March 17, 2004STScI Colloquium1 ACS Observations of Distant Clusters of Galaxies & Protoclusters: New Constraints on Cluster and Galaxy Formation & Evolution

March 17, 2004 STScI Colloquium 1

ACS Observations of ACS Observations of Distant Clusters of Galaxies & Distant Clusters of Galaxies &

Protoclusters:Protoclusters:New Constraints on Cluster and New Constraints on Cluster and

Galaxy Formation & EvolutionGalaxy Formation & Evolution

Marc PostmanMarc PostmanSTScISTScI


Talk OutlineTalk Outline• Overview - what we know and don’t know Overview - what we know and don’t know (about cluster & (about cluster &

cluster galaxy formation & evolution)cluster galaxy formation & evolution)

• Sample definitionSample definition• Results at z ~ 1Results at z ~ 1

– Constraining the SF history of early type cluster galaxiesConstraining the SF history of early type cluster galaxies– Tracking the evolution of cluster galaxy morphologiesTracking the evolution of cluster galaxy morphologies– Brightest Cluster Galaxy assembly and evolutionBrightest Cluster Galaxy assembly and evolution– Galaxies, x-rays, and gravitational lensing: looking for evidence Galaxies, x-rays, and gravitational lensing: looking for evidence

of cluster assemblyof cluster assembly

• High-z RGs - Tracers of Protocluster sites?High-z RGs - Tracers of Protocluster sites?– TN1138 - an intriguing system at z = 4.1 - evidence in support of TN1138 - an intriguing system at z = 4.1 - evidence in support of

an associated protocluster an associated protocluster

• Epilogue - an update to the structure formation storyEpilogue - an update to the structure formation story


My ACS IDT CollaboratorsMy ACS IDT Collaborators• Cluster OriginsCluster Origins

– John BlakesleeJohn Blakeslee (JHU) (JHU)– Frank Bartko Frank Bartko (Colorado)(Colorado)– Nicholas Cross (JHU)Nicholas Cross (JHU)– Ricardo deMarco Ricardo deMarco

(ESO/JHU)(ESO/JHU)– Holland Ford Holland Ford (JHU)(JHU)– Marijn Franx Marijn Franx (Leiden)(Leiden)– Brad Holden Brad Holden (UCSC)(UCSC)– Nicole Homeier Nicole Homeier (JHU)(JHU)– Garth Illingworth Garth Illingworth (UCSC)(UCSC)– Marco Lombardi (ESO)Marco Lombardi (ESO)– Felipe Manenteau Felipe Manenteau (JHU)(JHU)– Piero Rosati Piero Rosati (ESO)(ESO)

• Weak LensingWeak Lensing– Myoungkook Jee Myoungkook Jee (JHU)(JHU)

– Rick White Rick White (STScI)(STScI)

– Narciso Benitez (JHU)Narciso Benitez (JHU)

• Hi-z Radio GalaxiesHi-z Radio Galaxies– George Miley George Miley (Leiden)(Leiden)

– Roderik Overzier Roderik Overzier (Leiden)(Leiden)

– Andrew Zirm Andrew Zirm (Leiden)(Leiden)

• ACS IDT ArchiveACS IDT Archive– D. Golimowski, K. AndersonD. Golimowski, K. Anderson– T. Allen, W. J. McCannT. Allen, W. J. McCann– A. Framarini, G. MeurerA. Framarini, G. Meurer


Cluster Formation ScenarioCluster Formation Scenario• Primordial Intra-cluster medium (ICM) shocks Primordial Intra-cluster medium (ICM) shocks

at the intersection of matter streams and at the intersection of matter streams and begins to emit x-rays begins to emit x-rays (epoch?? Probably z > (epoch?? Probably z > 2).2).

• Since Since zz = 1, there is little or no evolution in the = 1, there is little or no evolution in the thermodynamics & metallicity of the ICM.thermodynamics & metallicity of the ICM.

• Massive ellipticals assemble in range 2 < Massive ellipticals assemble in range 2 < zz < 5 < 5 (How does assembly proceed? Direct (How does assembly proceed? Direct observations??);observations??); they are the first galaxies to they are the first galaxies to reach dynamic equilibrium with the cluster reach dynamic equilibrium with the cluster potential. potential. (Global cluster effects?)(Global cluster effects?)

• Most cluster galaxy SF activity is quenched by Most cluster galaxy SF activity is quenched by zz=0.5 (Dressler et al. 1997). =0.5 (Dressler et al. 1997). (Trigger?)(Trigger?)

