Broad-Band X-ray Variability of AGNs with Suzaku

Y. TerashimaEhime Univ.

and

The Suzaku SWG team

Outline

• The Suzaku Satellite

• Broad band X-ray spectral variability in　– MCG-6-30-15– MCG-5-23-16– NGC 4051

The Suzaku Satellite

Japan-US X-ray ObservatoryLaunched on July 10, 2005

The Suzaku Satellite

Japan-US X-ray ObservatoryLaunched on July 10, 2005 Named after legendary red bird

Suzaku in Chinese myth

The Four Guardians in Chinese Myth

Red Bird - Suzaku 朱雀[South]

White Tiger白虎[West]

Blue Dragon青龍 [East]

Black Turtle玄武 [North]

Infrared Images of inner walls of ancient tomb in Asuka, Japan

© National Research Institute for Cultural Properties

The Suzaku Satellite

• Broad band coverage• Low background / High sensitivity at High E

Detection of faint hard sources or highly absorbed sources

Spectral variability on short time scales

A powerful new tool to study the central engine of AGNsAO-2 deadline Dec.1see http://www.astro.isas.jaxa.jp/suzaku

1 10 100Energy (keV)

NGC 2110 Okajima et al.

X-ray Imaging Spectrometer (CCD)

Hard X-ray Detector

X-ray Spectral Components and Variability in AGNs

AGN spectral components - Compton refelection, Fe-K line etc.

Hard X-ray (>10 keV) essential for unambiguous interpretation ofcontinuum and broad Fe line

X-ray Variability Complex spectral variability

steeper slope at higher flux Intrinsic changes

l.o.s. absorption? multiple component ｓ ?

Time resolved spectroscopy with Suzaku

X-raysource

reflection

(1) MCG-6-30-15Miniutti, Fabian et al. 2006, PASJ in press(astro-ph/0609521)

Constant Reflection hump

Suzaku lightcurve

Factor >3 variability

PL + Strong Fe-K line and reflection hump

Broad Fe-K line from Kerr BH?

Smaller amplitude at higher E

High flux

Low flux

Net 300 ksec

MCG-6-30-15High - Low Difference Spectrum

Pure power law (=2.2)

Fe line and reflection hump appear constant.

Broad line only mildly varied.

Light bending effect around a Kerr BH?

(Miniutti & Fabian 2004)

5 10 40Energy (keV)

Direct spectral fits to variable component

(2) MCG-5-23-16Reeves et al. 2006, PASJ, in press

High flux = Red; Low flux = Blue; Reflection:Black

Continuum varied by ~40% over 220 ks duration

PL + Fe line + reflection

i=53+7/-9 deg Rin = 37+25/-10Rg=1.9 power law

Fe line

reflection

Narrow(<50 eV) + Diskline fit

MCG-5-23-15High - Low Difference Spectrum

Variable component:

pure power law (=1.9) modified by absorption

Fe line and reflection hump

~ constant

Two component model

var. PL + cont reflection

1

2

0 105 2x105 (s)

Time (s)

0.5-10 keVNet 86 ksec

(3) NGC 4051Terashima et al. in prep.

1/2-1/3 of historical average9x10-12 ergs s-1

Factor x7-8 flares

=2 PL

reflection

Smaller amplitude at higher E

Similar spec.

PL + Fe + reflection

C/S

NGC 4051Difference Spectrum

=2.1+0.2/-0.1

Variable power law ~2.1Constant Fe+reflectionTwo comp. model

Const. narrow Fe line (<50 eV), sharp Fe-K edge:

Consistent w/ reprocessing & reverberation by distant matter

Variable absorption at <3 keV

NGC 4051 in 2002Very low flux state with XMM-Newton

~1/2 of Suzaku flux

Highly absorbed component disappeared at the lowest flux state.

Presence of additional absorbed PL or variabiltiy of absorption column

Difference (Green - Blue)

NH = 1.5x1023 cm-2

1 5 10Energy (keV)

Haba et al. in prep.

Summary

• Suzaku - new powerful observatory to study AGNsAO-2 due Dec. 1 (http://www.astro.isas.jaxa.jp/suzaku)

• ``Two component’’ behavior commonVariable PL - vicinity of BHConstant Fe line + reflection hump - G.R. effect or distant matte

r

• Time dependent absorption in NGC 4051

• Future: Mechanism of intrinsic variability

G.R. effect, energy release process

Nature of variable absorber - physics of ``torus’’ / ionized absorber

NGC 4051