Fabio La Franca and N. Sacchi, S. Puccetti, F. Fiore, C. Gruppioni, C. Feruglio et al. Dipartimento di Fisica The nature and density of Spitzer selected X-ray absorbed AGN: Identification of sources with large Identification of sources with large MIR/Optical ratios in the MIR/Optical ratios in the XMM/SWIRE/ELAIS-S1 XMM/SWIRE/ELAIS-S1 Universita` degli Studi ROMA TRE
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Fabio La Franca and N. Sacchi, S. Puccetti, F. Fiore, C. Gruppioni, C. Feruglio et al.
The nature and density of Spitzer selected X-ray absorbed AGN: Identification of sources with large MIR/Optical ratios in the XMM/SWIRE/ELAIS-S1. Fabio La Franca and N. Sacchi, S. Puccetti, F. Fiore, C. Gruppioni, C. Feruglio et al. Dipartimento di Fisica. Universita` degli Studi ROMA TRE. - PowerPoint PPT Presentation
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Fabio La Franca
and N. Sacchi, S. Puccetti, F. Fiore, C. Gruppioni, C. Feruglio
et al.
Dipartimento di Fisica
The nature and density of Spitzer selected X-ray absorbed AGN:
Identification of sources with large Identification of sources with large MIR/Optical ratios in the MIR/Optical ratios in the XMM/SWIRE/ELAIS-S1XMM/SWIRE/ELAIS-S1
Universita` degli Studi ROMA TRE
-What is the fraction of AGN among the sources with large MIR/O?
-What is the fraction of absorbed AGN?
-Is the density of absorbed AGN compatible to other estimates orextrapolations (i.e. XLF)?
QUESTIONSQUESTIONS
What do we know about the AGN evolution?
A Luminosity Dependent Density Evolution(LDDE) for X-ray AGN isobserved(e.g. Ueda+03; Fiore+03; La Franca+05;Barger+05; Hasinger+05; Gilli+07; Silverman+07; Della Ceca+08)
Lower luminosity AGNpeak at lower redshifts:DOWNSIZING(see models of galaxy andAGN formations)
La Franca+05
*) Assuming no luminosity and redshift dependences
assumed *)
expected
What do we know about the AGN evolution?
The fraction of absorbed AGN as function of LX and z
DECREASE WITH LUMINOSITYEarlier evidences of a decrease of the fraction of absorbed AGN with luminosity from Lawrence & Elvis (1982), confirmed by Ueda et al. (2003).
INCREASE WITH THE REDSHIFT
Fract
ion o
f A
bso
rbed A
GN
La Franca+05
The LX-z plane
~1x10-15@2Ms
?
X-ray stacking analysis of MIR selected AGNsX-ray stacking analysis of MIR selected AGNsallows to probe more distand, more absorbed,allows to probe more distand, more absorbed,lower luminosity, regions of the Llower luminosity, regions of the LXX-N-NHH-z plane-z plane
Many studies indicate that the majorityof the sources with extremeF(24um)/F(R) (e.g. >1000) ratios areobscured/absorbed AGNs
(see e.g. Martinez-Sansigre+05; Houck+05;Weedman+06; Brown+06; Polletta+06; Yan+07; Daddi+07; Fiore+08; Georgantopoulos+08…)
However,1) these sources are so faint, that direct optical spectroscopic classifications
is available for very few of them;2) the density estimates are based on assumptions on the NH distribution.
Spirals Star Forming (SED:14-20)Spirals Star Forming (SED:14-20)
Ellipticals (SED:21)Ellipticals (SED:21)
Red Power Law ~AGN1 (SED:1-6) Red Power Law ~AGN1 (SED:1-6)
Adapted from Polletta et al. (2007)
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field Method: SED templates fitting
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field Method: SED templates fitting
(see Polletta et al. 2007)
AGN2
AGN1
Normal
χ2 best fit analysis
1st choice
2nd choice 3rd choice
SED
Normal
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field SED classification of high MIR/O sources
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field SED classification of high MIR/O sources
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field SED classification of high MIR/O sources
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field SED classification of high MIR/O sources
Local relationshipun-absorbed AGN
20%20%
4343%34%34%
3%3%
What is the fraction/densityof (possibly absorbed) AGNamong these high MIR/Osources?
First look at the OPT spectra…
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field OPTICAL VLT SPECTROSCOPY of faint (R>22) high MIR/O sources
TOTAL: 384 spectra
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field OPTICAL VLT SPECTROSCOPY of faint (R>22) high MIR/O sources
composite spectraTOTAL: 384 spectra
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field OPTICAL VLT SPECTROSCOPY of faint (R>22) high MIR/O sources
82% of SED-PWL are optical 82% of SED-PWL are optical AGNAGN93% of SED-ULIRG are optical 93% of SED-ULIRG are optical ELGELGSED-Seyfert2: no preferencesSED-Seyfert2: no preferences
composite spectraTOTAL: 384 spectra
40% AGN2 (& AGN1)
60% ELG
56 spectra
What about their SED?
X-ray detections and stacking (filled symbols)
STACKED DATA
Looking for absorbed AGN in the XMM/SWIRE/ELAIS-S1 field X-ray stacking analysys of faint (R>22) high MIR/O sources
82% of OPT-AGN82% of OPT-AGNare X-ray absorbed AGNare X-ray absorbed AGN
85% of OPT-ELG85% of OPT-ELGare mildly X-ray are mildly X-ray absorbed withabsorbed withLL2-102-10~10~1041-4241-42