• Infall of spirals results in morphological and Infall of spirals results in morphological and color gradients within the cluster color gradients within the cluster (When are (When are gradients first detectable?)gradients first detectable?). This process . This process continues into the present epoch.continues into the present epoch.

• S0 and dE populations develop within the S0 and dE populations develop within the cluster core cluster core (epoch?? Timescales?).(epoch?? Timescales?). HSB HSB spirals spirals S0; LSB spiralsS0; LSB spiralsdE (Moore et al dE (Moore et al 1998) 1998) (Verify. Find progenitors at high-z??)(Verify. Find progenitors at high-z??)

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are needed to see this picture.

Simulation by J. ColbergSimulation by J. Colberg(Starts at z = 20)(Starts at z = 20)


ACS GTO Cluster SurveyACS GTO Cluster Survey• Cluster Galaxy Formation & EvolutionCluster Galaxy Formation & Evolution

– Goals: Study, Goals: Study, with best precision to datewith best precision to date, the star , the star formation rates, internal structures, & fundamental formation rates, internal structures, & fundamental relationships in cluster galaxies at z ~ 1. Study the relationships in cluster galaxies at z ~ 1. Study the origins of the most massive cluster galaxies and origins of the most massive cluster galaxies and their link to possible progenitors.their link to possible progenitors.

– 8 rich galaxy clusters in the range 8 rich galaxy clusters in the range 0.8 < z < 1.30.8 < z < 1.3– 4 high-z radio galaxies: Protoclusters at 2 < z < 5?4 high-z radio galaxies: Protoclusters at 2 < z < 5?– ACS imaging in at least 2 bands, NIR & x-ray ACS imaging in at least 2 bands, NIR & x-ray

imaging, plus extensive optical spectroscopy.imaging, plus extensive optical spectroscopy.


ACS GTO Cluster SurveyACS GTO Cluster Survey• The ACS AdvantageThe ACS Advantage

– High sensitivity makes moderately wide coverage in High sensitivity makes moderately wide coverage in at least 2 passbands affordable for a modest size at least 2 passbands affordable for a modest size sample. sample.

– Higher angular resolution provides superior Higher angular resolution provides superior constraints on galaxy structure (e.g., morphology, constraints on galaxy structure (e.g., morphology, half-light radii) and lensing.half-light radii) and lensing.

– The combination yields superior photometric and The combination yields superior photometric and morphological data that enables study of mass morphological data that enables study of mass distributions and galaxy properties in z~1 clusters in distributions and galaxy properties in z~1 clusters in unprecedentedunprecedented detail. detail.


Cluster Survey TargetsCluster Survey TargetsClusterCluster RedshiftRedshift

VelocityVelocity

DispersionDispersion

X-ray Lum. X-ray Lum. (10(104444 erg/s)erg/s)

ACS FiltersACS Filters Total Total OrbitsOrbits

MS1054MS1054 0.831 0.831 (143)(143) 11121112 23.323.3 V,i,zV,i,z 2424

CL0152CL0152 0.837 0.837 (72)(72) 12831283 7.87.8 r,i,zr,i,z 2424

CL1604 CL1604 +4304+4304 0.897 0.897 (22)(22) 12261226 2.02.0 V,IV,I 44

CL1604 CL1604 +4321+4321 0.924 0.924 (44)(44) 935935 <1.2<1.2 V,IV,I 44

CL0910CL0910 1.101 1.101 (10)(10) N/AN/A 1.51.5 i,zi,z 88

CL1252CL1252 1.235 1.235 (34)(34) 755755 2.52.5 i,zi,z 3232

CL0848-CL0848-A,BA,B

1.265 1.265 (~40)(~40) 640 (A)640 (A) 1.5 (A), 1.5 (A),

~1 (B)~1 (B) i,zi,z 2424


CL0152 & MS1054 @ z = 0.83CL0152 & MS1054 @ z = 0.83CL0152 (z=0.837) MS1054 (z=0.831)CL0152 (z=0.837) MS1054 (z=0.831)


CL1604+43 @ z ~ 0.91CL1604+43 @ z ~ 0.91CL1604+4304 (z=0.897) CL1604+4321 (z=0.924)CL1604+4304 (z=0.897) CL1604+4321 (z=0.924)


CL0910 + CL1252 @ z > 1CL0910 + CL1252 @ z > 1CL0910+5422 (z=1.101) CL1252-2927 (z=1.235)CL0910+5422 (z=1.101) CL1252-2927 (z=1.235)


Constraining the ages of early-type cluster Constraining the ages of early-type cluster galaxies from the Color-Magnitude Relationgalaxies from the Color-Magnitude Relation

• ““Red” Sequence in clusters – a galaxy Red” Sequence in clusters – a galaxy population, largely of early-type morphology, population, largely of early-type morphology, with a relatively narrow range in color but with a relatively narrow range in color but spanning a modest range in luminosity. It is a spanning a modest range in luminosity. It is a common feature in most rich clusters to common feature in most rich clusters to zz < 1. < 1.

