Galaxy Dynamics in CLASH Clusters

CLASH team + VLT team + Margaret Geller, Michael J. Kurtz, and Kenneth

J. Rines

Doron Lemze (Johns Hopkins)

Clusters with reduced redshifts:

• A963 - Hectospec (Margaret’s team)• A2261 - Hectospec (Margaret’s team)• RXJ2129 - Hectospec (Margaret’s team)• MACS1206 – VLT & Magellan (Piero & DanK)

Cluster members – removing interlopers

Why?

• Effects estimated quantities such as virial mass and concentration parameter.• Effects substructure measurements.• Effects estimating the level of relaxation.

Cluster members – A963

# cluster members: 205

den Hartog & Katkert 1996

Cluster members – RXJ2129

# cluster members: 195

Cluster members – A2261

# cluster members: 213

Cluster members – MACSJ1206

# cluster members: 311

Substructure

2,2

,22 1

ilocalilocal

locali vvN

g

N

ii N

g

/1

2

Dressler & Shectman 1988 – a 3D method

Substructure – A963

Substructure – RXJ2129

Substructure – A2261

Substructure – MACSJ1206

Substructure – summary

A2261 & MACSJ1206: substantial substructure

A963 & RXJ2129: some substructure level, but maybe not very significant?

Is it consistent with X-ray info?

Yes!

Out of the 20 relaxed CLASH clusters 8 have some evidence for substructure, among them A2261 & MACSJ1206 (Postman et al. 2011).

Mass profiles

N

ji ij

N

i iv

R

vvGNrM

/123)(

N

iii

PMproj NvvR

GfrM /)( 2

r

c dRRAGF

rM0

2 )()(

Mass profiles – A963

Mass profiles – RXJ2129

Mass profiles – MACSJ1206

Mass profiles – A2261

M – C relation

Coe et al.

If at least some of the clusters are not fully relaxed, maybecomparing the unrelaxed clusters inferred concentrations to concentrations measured from simulated relaxed clusters is not comparing apples to apples.

However, since unrelaxed clusters should have slightly lower concentrations (Neto et al. 2007; Duffy et al. 2008), this actually increases the mass-concentration tension between observed inferred values and theoretical expectations.

MACSJ1206 – Astronomy Picture of the Day