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Spitzer Spitzer Reveals Activities of Reveals Activities of Supermassive Black Holes iSupermassive Black Holes i

n Elliptical Galaxiesn Elliptical Galaxies

Qiusheng Gu Qiusheng Gu

Nanjing UniversityNanjing University

in collaboration with

J.-S. Huang (CfA), G. Wilson (SSC), G. G. Fazio J.-S. Huang (CfA), G. Wilson (SSC), G. G. Fazio (CfA)(CfA)

SMBHs in Elliptical GalaxiesSMBHs in Elliptical Galaxies

Ferrarese & Merritt, 2000, ApJ, 539, L9Gebhardt et al., 2000, ApJ, 539, L13.

SMBHs in Elliptical GalaxiesSMBHs in Elliptical Galaxies• All galaxies contain supermassive black holes.All galaxies contain supermassive black holes.• The mass of SMBH is tightly correlated with the mass The mass of SMBH is tightly correlated with the mass

of the bulge.of the bulge.


Bower et al. 1998, ApJ, 492, L111Bower et al. 1998, ApJ, 492, L111

D = 17 Mpc,D = 17 Mpc,1” = 82 pc.1” = 82 pc.


Bower et al. 1998, ApJ, 492, L111Bower et al. 1998, ApJ, 492, L111


(1)(1) An S-shape velocity curvAn S-shape velocity curve with a peak amplitude of e with a peak amplitude of 400 km s400 km s-1-1 at 0.1”(8 pc) fro at 0.1”(8 pc) from the nucleus. m the nucleus.

(2)(2) A thin Keplerian disk fits A thin Keplerian disk fits the observed gas kinematthe observed gas kinematics very well if the rotatioics very well if the rotation axis of the gas disk is aln axis of the gas disk is aligned with the radio jet axigned with the radio jet axis. is.

(3)(3) A nuclear compact mass A nuclear compact mass of of 1.5×101.5×1099MM⊙⊙with an uncewith an unce

rtainty of (0.9-2.6)10rtainty of (0.9-2.6)1099MM⊙⊙

Es: QSOs’ hosts at high zEs: QSOs’ hosts at high z

• Radio-Loud QSOs– Exclusively in elliptical hosts

• Radio-Quiet QSOs– MB<-24: 100% in bulge-dominant hosts

– -21<MB<-24: 55% “

– MB<-21 (Sy1): 30% “

Floyd D. et al. 2004, MNRAS, 355, 196

SMBHs in local EllipticalsSMBHs in local Ellipticals• In the Palomar sample, In the Palomar sample, 57 Es57 Es

2626 with pure absorption nuclei with pure absorption nuclei

4 4 Seyferts +Seyferts + 21 21 LINERs + LINERs + 6 6 Transition Transition

● IR bands less affected by extinction

● Possible to detect the nuclear component as IR re-processed emission from a dusty torus (when stellar components properly removed)

Spitzer: Powerful IR TelescopeSpitzer: Powerful IR Telescope

• Wilson et al. (2006): at z ~1, 1/3 EROs arWilson et al. (2006): at z ~1, 1/3 EROs are detected at 24 um;e detected at 24 um;

• Pozzi et al. (2006): at 0.9<z<2.08,8 EROs Pozzi et al. (2006): at 0.9<z<2.08,8 EROs with high X-ray emission are all detected with high X-ray emission are all detected at 24um, 6 are elliptical galaxies.at 24um, 6 are elliptical galaxies.

• EROs: Counterparts and progenitors of lEROs: Counterparts and progenitors of local massive E and S0 galaxies.ocal massive E and S0 galaxies.

MotivationMotivation

MotivationMotivation

Wilson et al. 2006

Ks image with 24m contours (40" x40" )

Redshift: 0.9< z< 2.08(Mignoli et al. 04)

6/8 EXTENDED de Vaucouleurs profile No AGN signature

Our Goal

• To find the infrared indicator of SMBH To find the infrared indicator of SMBH activities in local elliptical galaxies;activities in local elliptical galaxies;

• To understand the origin of infrared To understand the origin of infrared emission in elliptical galaxies.emission in elliptical galaxies.

• All Es in Ho’s sample with Spitzer IRAC All Es in Ho’s sample with Spitzer IRAC observations.observations.

• We detected infrared-red cores in 6(24) EsWe detected infrared-red cores in 6(24) Es

One example: NGC 315One example: NGC 315

IRAC Color DistributionsIRAC Color Distributions

4.5um-3.6um 5.8um-3.6um

8.0um-3.6um 24um

After removing stellar population …After removing stellar population …

NGC 315

Another example: NGC 5322Another example: NGC 5322

What is behind ?What is behind ?

• The strength of SMBHs activities ?

• The dust mass ?

• IR emission mechanism: dust reradiation

optical-UV-soft X-ray photons (AGNs/Starburst) --- dust --- infrared

Emission Line Emission Line

Hubble WFPC2 image of NGC 315

Central Dust StructuresCentral Dust Structures

Hubble WFPC2 image of NGC 4374

Central Dust StructuresCentral Dust Structures

Hubble WFPC2 image of NGC

4278

Hubble WFPC2 image of NGC

5322

Adopt from Lauer et al., 2005, AJ, 129, 2138

NGC 5077

Exception: Central DustException: Central Dust

NGC 4125 NGC 4552

NGC 7626NGC 5813

Elliptical Galaxies without an Infrared-red Core

Origin of Dust in EsOrigin of Dust in Es

• Internal origin :Internal origin : stellar mass loss stellar mass loss

• External origin:External origin: minor merger of s minor merger of small gas-rich satelliate system (Indimall gas-rich satelliate system (Indications: off-set clouds , polar disccations: off-set clouds , polar discs)s)

Origin of Dust in EsOrigin of Dust in Es

• Mergering remnants; gaseous morphology

• MHI/LB

• Gaseous kinematics:

For fast-rotating galaxies, gas and stars are co-rotating, closely linked internal; For slow-rotating (rounder and more triaxial) Es, no alignment between gas and stars external accretion

(Sarzi et al. 2006).

SummarySummary

• We detected an infrared-red core in ~1/4 elliptical galaxies;

• Es with infrared-red cores always contain significant dust in the central regions;

• The infrared-red core is due to the dust reradiation heated by central AGNs.

• We will investigate how the central dust in Es originate from HI contents and gaseous kinematics.

Download - Spitzer Reveals Activities of Supermassive Black Holes in Elliptical Galaxies

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