• The CM relation is most likely due to an The CM relation is most likely due to an underlying mass-metallicity relation (underlying mass-metallicity relation (e.g., e.g., Kodama et al. 1997).Kodama et al. 1997).

• Slope of and scatter about the CM relation Slope of and scatter about the CM relation provide constraints on the formation epoch provide constraints on the formation epoch and star formation history of galaxies.and star formation history of galaxies.


r-i vs i V-i vs i V-I vs I

V-I vs I i-z vs z

Elliptical

S0

Spiral


Estimating Epoch of Last Major Star Formation EventEstimating Epoch of Last Major Star Formation Event

zzFF > 1.6 > 1.6


Additional constraints from the observed evolution of Additional constraints from the observed evolution of scatter about & slope of the CM relationscatter about & slope of the CM relation

INTINT = 0.023±0.007 mag (15 Egal spec-confirmed members) = 0.023±0.007 mag (15 Egal spec-confirmed members)

INTINT = 0.026 mag (31 Egals, sigma-clipped result) = 0.026 mag (31 Egals, sigma-clipped result)

INTINT = 0.029 mag (All 52 Egals with z mag < 24.5) = 0.029 mag (All 52 Egals with z mag < 24.5)

CL1252 @ z=1.24CL1252 @ z=1.24

Coma Cluster @ z =0.02

Blakeslee et al. 2003Blakeslee et al. 2003


Modeling the scatterModeling the scatterModel 1: Galaxies form stars in single bursts at Model 1: Galaxies form stars in single bursts at random times between trandom times between t00 (z~1000) and t (z~1000) and tEND END (z > (z > 1.24). 1.24).

Model 2: Galaxies form stars at constant rates in Model 2: Galaxies form stars at constant rates in selected times (tselected times (t11,t,t22) where t) where t00 < t < t11< t< t22 < t < tENDEND

In both model scenarios, we vary tIn both model scenarios, we vary tENDEND and at each and at each step compute the colors for 10,000 galaxies by step compute the colors for 10,000 galaxies by interpolation and integration of the BC (2003) solar interpolation and integration of the BC (2003) solar metallicity models.metallicity models.

Then find tThen find tENDEND that yields the best match to the that yields the best match to the observed intrinsic scatter of a given early type observed intrinsic scatter of a given early type population (E or S0)population (E or S0)


Model 1:Model 1:Minimum age of last epoch of SF in CL1252 ellipticals is 1.6 Gyr Minimum age of last epoch of SF in CL1252 ellipticals is 1.6 Gyr prior to z=1.24 lookback time (zprior to z=1.24 lookback time (zENDEND = 1.9) = 1.9)Mean Luminosity weighted age is 3.3 Gyr (z = 3.6) with a scatter Mean Luminosity weighted age is 3.3 Gyr (z = 3.6) with a scatter of ~30%of ~30%For S0’s: zFor S0’s: zENDEND = 1.5 with age scatter ~44% = 1.5 with age scatter ~44%

Model 2:Model 2:Minimum age of last epoch of SF in CL1252 ellipticals is 0.53 Gyr Minimum age of last epoch of SF in CL1252 ellipticals is 0.53 Gyr prior to z=1.24 lookback time (zprior to z=1.24 lookback time (zENDEND = 1.4) = 1.4)Mean Luminosity weighted age is 2.6 Gyr (z = 2.7) with a scatter Mean Luminosity weighted age is 2.6 Gyr (z = 2.7) with a scatter of 38%of 38%Even though epoch of last star formation activity is “recent” the Even though epoch of last star formation activity is “recent” the mean age of the ensemble is still high.mean age of the ensemble is still high.For S0’s: zFor S0’s: zENDEND = 1.3 with age scatter ~47% = 1.3 with age scatter ~47%

Both models give observed colors that match the Both models give observed colors that match the observations.observations.

