Activity and quiescence in early cluster environments Veronica - - PowerPoint PPT Presentation

High-redshift (proto-)clusters: anecdotal or important phase? - Paris, Oct. 2016

Veronica Strazzullo (LMU USM)

• E. Daddi, R. Gobat, F

. Valentino, M. Pannella, A. Cimatti, M. Dickinson, A. Renzini,

• G. Brammer, M. Onodera, A. Finoguenov, M. Bethermin, A. Zanella, M. Carollo, N. Arimoto

Activity and quiescence in early cluster environments

Brodwin+ 2013

On-going star formation even deep into cluster cores

Cluster galaxies at z≳1.5 – the SF vs quiescent views

Some fraction of already evolved galaxies in the core population

(Tran+2010, Hayashi+2010, Santos+2011, Fassbender+2011, Stanford+2012, Zeimann+2012, Brodwin+2013, Alberts 2013, Bayliss+2014, Stacey+2014, Ma+2014, Santos+2015, Alberts+2016, …) (Kurk+2009, Papovich+2010, Andreon+2011, 2014, Spitler+2012, Stanford+2012, Zeimann+2012, Tadaki+2012,Tanaka+2013ab, Strazzullo+2013, Newman+2014, Cooke+2015, … )

Newman+ 2014

Tran+2015 Smail+2014 CIG J0218-0510, z=1.6 (Papovich+2010, Tanaka+2010, Tran+2010, 2015, Rudnick+2012, Smail+2014, Santos+2014, …)

Papovich+2010

…in some cases, within the same cluster

Tran+2010

What was the forecast…?

De Lucia+ 2006

Observations to z~1: Simulations:

Gobat+2008 Thomas+2005

Fossil record (z~0): Fossil record (z~1):

MB Mei+ 2009 U-B

Observations to z>2:

Cluster diversity and/or mass dependence?

Dependence of galaxy population properties on cluster mass are possible/likely, but younger populations and/or high SF levels found also in very massive clusters

Stanford+2012 Santos+2015

Fakhouri+2010

By z≈2, an average mid-1014 M◉ today’s cluster is formally well into group regime…

Brodwin+2012

What clusters ?

Strazzullo+13

A „typical“ cluster progenitor, Cl J1449+0856 at z=2

(Gobat+2011, 2013, Strazzullo+2013, Valentino+15,16)

Strazzullo+13

IR-selected, X-ray detected (Gobat+2011). A low-mass structure typical of a massive cluster progenitor at z~2.

• massive quiescent (often

morphologically early-type) galaxies in the cluster central region (<200kpc)

• at the same time – and in

contrast with z<1.5 cluster cores – central regions also host still actively star forming sources

A „typical“ cluster progenitor, Cl J1449+0856 at z=2

(Gobat+2011, 2013, Strazzullo+2013, Valentino+15,16)

IR-selected, X-ray detected (Gobat+2011). A low-mass structure typical of a massive cluster progenitor at z~2.

• massive quiescent (often

morphologically early-type) galaxies in the cluster central region (<200kpc)

• at the same time – and in

contrast with z<1.5 cluster cores – central regions also host still actively star forming sources

Strazzullo+13

A further look at galaxy populations in Cl J1449+0856:

Strazzullo+in prep.

200 kpc

Red sequence seeds at z~2

A clear, small population of red sources …

Red sequence seeds at z~2

… mostly seemingly quiescent galaxies

Red sequence seeds at z~2

… clearly segregated deep into the cluster center

r<150 kpc

Red sequence seeds at z~2

Statistically subtracted CMD - (largely) independent of individual membership determination.

