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ULIRGs: IR-Optical-X-ray properties. Valentina Braito. ULIRGs: IR-Optical-X-ray properties. Results from XMM observations of 10 ULIRGs Searching possible multi wavelength diagnostics Results on L band observations (P.I. Risaliti). Background. - PowerPoint PPT Presentation
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ULIRGs: ULIRGs: IR-Optical-X-ray IR-Optical-X-ray
propertiesproperties Valentina Braito
ULIRGs: ULIRGs: IR-Optical-X-ray propertiesIR-Optical-X-ray properties
• Results from XMM observations of 10 ULIRGs
• Searching possible multi wavelength diagnostics
• Results on L band observations
(P.I. Risaliti)
ULIRGs are a class of sources with ULIRGs are a class of sources with
LLIRIR>10>101212LL comparable to QSO luminosities.comparable to QSO luminosities.
BackgroundBackground
ULIULIRRGs are predominantly powered by Gs are predominantly powered by heavily heavily ddust enshrouded AGN or ust enshrouded AGN or
circumnuclear starburstscircumnuclear starbursts??ULIRGs classification strongly depends on the ULIRGs classification strongly depends on the
energy bandenergy band Starburst dominated ULIRGs revealing an obscured AGN when observed in the X-rays (i.e. NGC6240)
With this survey all the ULIRGs of Genzel sample With this survey all the ULIRGs of Genzel sample (complete at F(complete at F6060mm>5.4 Jy and L>5.4 Jy and LFIRFIR~10~101212LL ) )
will have X-ray datawill have X-ray data
AGN activity is present in 1/3 of the observed
sources
AGN-ULIRGs have hard X-ray luminosity lower than
typical QSO luminosity
We found 2 ULIRG with high X-ray luminosity &
deeply absorbed (Superantennae; Mkr231)
SB-ULIRGs have LX(2-10 keV) 1041-1042ergs/s
Main goals characterize the hard X-ray Main goals characterize the hard X-ray continuum continuum
investigate the presence of AGN investigate the presence of AGN activityactivity
Thermal emissionabsorbed power law (AGN) ~1.7-2or a flat power law (X-ray binaries)
E1-e-E/Ec Ec=8 keV
X Ray Spectral propertiesX Ray Spectral properties
X-ray & FIR emission X-ray & FIR emission
No evident correlation between X-ray thermal and FIR luminosity
No evident difference between SB and AGN ULIRGs
Thermal vs FIR luminosity
X-ray AGN-ULIRGs
X-ray SB-ULIRGs
X-ray & FIR emissionX-ray & FIR emission2-10 keV luminosity vs FIR luminosity
AGNAGN
SBSBX-ray AGN-ULIRGs
X-ray SB-ULIRGs
Our results confirm that for ULIRGs without a dominant AGN component, the 2-10 keV
emission is a good SFR indicator (Persic et al. 2004).
Arp 299
Comparison with local SBs
SB-ULIRGs
The observed hard X-ray emission can be used to highlight AGNs in LIRGs
X-ray & FIR emissionX-ray & FIR emission
X-ray AGN-ULIRGs
X-ray SB-ULIRGs
Optical-IR-X-rayOptical-IR-X-ray
Work in progress…
AGN REGIONSB REGION
Compton-thin
Compton-thick
Results from L band Results from L band spectroscopyspectroscopy
The waveband coverage allows
to determine of the 3-4 m continuum level
a correct estimate of the PAH strength
Broad absorption feature at 3.4m indicative of heavily absorbed AGN
PAH at 3.3m with low EW typical of AGN dominated sources
IRAS 19254-7245
P.I. Guido Risaliti
see poster by Risaliti for all the spectra
A possible dignostic diagram A possible dignostic diagram
PAH EW vs LIR
Risaliti et al. in prep
PURE SB
AGN
Composite SB AGN
vs PAH EW
AGN-dominated
SB-dominated
Conclusion and futureConclusion and future
• LX(2-10) keV as a SFR indicator or to preselect AGN in IR sources
• the Fx/FIR vs FOIII /FIR diagram allows to select heavily absorbed AGN in composite sources like ULIRGs
• check the peculiar sources in this diagram
• complete the Genzel sample (IRAS22491-1808 and IRAS 20100-4156) in L band
• spectra of the 4-5 brightest ULIRGs at 4-5 m