Modeling the scatterModeling the scatter


Mean Spectral Features in CL1252 (z=1.24)Mean Spectral Features in CL1252 (z=1.24)

Significant H in

absorption seen in co-added spectrum from 10 brightest early type cluster members

Most of the early type galaxies contain “post-starburst” stellar population

Consistent with a formation redshift of zF ~ 3

Local Elliptical

Local Spiral

Rosati et al. 2003Rosati et al. 2003deMarco et al. 2004, in prepdeMarco et al. 2004, in prep


Constraints from the Evolution of the Constraints from the Evolution of the Mass-to-Light RatioMass-to-Light Ratio

E+A Galaxy

The M/L evolution is ~1.1 magnitudes in the rest-frame B band between z=0.33 and z~1.25. This amount of evolution is consistent with a solar metallicity BC03 SSP model with an initial star formation epoch at z=3.

M 2RL R2

M/L 2/ R

Kelson et al 2000

Holden, van der Wel et al 2004

Van Dokkum & Stanford 2003

Jorgenson, Franx & Kjaegaard 1995

Results for CL1252 are Results for CL1252 are preliminary! (good to preliminary! (good to

within ~20%)within ~20%)


Within central 1.5 Mpc region of distant (z ~ 0.8 - 0.9) Within central 1.5 Mpc region of distant (z ~ 0.8 - 0.9) clusters, the fraction of galaxies with OII EQW > 15 Å is ~45% clusters, the fraction of galaxies with OII EQW > 15 Å is ~45% (Postman, Lubin, Oke 2001), substantially higher than the 10 (Postman, Lubin, Oke 2001), substantially higher than the 10 to 20% active fraction seen in the centers of 0.2 < z < 0.55 to 20% active fraction seen in the centers of 0.2 < z < 0.55 clusters (Balogh et al. 1997)clusters (Balogh et al. 1997)

SFRs in z~1 clusters are also substantially higher than in z~0 clusters. Within central 1 Mpc, evidence for suppressed SFRs relative to those at larger radii.

deMarco et al. 2004


Ages of Early Type Cluster Ages of Early Type Cluster GalaxiesGalaxies

• Ellipticals are well established in x-ray luminous Ellipticals are well established in x-ray luminous clusters when universe was ~1/3 its present ageclusters when universe was ~1/3 its present age

• There is no significant evolution in the CMR There is no significant evolution in the CMR (other than expected from passive evolution)(other than expected from passive evolution)

• Photometric and spectroscopic data suggest a Photometric and spectroscopic data suggest a mean formation era of z ~ 3 with a spread in mean formation era of z ~ 3 with a spread in formation times of ~34 (±15) % (~0.7 Gyr)formation times of ~34 (±15) % (~0.7 Gyr)

• Star formation is higher and more frequent in Star formation is higher and more frequent in z>0.8 cluster S0s and spirals than what is seen z>0.8 cluster S0s and spirals than what is seen todaytoday


Goto et al 2003Goto et al 2003

Quilis, Moore, & Bower 2000: Ram pressure induced evolution of gaseousdisk moving thru hot ICM - all HI gas is stripped in 100 Myr

• What we know:What we know:– The relative fraction of galaxy The relative fraction of galaxy

morphologies depends on density morphologies depends on density (Dressler 1980, Postman & Geller (Dressler 1980, Postman & Geller 1984) and/or on clustocentric 1984) and/or on clustocentric radius (Whitmore & Gilmore 1993)radius (Whitmore & Gilmore 1993)

Are the morphologies of Are the morphologies of cluster galaxies evolving?cluster galaxies evolving?

– Physical processes exist that can Physical processes exist that can alter galaxy morphology on alter galaxy morphology on timescales much less than the timescales much less than the current age of the universe: ram current age of the universe: ram pressure, tidal disruption, mergerspressure, tidal disruption, mergers

– Some data suggests there is Some data suggests there is detectable evolution in the detectable evolution in the morphological composition of morphological composition of clusters over the past ~5 Gyrs clusters over the past ~5 Gyrs (z~0.5 to the present epoch)(z~0.5 to the present epoch) Poggianti 2000Poggianti 2000


Classifying GalaxiesClassifying Galaxies• VisuallyVisually

– Over 3500 galaxies with i,z < 24 classified. No selection Over 3500 galaxies with i,z < 24 classified. No selection in color or position. Classifications done in bandpass that in color or position. Classifications done in bandpass that is closest to the rest-frame B-band.is closest to the rest-frame B-band.

– Methodology: ~3 team members (MP+) classify galaxies Methodology: ~3 team members (MP+) classify galaxies using a common reference set. Agreement in E, S0, Sp, using a common reference set. Agreement in E, S0, Sp, Irr typically 75 - 85%. No systematic errors between Irr typically 75 - 85%. No systematic errors between classifiers detected.classifiers detected.

