Presentation: Daniel Asmus: MId-infrared properties of local active galactic nuclei
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Transcript of Presentation: Daniel Asmus: MId-infrared properties of local active galactic nuclei
Daniel AsmusPoshak Gandhi
Sebastian F. HönigAlain Smette
Wolfgang J. Duschl
Santiago 2012
MID-INFRARED PROPERTIESOF LOCAL
ACTIVE GALACTIC NUCLEI
Types of nuclear activity
B. Keel
Types of nuclear activity
B. Keel
NASA
Type 1 AGN
Type 2 AGN
AGN in the mid-infrared
VISIR manual
AGN N-band SED
Spitzer/IRS (~0.8m) Hernán-Caballero & Hatziminaoglou (2011)
Aver. Sy 1 Aver. Sy 2
AGN N-band SED
Spitzer/IRS (~0.8m) Hernán-Caballero & Hatziminaoglou (2011)
PAH silicate PAH [NeII] PAH silicate PAH [NeII]
Aver. Sy 1 Aver. Sy 2
Importance of angular resolution in the MIR
Spitzer/IRS (~0.8m) versus VLT/VISIR (~8m)Hernán-Caballero & Hatziminaoglou (2011) and Hönig et al. (2010)
PAH silicate PAH [NeII] PAH silicate PAH [NeII]
Aver. Sy 1 Aver. Sy 2
“continuum”
The MIR--X-ray luminosity correlation● Strong correlation
– (e.g. Gandhi et al. 2009)
● No noticeable dependence on object type!
Gandhi et al. 2009
LINERType 1 AGN (other)Type 2 AGN (other)
absorption-corr. X-ray luminosity
obse
rve d
MIR
lum
inos
ity
Open issues
● Sample not uniform or complete in any sense→ extend study to such a sample
● Possible trend of MIR excess for log L2-10keV < 41.5
→ real?→ enlarge coverage at lowest luminosities
Gandhi et al. 2009
Structure of the talk
Low-luminosity AGN BAT AGN
High-res.Photometry
High-res.Photometry
Non-AGN Contamination
MIR SED
M 87
NGC 4261NGC 1097
M 104 Sombrero
Low-luminosity AGN
MIR emission sources in LLAGN
The LLAGN programme● Goals:
– Investigate existence of obscuring tori around LLAGN– Test apparent deviation of MIR--X-ray relation at low L
● Estimate contamination by star-formation
The LLAGN programme● Goals:
– Investigate existence of obscuring tori around LLAGN– Test apparent deviation of MIR--X-ray relation at low L
● Estimate contamination by star-formation
● Method: photometry at highest available angular resolution – in 2 narrow-band filters (12μm continuum and PAH at 11.3μm)
● Samples: <D> ~ 20 Mpc, <r0> ~ 40 pc, <log L
X> ~ 40.8
– Southern hemisphere - VLT/VISIR ● Observed in 2009● 11 new LLAGN
(+7 with additional data) ● Mixed properties
The LLAGN programme● Goals:
– Investigate existence of obscuring tori around LLAGN– Test apparent deviation of MIR--X-ray relation at low L
● Estimate contamination by star-formation
● Method: photometry at highest available angular resolution – in 2 narrow-band filters (12μm continuum and PAH at 11.3μm)
● Samples: <D> ~ 20 Mpc, <r0> ~ 40 pc, <log L
X> ~ 40.8
– Southern hemisphere - VLT/VISIR ● Observed in 2009● 11 new LLAGN
(+7 with additional data) ● Mixed properties
– Northern hemisphere - Gemini/Michelle● Observed in 2010● 15 LL-Seyferts from Palomar Sample
(Ho et al. 1997)● 13 observed (but not all in both filters)
Results: Photometry
● 18 detections (out of 31)
– Point-like – No evidence for
extended emission
● 13 non-detections– One reason:
high uncertainty in L
X
● Add 7 objects from the archive
→ total of 25 detected LLAGN
smoothed
DE
C o
f fse
t [“
]
Ra offset [“]
PAH continuum PAH continuumGemini/Michelle VLT/VISIR
Comparison to Spitzer/IRS
Solid line: Spitzer/IRS Red points: VISIR photometry
Comparison to Spitzer/IRS
Solid line: Spitzer/IRS Red points: VISIR photometry
For LLAGN: 0.4” ≠ 4”-scale
Maximum SF contamination
Spitzer/IRS VISIR photometry maximum SF contribution
● Scale the SF template by the PAH 11.3μm from the IRS of the LLAGN→ maximum of SF contribution (to 12μm)
>75%(4)
>75%(4)
50 - 75%(6)
50 - 75%(6)
25 - 50%(4)
25 - 50%(4)
<25%(10)
<25%(10)
Maximum SF contamination
Spitzer/IRS VISIR photometry maximum SF contribution
● Scale the SF template by the PAH 11.3μm from the IRS of the LLAGN→ maximum of SF contribution (to 12μm)
● For the 24 detected LLAGN with IRS:
>75%(4)
>75%(4)
50 - 75%(6)
50 - 75%(6)
25 - 50%(4)
25 - 50%(4)
<25%(10)
<25%(10)
Maximum SF contamination
Spitzer/IRS VISIR photometry maximum SF contribution
● Scale the SF template by the PAH 11.3μm from the IRS of the LLAGN→ maximum of SF contribution (to 12μm)
● For the 24 detected LLAGN with IRS:
→ Star formation is weak at 0.4”-scale in most LLAGN
(if PAH remains a valid tracer...)
