Massive galaxies in massive datasetsMassive galaxies in massive datasets M. Bernardi, J. Hyde and E. TundoM. Bernardi, J. Hyde and E. Tundo

University of Pennsylvania

Importance of Early-Type Galaxies Importance of Early-Type Galaxies – Stellar masses & Black HolesStellar masses & Black Holes

The Hierarchical formation pictureThe Hierarchical formation picture– Down-sizing and Dry mergersDown-sizing and Dry mergers

Testing Dry mergers using scaling relationsTesting Dry mergers using scaling relations– Luminosities, Sizes, Velocity dispersions, Luminosities, Sizes, Velocity dispersions,

ColorsColors

Selection bias in the MSelection bias in the Mbhbh – L – – L – relations relations

OUTLINE

Early-types don’t dominate number, but they do dominate stellar mass

57%

17%

43% 83%

Renzini 2006

The most massive galaxies are red and dead

Super Massive Black HolesSuper Massive Black Holes

Gebhardt et al. 2000

Connection with “AGN feedback”!!

Ferrarese & Merritt 2000

We need to find out when ….We need to find out when ….

stars were formedstars were formed

the galaxy was assembledthe galaxy was assembled

DownsizingDownsizing

Star formation Star formation only in only in smaller smaller systems at systems at late timeslate times

Environmental Environmental dependence dependence important, but important, but controversial controversial ((Thomas et al. Thomas et al. 2005; but see 2005; but see Bernardi et al. Bernardi et al. 2006a; Bundy et 2006a; Bundy et alal. . 20062006))

Old stellar population (OK for everybody!!)Old stellar population (OK for everybody!!)?? When were galaxies assembled ???? When were galaxies assembled ??Population of massive red galaxies seen even at Population of massive red galaxies seen even at z~1.5 z~1.5 (K20 Survey, VVDS)(K20 Survey, VVDS) Consistent with passive evolution Consistent with passive evolution (e.g. Cimatti et al. 2006, (e.g. Cimatti et al. 2006, Bundy et al. 2006, Brown et al. 2006)

ORStill assembling at low z Still assembling at low z (e.g. (e.g. Faber et al. 2006)??

In the hierarchical formation picture …..In the hierarchical formation picture ….. the problem is to the problem is to form starsform stars, and , and assemble themassemble them into into

a single massive system, in a relatively short time (in a single massive system, in a relatively short time (in this respect, LCDM is friendlier than SCDM)this respect, LCDM is friendlier than SCDM)

How to do this?How to do this?

Importance of Early-Type Galaxies Importance of Early-Type Galaxies – Stellar masses & Black HolesStellar masses & Black Holes

The Hierarchical formation pictureThe Hierarchical formation picture– Down-sizing and Dry mergersDown-sizing and Dry mergers

Testing Dry mergers using scaling relationsTesting Dry mergers using scaling relations– Luminosities, Sizes, Velocity dispersions, Luminosities, Sizes, Velocity dispersions,

ColorsColors

Selection bias in the MSelection bias in the Mbhbh – L – – L – relations relations

OUTLINE

New models New models match K-band match K-band luminosity luminosity function at z~0function at z~0

Main change is Main change is to include AGN to include AGN related effectsrelated effects

No AGN feedback

AGN feedback

Croton et al. 2006 (Munich)Bower et al. 2006 (Durham)

Massive Massive Redheads?Redheads?

Latest generation of Latest generation of semi-analytic models, semi-analytic models, calibrated to z=0, calibrated to z=0, able to match K-band able to match K-band luminosity function at luminosity function at z~1.5z~1.5Main change is to Main change is to include AGN related include AGN related effects effects BCG BCGDry mergers commonDry mergers common

Bower et al. 2006 (Durham)

Passive evolution + Dry mergers

BimodalityBimodality

Models now Models now produce produce reasonable reasonable color-color-magnitude magnitude relationsrelations

BCGs BCGs bluer?bluer? Bower et al. 2006 (Durham)

BCGs

Satellite galaxies(not BCGs)

Croton et al. 2006 (Munich)

BCGs

Importance of Early-Type Galaxies Importance of Early-Type Galaxies – Stellar masses & Black HolesStellar masses & Black Holes

The Hierarchical formation pictureThe Hierarchical formation picture– Down-sizing and Dry mergersDown-sizing and Dry mergers

Testing Dry mergers using scaling relationsTesting Dry mergers using scaling relations– Luminosities, Sizes, Velocity dispersions, Luminosities, Sizes, Velocity dispersions,

ColorsColors

OUTLINE

Selection bias in the Mbh – L – Selection bias in the Mbh – L – relations relations

Brightest Brightest Cluster Cluster

GalaxiesGalaxies

C4 cluster C4 cluster catalogcatalog

Uses both Uses both position and position and color infocolor info

Miller et al. 2005

Properties of early-type galaxiesProperties of early-type galaxies

Pairwise scaling relationsPairwise scaling relations– Faber-Jackson: L-Faber-Jackson: L-– Kormendy: IKormendy: Iee-R-Ree

– L-RL-Ree

– Color - LColor - L

Inclusion of third parameterInclusion of third parameter– The Fundamental Plane: IThe Fundamental Plane: Iee-R-Ree--

Are they the same for BCGs????