– Morphological “k-correction” has been shown to be a Morphological “k-correction” has been shown to be a small effect (e.g., Bunker et al. 2000; Windhorst et al. small effect (e.g., Bunker et al. 2000; Windhorst et al. 2002)2002)

• Machine-generated ParametersMachine-generated Parameters– Compactness, Asymmetry, BPZ Spectral template type Compactness, Asymmetry, BPZ Spectral template type

show good correlations with visually determined typeshow good correlations with visually determined type


S0/a E S0/E Sa E/S0 E ES0/a E S0/E Sa E/S0 E E

S0/a Sb/Sc S0/E S0/E S0/E S0/a Sc/SdS0/a Sb/Sc S0/E S0/E S0/E S0/a Sc/Sd

Sa or later S0/E Sb/Sc E E S0/a ESa or later S0/E Sb/Sc E E S0/a E

S0/E E S0/a S0/E E/S0 E S0/aS0/E E S0/a S0/E E/S0 E S0/a

Sb or later E S0/a Sa or later S0/E Sb or later Sb/ScSb or later E S0/a Sa or later S0/E Sb or later Sb/Sc

E Sc/Sd S0/E Sb/Sc E/S0 Sa or later S0/aE Sc/Sd S0/E Sb/Sc E/S0 Sa or later S0/a

S0/a E/S0 E/S0 E Sb or later S0/a Sb/ScS0/a E/S0 E/S0 E Sb or later S0/a Sb/Sc

22.2 mag

23.0 mag


Photometric RedshiftsPhotometric Redshifts

0.33 ≤ zB≤ 0.53 0.53 ≤ zB≤ 0.73 0.73 ≤ zB≤ 0.93

0.93 ≤ zB≤ 1.13 1.13 ≤ zB≤ 1.33 1.33 ≤ zB≤ 1.53


Morphology-Density Relation @ z = 0.83Morphology-Density Relation @ z = 0.83 CL0152 + MS1054: BPZ Sample Spectroscopic Sample

10 100 1000 10 100 1000

Density (Galaxies Mpc-2)

Postman et al 2004, in prep


Morphology-Density Relation @ z = 1.24Morphology-Density Relation @ z = 1.24



Morphology-Radius RelationMorphology-Radius Relation

Whitmore & Gilmore 1993


All Galaxies (photo-z sample)CL1252-2927 CL0152-1357


Spiral Galaxies (photo-z sample)CL1252-2927 CL0152-1357


S0 Galaxies (photo-z sample)CL1252-2927 CL0152-1357


Elliptical Galaxies (photo-z sample)CL1252-2927 CL0152-1357


Lubin, Oke, Postman 2002Lubin, Oke, Postman 2002

1.241.24

CL1252

CL0152

MS1054

Evolution of the Early Type Population FractionEvolution of the Early Type Population Fraction


Poggianti 2000Poggianti 2000 0.83 1.24

No significant evolution of No significant evolution of morphological population morphological population between z=1.24 (8.5 Gyr ago) between z=1.24 (8.5 Gyr ago) and z=0.4 (4.3 Gyr ago)and z=0.4 (4.3 Gyr ago)



Evolution of Morphological Evolution of Morphological Composition in ClustersComposition in Clusters

• Morphological segregation is in-place by z=1.24, at least in Morphological segregation is in-place by z=1.24, at least in clusters with x-ray luminosities greater than 2.5 x 10clusters with x-ray luminosities greater than 2.5 x 104444 erg/s. M-D erg/s. M-D and M-R relations are qualitatively consistent with what is seen and M-R relations are qualitatively consistent with what is seen locally - spiral galaxies are not common in dense environments.locally - spiral galaxies are not common in dense environments.

• Given the irregularityGiven the irregularity**** of the galaxy distributions, the presence of of the galaxy distributions, the presence of a strong M-D relation suggests that density, rather than a strong M-D relation suggests that density, rather than clustocentric radius, may be the more fundamental variable.clustocentric radius, may be the more fundamental variable.

• There is no strong evolution in the early type fraction in x-ray There is no strong evolution in the early type fraction in x-ray selected clusters between z ~ 1.24 and z ~ 0.5 - but, as always, a selected clusters between z ~ 1.24 and z ~ 0.5 - but, as always, a larger sample is needed.larger sample is needed.

• This may suggest that morphological fractions in current epoch This may suggest that morphological fractions in current epoch clusters are the result of more recent environmental interactions clusters are the result of more recent environmental interactions (a la MORPHs)(a la MORPHs)

• ACS / WFC enables relatively easy and robust early vs late type ACS / WFC enables relatively easy and robust early vs late type classification down to i = 23 mag & down to i = 24 mag with care.classification down to i = 23 mag & down to i = 24 mag with care.


