobscured and unabsorbed sources increases in the variable sub-sample

AGN9 – Ferrara, 24/27 May 2010

slide16

Summary

  • Radio properties and X-ray variability of a sample of 95 X-Ray detected AGN in the deep SWIRE field.
  • AGN-driven radio activity identified through q24parameter and radio spectral indexα20,50.
  • Examples of peculiar radio sources.
  • X-Ray Absorption vs. Dust Obscuration.
  • X-Ray Variability vs. X-Ray Absorption and Dust Obscuration.

AGN9 – Ferrara, 24/27 May 2010

slide17

Conclusions

  • Radio properties and X-ray variability of a sample of 95 X-Ray detected AGN in the deep SWIRE field.
  • Efficiently radiating (X-Ray Bright) AGN are mostly RQ with typical radio spectra and contain only a few sources (3%) with AGN-driven radio activity.
  • A certain number of X-Ray Bright AGN are RW, suggesting that any radio emission is the relic of a past AGN or SF activity.
  • Inverted spectrum sources tend to be absorbed and obscured. Steep/ultra-steep spectrum sources tend to be unabsorbed and unobscured (is this in contraddiction with UM predictions?).
  • AGN-driven radio emission is rare among X-Ray bright sources, suggesting that the quasar and radio feedback modes require different conditions and occur in AGN with intrinsic differences.
  • Evidence of dying activty (radio-weak) in some AGN 1 : last phase of evolution?

AGN9 – Ferrara, 24/27 May 2010

slide19

Conclusions

  • q24andα20,50provide good diagnostic tool for identifying “peculiar” sources
  • Different kinds of radio emission processes related to different evolutionary stages, ages and physical properties of sources.
  • Peculiarities observed in radio domain only
  • Almost half of the unabsorbed sources are obscured
  • Most of the absorbed sources are also obscured
  • The fraction of unobscured and unabsorbed sources increases in the variable sub-sample
  • Absorbed sources have flat/inverted radio spectra, while unabsorbed sources have steep/ultra-steep radio spectra, opposite to what expected from UM

AGN9 – Ferrara, 24/27 May 2010

slide20

X-Ray Variability

Variability vs SED Class

  • 44% AGN1
  • 9% SY 1.8

53% UNOBSCURED

  • 31% AGN2
  • 12% SF

47% OBSCURED

Variability is NOT related to SED Class

  • 10 Unobsc. AGN (36%)
  • 11 Obsc. AGN (64%)
  • 1 NA (4%)
  • 4 Unobsc. AGN (66%)
  • 2 Obsc. AGN (34%)

Flux Variability

Spec. Variability

  • 3 Unobscured AGN (83%)
  • 1 Obscured AGN (17%)

Flux+Spec. Variability

Variability vs X-ray Absorption

  • 76% Flux
  • 6% Spectrum
  • 18% Flux+Spec.
  • 60% Flux
  • 33% Spectrum
  • 7% Flux+Spec.

Log(NH)<22

53%

Log(NH)>22

47%

As expected, unobscured sources tend, on average, to be more variable than obscured ones

AGN9 – Ferrara, 24/27 May 2010

slide21

Radio Properties of the X-Ray Sources

Lx<1044 erg s-1

Lx>1044 erg s-1

unobsc. AGN

unobsc. AGN

obsc. AGN

obsc. AGN

  • Median Obsc. = 0.58
  • Median Unobsc = 0.85
  • Unobsc. AGN have slightly flatter radio spec. indices
  • KS test suggests that the two subsets belong to different populations.
  • Median Obsc. = 0.76
  • Median Unobsc = 0.73
  • Unobsc. AGN have slightly flatter radio spec. indices.
  • KS test suggests subsets might belong to same population of sources.

AGN9 – Ferrara, 24/27 May 2010

slide22

Radio Properties of the X-Ray Sources

Vir Lal & Ho (2010) find, in a radio-selected sample, a prevalence of sources with flat and highly inverted radio spectra. They also suggest that flat radio spectra are more frequent in type 2 quasars than in type 1, challenging UM.

Is there a correlation between SED type and radio spectral index?

  • Bimodality in distributions
  • Unobscured AGN peaking at around 0.6 and 0.3
  • Obscured AGN peaking at around 0.7 and 0.2
  • Are Obscured and Unobscured AGN from the same population of sources? KS test hints at a different population
  • Obscured AGN also seem to have slightly flatter radio spectra than unobscured ones.

AGN9 – Ferrara, 24/27 May 2010

slide23

Multi-λAnalysis

Are “peculiarities” observed only at radio frequencies?

YES! Peculiar sources do not occupy any specific region in the plot

AGN9 – Ferrara, 24/27 May 2010