The Chandra/SWIRE Survey: Radio Properties Of X-Ray Selected AGN Manuela Molina INAF/IASF Milano AGN9 – Ferrara, 24/27 May 2010 In collaboration with:

The Chandra/SWIRE Survey: Radio PropertiesOf X-Ray Selected AGN

Manuela MolinaINAF/IASF Milano

AGN9 – Ferrara, 24/27 May 2010

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

Talk Outline

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

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

THE DATASET

X-RAY PROPERTIES OF THE XMM SAMPLE

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

RADIO PROPERTIES OF THE XMM SAMPLE

SUMMARY & CONCLUSIONS


Open Questions & Objectives

AGN FEEDBACK

AGN

Host Galaxy

AGN

Star Formation

Signatures of AGN feedbackIdentify efficiently radiating AGN and radio-

active AGNStudy and comparison of their properties

GOALS:

STRATEGY:Study of Radio and X-Ray Properties of an X-Ray

Selected AGN Sample with deep multi-frequency radio coverage

QUASAR or BRIGHT MODE

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

(e.g. Di Matteo+05)

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

(e.g. Croton+06)

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

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)


XMM-Newton

RED 0.5-2 keVGREEN 2-4.5 keVBLUE 4.5-10 keV


The Sample

Count rates and fluxes in 5 bands 3 Hardness Ratios NH estimated from Xspec or HR

93 sources with Chandra counterpart 71 with spectroscopic z 24 with photometric z All detected in Optical and/or Infrared (IR)

Selection: XMM Detected AGN (95)

FUV-Mid IR Spectral Energy Distribution (SED)

29%

8%38%

20% 4%

Source Classification

AGN1SY 1.8AGN2SFNA

38% UNOBSCURED

58% OBSCURED


Criteria for identifying AGN–driven radio activity

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

q24 parameterq24=Log(F24μm/F20cm)

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

Radio Spectral Index

α20,50 (Sν∝ν-α)

• 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

(Prandoni+09)

-1

1

2

inverted

ultra-steep


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

Opposite to UM expectations

Inverted spectrum sources tend to be absorbed and obscured. Steep/ultra-steep spectrum sources tend to be unabsorbed and unobscured.


Semimajor Axis Distribution

Redshift Distribution

Radio Semimajor Axis and z Distributions


A RW, Steep Spectrum Source

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

α20,50=0.7

Absorbed

AGN1 (Unobscured)

Fossil Synchrotron Emission?

Central engine and SF can no longer accelerate electrons

(e.g. Barvainis&Lonsdale 98)


Ultra Steep Spectrum Sources

α20,50=1.51

Unabsorbed

• Compact Source• Lobes/jets?• Radio Weak

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

(e.g. Barvainis&Lonsdale 98)


Inverted Spectrum Sources

• Extended Source• AGN driven radio emission• Radio Weak

Free-Free Absorption responsible for inverted spectrum?

α20,50=-0.07

Absorbed

SFG(Obscured)

A RL, Flat Spectrum Source

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

Radio emission indicative of Synchro-Self Absorption

α20,50=0.31Absorbe

d

AGN2 (Obscured

)

X-Ray Absorption vs Dust Obscuration

40%

12%

31%

14% 2%

44% Unabsorbed: Log(NH)<22

AGN1

SY 1.8

AGN2

SF

NA

• UNOBSCURED: 52%• OBSCURED: 45%

21%

6%

43%

25%6%

56% Absorbed: Log(NH)>22

AGN1

SY 1.8

AGN2

SF

NA

• UNOBSCURED: 27%• OBSCURED: 67%

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

Almost half of the unabsorbed sources are obscured



X-Ray Variability (Chandra vs XMM)

69%19%

12% Flux

Spec.

Flux+Spec.

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.


NH>102247%

NH<102253%

Variability vs. Absorption (NH)

X-Ray Variability vs Obscuration and Absorption

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

44%

9%31%

13% 3%

Variability vs Obscuration (SED Class)

AGN1

SY 1.8

AGN2

SF

NA

Var. Sources

All Sources

Unobscured

53% 38%

Obscured 44% 58%

Var. Sources

All Sources

Unabsorbed

53% 44%

Absorbed 47% 56%

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 q24 parameter 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.



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?


Conclusions

• q24 andα20,50 provide 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


X-Ray Variability

Variability vs SED Class

Variability vs X-ray Absorption

Flux Variability

10 Unobsc. AGN (36%) 11 Obsc. AGN (64%) 1 NA (4%)

Spec. Variability

4 Unobsc. AGN (66%) 2 Obsc. AGN (34%)Flux+Spec.

Variability

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

44% AGN1 9% SY 1.8 53% UNOBSCURED 47% OBSCURED31%

AGN2 12% SF

Log(NH)<2253%

76% Flux 6% Spectrum 18% Flux+Spec.

Log(NH)>2247%

60% Flux 33% Spectrum 7% Flux+Spec.

Variability is NOT related to SED Class

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



Lx<1044 erg s-1

obsc.

AGN

unobsc. AGN

Lx>1044 erg s-1

obsc.

AGN

unobsc. AGN

• 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.

• 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.



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

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.

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.


Multi-λAnalysisAre “peculiarities” observed only at radio

frequencies?

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

The Chandra/SWIRE Survey: Radio Properties Of X-Ray Selected AGN Manuela Molina INAF/IASF Milano AGN9 – Ferrara, 24/27 May 2010 In collaboration with:

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