PHEMIS teamHigh Energy Phenomena

and InterStellar Medium

Active Galactic Nuclei and High Energy Phenomena

LUTH, AERES committee Meudon, March 16-17 2009

Outline

• Short presentation of the PHEMIS team

• « AGN and High Energy Astrophysics »

1) Report on 2004-2008- Selected results of fundamental research- Realizations and social impact

2) Perspectives 2010-2013 - High Energy Astrophysics- Acceleration of particles

The PHEMIS teamNow :9 permanent researchers (Boisson, Le Bourlot, Le Petit, Mottez,

Pelat, Péquignot, Roueff, Sol, Zech)

4 associated researchers (Collin, Goosmann, Joly, Mouchet)2 engineers (Abgrall, Castarède UMS)2 post-docs (Médina, Venter)2 doctorants (Lenain, Gonzalez-Garcia)

18 scientists on site

Recent history :1 recruitment in 2007 (Zech)1 small team spread to AME in 2008 (Cayatte, Sauty)1 arrival from AME in 2008 (Mottez)1 engineer ‘NOEMI’ (UMS/LUTH) in 2008 (Castarède)1 CDD - 6 months in 2007-2008 (Ozou-Mathis)9 post-doc, 9 doctorants, 10 students and 11 visiting scientists (> 1mois) in 2004-2008

Direct participation of 58 scientists in 2004-2008

The Frontiers of Knowledge : Astrophysical Sources and Physical Mechanisms at work

• Modelling AGN and ISM• Development of numerical codes for physical

and chemical processes in low density astrophysical plasmas (microphysics, radiation, transfert, MHD, particle acceleration)

• Pluridisciplinarity : from theory of atomic and molecular physics to multi-lambda observations (radio to TeV)

189 refereed articles with ~ 5000 citations between October 2004 and October 2008

Map of host galaxy (blue) Radio emission (orange)

« AGN and High Energy Astrophysics »

Cartoon of AGN

Key questionsDo we understand the extremes of the universe ? How does accretion on

compact objects operate ?

What is the origin of jets and outflows ?

Can we probe strong gravity around black holes ?

How do galaxies and nuclei form and evolve ?

How does the energy output from AGN affect the universe and its history ?

How does our universe look like at very high energies ?

How do extreme cosmic particle accelerators operate ?

Selected results of fundamental research on AGN

following the accretion-ejectioncycle of the matterISM AGN ISM

torus

jet

disk

ISM and stars

ISM

blackhole

Stellar population around AGN

Fueling AGN requires a reservoir of gas in host + a mechanism to extract angular momentum and allow infall link AGN-host

• Analysis of respective influence of nucleus activity and stellar population of the host (development of inversed methods of stellar population synthesis + libraries of stellar spectra)

• New VLT data in near IR with high spectral and angular resolution, to solve the metallicity/age degeneracy

Stellar population around AGN :Exemple of observed spectrum (grey) and model (red)

Stellar population around AGN

Fueling AGN requires a reservoir of gas in host + a mechanism to extract angular momentum and allow infall link AGN-host

• Analysis of respective influence of nucleus activity and stellar population of the host (development of inversed methods of stellar population synthesis + libraries of stellar spectra)

• New VLT data in near IR with high spectral and angular resolution, to solve the metallicity/age degeneracy

• Find significant differences in circumnuclear stellar population with activity type evolutive effects between different types and link between activity and starbursts : questions standard AGN unified models purely based on viewing angle

(Moultaka et al, 2004, A&A; Frémaux et al, 2006, 2007, A&A)

NGC 1068

Dust torus : high angular resolution and infrared interferometry

VLTI (MIDI)- First resolution of an extragalactic source by IR interferometry.- First direct signature of small size dust torus : 2 components, one compact ~ 0.75 pc + one more extended ~ 3 pc x 4 pc (Jaffe et al, 2004, Nature)

Multi-scale analysis of NGC 1068Multi-scale analysis of NGC 1068

Detailed analysis of MIDI + VISIR data- Compact dust torus with silicates, core + layer, within 3 pc from nucleus- Rather low temperatures even at < 1 pc from BH favours inhomogeneous scenarios for torus- At larger distances, hollow cone with wind at 1000km/s

(Poncelet et al, 2006, 2007, 2008)

Star formation in accretion disk

• Opening the question of star formation around supermassive black holes : importance of heating by stars, massive stars and SN explosions to allow survival of the accretion disk and accretion rate despite the gravitational instability to fragmentation inducing collapse to stars beyond 1000 Rs.

