Dust and PAHs in X-ray Plasma of Elliptical Galaxies Hidehiro Kaneda （ Nagoya U. ） , et al

Dust and PAHs in X-ray Plasma of Elliptical Galaxies　　　　 Hidehiro Kaneda （ Nagoya U. ） , et al.

Ellipticals: ▪ old stars not productive of dust

▪ hot plasma destructive to

dust

BUT,dust still existsdespite harshenvironments

X-ray visible IR

Dust and PAHs in X-ray Plasma of Elliptical Galaxies　　　　 Hidehiro Kaneda （ Nagoya U. ） , et al.

Wavelength (m)10 100

DustPAHStars

NGC4125

Kaneda et al. 2011

AKARI 3 m

d = 1 arcmin

AKARI + Spitzer SED (d < 30”)

PAH

Balance between supply and destruction of dust

Sputtering destruction in hot plasma of Te ≥ 107 K

Typical lifetime: ～ 107 yr

Stellar mass loss 　（ gas-to-dust ratio: 100 ）

-11 11.5 10 /dustB sun sun

dM= × L L M yr

dt

Draine ＆ Salpeter 1979Tielens et al. 1994

Faber ＆ Gallagher 1976, Knapp +, 1992

LB / LSun (MSun yr-1)

Arimatsu et al. 2011

AKARI 24 m

P+

PAH lifetime: ～ 1000 yr

1.5×10-13

PAHs are much more easily destroyed! P+

CSi,,

Micelotta et al. 2010

<< Galaxy evolution timescale (at least, a few Gyr since merger)

Motivations

• Possible origins

(0) stellar mass loss, (1) cooling flow, (2) merger origin, (3) others?

Mdust vs. LB (IRAS)

dust lifetime 107 yr

Knapp et al. 1989Goudfrooij & de Jong 1995

There exist much larger amounts of dust than expected for the balance.

Even PAHs exist?

What are their origins?How can they survive?

Xilouris et al. 2004

Goudfrooij & de Jong 1995

We observed 18 nearby IRAS-detected elliptical galaxies with AKARI and Spitzer. AKARI: NIR-FIR 9-band images from the nearby galaxy project

Spitzer : MIR spectra from GO1 + GO3 + GO5

Infrared observations by AKARI & Spitzer

Blue: 90 m Red: 15 m Grey image: 3 m

(Kaneda et al. 2010)

• PAH features detected from spectra of elliptical galaxies with Spitzer: 14 out of 18 galaxies.• PAH7.7 is unusually weak relative to PAH11.3 & 17.

(Kaneda et al. 2005; 2008)

5m 40m 5m 40m

NGC4125 NGC4589

Detection of PAHs & unusual PAH band ratios

(Kaneda et al. 2010)

• PAH features detected from spectra of elliptical galaxies with Spitzer: 14 out of 18 galaxies.• PAH7.7 is unusually weak relative to PAH11.3 & 17.

(Kaneda et al. 2005; 2008)

5m 40m 5m 40m

NGC4125 NGC4589

Detection of PAHs & unusual PAH band ratios

C-C stretching ： <10m 、 C-H bending:>10mNeutral PAHs are dominant. Very inactive in galaxies. Not as tracers of star formation

Smith et al. 2007

Relation among PAHs, dust, and hot plasma

PAH vs FIR

PAH11.3 EW vs. LX / LB

Kaneda et al. 2008

FIR/11m vs. LX / LB

FIR-brightPA

H-b

rig

ht

PAHs correlate well with dust.Dust & PAHs do not correlate with X-ray intensity.

X-ray-brightFIR

-bri

gh

tX-ray-bright

PA

H-b

rig

ht

They are supplied not continuously, rather sporadically?

NGC4125

Spitzer/IRS spectral mapping observations

NGC4589

Spatial distributions of PAHs & dust

one slit apertureone slit aperture

Color: 2MASS J ~1’x1’Kaneda et al. 2010Kaneda et al. 2011

NGC4125

PAH11.3 m emission: compact distributions near the centers, predominantly from the dust lanes

NGC4589


~1’x1’

~1’x1’

NGC4125 NGC4589

B ： 90 m dust (AKARI)R ： PAH 11.3 m (Spitzer)W ： 3m starlight (AKARI) G: diffuse X-ray (Chandra), point sources removed

PAHs are more centrally-concentrated than dust.Dust and PAHs are distributed differently from stars.


Color: AKARI 90 mContours: Chandra 　 0.3-7 keV

3nkT/(n2) = (2 - 9)x107 yr ～ dust lifetime << 　 a few Gyr

2 kpc < r < 10 kpc

・ dust mass ： ~7x105 M⊙

Fukazawa et al. 2006

Comparison between X-ray and FIR distributions

・ X-ray plasma ： ~3x108 M⊙

LFIR=5x108 L⊙ LX=2x107 L⊙

E6pec 、Lx = 1×1041 erg s-1 (0.6-2.4 keV) 6-8 Gyr old major merger? Schweizer&Seitzer 1992

NGC4125

: cooling function of dusty plasma by gas-grain collision Dwek 1987


2 kpc < r < 10 kpc

・ dust mass ： ~7x105 M⊙



・ X-ray plasma ： ~3x108 M⊙


E6pec 、Lx = 1×1041 erg s-1 (0.6-2.4 keV) 6-8 Gyr old major merger? Schweizer&Seitzer 1992

NGC4125



NGC4125

Color: Herschel/PACS 70 m


0.3-0.8 keV / 0.8-7 keV


2 kpc < r < 10 kpc

・ dust mass ： ~7x105 M⊙Fukazawa et al. 2006

: cooling function of dusty plasma by gas-grain collision


NGC4125・ X-ray plasma ： ~3x108 M⊙


Dwek 1987



2 kpc < r < 10 kpc

・ dust mass ： ~7x105 M⊙Fukazawa et al. 2006


NGC4125・ X-ray plasma ： ~3x108 M⊙


Color: Herschel/PACS 70 mPAH 11.3 m


dust lifetime

Log(L B) [L ⊙ ]

Lo

g(M

du

st) [

M⊙

]

If mergers are important,

did mergers increase both stars and dust?