(… independent of photo-zs… )

Red sequence seeds at z~2

Statistically subtracted CMD - (largely) independent of individual membership determination.

r<150 kpc

Quite a clear signature of the inner, densest cluster core

Red sequence seeds at z~2

• Further constrains BCG complex
• All but one sources on the bright red-sequence are undetected at

870μm (<2σ, ~40M⊙/yr) ➜ would suggest suppressed SF for most massive red galaxies

A different viewpoint – a 10x overdensity of ALMA 870μm sources

• Further constrains BCG complex
• All but one sources on the bright red-sequence are undetected at

870μm (<2σ, ~40M⊙/yr) ➜ would suggest suppressed SF for most massive red galaxies

A different viewpoint – a 10x overdensity of ALMA 870μm sources

A different viewpoint – a 10x overdensity of ALMA 870μm sources

One bright red-sequence source 870μm-detected: new cycle 3

• bservations of CO(4-3) confirm it at the cluster redshift.

BCG building site…

At the cluster center, a complex of multiple sources, apparently a mixture of star-forming and suppressed/quiescent galaxies, is likely the future BCG still in its build-up phase.

r∼1.8“, ~15 kpc F105W F140W Ks quiescent SF/suppressed? 870μm-source, ~200 M⊙/yr

• In densest regions of (one, supposedly) ordinary cluster progenitor

environment(s), some massive galaxies are already evolved and make for a first red sequence seedling at z~2. This population is confined to the very central cluster region.

• Star formation is still occurring even deep into the cluster core -

different selections and observations highlight different aspects of a likely diverse galaxy population. Among the points deserving further thought:

• the link between suppression of star formation and densest

environments at this redshift - this tells something more/different than environmental effects due to few/several billion years spent in a massive hot halo

• stellar populations of passive cluster galaxies vs field analogs -- at z≈2

Following up on two crucial issues (for galaxy population studies):

• probe established, massive clusters, at the high extreme of the density range
• avoid cluster selection biases involving galaxy population properties

Five very massive (M200≳5x1014M⊙) SZ-selected clusters at z≥1.4

(only very few confirmed such massive structures found to date at this redshift, by different means (X-ray, SZ, red galaxies, Rosati+2009, Santos+2011/Tozzi+2015, Stanford+2012/ Brodwin+2012,2015, Andreon+2009,2014, Bleem+2015/Bayliss+2014, Mantz+2015)

0.0 0.5 1.0 1.5 1 10 SPT-SZ 2500 deg2 ROSAT-All sky Planck-DR1 ACT

Redshift

M500c [1014 MO

• h70
• 1 ]

Quick ad – Galaxy populations in the high-z SPT tail

with J. Mohr, M. Pannella, A. Saro, M. Ashby, S.A. Stanford and SPT-clusters

Bleem+2015

Following up on two crucial issues (for galaxy population studies):

• probe established, massive clusters, at the high extreme of the density range
• avoid cluster selection biases involving galaxy population properties
• A complete sample of massive distant clusters over 2500 deg2, among the

few most massive clusters known at these redshifts

• Cluster selection independent of cluster galaxies - ideally suited for

galaxy populations studies

• High cluster mass ideal for probing environmental effects on galaxy

populations in most massive haloes, and to improve statistics

• A dedicated deep optical/NIR follow-up with HST (F105+F140, 2+1
• rbits) & Spitzer (3.6+4.5𝜈m, 6000-8000s per channel).

Quick ad – Galaxy populations in the high-z SPT tail

with J. Mohr, M. Pannella, A. Saro, M. Ashby, S.A. Stanford and SPT-clusters

Star formation and quenching

• quiescent fraction
• environmental

dependence of stellar populations

• red sequence evolution

Stellar mass assembly

• restframe NIR LF down

to M*+3

• stellar mass function

and mass assembly at z>1.3

Structural evolution

• morphological vs. stellar

population properties in dense environments

• mass-size relation and

environmental dependence

Composite LF simulation Wylezalek+2014 Newman+2014 Wang+ 2016 Alberts+ 2016

A first, „minimal“ 4-bands study…

z~1.4 z~1.5 z~1.7

first-look, preliminary!

SPT-CLJ2040 z=1.48

full WFC3 field core (<280 kpc) >280 kpc