• Continuous or clumpy disks can produce the observed spectra.• Interest of non-stationary disks with intermittent accretion as in

the Galactic Center (Collin, Zahn, 1999, 2008, A&A)

Now well admitted ideas, supported by recent numerical simulations

• Careful selection of sources to select disk emission (geometrical criteria)

• Find Balmer edge in polarized flux confirms thermal nature of big blue bump (disk)

Thermal emission from accretion disk, from IR to UV

torus

BLR

diskpolarizing medium

Thermal emission from accretion disk, from IR to UV

For sources with Balmer edge :observation in polarized near IRof spectra Fν in ν1/3 : naked engine spectra are revealed !

Signature of standardaccretion disk

Possible truncation of disk, as a bit bluer than 1/3(Kishimoto et al, 2004, Kishimoto et al, 2008, Nature)

Gravitational potentials and forces in flat finite size disks

• A new powerful method to compute gravitational potentials ψ(r) of disks as a function of disk surface density Σ(r) has been developed

• Efficiently overcomes the difficulties due to the singularity of ψ inside matter by « splitting » into uniform disk + residual component (infinite series of integrals, with cubic convergence rate inside the source, fully analytical for power-law Σ(r) ~ rs)

Very accurate values of the potential ψ(r) can be obtained, useful for most practical applications

(Hure, Pelat, Pierens, 2007, A&A)

FeII iron lines emission around the central engine

At high resolution, FeII lines can show several components with different positions and widths This requires different emitting zones (BLR/NLR) : their relative importance explains the large variety of spectra observed in emission (Véron-Cetty, Joly et al, 2004, 2006; Véron-Cetty et al, 2007, A&A)

Here the BAL Seyf 1IRAS 07598+6508

AGN central engine and X-ray radiation

• The TITAN code : a powerful tool developped at LUTH for radiation transfer in X-rays

Observed X-ray spectrum (grey) of the Seyfert NGC 3783, and model (red) of the absorption by the TITAN code with one free parameter prad/pgas

AGN central engine and X-ray radiation

• X-ray He-like ion diagnostics : shown with TITAN to be quite dependent on opacity phenomena, which were usually just ignored in the literature

Need to use different diagnostics for Seyf1 (emission) and for Seyf2 (reflection)

• TITAN also allowed to determine evolution of emitted spectra due to thermal instabilities in a pressure equilibrium medium

• A new method to overcome the degeneracy between plasma density and distance has been proposed for quasars

(Godet, Collin, Dumont, 2004, A&A; Goncalves, Godet, 2008,

MNRAS; Goncalves et al, 2007, A&A; Rozanska et al, 2008, A&A)

AGN central engine and X-ray radiation• Warm absorber : ionized winds have been described by a

medium in pressure equilibrium, which reduces the number of free parameters while keeping plasma stratification and complexity of the spectra.

• Soft X-ray excess has been interpretated with a midly relativistic absorbing medium Observed X-ray spectra : a combination of several components (direct, absorbed, reflected)

(Goncalves et al, 2006, A&A; Chevallier et al, 2006; Chevallier et al, 2007, A&A)

disk

primary source

Modelling X-ray flares and constraining black hole parameters

Scenario of accretion disksilluminated by fast flares(Goosmann et al, 2006;2007, A&A)

Reproduce X-ray variability and spectra (codes TITAN + NOAR, and KY) Temporal evolution of the Kα iron line emitted in the black hole vicinity, at a few Schwarschild radii. BH spin ~ 0.95 in MCG-6-30-15

Kα iron line profile

Kα Fe

redshifted blueshifted

Masses of central Black Holes

• Reverberation mapping methods allow to determine the BLR sizes and BH masses. Through accretion disk modeling, super-Eddington regime was found in NL Seyf1.

• Uncertainty of a factor ~ 3 to 10 can affect the mass estimates. Analysis of systematic effects in such measurements of BH masses has been performed (Eddington ratio, inclination effects, shape of BLR), comparing reverberation-based masses and the masses predicted by bulge velocity dispersion.