~1 Jy detection limitE&S0 complete sample

Mdust increases

with LB !

F90m/F140m ⇒ Mdust

AKARI FIR all-sky survey

Presence of excess dust is clear.

stellar mass loss

dust lifetime

▪ Central reservoirs of dust & PAHs

Mathew et al. 2004

▪ LLAGN-assisted energy feedback outflow in response to in-falling gas, distributing dust & PAHs from the centerto the outer interstellar space.

Temi et al. 2007

Outflow velocity ~400 km/s 　⇒ 　 Dust of 0.1 m size reaches ~5 kpc in a sputtering lifetime of ~107 yr.

Candidate for the origin of excess dust & PAHs

AKARISpitzer

PAHs cannot be distributed because their destruction timescales are too short (~1000 yr).

2m 100mKaneda et al. 2011

Relics of mergers? Recycled products?

1’

LINER activity

Cont.:80- 10%

AKARI 3 m 15 m 90 m

NGC1052

2. For NGC4125 & 4589, PAH & dust emissions were spatially resolved; PAHs are centrally concentrated, while dust is more distributed. Signature of their interaction with X-ray plasma was obtained.

Summary1. Large amounts of dust & PAHs exist in X-ray elliptical

galaxies. Stellar mass loss cannot account for them.

3. Reservoirs of dust and PAHs seem to exist near the center. Dust may be distributed by LLAGN-assisted outflow from the center to outer interstellar space, where hot plasma is cooled. PAHs cannot be distributed due to their short destruction timescales.

SPICA SPICA (Japan-Europe collaboration)(Japan-Europe collaboration)

Launched around 2020Core wavelengths: 5 – 200 m Imaging spectroscopywith a 3-m cold (6 K) telescope

Posters by Roelfsema et al. by Kaneda et al.

Chandra 　 0.3-0.8 keV

Chandra 　 0.8-7 keV


Color: AKARI 90 mContours: Spitzer [SiII]34.8 m

Comparison between X-ray and FIR

NGC4125Kaneda et al. 2011

How do we sustain the X-ray plasma?

Raymond Smith

dust emission

Cooling function of a dusty plasma by gas-grain collision

Dwek 1987

・ dust mass ：（ 2 kpc < r < 10 kpc ）

7x105 M⊙・ X-ray plasma ：（ 3 kpc < r < 10 kpc ）

(0.2 – 1)x10-2 cm-3

0.36 - 0.44 keV

3x108 M⊙

LFIR=5x108 L⊙

LX=2x107 L⊙


Gas-to-dust mass ratio = 200


NGC4125

Interpretation of unusually low PAH7.7/11.3

neutral

Draine & Li 2007

ionized

C-C stretching ： <10m 、 C-H bending:>10mNeutral PAHs are dominant. Very inactive in galaxies. Not as tracers of star formation

NGC4125 ：Dust is distributed more widely than PAHs

PAH 11.3 m

FIR 90 mPSF

Kaneda et al. 2011

Radius

En

circ

led

flu

x

100”0”

0.0

1.0

We observed 20 nearby dusty elliptical galaxies with AKARI and Spitzer: NGC708, 1052, 1316, 1395, 1407, 1549, 2974, 3557, NGC3894, 3904, 3962, 4125, 4589, 4696, 5018, 5044, NGC5090, 7052, IC1459, IC3370. AKARI: NIR-FIR 10-band images + NIR spectra from the nearby galaxy project

Spitzer: MIR spectra from GO1 + GO3 + GO5

AKARI と Spitzer による観測

AKARI Near-IR spectra of NGC4125 & NGC4589AKARI Near-IR spectra of NGC4125 & NGC4589

Low-resolution spectra

3m 4m

x1.1

x1.6

x2.3

x4

Heavily-smoothedhigh-resolution spectra

3m 4m

x1.1

x2.6

x3.5

NGC4589

NGC4125

Normalized to background spectrum

3.4 3.5m 3.4 3.5m

Absorption due to aliphatic hydrocarbon groups.Abundant carbonaceous grains → sources of PAHs?

PAH11.3m images

Temi et al. 2007

PAH

HContours ： X-ray （ Chandra ）Gray: optical

LLAGN-assisted energy feedback outflow? Outflow velocity ~400 km/s 　⇒　 Dust of 0.1 m size reaches ~5 kpc in a sputtering lifetime of ~107 yr.

NGC5044NGC5044

Strong H2 lines, [SiII]

Temi et al. 2007

Kaneda et al. 2008

Documents

Dust and PAHs in X-ray Plasma of Elliptical Galaxies Hidehiro Kaneda （ Nagoya U. ） , et al