tracing the coronal emission in agn with vlt/naco

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Tracing the coronal emission

in AGN with VLT/NACO

Olivier MarcoOlivier Marco

NACO is here !

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What is an AGN ?

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AGN: a closer view

Scale: << 1 pc

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From seeing limited to AO images

2mass10”x10”

DSS infrared60”x60”

An example: NGC1068

COME-ON+

1”x1”

NACO

1”x1”deconvolved

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So we can we NACO for AGN…

Yes !

But… very red objects & extended

Visible-WFS (all IR flux to CONICA)

or

IR-WFS with 90% flux to WFS… not much left for CONICA (10%) hard for NB filters & spectroscopy

Usually (always ?) self-reference hard to get a (real) PSF

Extended objects hard to get a sky (even with jittering)

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Circinus

HST &

NACO J, Ks

combined images

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What/where is the coronal region in an

AGN ?What: region of high density gas where lines of high ionization (IP > 50 eV) species are excited

Where: very close to the ionization source (UV X-ray), BLRNLR & farther away(photoionized by the nuclear continuum or excited by fast (v>300 km/s) shocks)

Coronal lines can be used to directly pinpoint the location of the AGN, and measure a (parsec-scale) size

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Ionization Potential vs line width of the

forbidden lines– An example: 1H 1934-063 (Sy1)(Rodriguez-Ardilla et al., ApJ 2003)

Line IP eV FWHM km/s

[Si VI] 167 650

[Fe XI] 262 1000

[Fe XIII] 331 1600

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Why use [Si VII] 2.48 µm ?

Already detected in NGC1068Our sample: Circinus, ESO428+G014, NGC3081

[Si VI] 1.963 µm is contaminated by H2 1-0 S(3) 1.957 µm

[Si VII] is very strong

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NACO images of Circinus

Coronal emission shows:

Extended (resolved) emission (10 pc diameter)

Hot dust mixed with CLR & NLR

FWHM:

0.12"

2.42 µm continnum [Si VII] 2.48 µm line

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Where the CLR spots the true nucleus & the apex

of the H coneAstrometry of [Si VII] vs HST H

[Si VII] 2.48µm line emissionon top of HST H image

True color image with HST 8140 Å

NACO J & K bands

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NACO images of ESO428

Coronal region shows:– A bright unresolved peak (size 10 pc)

[Si VII] 2.48µm line emission 2.42µm continuum emission

FWHM:

4.3 pixels= 0.12"

same on stars into the field & PSF

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H vs [Si VII]

ESO428 NGC3081

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More to come…

Survey has 4 objects but already…2 objects have shown the possibilities of:– Localization of the central source of the AGN– Measure size of [Si VII]-CLR (limit of NLR)– Trace cone illumination

Relation with luminosity of the central engine?Fast shocks (v300 km/s) along the radio jet?

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tracing the coronal emission in agn with vlt/naco

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