Structure of the talk
Low-luminosity AGN BAT AGN
High-res.Photometry
High-res.Photometry
Non-AGN Contamination
MIR SED
BAT AGN
The “BAT AGN”
Credit: NASA
Swift/BAT AGN observations● Swift
– Launched 2004– Gamma-ray burst hunter– 3 instruments:
● UVOT (UV & optical, 170-650 nm)● XRT (X-ray, 0.2-10keV) ● BAT (gamma-ray, 14-195 keV)
● Hardest X-rays (>20keV) are absorbed only in the Compton-thick case
→ BAT is well-suited for unbiased AGN searches
Credit: NASA
Swift/BAT AGN observations● Swift
– Launched 2004– Gamma-ray burst hunter– 3 instruments:
● UVOT (UV & optical, 170-650 nm)● XRT (X-ray, 0.2-10keV) ● BAT (gamma-ray, 14-195 keV)
● Hardest X-rays (>20keV) are absorbed only in the Compton-thick case
→ BAT is well-suited for unbiased AGN searches
Credit: NASA
Unbiased, flux-limited, complete, all-sky sample of 104 AGN (Tueller et al. 2008, Winter et al. 2009)
Swift/BAT AGN observations● Swift
– Launched 2004– Gamma-ray burst hunter– 3 instruments:
● UVOT (UV & optical, 170-650 nm)● XRT (X-ray, 0.2-10keV) ● BAT (gamma-ray, 14-195 keV)
● Hardest X-rays (>20keV) are absorbed only in the Compton-thick case
→ BAT is well-suited for unbiased AGN searches
Credit: NASA
We observed 77 of the 104 BAT AGN (high-res MIR photometry)
Unbiased, flux-limited, complete, all-sky sample of 104 AGN (Tueller et al. 2008, Winter et al. 2009)
Results: MIR imaging
● 75 of 77 detected – Point-like – mostly no evidence for extended
emission (except NGC 6240)
● Star formation (PAH) weak in majority of BAT AGN at 0.4”-scale
silicate PAH continuum
Results: average MIR SED
Type 1Type 2
Silicate in emission in type 1 & in absorption for type 2 AGN
Results: average MIR SED
Comparison to:- - - clumpy torus models (Hönig &
Kishimoto 2010)
Type 1Type 2
Silicate in emission in type 1 & in absorption for type 2 AGN
Structure of the talk
Low-luminosity AGN BAT AGN
High-res.Photometry
High-res.Photometry
Non-AGN Contamination
MIR SED
12μm – 2-10keV correlation
(absorption-corrected)
Correlation from Gandhi et al. 09...
● Objects: 42● Spearman Rank:
ρ = 0.88 (log p = -17)
● Power-law fit: log L
MIR ~
(1.00 ±0.08) log LX
Power-law fit to:─── all AGN from G09
12μm – 2-10keV correlation
(absorption-corrected)
Adding the LLAGN...
● Objects: 77● Spearman Rank:
ρ = 0.94 (log p = -30)
● Power-law fit: log L
MIR ~
(1.05 ±0.05) log LX
Power-law fit to:─── all AGN from G09
12μm – 2-10keV correlation
Power-law fit to:─── all AGN from G09─── all AGN
(absorption-corrected)
Adding the BAT AGN...
● Objects: 134● Spearman Rank:
ρ = 0.90 (log p = -42)
● Power-law fit: log L
MIR ~
(1.00 ±0.04) log LX
● Fit depends somewhat on algorithm used
● Correlation dominated by X-ray uncertainties
12μm – 2-10keV correlation
Power-law fit to:─── all AGN from G09─── all AGN
(absorption-corrected)
Adding the BAT AGN...
● Objects: 134● Spearman Rank:
ρ = 0.90 (log p = -42)
● Power-law fit: log L
MIR ~
(1.00 ±0.04) log LX
● Fit depends somewhat on algorithm used
● Correlation dominated by X-ray uncertainties
Correlation applicable to all AGN
Conclusions● High-angular resolution mid-infrared imaging of ~120 local AGN
– Most objects show point-like MIR emission at ~0.4” resolution
● Comparison to Spitzer/IRS spectra– No correlation between MIR properties at 4” and 0.4” scale – Most AGN show weak or absent nuclear PAH emission
→ Nuclear MIR emission contribution due to star formation likely minor
● MIR--X-ray luminosity correlation– Strongest 12μm—2-10keV correlation for all AGN combined (slope ~1)
→ MIR--X-ray correlation valid for all AGN down to LX ~1040 erg/s!
→ fundamental physical connection → uniform structure in all AGN
● Origin of MIR emission in AGN– Results favor dusty obscuring torus...– LLAGN might have additional non-thermal component, e.g., jet...
Future work● Add radio data into the multiwavelength analysis
● For lowest accretion rate objects:– Assemble high spatial resolution IR SEDs and N-band spectroscopy – Model comparisons and SED fitting with various components– Complete Palomar LLAGN
● For all AGN:– Assess importance of CT AGN– Intrinsic indicator comparison– Obtain N-band spectra– Test AGN unification
● ...