Bililign T. Dullo Swinburne University of Technology (Alister W. Graham) Centre for Astrophysics and Supercomputing NGC 4291 NGC 1426

Bililign T. Dullo Swinburne University of Technology

(Alister W. Graham)

Centre for Astrophysics and Supercomputing

NGC 4291 NGC 1426

Core-Sérsic

Giant galaxies with MB ≤ -20.5 mag (core-Sérsic, cS)

Intermediate mass galaxies with MB ≥ -20.5 mag (Sérsic)

- depleted cores are signatures left by coalescing SMBH binaries (e.g., Begelman et al. 1980; Ebisuzaki et al. 1991; Merritt 2006)

Two families of Early-type galaxies: Core-Sérsic vs. Sérsic dichotomy

light deficitlight excess

19/11/2013Structure and Morphology in the Era of Large Surveys, Santiago, Chile 2

Two families of Early-type galaxies: Core-Sérsic vs. Sérsic dichotomy

Giant galaxies (core-Sérsic) Intermediate mass galaxies (Sérsic)

- luminous (MB < -20.5 mag)- stellar light deficits created by decaying SMBH binary (e.g., Begelman et al. 1980)

- slow (or no) rotation - tend to show boxy isophotes- dynamics supported by anisotropyin velocity dispersion

- less luminous (MB > -20.5 mag) - light excess (starburst)

- fast rotators - have disky isophotes - isotropic and rotationally supported

Why are these two systems so different?


(Cappellari’s talk)

Two families of Early-type galaxies: Core-Sérsic vs Sérsic dichotomy

4

Giant galaxies (core-Sérsic) Intermediate mass galaxies (Sérsic)

- luminous (MB < -20.5 mag)- stellar light deficits created by decaying SMBH binary (e.g., Begelman et al. 1980)

- slow (or no) rotation - tend to show boxy isophotes- dynamics supported by anisotropyin velocity dispersion

- less luminous (MB > -20.5 mag) - light excess (starburst)

- fast rotators - have disky isophotes - isotropic and rotationally supported

- last mergers were ‘dry’ - last mergers were gas-rich


Evolution of SMBH Binaries

Post major (‘dry’) merger scenario

Phase I: Dynamical friction (binary separation decays)

Phase II: Three-body interaction (Ejects stars) Depleted mass ∝ mass of the binary (e.g., Ebisuzaki et al. 1991; Merritt 2006)

Phase III: Anisotropic gravitational radiation(Coalescence ensues, and SMBH recoils)


Core-Sérsic model fits to luminous early-type galaxies

Es

S0s

- HST (WFPC2/ACS) data

- 31 core-Sérsic galaxies (26 Es + 5 S0s)

- median Δ for the 31 cS galaxies ≈ 0.045 mag arcsec-2

Central stellar mass deficits (Mdef) of luminous galaxies

- Ldef converted into Mdef using stellar M/L ratios obtained from the color-age-metallicity-(M/L) diagram by Graham & Spitler (2009)

Ldef

Ldef – the difference in luminosity between the Sérsic model and the core-Sérsic model

NGC 4382


Mdef/MBH ≃ 0.5 –1 per major merger (N-body simulations by Merritt 2006, Phase II)

Mdef –MBH relation and galaxy merger history

- core formation is a cumulative process

Mdef ~ (0.5 – 4) MBH

(e.g., Graham 2004; Ferrarese+2006)

a few (1 to 8) major mergers- consistent with observations (0.5 – 2 mergers since z~1, e.g., Bell+2006; Bluck+2012, Conselice’s talk) and theories (Haehnelt & Kauffmann 2002)

- predicted black hole masses (MBH) obtained using the Graham & Scott (2013) non-barred M-σ relation - two dynamically determined BH masses for NGC 1399 (Houghton+2006; Gebhardt+2007)


- Mdef/MBH ≥ 4 may be due to recoiled SMBHs, Phase II +III

Core-Sérsic bulge + exponential disk fits to 4 luminous S0s

(Dullo & Graham 2013)

Mdef ~ (0.5 – 2) MBH, for S0s

Formation origin for luminous S0s

Core-Sérsic lenticular galaxies have undergone violent major merger/s

Main question: how do these

galaxies have disks?


