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

Core-Sérsic  Giant galaxies with M B ≤ mag (core-Sérsic, cS)  Intermediate mass galaxies with M B ≥ 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 deficit light excess 19/11/2013 Structure 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 (M B < 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 anisotropy in velocity dispersion - less luminous (M B > mag) - light excess (starburst) - fast rotators - have disky isophotes - isotropic and rotationally supported Why are these two systems so different? 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 3 (Cappellari’s talk)

Two families of Early-type galaxies: Core-Sérsic vs Sérsic dichotomy 4  Giant galaxies (core-Sérsic)  Intermediate mass galaxies (Sérsic) - luminous (M B < 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 anisotropy in velocity dispersion - less luminous (M B > mag) - light excess (starburst) - fast rotators - have disky isophotes - isotropic and rotationally supported - last mergers were ‘dry’ - last mergers were gas-rich 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 4

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) 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 5

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 ≈ mag arcsec -2

Central stellar mass deficits (M def ) of luminous galaxies - L def converted into M def using stellar M/L ratios obtained from the color-age-metallicity-(M/L) diagram by Graham & Spitler (2009) L def L def – the difference in luminosity between the Sérsic model and the core-Sérsic model NGC /11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 7

M def /M BH ≃ 0.5 – 1 per major merger ( N-body simulations by Merritt 2006, Phase II ) M def –M BH relation and galaxy merger history - core formation is a cumulative process M def ~ (0.5 – 4) M BH (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 (M BH ) obtained using the Graham & Scott (2013) non-barred M-σ relation - two dynamically determined BH masses for NGC 1399 (Houghton+2006; Gebhardt+2007) 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 8 - M def /M BH ≥ 4 may be due to recoiled SMBHs, Phase II +III

Core-Sérsic bulge + exponential disk fits to 4 luminous S0s ( Dullo & Graham 2013) M def ~ (0.5 – 2) M BH, 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? 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 10

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

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) 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 12

Compact high redshift (z~2) galaxies vs. local disk bulges Bulges of our core-Sersic S0s are - red - compact R e ≤ 2 kpc - massive, M * ~10 11 M  19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 13

 Compact, quiescent and dense galaxies at z ~2 ( Daddi+2005; Trujillo+2006 ) - R e < 2 kpc and stellar mass M * ~10 11 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 - minor mergers - major mergers - adiabatic expansion ? There aren’t enough satellite galaxies around (Trujillo 2013) ? 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 14

Graham ( ) Compact high redshift galaxies vs. local disk bulges Compact high redshift galaxies from Damjanov et al. (2009) 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 15

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 T wo 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) 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 16

Conclusions  We measure central stellar mass deficits (M def ) in core- Sérsic galaxies which are 0.5 – 4 M BH. The M def – M BH correlation is a physical signature connecting SMBHs to their host galaxies.  The depleted cores/stellar mass deficits (0.5 – 2 M BH ) 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. 19/11/2013 Structure and Morphology in the Era of Large Surveys, Santiago, Chile 17

Thank you

CORE-SERSIC LENTICULAR GALAXIES NGC 2300 NGC 4382 NGC 507, NGC 2300, NGC 3607, NGC 3706, NGC 4382 and NGC 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 19/11/2013 STRUCTURE AND MORPHOLOGY IN THE ERA OF LARGE SURVEYS, SANTIAGO, CHILE 19

StudyModelM def /M BH Faber et al. (1997)Nuker~ Milosavljevic & Merritt (2001))Nuker~ Ravindranath, Ho, & Filippenko (2002)Nuker~ Graham (2004)Core-Sersic~ Ferrarese et al. (2006)Core-Sersic~ Lauer et al. (2007)NukerUp to 19 Hyde et al. (2008)Core-Sersic~ 2 Kormendy et al. (2009)Sersic~ Dullo & Graham (2012)Core-Sersic~ Dullo & Graham (2012) (submitted)Core-Seisic~ Literature results

Core-Sersic Core detection HST/WFPC2 images NGC 4291NGC 1426 a) b) 19/11/2013 STRUCTURE AND MORPHOLOGY IN THE ERA OF LARGE SURVEYS, SANTIAGO, CHILE 21

ENVIRONMENT Morphology-Density Relation (Dressler 1980) S S0 E Isolated | Groups | Cluster 19/11/2013 STRUCTURE AND MORPHOLOGY IN THE ERA OF LARGE SURVEYS, SANTIAGO, CHILE 22

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 and Arnold et al. 2011, NGC 3115) Environment 19/11/2013 STRUCTURE AND MORPHOLOGY IN THE ERA OF LARGE SURVEYS, SANTIAGO, CHILE 23

Structural parameter relations 19/11/2013 STRUCTURE AND MORPHOLOGY IN THE ERA OF LARGE SURVEYS, SANTIAGO, CHILE 24

Core-Serisc model Sersic model 19/11/2013Structure and Morphology in the Era of Large Surveys, Santiago, Chile 25

(Komossa et al ) 19/11/

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

Alternative core formation mechanisms  Disipationless collapses in preexisting dark matter haloes (Nipoti et al. 2006)  Sinking massive objects, 3kpc (Goerdt et al. 2010)  AGN feedback + inspiraling massive black holes, kpc ( Martizzi et al. 2012) 19/11/2013Structure and Morphology in the Era of Large Surveys, Santiago, Chile 28