(Collin, Kawaguchi, 2004; Collin et al, 2006)

Acceleration of particles and jets from central engine

• Studies of particle acceleration in the BH vicinity :- Accretion disk : stochastic acceleration in turbulent low-

luminosity disks Efficient for protons (up to 1017-1019 eV), not for electrons due to synchrotron losses.

- Black hole magnetosphere : centrifugal acceleration in (co)rotating magnetospheres Electrons can reach 10-100 TeV and protons about 1020 eV. Both p+ and e- can radiate in VHE range.

Efficient acceleration can occur well inside a few Rs as requested by observed VHE variability (see hereafter)

Suggests a mixture of hadronic and leptonic scenarios for VHE emission of AGN, with both slow and fast processes.

(Istomin, Sol, 2009)

AGN at Very High Energy gamma-rays

More than 22 TeV AGN presently known, mainly blazars (red)

Studying TeV blazars with HESS and in multi-lambda

• Discovery of VHE gamma-rays from the high-frequency peaked BLLac RGB J0152+017 (HESS paper, A&A Lett, 2008; data analysis, modelling and Lenain contact author at LUTH)

Contemporaneous observations with Swift and RXTE, ATOM, and Nançay. SED reproduced by 2 components non-thermal SSC leptonic model + thermal host galaxy component

• HESS observations and VLT spectroscopy of PG 1553+113 (HESS paper, A&A, 2008; multi-lambda observations, data analysis and Boisson contact author at LUTH)

Attempt to measure the unknown redshift of this BL Lac, HESS + Sinfoni/VLT data the most sensitive near IR spectrum ever reported, but no absorption or emission line were found

high z (> 0.3) or dwarf host galaxy ?

Probing highly variable events in TeV blazars with HESS

Monitoring of an extraordinary active state of PKS 2155-304 in 2006, detected by HESS + multi-lambda campaign(Several HESS papers; observation, modelling, Zech multi-lambda contact author at LUTH)

Down to minute time scale !

1st big flare

2nd flare

Fit of the 2nd flare by SSC time-dependent modeling : Reproduce light curves and spectra in X and gamma rays

Exploring radiogalaxies at VHE

• Discovery of VHE variability in M 87 by HESS (HESS paper, Science, 2006; modelling + Sol internal referee at LUTH)

Questions scenarios of TeV emission from AGNJets not highly beamed weak Doppler boosting ?Variability very small acceleration zone ~ a few Rs of BH

• Development of a multi-blob SSC model :

TeV emission zone located in the jet formation region with large opening angle at ~ 50 -100 Rs , above the Alfven surface : can explain VHE spectra (Lenain et al, 2008, A&A)

VHE light curve

Jet formation region (in radio VLBI)

Exploring radiogalaxies at VHE

• Discovery of VHE emission from Cen A with HESS (modelling, prediction, detection, Lenain HESS contact author at LUTH; HESS paper accepted by ApJ Letters ten days ago.

• Together with M87, establishes radio galaxies as a new class of VHE emitters

• Three different types of AGN now detected at VHE (blazars, radiogalaxies, and weak AGN as Galactic Center)

VHE emission, a general feature of AGN ?

Richness of the extragalactic space at VHE, to further explore with HESS 2 and CTA (cf talk of A. Zech)

Cen A

5σ

Origin of the VHE emission ? Compatible with radio core and inner kpc jets of Cen A

SSC emission from jet formation zoneModels by Lenain et al, 2008

Possible VHE zones ?- BH magnetosphere- base of jets- jets and inner lobes- pair halo in host galaxy

Link to UHECR ?

predicted spectrum

observeddatapoints

Realizations and social impact

• Publications : not all presented here (others TeV blazars; also on nebulae, supernovae, cataclysmic variables; HESS papers on EBL, all galactic issues and others; nulling interferometry …). 127 publications with ~ 4360 citations in oct 2004-2008.

• Impact : HESS among the first ten « high-impact observatories », after SDSS, Swift, HST, ESO, Keck, CFHT, Spitzer, Chandra, Boomerang, and before WMAP, 2MASS, Gemini, Subaru, NOAO (citation analysis by Madrid, Macchetto, 2009, arXiv:0901.4552v1).