Ram pressure stripping (Gunn & Gott 1972)

- hot intra-cluster medium removes gas from moving galaxy

Harassment (Moore et al. 1996)

- frequent, close high-velocity encounters

- interaction with the cluster potential

Strangulation (Larson 1980)

- gas supply is cut off, cold gas exhausted through star formation

Formation mechanism(s) for S0s with depleted cores / Environment

- NGC 507, NGC 2300 and NGC 5813 reside in galaxy groups - NGC 6849 is an isolated galaxy - NGC 4382 is a member of the Virgo cluster, situated at the outskirt

Popular mechanisms

Environment


Ram-pressure stripping ✗

Harassment ✗

Strangulation ✗

Major dry merger + (subsequent cold gas accretion)

✔

Two stage galaxy assembly: early violent `dry’ merger (bulge) followed by late accretion of gas and stars (disk) (e.g., Steinmetz & Navarro 2002; Birnboim & Dekel 2003; Arnold et al. 2011)

Formation mechanism(s) for S0s with depleted cores / Environment

(Dullo & Graham 2013)


Compact high redshift (z~2) galaxies vs. local disk bulges

Bulges of our core-Sersic S0s are

- red- compact Re ≤ 2 kpc- massive, M*~1011 M


Compact, quiescent and dense galaxies at z ~2 (Daddi+2005; Trujillo+2006)

- Re < 2 kpc and stellar mass M*~1011 M - a factor of 2 to 5 smaller than today’s ellipticals of comparable stellar mass

Compact high redshift (z~2) galaxies vs. local disk bulges

Compact galaxy at z =1.6 (van der Wel+ 2011)

Virgo elliptical galaxy M87

- minor mergers - major mergers- adiabatic expansion

? There aren’t enough satellite galaxies around (Trujillo 2013)

?


Graham (2011-2013)

Compact high redshift galaxies vs. local disk bulges

Compact high redshift galaxies from Damjanov et al. (2009)


From compact high redshift galaxies to bulges of today’s S0s

Bulges of local massive S0s may be modern day counterparts to compact high-z galaxies

Two stage galaxy assembly: early violent `dry’ merger (bulge, i.e., compact high-z galaxy) followed by late accretion of gas and stars (disk)

(Dullo & Graham 2013, high-z galaxies were taken from Damjanov et al. 2011)


Conclusions

We measure central stellar mass deficits (Mdef) in core-Sérsic galaxies which are 0.5 – 4 MBH. The Mdef – MBH correlation is a physical signature connecting SMBHs to their host galaxies.

The depleted cores/stellar mass deficits (0.5 – 2 MBH) in core-Sérsic lenticular galaxies suggest a two-step inside-out scenario for their assembly.

Today’s massive bulges may be local analogs to compact high redshift early-type galaxies.


Thank you

Core-Sersic lenticular galaxies

NGC 2300NGC 4382

NGC 507, NGC 2300, NGC 3607, NGC 3706, NGC 4382 and NGC 6849

- taken from the (public) Hubble Legacy Archive (HLA)

Core-Sersic galaxies are believed to have undergone major mergers

It is assumed that major mergers destroy disks

- Bias subtraction - Geometric distortion correction- Dark current subtraction- flat fielding - Sky subtraction

19/11/2013Structure and Morphology in the Era of Large Surveys, Santiago, Chile

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Study Model Mdef/MBH

Faber et al. (1997) Nuker ~ 4 - 7

Milosavljevic & Merritt (2001)) Nuker ~ 1 - 20

Ravindranath, Ho, & Filippenko (2002) Nuker ~ 2 - 25

Graham (2004) Core-Sersic ~ 1 - 4

Ferrarese et al. (2006) Core-Sersic ~ 1 - 4

Lauer et al. (2007) Nuker Up to 19

Hyde et al. (2008) Core-Sersic ~ 2

Kormendy et al. (2009) Sersic ~ 5 - 20

Dullo & Graham (2012) Core-Sersic ~ 0.5 - 4

Dullo & Graham (2012) (submitted) Core-Seisic ~ 0.5 - 2

Literature results

Core-Sersic

Core detection H

ST/W

FPC

2

imag

esNGC 4291 NGC 1426a) b)


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Environment

Morphology-Density Relation (Dressler 1980)

S

S0

E

Isolated | Groups | Cluster


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Galaxy merger (Toomre & Toomre 1972)

NGC 507, NGC 2300 and NGC 3607 reside in X-ray bright galaxy groups

NGC 6849 is an isolated galaxy- isolated early-type galaxies have merger related origin (Reda et al. 2004 and Arnold et al. 2011, NGC 3115)

Environment


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Structural parameter relations


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Core-Serisc model

Sersic model


(Komossa et al. 2003) 19/11/201326

- majority of compact high redshift galaxies have small undeveloped disks (van der Wel et al. 2011)

Alternative core formation mechanisms


Documents

Bililign T. Dullo Swinburne University of Technology (Alister W. Graham) Centre for Astrophysics and Supercomputing NGC 4291 NGC 1426