hard x-ray study of lobes of radio galaxy fornax a

July 7-11, 2008 Radio Galaxies in the Chandra Era 1

Hard X-rayHard X-ray study of lobes o study of lobes of radio galaxy Fornax Af radio galaxy Fornax A

Naoki IsobeNaoki Isobe(RIKEN/(RIKEN/SuzakuSuzaku Help Desk) Help Desk)

Makoto Tashiro, Hiromi Seta, Yuichi Yaji (Saitama Univ.)Makoto Tashiro, Hiromi Seta, Yuichi Yaji (Saitama Univ.)Keiko Matsuta, Hidehiro Kaneda (ISAS/JAXA), Keiko Matsuta, Hidehiro Kaneda (ISAS/JAXA), Kazuo Makishima (RIKEN/Univ.of Tokyo)Kazuo Makishima (RIKEN/Univ.of Tokyo) 　　 etc.etc.

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Radio Galaxy Fornax ARadio Galaxy Fornax A Nearby radio galaxy (Nearby radio galaxy (DD = 18.6 Mpc) = 18.6 Mpc) The 1The 1stst source, source, from whichfrom which the lobe IC the lobe IC

X-ray emission was detected with X-ray emission was detected with ASCASCAA and and ROSATROSAT (e.g., Kaneda et al. 1995)(e.g., Kaneda et al. 1995)

The flux of IC X-ray emission indicate The flux of IC X-ray emission indicate a magnetic field of 1.2 a magnetic field of 1.2 G G (Isobe et al. 200(Isobe et al. 200

6)6) , which is slightly smaller than the fi , which is slightly smaller than the field under the minimum energy conditield under the minimum energy condition (1.55on (1.55G).G).

The X-ray/radio distribution suggest a The X-ray/radio distribution suggest a homogeneous electron and edge-strehomogeneous electron and edge-strengthened magnetic field distributions ngthened magnetic field distributions (Tashiro et al. 2001)(Tashiro et al. 2001) . .

Color : ASCA (2-10 keV)Contour : VLA 1.4 GHz

July 7-11, 2008July 7-11, 2008 Radio Galaxies in the Chandra EraRadio Galaxies in the Chandra Era 33

Radio Galaxy Fornax ARadio Galaxy Fornax A Nearby radio galaxy (Nearby radio galaxy (DD = 18.6 Mpc) = 18.6 Mpc) The 1The 1stst source, source, from whichfrom which the lobe IC the lobe IC

X-ray emission was detected with X-ray emission was detected with ASCASCAA and and ROSATROSAT (e.g., Kaneda et al. 1995)(e.g., Kaneda et al. 1995)

The flux of IC X-ray emission indicate The flux of IC X-ray emission indicate a magnetic field of 1.2 a magnetic field of 1.2 G G (Isobe et al. 200(Isobe et al. 200

6)6) , which is slightly smaller than the fi , which is slightly smaller than the field under the minimum energy conditield under the minimum energy condition (1.55on (1.55G).G).

The X-ray/radio distribution suggest a The X-ray/radio distribution suggest a homogeneous electron and edge-strehomogeneous electron and edge-strengthened magnetic field distributions ngthened magnetic field distributions (Tashiro et al. 2001)(Tashiro et al. 2001) . .

XMM-Newton Spectrum of Fornax A east lobe

X = 1.62 -0.15 +0.24

(Isobe et al. 2006)

July 7-11, 2008July 7-11, 2008 Radio Galaxies in the Chandra EraRadio Galaxies in the Chandra Era 44

Radio Galaxy Fornax ARadio Galaxy Fornax A Nearby radio galaxy (Nearby radio galaxy (DD = 18.6 Mpc) = 18.6 Mpc) The The 11stst source, source, from whichfrom which the lobe IC the lobe IC

X-ray emission was detected with X-ray emission was detected with ASCASCAA and and ROSATROSAT (e.g., Kaneda et al. 1995)(e.g., Kaneda et al. 1995)

The flux of IC X-ray emission from the The flux of IC X-ray emission from the east lobe indicate a magnetic field of east lobe indicate a magnetic field of 1.2 1.2 G G (Isobe et al. 2006)(Isobe et al. 2006) , which is slightly , which is slightly smaller than the field under the minismaller than the field under the minimum energy condition (1.55mum energy condition (1.55G).G).

The X-ray/radio distribution suggest a The X-ray/radio distribution suggest a homogeneous electron and edge-strehomogeneous electron and edge-strengthened magnetic field distributions ngthened magnetic field distributions (Tashiro et al. 2001)(Tashiro et al. 2001) . .

ASCA (2-10 keV)VLA 1.4 GHz

(Tashiro et al. 2001)

July 7-11, 2008July 7-11, 2008 Radio Galaxies in the Chandra EraRadio Galaxies in the Chandra Era 55

What we have to do nextWhat we have to do next The Lorents factor of radio The Lorents factor of radio

electrons is larger than thaelectrons is larger than that of X-ray onest of X-ray ones

It is important to detect radiIt is important to detect radio/X-ray emission from o/X-ray emission from electelectrons with the same Lorentz rons with the same Lorentz factorfactor..

