ACTIVE GALACTIC NUCLEIX-ray broad--band studyA. De Rosa, L. Piro

1987 - 2000 Ginga/ROSAT/ASCAIASF-RomaUniversita' di Roma La SapienzaInstitute of Physical and Chemical Research Japan

1996-2002 BeppoSAX: Broad band spectral variability. T

obs~ 1.5 Ms on bright Sy 1 galaxies

IASF-Roma, BolognaUniverista' di Roma Roma treOsservatorio Astronomico di RomaOsservatorio Astronomico di Brera

1999 - now XMM-Newton/BeppoSAX & ChandraIASF-RomaUniverista' di Roma Roma treInstitute of Astronomy Cambridge (UK)

Why study AGN in X-ray?

– They emit about 5-10 % their power in X-ray

– Rapid time scale variations (on timescales as small as 1000 s)

X-ray observations probe deep inside the AGN's core

The complex X-ray spectra

● Intrinsic continuum● Warm absorber(s) ● Soft excess emission● Compton reflection features

Broad-band BeppoSAXobservation NGC 3783. De Rosa et. al 2002

Broad band spectral variability of bright Sy 1 galaxies with BeppoSAX: Main results I

First detection of the high energy cut-off in a single source and intrinsic spectral variability.

NGC 4151, Perola et al. 1986

MCG-6-30-15Vaughan & Edelson 2001

Thermal Comptonization: two-phases model

Probing the close and distant environment in AGN: The reflection component and the iron line

MCG -6-30-15 ASCA. Tanaka et al. 1995

BeppoSAX Guainazzi et al 1999

Wilms et al 2001

... and the narrow iron line

Mkn 509, XMM. Pounds et al 2001

NGC 5548. Chandra. Yaqoob et al 2001

Regions: molecular torus, BLR, NLR. Do they contribute to the Compton reflection hump?(NGC5506, Matt et. Al 2001,

NGC 4051, Guainazzi et al. 1998)

NGC 5548. Nicastro et al. 2000

Future prospects Sample of 20 Seyfert 1s in the BeppoSAX archive

Compton reflection features. Iron line(s). Extend the ionization model to a larger sample of sources to investigate as the ionization changes with the source's parameters (accretion rate, black hole mass)IASF Roma-Bologna, Univ di Roma Roma Tre, Oss. astronomico di Roma, Institute of Astronomy, Cambridge-UK)

Intrinsic continuum. Detailed Comptonization code (Petrucci et al. 2000, 2001). Physical parameters of the hot corona, Electron temperature T

e and optical depth

IASF Roma-Bologna, Univ di Roma Roma Tre, Oss. astronomico di Roma, Oss. astronomico di Brera)

BeppoSAX & XMM-Newton simultaneous observations!!!!

Warm-Hot Intergalactic Medium: the missing baryons at z<2

●At z~0 the baryon in stellar systems, neutral Hydrogen, X-ray emitting gas in cluster of galaxies is one order of magnitude less than the predictions.●Chen & Ostriker 1999 propose that the gas is shock-heated at T 105-107 K by the gravitational pull of Dark Matter and is in the form of sheets/filaments (Warm-Hot Intergalactic Medium:WHIM). Supported by recent observations of EUV and X-ray absorption lines (Nicastro et.al 2002)

Current searches are concentrated towards two approaches: narrow absorption features (OVII) produced by the WHIM in the spectrum of bright background source or detection of the emission. As for the latter method, the relevant parameter is the product of eff area * solid angle. Simulated spectra observed by a microcalorimeter (IMBOSS), assuming a FOV of 10°, an integration time of 30 ksec and assumingthat all the WHIM is located at z=0.1.

The quest for WHIM in soft X-rays

Gamma-ray observations: Integral and SuperAGILE

3C273. Courvoisier et al. 2003

Normal galaxies and AGN●Luminosity

Normal galaxies: Lbol

~1040- 44erg s-1

AGN: Lbol

~1040-48 erg s-1

●Variations

large amplitude: I/I~1

rapid: T < 1 day or shorter

==> ACCRETING

BLACK HOLE

Why study AGN in X-ray?● They emit about 5-10 % their power in X-ray

● Rapid time scale variations (on timescales as small as 1000 s)

The observed radiation comes from the innermost region

1) F2-10 keV

> 2x10-11 erg cm-2 s-1

2) Variations of a factor of two on timescales of days

3) Long exposure time (about a week)

• Continuum shape with a very good accuracy• Good S/N up to 100 keV High energy cut-off and

reflection hump• Spectral variability study Spectral behaviour in different

flux level states

Broad band BeppoSAX observations. Target selection and observational strategy

Questions

• Compton reflection components– Is the (ionized?) accretion disc the reprocessing gas?

Broad ionized iron line– There is a contribute from a far away medium?

Intrinsic continuum & spectral variablity

– Is a thermal Comptonization scenario a good model?

● High energy cut-off, Ec.

● Photon Index vs Luminosity correlation● Photon Index vs E

c correlation