infrared selected highly obscured qso
DESCRIPTION
INFRARED SELECTED HIGHLY OBSCURED QSO. C. Feruglio (INAF-OAR) & F. Fiore, E. Piconcelli, R. Maiolino, + many others (OABo, UniBo, MPE, ASDC). High MIR/O High luminosity obscured AGN. SAMPLE SELECTION. High MIR/Optical flux ratio indicates the presence of an obscured AGN. - PowerPoint PPT PresentationTRANSCRIPT
INFRARED SELECTEDHIGHLY OBSCURED QSO
C. Feruglio (INAF-OAR)
& F. Fiore, E. Piconcelli, R. Maiolino,
+ many others (OABo, UniBo, MPE, ASDC)
SAMPLE SELECTION
High MIR/Optical flux ratio indicates the presence of an obscured AGN
Strong correlation of MIR/O with
24 um luminosity for moderately obscured AGN
Recalls the correlation between
X/O and L(2-10 keV) for moderately obscured AGN selected in X-rays
X-ray samples; GOODS-MUSIC, ELAIS-S1, HELLAS2XMM (Pozzi et al 2007)
Filled symbols=moderately obscured AGN
High MIR/O
High luminosity obscured AGN
SAMPLE SELECTION
This selection is equilvalent to SFR (IR) >> SFR (UV)
(Fiore et al 2007)
MIR/O correlated with R-K color
Bimodal distribution of R-K for sourcess with MIR/O>1000, separate population
F24um/FR >1000 R-K>4.5
The stack produces a detection in both soft and
hard bands
F24um/FR <100 R-K>4.5
Detection only in 0.3-1.5 keV
0.3-1.5 keV 1.5-4 keV
0.3-1.5 keV 1.5-4 keV
(Fiore et al 2007)
A new population of CT AGN
Fiore et al. 2007
Stack of Chandra images excluding X-ray detections
Using the observed counts rate and hardness ratios we evaluated the fraction of highly obscured AGN (logNH>24) in the samples
Assuming a reasonable LIR/LX ratio, a flat NH distribution from logNH=24-26 and a reflection component =1% of the direct one
HIGH MIR/O SWIRE SOURCES
Blue circles = XMM pointings; Red polygons = Chandra ACIS-I and ACIS-S pointings
Elais N1 Elais N2 Elais S1
Lockman Hole XMM-LSS
Large area (50 deg2) with sensitive IR (Spitzer) and optical data,
suitable for searching for type2 QSO
Small fraction covered with shallow X-ray observations below 10 keV
~ 30% of the high MIR/O sources with XMM/Chandra coverage are detected below 10 keV
SWIRE highly obscured QSO
About 30 SWIRE sources with
MIR/O > 2000 Flux(24um) > 2 mJy and R-mag(3.6um)>4.5
SWIRE
CDFS X-ray sources
SWIRE
Bright MIPS sources
Fl 24 um > 4 mJy
with faint optical counterparts (R>24)
The template obscured QSO: IRAS 09104+4109
Template Compton-thick QSO
High L(IR)/Lx ratio
No PAH emission features in IRS spectrum
IR SED dominated by the AGN
Abell 112690#75
(Pozzi et al 2007)IRAS 09
IRAS 09 SDSS spectrum
Use the observed SED and L(24 um) to evaluate
L(2-10 keV)
for high MIR/O sources
The template obscured QSO: IRAS 09104+4109
L(2-10 keV) = 8.8 1044 cgs
rest
log(
L
/ L
2-1
0 k
eV )
Candidate highly obscured QSO
targets for Simbol-X
SW110013.92+581034.9 SW163515.61+405607 z = 1.5
L (24 um) = 5.8 1045
L (2-10 keV) = 4.7 1044
z = 1
L (24 um) = 3.2 1045
L (2-10 keV) = 1.1 1044
IRAS09104+4109
SWIRE
Simbol-X view of SW110013.92+581034.9 z=1 Binned, bkg-subtracted, 200 ks spectrum;
A typical Compton-thick source spctrum is assumed :
NH = 2 1024 cm-2 , Gamma=1.8, EW(Fe Ka )= 1keV
Normalization of the reflected vs transmitted component : A_refl/A_trans =0.2 (e.g. Circinus, Matt et al. 99)
L(2-10 keV) = 1.1 1044 cgs intermediate luminosity AGNF(2-10 keV) = 7.1 10 -15 cgs F(20-40 keV)=1.7 -14 cgs
Simbol-X view of SW163515.61+405607 z=1.5
The same model with T_exp=300 ks
SX allows to constrain NH for the most heavily obcured AGN up to z=2
with ~ 30% error at 2 sigma
L(2-10 keV)=3.03 1044 ,
F(2-10 keV)=1.07 10 -14 cgs, F(20-40 keV)=1.7 10-14 cgs
We selected a sample of ~ 30 candidate type 2 QSOs using deep IR and optical photometry in the SWIRE fields These are going to be targets of several present and future observatories (Chandra, XMM, Herschel, ALMA...)
We used the SED of IRAS09104+4109 and Abell112690 to evaluate the intrinsic X-ray luminosity
Assuming NH typical of a Compton thick AGN we obtained simulations of SX observationsThe simulations show that the sources are detected up to 60 keV and the 90% uncertainty on NH is < 30%
SX Observations of this sample of IR selected QSOs will allow us to : 1) obtain a complete census of SMBH up to z 1.5-2 ;
2) obtain a well constrained NH distribution
Conclusions