LUTH team ~ 5% of the current HESS collaboration.

• Productions : - Numerical codes to be open to the community by VO, - A first VHE database, definition of standards

Realizations and social impact

• Visitors programme through the LEA « ELGA » (OP)• Many international collaborations, exchanges of students

(Durham), programme ARCUS with South Africa

• 2 post-doc : Paris Observatory and « GIS P2I » • Budget : - from CNRS and OP/MR, - ‘ligne TGE’ for HESS 2, CNRS/INSU/IN2P3 - PID ‘Astroparticules’ and ‘Particules et Univers’, - PCHE, - PPF « AGN », - ‘ARCUS’ (MAE + region) ( total ~ 380 k€ in 2008)

Realizations and social impact

• Teaching : - a significant contribution to master and ED (now 1 MdC,

3 CNAP, responsability of Master-Recherche M2 for OP and of bureau of ED)

- 2 teaching mission in Benin (2006 and April 2009)- Educational tools (astronomy on line)- 1 book

• Outreach : - 1 book - chapters in UNESCO encyclopedia, in AMA09 Ellipses- publications in popularization scientific journals - participation to scientific films

Perspectives 2010-2013

• 2 main axes of prospective for the PHE(MIS)-team :

- High Energy Astrophysics

- Acceleration of particles

• A small team, with promizing young scientists• Several synergies with the prospective of other

teams of the laboratory (BH vicinity, jet physics and feedback, cosmology)

High Energy Astrophysics

• VHE gamma-ray astronomy : continue exploitation of HESS 1. Prepare the advent of HESS 2 in 2010. HESS 2 should gather large samples of AGN and pulsars and open the possibility of statistical studies at VHE.

- Modeling : development of hadronic models/codes for AGN VHE emission, to directly compare to leptonic ones already available in the team and tackle this long standing question.

- Further explore particle acceleration processes at the origin of the VHE emission, first for AGN

- Extend our studies to others VHE sources (pulsars, SNR, CR, ISM, EBL and cosmology) depending on the team strengths. Keep an eye on major discoveries which may come out from HESS or CTA (dark matter, quantum gravity …)

High Energy Astrophysics• VHE gamma-ray astronomy : recent breakthroughs

by HESS and MAGIC motivate further developments in Cherenkov astronomy

significant contribution of the team to the project CTA, Cherenkov Telescope Array for the next decade, with jumps in sensitivity, resolution, spectral range, flexibility (cf talk of A. Zech tomorrow)

CTA artist’s view

High Energy Astrophysics

• X-ray astronomy : exploitation of the codes TITAN and NOAR, among the best tools to describe hot media close to black holes

- Interpretation of data from Chandra, XMM, Newton, Suzaku; prediction and simulation for future X-ray satellites as Simbol-X.

- Scenarios for outflows and winds in hot media around BH

- Further modelling of X-ray flares in AGN by more detailed dscription of the illuminating primary source (add a bremsstrahlung component)

Acceleration of particles in magnetic fields

• Analyse acceleration in highly magnetized plasmas and possible applications to pulsars and AGN, based on the expertise already gained from better known plasmas in the solar system

• Approaches : modelling + numerical simulation, in collaboration with observation of related radiation + laboratory experiment on double layers.

• Further developments on acceleration in pulsars compute the distribution functions, couple them with radiation codes, predict spectra for gamma, X-ray and radio observatories (HESS, CTA, Fermi, Simbol-X, LOFAR, SKA …)

• Coordination by Mottez of a Paris Observatory ‘Action spécifique’ (LUTH, LESIA, LERMA) on « Acceleration in astrophysical plasmas ».

Towards exploring Fermi processes in colliding galaxies ?...

Absorption des par le fond diffus infrarouge

Absorption des photons au TeV par le fond IR extragalactique

La valeur du fond IR est encore débattue (comptage # mesures directes).Les modèles ‘standard’ d’émission au TeV d’AGN à grand z nécessitent des valeurs minimales pour le fond IR, correspondantaux valeurs déduites par simple comptage de galaxies.

Spectre au TeV de 1ES1101 (Fint en E – Γint)

Distribution d’énergie spectrale de l’EBL Coeff. d’absorption

Fint = Fobs exp τ(z,E)