Brightest Cluster GalaxiesBrightest Cluster Galaxies

• BCGs could exhibit BCGs could exhibit significant photometric & significant photometric & morphological evolution morphological evolution between z~1 and now.between z~1 and now.

• What fraction of z~1 What fraction of z~1 BCGs appear to be in BCGs appear to be in process of merging?process of merging?

• How does the rest-frame How does the rest-frame B-band BCG luminosity in B-band BCG luminosity in our z~1 clusters our z~1 clusters compare with current compare with current epoch BCGs?epoch BCGs?

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BCG Formation Simulation BCG Formation Simulation by J. Dubinski (1998)by J. Dubinski (1998)

10 Gyr in 15 seconds10 Gyr in 15 seconds


Brightest Cluster GalaxiesBrightest Cluster GalaxiesCL0152-13 MS1054 CL1604+4304CL0152-13 MS1054 CL1604+4304

CL1604+4321 CL0910+54 CL1252-29CL1604+4321 CL0910+54 CL1252-29

Elliptical Elliptical Sb/ScElliptical Elliptical Sb/Sc

S0/a S0/a EllipticalS0/a S0/a Elliptical


BCG Mergers?BCG Mergers?

• MS1054 has asymmetric MS1054 has asymmetric outer isophotes.outer isophotes.

• CL1252 BCG “pair” leave CL1252 BCG “pair” leave significant residuals significant residuals when best-fit elliptical when best-fit elliptical isophotes subtracted - isophotes subtracted - suggestive of tidally suggestive of tidally stripped stars. This pair stripped stars. This pair will likely merge within a will likely merge within a few Gyr.few Gyr.

• CL0152 BCG is well-fit by CL0152 BCG is well-fit by concentric elliptical concentric elliptical isophotes.isophotes.


BCG Luminosity EvolutionBCG Luminosity Evolutionz ~ 1 BCG exhibit a similar z ~ 1 BCG exhibit a similar dispersion in their rest-dispersion in their rest-frame B-band luminosities frame B-band luminosities (~32%) as their z=0 (~32%) as their z=0 counterpartscounterparts

MM22 - M - M11 in all but one of in all but one of these z~1 clusters is these z~1 clusters is smaller (<0.13 mag) than smaller (<0.13 mag) than that in ~90% of the z~0 that in ~90% of the z~0 rich Abell clusters rich Abell clusters [Exception is MS1054 which [Exception is MS1054 which has 0.36 mag contrast]has 0.36 mag contrast]

We expect some of these We expect some of these BCGs to undergo a doubling BCGs to undergo a doubling in mass by z~0.5 (e.g., in mass by z~0.5 (e.g., CL1252)CL1252)


Mapping the Cluster Mass DistributionMapping the Cluster Mass Distribution

• Key questions:Key questions:– Is the distribution Is the distribution

of luminous of luminous matter an matter an accurate tracer of accurate tracer of the total mass? the total mass? Are substructures Are substructures seen in x-rays and seen in x-rays and galaxies reflected galaxies reflected in mass as well?in mass as well?

– Is the mass Is the mass estimate from estimate from gravitational gravitational lensing consistent lensing consistent with other (x-ray, with other (x-ray, kinematic) mass kinematic) mass estimators?estimators?


Chandra imaging: Evidence for Chandra imaging: Evidence for On-going Cluster AccretionOn-going Cluster Accretion

Rosati et al. 2002Rosati et al. 2002

CL0152-1357 MS1054-0321 CL1252-2927


Cluster Mass Distribution: CL0152Cluster Mass Distribution: CL0152

M. Jee et al. 2003M. Jee et al. 2003Luminosity Density for cluster membersLuminosity Density for cluster members


Cluster Mass Distribution: MS1054Cluster Mass Distribution: MS1054

M. Jee et al. 2003M. Jee et al. 2003Luminosity Density for cluster membersLuminosity Density for cluster members


Cluster Mass Distribution: CL1252Cluster Mass Distribution: CL1252

Lombardi, Rosati et al. 2003Lombardi, Rosati et al. 2003

Contours show the surface mass distribution as derived from the co-added i+z band image. The

detection shown is significant at the 6 level.

Luminosity Density for probableLuminosity Density for probablecluster memberscluster members

------ NIS model------ NFW model------ X-ray, T=[5.6, 6, 6.4] keV


Gravitational arcs discovered in CLGravitational arcs discovered in CL1252-2927 1252-2927 @@ z=1.24 z=1.24

Arc A

Arc B

Galaxy @ z= 3.36


Cluster Mass DistributionCluster Mass Distribution• Strong lensing is detected in at least two clusters at Strong lensing is detected in at least two clusters at

z=0.83 and z=1.24. Weak lensing detected in all z>0.8 z=0.83 and z=1.24. Weak lensing detected in all z>0.8 clusters studied so far.clusters studied so far.

