Thermal / Non-thermal plasmaInteractions in Clusters

The Good, the Bad & the Puzzling

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

The BIG Questions

• How can relativistic plasmas, seen through synchrotron radiation, reveal the dynamics and evolution of clusters? SYNCHROTRON, clues to DYNAMICS ?

• How does the dynamics of the thermal plasma affect the growth of the magnetic field and the acceleration of relativistic particles?

DYNAMICS causes B field and CRs ?

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

Key Messages

L. Rudnick MN Inst. for Astrophysics Zeldovich 100

GOOD NEWS: хорошие новости • AGN influences on thermal X-ray plasma are welldocumented (heating, cavities, etc) • Shocks seen in radio, sometimes in X-ray & S-Z, are consistent with expectations from theory, connected to cluster mergers • Radio halos likely result from expected turbulence in mergers

BAD NEWS: плохие новости • Mach numbers expected from simulations and measured in X-ray inconsistent with spectral index of radio emission. • Missing shocks, either radio or X-ray

PUZZLING NEWS: головоломки • Mild mergers with no shocks also produce giant radio halos. • 3D structure of giant shock in Abell 2256 is not simple to explain • Radio galaxies sometimes seen at edge of shocks – why?

Юрий Никулин

Max Otto von StierlitzМаксим Максимович Исаев

with support from U.S. NSF, AST112195

The GOOD News

Radio galaxy ICM interactions

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

ACTIVEPASSIVE

The GOOD News• Merger shocks: simulations and observed relics

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

Vazz

a et

al.

2012

, MN

RAS

421

1868

The GOOD News

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

Keeping electrons energized: CRe lifetimes ~ 108 y

CRe diffusion times ~ 1010 y

W. Couch

M. O

wers

Merger-driven turbulence

The GOOD News

• Radio halos mergers

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

Cassano+ 2011

HalosDISTURBED

RELAXE

D

The GOOD News

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

A. S

imio

nesc

u et

al.

2013

ApJ

775

4

Planck intermediate results. X. Physics of the hot gas in the Coma cluster, 2013

Consistent shock story - Radio, X-ray, S-Z

Brown & Rudnick, 2011

RADIO

X-RAY

S-Z

Mismatched Mach numbers ?

M < 2

3.3 < M < 4.6

X-ray shock

radio spectrum

The BAD NewsO

grea

n+20

13

X-ra

y sh

ock

radi

o sp

ectr

umva

n W

eere

n+ 1

2 ainj= -0.6 to -0.7

Do shocks look too efficient?

Tension with g-ray limits?

The BAD News

The BAD NewsX-ray shock

Radio shock

Where’s the radio shock?

Why theoffset?

The PUZZLING Newsголоволомки

L. Rudnick, MN Inst. for Astrophysics, Zeldovich 100

Expl

orin

g

low s

urfa

ce b

right

ness

radi

o em

ission

Farnsworth+2013

Can MILD mergers Giant Radio Halos?

Farnsworth+ 2013

The PUZZLING News

RADIOX-Ray

Rossetti+ 2013Abell 2142

Abell 2256 – where’s the shock?

with F. Owen, NRAO & J. Eilek, NMIMT

RadioX-ray

The PUZZLING News

Abell 2256 – where’s the shock?

with F. Owen, NRAO & J. Eilek, NMIMT

The PUZZLING News

Flat spectrum

Steep spectrum

The PUZZLING NewsRadio Galaxy – relic/shock connection?

Bonafede+14

van Weeren+ 2010

Pizzo+2010

Key Messages

L. Rudnick MN Inst. for Astrophysics Zeldovich 100

GOOD NEWS: хорошие новости • AGN influences on thermal X-ray plasma are welldocumented (heating, cavities, etc) • Shocks seen in radio, sometimes in X-ray & S-Z, are consistent with expectations from theory, connected to cluster mergers • Radio halos likely result from expected turbulence in mergers

BAD NEWS: плохие новости • Mach numbers expected from simulations and measured in X-ray inconsistent with spectral index of radio emission. • Missing shocks, either radio or X-ray

PUZZLING NEWS: головоломки • Mild mergers with no shocks also produce giant radio halos. • 3D structure of giant shock in Abell 2256 is not simple to explain • Radio galaxies sometimes seen at edge of shocks – why?

Юрий Никулин

Max Otto von StierlitzМаксим Максимович Исаев

with support from U.S. NSF, AST112195

radio.galaxyzoo.org