2 options2 options• low-frequency radiolow-frequency radio• Hard X-rayHard X-ray

Low-frequency radio observLow-frequency radio observation is difficult.ation is difficult.

Hard X-rayHard X-ray observation with observation with SuzakuSuzaku is the ideal tool. is the ideal tool.

Spectral Energy Distribution(Isobe et al. 2006)

102 103 104

103 104 105

Lorents factor e

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The X-ray ObservatoryThe X-ray Observatory Suzaku Suzaku The 5The 5thth Japanese X-ray satellite, launc Japanese X-ray satellite, launc

hed July 10, 2005. (about hed July 10, 2005. (about 3 years ol3 years oldd.).)

2 X-ray detectors 2 X-ray detectors • XIS (X-ray Imaging Spectrometer)XIS (X-ray Imaging Spectrometer)

3 CCD cameras active3 CCD cameras active 1 BI CCD (XIS1)1 BI CCD (XIS1) 2 FI CCD (XIS0, 3)2 FI CCD (XIS0, 3)

0.2 – 10 keV0.2 – 10 keV Low background Low background Good energy resolution Good energy resolution

• HXD (Hard X-ray Detector)HXD (Hard X-ray Detector) Si-Si-PIN PIN diode diode : 10 – 60 keV: 10 – 60 keV GSOGSO scintillator scintillator : 60 – 300 keV: 60 – 300 keV Wide energy bandWide energy band low background low background

HXD XIS

Suzaku

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SuzakuSuzaku observation of Fornax A observation of Fornax A

HXD/PIN FoV(FWHM)

XIS 0.5 – 10 keVVLA 1.4 GHz (Fomalont et l 1989)

2 Suzaku exposures : Host Galaxy (40 ks) and West Lobe (80 ks)

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SuzakuSuzaku HXD/PIN Spectrum HXD/PIN SpectrumComparison with Data & NXB

Hard X-ray signals from the west lobe are significant up to 20 keV.

NXB-Subtracted

Comparison with Data & CXB

CXB (Boldt 1987)

DataNXB (Tuned)

NXB-Subtracted

2% of NXB

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Wide-band X-ray spectrum Wide-band X-ray spectrum of the west lobeof the west lobe

0.2 keV 0.8 keV

PL component = 1.82 ±0.22 S1keV = 137 -29 +32 nJy

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Spectral Energy DistributionSpectral Energy Distribution

e = 4200

R= 1.68 ± 0.05

X= 1.82 ± 0.22X= 1.82 ± 0.22

e = 4200

Spectrum of the radio electrons is connected to that of IC X-ray electrons

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Physical quantities in lobesPhysical quantities in lobes

R (arcmin) (kpc)S1.4GHz (Jy)R

X

S1keV (nJy)

10 54.1 44 ±5.91.68 ± 0.051.62 -0.15 +0.2490 +8 -9

East Lobe(XMM-Newton, Isobe et al. 2006)

West Lobe(Suzaku, This Work )

1264.974 ± 7.7 1.68 ± 0.051.82 ± 0.22137 -29 +32

Bme (G)

BIC (G)

uB (10-13 erg cm-3)

ue (10-13 erg cm-3)

ue/um

1.551.23 ± 0.07 0.61 ± 0.073.0 ± 0.35.0 ± 1.0

1.591.4 ± 0.1 0.78 ± 0.102.36 ± 0.253.0 ± 0.7

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Future perspectiveFuture perspective

103 104 105

GLAST Sensitivity (5 s / 1year)

Cheung et al. 2006Sambruna @ 1st GLAST Symp.

NeXT SXI/HXT

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SummarySummary IC X-ray emission was detected IC X-ray emission was detected up to 20 keVup to 20 keV from the west l from the west l

obe of Fornax A, with Suzaku HXD.obe of Fornax A, with Suzaku HXD. The X-ray spectrum of the west lobe is described with a PL mThe X-ray spectrum of the west lobe is described with a PL m

odel with odel with = 1.82±0.22 = 1.82±0.22 and and SS1keV1keV = 137-29+34 nJy = 137-29+34 nJy.. A comparison between the radio and X-ray fluxes gives A comparison between the radio and X-ray fluxes gives BB = =

1.4±0.1 1.4±0.1 GG, which is slightly smaller than the minimum ener, which is slightly smaller than the minimum energy field gy field BBmeme = 1.59 = 1.59 G.G.

The X-ray photons of 20 keV corresponds to the electron LorThe X-ray photons of 20 keV corresponds to the electron Lorents factor of ents factor of ee ～ ～ 50005000. As a result, we have succeeded i. As a result, we have succeeded in connecting the electron spectra of synchrotron and IC emitn connecting the electron spectra of synchrotron and IC emitting electrons.ting electrons.

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ReferencesReferences

Kaneda et al. 1995 ApJ 453, L13Kaneda et al. 1995 ApJ 453, L13 Iyomoto et al. 1998 ApJ 503, L31Iyomoto et al. 1998 ApJ 503, L31 Tashiro et al. 2001 ApJ 546, L19Tashiro et al. 2001 ApJ 546, L19 Isobe et al. 2006 ApJ 645, 256Isobe et al. 2006 ApJ 645, 256