• Galaxies, ICM, and mass exhibit qualitatively similar Galaxies, ICM, and mass exhibit qualitatively similar distributions. The frequency of significant substructure distributions. The frequency of significant substructure or elongated cluster galaxy distributions tends to or elongated cluster galaxy distributions tends to increase with redshift (cf. Lubin & Postman 1996) - increase with redshift (cf. Lubin & Postman 1996) - consistent with our ACS observations and current consistent with our ACS observations and current theoretical models.theoretical models.

• Lensing maps reveal, however, that highest galaxy Lensing maps reveal, however, that highest galaxy overdensities don’t always correspond to highest mass overdensities don’t always correspond to highest mass peaks, suggesting variations in M/L within a cluster.peaks, suggesting variations in M/L within a cluster.

• Lensing mass profile in good agreement with x-ray Lensing mass profile in good agreement with x-ray temperature and galaxy kinematics.temperature and galaxy kinematics.


WFPC2 (F606W) image of PKS1138-262 at z=2.2 WFPC2 (F606W) image of PKS1138-262 at z=2.2 with VLA radio contours (Pentericci et al. 1998)with VLA radio contours (Pentericci et al. 1998)

Finding Protoclusters at z > 1.3Finding Protoclusters at z > 1.3

• Powerful High-z Radio Powerful High-z Radio Galaxies: Forming BCGs?Galaxies: Forming BCGs?– Amongst the brightest galaxies at every Amongst the brightest galaxies at every

z (e.g. De Breuck et al. 2000)z (e.g. De Breuck et al. 2000)

– Merging of multiple L* clumps (e.g. Merging of multiple L* clumps (e.g. Pentericci et al. 1998)Pentericci et al. 1998)

– ~100 kpc envelopes of emission-line ~100 kpc envelopes of emission-line gas (e.g. vOjik et al. 1996)gas (e.g. vOjik et al. 1996)

– LLFIR FIR > 10> 1013 13 LLoo implying SFR > 2000 M implying SFR > 2000 Moo/yr /yr

– Highly clustered (e.g. Blake & Wall Highly clustered (e.g. Blake & Wall 2003, 2003, Overzier et al. 2003Overzier et al. 2003))

– SM blackholes powering AGNSM blackholes powering AGN

– Associated with GALAXY Associated with GALAXY OVERDENSITIES!OVERDENSITIES!


NARROW-BAND LYA IMAGING of POWERFUL RADIO GALAXIES has NARROW-BAND LYA IMAGING of POWERFUL RADIO GALAXIES has revealed z > 2 ‘PROTOCLUSTERS’revealed z > 2 ‘PROTOCLUSTERS’

(Keel et al. 1999, Pentericci et al. 2000, Venemans et al. 2002,2004, Kurk et al. 2001,2003)(Keel et al. 1999, Pentericci et al. 2000, Venemans et al. 2002,2004, Kurk et al. 2001,2003)

VLT/FORS

Lya at z = 4.11

TN J1338-19 at z = 4.11:TN J1338-19 at z = 4.11:

•33 confirmed Ly33 confirmed Ly emitters emitters (Venemans et al. 2002, 2004 (Venemans et al. 2002, 2004 in prep)in prep)

•Velocity dispersion ~350 Velocity dispersion ~350 km/skm/s

•Comparable to mass of Coma Comparable to mass of Coma clustercluster

However, Lya only detects about However, Lya only detects about ~20% of Lyman Break galaxies ~20% of Lyman Break galaxies (Steidel et al. 1999, Shapley et al. (Steidel et al. 1999, Shapley et al. 2001)2001)


HST/ACS observations of TN J1338 at z = 4.11HST/ACS observations of TN J1338 at z = 4.11

Miley et al. 2004; Miley et al. 2004; Overzier et al. in prep.Overzier et al. in prep.

18 18 orbits (5orbits (5g,4r,4i,5zg,4r,4i,5z),),single pointing.single pointing.

Look for LBG Look for LBG population population associated with associated with protocluster at z~4:protocluster at z~4:

g-r > 1.5, g-r > 1.5, g-r > (r-i)+1.1g-r > (r-i)+1.1r-i < 1.0r-i < 1.0i < 27i < 27


2 arcsec/16 kpc

Radio Galaxy

56 LBGs to iAB=27

Cloning (R. Bouwens) of B-Cloning (R. Bouwens) of B-dropouts suggests 3-5 dropouts suggests 3-5 sigma overdensity of LBGs sigma overdensity of LBGs compared to GOODS compared to GOODS (Giavalisco et al.); (Giavalisco et al.); Concentrated towards radio Concentrated towards radio galaxy.galaxy.

