Astronomical Spectroscopy & the Virtual Observatory - ESAC – March 23rd 2007

Stefano Bianchi

Matteo Guainazzi Isa Barbarisi Pedro Osuna Jesus Salgado

Guainazzi et al. 2005

Predicted starburst contribution

Ac

tua

l s

oft

X-r

ay

lu

min

os

ity

Turner et al. 1997

ASCA

Soft X-ray excess in obscured AGN

NGC1068

Kinkhabwala et al. 2002

XMM RGS

Strong emission lines dominateNo continuum => log(NH )<22.7

NGC1068Kinkhabwala et al. 2002

Detection of narrow Radiative Recombination

Continua (RRC)=>

Low temperature gas=>

Photoionization(Liedhal et al. 1995)

Diagnostic on triplets AND higher order series lines:• confirm photoionization• constraint <10% contribution from collisional plasma• unveil the important role of resonant scattering(Band et al. 1990, Matt 1994, Krolik & Kriss 1995)

Can we do the same with low resolution?

OVIII Kα

OVII Kα

OVIIhigh orders

RRCs

We proudly announceproudly announce the first catalogue of soft X-ray emission lines in a sample which includes all the type ≥ 1.5 AGNall the type ≥ 1.5 AGN observed by the RGSRGS

CIELO-AGN[Catalogue of Ionized Emission Lines in Obscured-AGN]

66 objects<F0.1-2 keV> ~ 10-13 cgs

• OVIII Lyα detected in ~50% of the sample• OVII triplet in ~40%• Many other lines from O, Fe, C, Si, Mg, Ne, N detected in ~15%

Guainazzi & Bianchi 2007

CIELO-AGN

Critical diagnostics

RRCs are:CommonCommon (detected in 40% o.t.s.)

NarrowNarrow (σ<10 eV)=>

Photoionization

Strong higher order lines=>

Resonant scattering

Where is the gas?

Circinus

Sm

ith &

Wils

on

20

01

NGC4151

Yang e

t al. 2

00

1

NGC3393 – z=0.0125

NGC1386 – z=0.0029

Bia

nch

i et

al. 2

006

(+

6 o

ther

obje

cts)

What is the gas?

The comparison between the Chandra and the HST images shows that the [OIII]/soft X-ray ratio is fairly constant along with the

radius, up to hundreds of pc. Photoionization models reproduce this behavior if ner-β, with β=2 (i.e. constant ionization

parameter). This is in agreement with NLR emission line ratios(e.g. Kraemer et al. ’00, Kraemer & Crenshaw ’00, Bradley et al. ’04, Collins et al.

‘05).

Bianchi et al., 2007

What about the starburst contribution?

HST Chandra

110 pc

3 pc

In the immermost 110 pc:• low luminosity AGN: LX≈1039 erg s-1

• young stellar cluster: LX≈6×1038 erg s-1

NGC4303

Jiménez-Bailón et al. 2003NGC7130

Levenson et al. 2005

AGN

-Total LO≥1040 erg s-1

-OVII/OVIII≥1

So… AGN or starburst? Empirical diagnostic diagram based on high resolution spectroscopy

Guainazzi & Bianchi 2007

STARBURST

… of course this is too simple

OVIII/OVII excess is NOT

coincident with star formation

regions!Bianchi et al., 2007 NGC7582

The VO Connection

One needs: A Data Model, i.e. a standard abstract representation of

the database structure A Data Access Protocol, i.e. standard rules to be

followed by software designed to access line databases A Software Implementation capable of interfacing with

other access protocols (spectra, images etc.)

The process is close to be finalized: Relevant documents aiming at being

promoted to formal recommendation at the next IVOA Interoperability Meeting

The International Virtual Observatory Alliance started about 2 years ago a discussion on how to make line

catalogues accessible in the VO context

SeeJ. Salgado’s

Talk

Why is the Line Data Model appropriate for us?

1. It supports atomic and molecular “laboratory” databases as well as catalogue of observed lines (such as

CIELO)

2. It is organized around the concept of line

3. It allows catalogue publishers to provide full characterization of the atomic/molecular state, the

physical processes generating a line and the physical properties of the plasma where the line is emitted

4. Pilot implementation possible

CIELO VO implementation

CIELO-AGN is the first astrophysical line catalogue compatible with the (draft) IVOA Line Data Model and

accessible through the (draft) Simple Line Access Protocol

(IVOA Line Data Model: Dubernet, Osuna et al., in prep.)

(Simple Line Access Protocol: Salgado et al., in prep.)

Conclusions

High-resolution spectroscopy IS fundamental to understand the physical properties of the gas in the AGN circumnuclear environment (as high-resolution imaging IS fundamental to unveil its true location)

CIELO unveils a criterion to discriminate between AGN- and starburst-dominated sources on the basis of the OVII(f)/OVIII ratio

In obscured AGN, CIELO unveils mounting evidence for

Dominant role of AGN-photoionization,

Important role of resonant scattering,

Broadly constant ionisation parameter ...

on scales as large as a few hundreds parsec

The VO is almost ready to be a tool for scientific investigation in this field.

Stay tuned!