Radio Properties Of X-Ray Selected AGN

21 Pages·2010·7.87 MB·English

by  Manuela Molina

Radio Properties
Of X-Ray Selected AGN
Manuela Molina
In collaboration with: M. Polletta, L. Chiappetti,
L. Paioro (INAF/IASF-Mi), G.Trinchieri (OA
Brera), F. Owen (NRAO) and Chandra/SWIRE
Team.
Astrosiesta, 7 Oct., 2010
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
 
Fraction of sources with AGN-driven radio
activity
 
Some examples of peculiar sources
SUMMARY & CONCLUSIONS
Astrosiesta, 7 Oct. 2010
Open Questions & Objectives
AGN
Host Galaxy
AGN
FEEDBACK
AGN
Star Formation
• 
AGN driven emission from sources close
QUASAR or BRIGHT MODE
to Eddington limit (EFFICIENT
ACCRETION)
(e.g. Di Matteo+05)
• 
X-ray bright sources
• 
Mechanical Origin
• 
RADIO MODE
INEFFICIENT ACCRETION
• 
Jets on small/large scales
(e.g. Croton+06)
• 
Outflows and winds
• 
How to discriminate between X-RAY OBS. (ACCRETION)
• 
Accretion Modes?
RADIO OBS. (JETS)
Astrosiesta, 7 Oct. 2010
The XMM-Chandra/SWIRE Survey "
in the Deep SWIRE Field
XMM-Newton
The Deep SWIRE Field
 
Lockman Hole North
  ′
RA = 10h45m, DEC = 58o58
 
Area: 0.2 deg2
λ
The Multi- Data
  µ σ
VLA @ 90 and 20 cm (12 Jy@5 )
 
GMRT @ 50 cm
  µ
MIPS @ 24, 70 and 160 m
  µ
IRAC @ 3.6, 4.5, 5.8 and 8.0 m
 
UH/UKIRT J, H, K
 
KPNO Ugriz
 
GALEX @ FUV (1500Å) and NUV (2500Å)
RED 0.5-2 keV
 
Chandra @ 0.3-8 keV (3 bands)
GREEN 2-4.5 keV
 
XMM @ 0.3-10 keV (5 bands)
BLUE 4.5-10 keV
(Polletta et al. 2006; Owen at eal. 2008; Wilkes et al. 2009)
Astrosiesta, 7 Oct. 2010
The Sample
Selection: XMM Detected AGN (95)
 
93 sources with Chandra counterpart
 
Count rates and fluxes in 5 bands
 
71 with spectroscopic z
 
3 Hardness Ratios
 
24 with photometric z
 
N estimated from Xspec or HR
H  
All detected in Optical and/or Infrared (IR)
FUV-Mid IR Spectral Energy Distribution (SED)
Source Classification
4%
AGN1
20%
30%
38% UNOBSCURED
SY 1
8%
AGN2
38%
58% OBSCURED
SF
Unclass.
Astrosiesta, 7 Oct. 2010
Criteria for identifying AGN–driven radio activity
q parameter
24 • 
q <0.21: Radio Loud (RL)/ Radio
24
q =Log(F μ /F )

Intermediate (RI)
24 24 m 20cm
• 
0.21<q <1.45: Radio Quiet (RQ)
24
• 
q >1.45: Radio Weak (RW)
24
<q >=0.83±0.31 for RQ and
24
SFGs (Appleton+04)
Radio Spectral Index
α ∝να
-
(Sν )
20,50
• α -1
<0.15: Inverted
20,50 inverted
•  α
0.15≤ ≤0.5: Flat
20,50
•  α
0.5< <1.1: Steep
20,50
• α
1
≥1.1: Ultra Steep
20,50
ultra-steep
2
(Prandoni+09)
Astrosiesta, 7 Oct. 2010
Radio Properties of the X-Ray Sources
 
Majority with STEEP spectra (51%), only 7%
 
with INVERTED spectra.
Inverted spectrum sources tend to be absorbed
 
RW and RI/RL have steep/flat spectra
and obscured.
   
ULTRA-STEEP spec. sources mostly RW or Steep/ultra-steep spectrum sources tend to be
in between RQ/RW class.
unabsorbed and unobscured.
 
INVERTED spec. sources are RQ
Opposite to UM expectations
Astrosiesta, 7 Oct. 2010
Radio Emission Mechanisms
• 
Synchro-Self Absorption (SSA): abs. intrinsic to radio
INVERTED/FLAT
source, originating in presence of optically thick plasma.
• 
RADIO SPECTRA
Free-Free Absorption (FFA): originating in compact
sources (dusty torus).
• 
SN explosions in star forming regions in RQ AGN and
STEEP
SF galaxies.
• 
RADIO SPECTRA
Optically thin synchrotron emission, from extended
sources in RL AGN.
• 
Optically thin synchrotron emission from radiative
ULTRA-STEEP
losses of aging electrons, associated with relic of past
RADIO SPECTRA
radio activity.
Astrosiesta, 7 Oct. 2010
AGN-driven radio emission
• 
Radio Intermediate (RI)/ Radio Loud (RL) (q <0.21): 3 sources (excess
24
of radio emission in the host due to the AGN).
Astrosiesta, 7 Oct. 2010
A RL, Flat Spectrum Source
• 
RL
• 
Slightly
AGN2
extended
(Obscured)
• 
Beamed QSO?
• 
Obscuration
α
=0.31 from host
20,50

Absorbed galaxy?
Radio emission indicative of Synchro-Self Absorption
occurring in a jet
Astrosiesta, 7 Oct. 2010