BCGs show deviation from Kormendy relation

Oegerle & Hoessel 1991

BCGs

ETGs

Luminosity-Size relationLuminosity-Size relation

Upturn to Upturn to larger sizes larger sizes at large at large luminositiesluminosities

Why?Why? ● BCGs ● High-

Oegerle & Hoessel 1991

R ~ L0.8

R ~ L0.6

Dry merging?

Bernardi et al. 2007a

L-R relation expected to depend on mass ratio and impact parameter of merging spheroids

(Robertson et al. 2006)

Flattening?

Scatter correlates with size: consistent with Virial theorem:

2 ~ M/R

Luminosity- relation

● 2 comp ● deV

The Fundamental Plane

BimodalityBimodality

Models now Models now produce produce reasonable reasonable color-color-magnitude magnitude relationsrelations

BCGs BCGs bluer?bluer? Bower et al. 2006 (Durham)

BCGs

Satellite galaxies(not BCGs)

Bower et al. 2006 (Durham)

BCGs

Color-MagnitudeColor-Magnitude

Croton et al. 2006 (Munich)

SDSS measurements OUR measurements

B03-EtypesC4-BCGsPL-BCGs

Color-MagnitudeColor-Magnitude

Models

Hyde & Bernardi 2007

OUR-SDSS

B03-EtypesC4-BCGsPL-BCGs

Another class of massive galaxies?Another class of massive galaxies?

BCGs are most luminous galaxiesBCGs are most luminous galaxies

What about galaxies with largest What about galaxies with largest ::– these host the most massive BHs these host the most massive BHs – constraints on formation mechanism constraints on formation mechanism

(cooling cutoff)(cooling cutoff)

Once again, to select a clean sample must Once again, to select a clean sample must worry about systematics! worry about systematics!

Expect 1/300 objects to be a superposition

Galaxies with the largest velocity dispersion

● Single/Massive Double ◊ BCG

Sheth et al. 2003

Bernardi et al. 2006b

‘Double’ from spectrum and image

‘Double’ from spectrum, not image

‘Single?’

HST images: with ACS-HRCHST images: with ACS-HRC

SDSS

= 412 ± 27 km/s

SDSS J151741.7-004217.6

3”

1’

HST

SDSS J204712.0-054336.7

= 404 ± 32 km/sHST

SDSS

1’

3’

HST: ACS-HRC

28 single 15 multiple

= 369 ± 22 = 383 ± 27 = 385 ± 34 = 385 ± 24

= 395 ± 27 = 402 ± 35 = 404 ± 32 = 407 ± 27

= 408 ± 39 = 413 ± 35

Large not likely due to projection

Luminosity-Size relationLuminosity-Size relation

● High- ● BCGs

Oegerle & Hoessel 1991

L ~ R0.8

L ~ R0.6

Compared to BCGs, large sample has smaller sizes

Large from extreme dissipation?

Bernardi et al. 2006b

Importance of Early-Type Galaxies Importance of Early-Type Galaxies – Stellar masses & Black HolesStellar masses & Black Holes

The Hierarchical formation pictureThe Hierarchical formation picture– Down-sizing and Dry mergersDown-sizing and Dry mergers

Testing Dry mergers using scaling relationsTesting Dry mergers using scaling relations– Luminosities, Sizes, Velocity dispersions, Luminosities, Sizes, Velocity dispersions,

ColorsColors

OUTLINE

Selection bias in the MSelection bias in the Mbhbh – L – – L – relations relations

Selection bias in the MSelection bias in the Mbhbh - L - - L - ! !

From L

From

Discrepancy between Mbh function from L and

Tundo et al. 2007

What is the cause for this discrepancy?What is the cause for this discrepancy?Selection bias in the -L relation!!

Bernardi et al. 2007b

ConclusionsConclusions

Hierarchical models getting closer to Hierarchical models getting closer to observations … but not there yetobservations … but not there yet

BCGs should be good testing groundBCGs should be good testing ground

BCGs appear to be consistent with dry BCGs appear to be consistent with dry merger formationmerger formation

Large Large objects consistent with more objects consistent with more dissipationdissipation

Selection bias in the MSelection bias in the Mbhbh – L - – L -