12 Lya emitters

iAB=23.3


Does the structure of galaxies depend on their Ly emission?

Preliminary result from Preliminary result from Overzier et al. 2004Overzier et al. 2004

Ferguson et al. 2003

TN1338 z=4.1TN1338 z=4.1

R H(z)-1 ( virial velocity)

No evolutionR H(z)-2/3 ( virial mass)

Bias? Lya = invf(L,SFR)


HST/ACS IDT protocluster program HST/ACS IDT protocluster program Target z Note

TN0924 5.19 OBSERVED

TN1338 4.11 OBSERVED

0316 3.15 GO PROPOSED

1138 2.16 SCHEDULED

Blue: EROsBlue: EROsBlack: LyBlack: Ly emitters emittersRed: HRed: H emitters emittersGreen: X-ray emitters (6 confirmed)Green: X-ray emitters (6 confirmed)(Kurk et al. 2003, Pentericci et al. 2002)(Kurk et al. 2003, Pentericci et al. 2002)

1138-262 at z=2.161138-262 at z=2.16

Richest structure of Richest structure of galaxies known at galaxies known at z~2:z~2:


• Distant Radio Galaxies are excellent signposts for Distant Radio Galaxies are excellent signposts for locating distant protoclusters.locating distant protoclusters.

• TN1338 (z=4.1) has a significant excess of TN1338 (z=4.1) has a significant excess of spectroscopically confirmed Lyspectroscopically confirmed Ly emitters and g- emitters and g-band drop outs.band drop outs.

Summary: Hi-z RG/Proto-clusterSummary: Hi-z RG/Proto-cluster

LyLy halo morphology halo morphology unusually assymetric and unusually assymetric and narrow – points away from narrow – points away from center of overdensity - effects center of overdensity - effects of bouyancy? SF injects of bouyancy? SF injects lighter gas into heavier intra-lighter gas into heavier intra-protocluster medium?protocluster medium?

to center of protocluster

Ground-based Lya map


Updates to the Structure Updates to the Structure Formation StoryFormation Story

• Protoclusters exist at z~4 (~10% current age of universe)Protoclusters exist at z~4 (~10% current age of universe)• High-z clusters with high elongations or significant substructures are common, High-z clusters with high elongations or significant substructures are common,

consistent with the idea that significant cluster accretion is occurring along consistent with the idea that significant cluster accretion is occurring along filamentary structures.filamentary structures.

• The bulk of the stars in early type cluster galaxies are formed over a relatively The bulk of the stars in early type cluster galaxies are formed over a relatively narrow timeframe (~0.5 - 1 Gyr) in the redshift range 2.3 < z < 4.5.narrow timeframe (~0.5 - 1 Gyr) in the redshift range 2.3 < z < 4.5.

• The Brightest Cluster Galaxies at z~1 are still very much “works in progress”. Many The Brightest Cluster Galaxies at z~1 are still very much “works in progress”. Many are not much brighter than their nth-ranked companions and some are up to a factor are not much brighter than their nth-ranked companions and some are up to a factor of 2 below the predicted rest-frame B-band passively evolving luminosity.of 2 below the predicted rest-frame B-band passively evolving luminosity.

• The overall morphological population of clusters does not appear to change The overall morphological population of clusters does not appear to change significantly until more “recent” (z ~ 0.4 - 0.5) epochs. significantly until more “recent” (z ~ 0.4 - 0.5) epochs. If true, what triggers this If true, what triggers this recent evolution?recent evolution? There is plenty of ICM and time for a variety of environmental There is plenty of ICM and time for a variety of environmental processes to have modified galaxies prior to z = 0.4. Alternatively, one can argue processes to have modified galaxies prior to z = 0.4. Alternatively, one can argue that the strength of even the recent “evolution” in morphological fractions is not that the strength of even the recent “evolution” in morphological fractions is not highly significant - perhaps the answer to the “origins” of the morphological fractions highly significant - perhaps the answer to the “origins” of the morphological fractions in clusters lies beyond z=1.3.in clusters lies beyond z=1.3.


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Clusters: They’re not just for Clusters: They’re not just for research anymore!research anymore!

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Documents

March 17, 2004STScI Colloquium1 ACS Observations of Distant Clusters of Galaxies & Protoclusters: New Constraints on Cluster and Galaxy Formation & Evolution