17.25 Sergio COLAFRANCESCO Multifrequency Study of the SZ ...

Multi-n study of the 

SZ Effect 

in cosmic structures 

Wits University - DST/NRF SKA Research Chair 

INAF-OAR 

Email: Sergio.Colafrancesco@wits.ac.za 

1

LSS @ Multi-frequency

A Galaxy Cluster 

Perseus Cluster 

X-ray: NASA/CXC/IoA/A.Fabian et al. 

Radio: NRAO/VLA/G. Taylor 

Optical: NASA/ESA/Hubble Heritage (STScI/AURA) & Univ. of Cambridge/IoA/A. Fabian


Radio 

Radio 

X-ray 

Gamma-ray 

Optical 

Th. Bremsstrahlung 

p 0 decay 

X-ray 

Synchrotron 

ICS 

Bremsstrahlung 

g-rays 

TeV 

Galaxy clusters show various non-thermal phenomena 

related to the presence of Thermal plasma, Cosmic Rays, B- 

fields, BHs, Dark Matter, Galaxies, Active Galaxies, … 

that are not yet fully understood. (see, e.g., 

4


Radio 

Perseus cluster 

X-rays 

Radio Halo 

NGC1275 

Blazar core 

n-plasmoids 

Optical 

X-ray 

[Colafrancesco et al. 2010]] 

g-rays 

TeV 

Multi-n emission of Galaxy Clusters is often over-shined by 

the emission of the central Radio Galaxy 

(see, e.g., Perseus/NGC1275) 

5

Clusters: crossroads of cosmic physics 

Dark Matter 

Cosmic rays 

AGNs 

B field 

Thermal plasma

Strategy 

Multi-D tomography 

(disentangle cluster atmospheres) 

Multi-technique 

single-purpouse 

(Radio to TeV) 

Multi telescopes 

Multi techniques 

Single-technique 

multi-purpouse 

(mm) 

Single telescope 

Single technique 

radio mwave-mm X-ray g-ray TeV mwave-mm

What is the SZE Physics 

Photon fields 

Internal 

↓ 

External 

↓ 

Use CMB photons 

to extract 

plasma information 

↑ 

Internal 

High-E electrons 

- thermal (supra-thermal) 

- relativistic 

high-energy 

photon

Why the SZE General derivation 

SZE yields a measure of the total pressure in cluster atmospheres 

I 0 (x) 

Thermal 

I(x) 

Relativistic 

I rel (x) 

thermal NR e - 

n 

kT 

4 

n m c 

e 

2 

e 

n 4 

relativistic e - g 

2 

n 3

SZE-kinematic: general derivation 

Intensity change 

Momentum 

T 

T 

0 

p 

e 

kin 

g 

h( 

x) 

 

m v 

e 

1 

m c 

e 

 

pe 

d Tne 

p 

p 

h( 

x) 

 

m c 

Relativistic generalization 

e 

Spectral shape 

4 x 

x e 

h( x) 

 

2 

1 

( x ) 

x 

rel 

e 1 

CMB spectrum

SZE: polarization 

Polarizations arises as 

a natural outcome of 

g-e ± scattering 

→ various SZE polarizations 

Polarization due to peculiar 

motion of clusters 

t 

 

2 

t 

V 

Polarization due to transverse 

motions of plasma within 

the cluster 

2 

V 

t 

 

Polarization due to 

multiple scattering g-e ± 

within the cluster 

 

T 

 

 

 

 

kT 

m c 

e 

 

 

 

2 

2

How is the SZE Spectro-polarimetry 

SZE Intensity 

sensitivity to projected 

physical parameters 

SZ kin 

SZ th 

SZ warm 

, kT e , P e , E e , M c , V t 

SZ DM 

SZ rel 

SZE polarization 

sensitivity to 3-D distribution of 

physical parameters 

For a thermal plasma: 

• Velocity sub-structure (≈ 2 ) 

• Temp. sub-structure (≈T e 2 ) 

5 keV 

20 keV

Astrophysics & Cosmology 

The SZE is independent of redshift 

and therefore it is an optimal tool 

for Cosmological applications 

Standard-rod “physical” effect 

X-rays 

X-rays 

X-rays 

The SZE depends directly on the 

electron distribution in the atmospheres 

of cosmic structures and therefore it is an 

optimal tool for Astrophysical applications 

Cosmic Lepto-meter, Speed-meter

Simple SZE AstroPhysics 

Shape 

Spectrum 

Contamination 

First SZE spectrum Coma 

cluster (MITO exp.) 

(DePetris et al. 2002) 

30GHz 

90GHz 

OVRO (30 GHz) 

SZE has larger angular 

size than X-ray image 

L X ~ n 2 (r) T 1/2 

Y SZ ~ n(r) T 

• Spectrum observed in a few 

bands (30, 150, 220, 275 GHz) 

• The zero near the peak of 

CMB spectrum (~ 220 GHz) 

RXJ1347-1145.

MACS J07017.5+3745 

A Triple-Merger 

Cluster 

B) kT = 12.8 kev (+2.1/-1.6) 

V = 3600 km/s (+3440/-2160) 

V = 3238 km/s (252/-242) 

C) kT = 34.0 kev (+11/-7.9) 

V = -3720 km/s (+2960/-2480) 

V = -733 k/s (+486/-478) 

D) kT ≈ 4 keV 

V = 831 km/s (843/-700) 

A) kT ≈ 2 keV 

V = 278 km/s (+295/-339) 

[Mroczkowski et al. 2011]

MACS J07017.5+3745 


Cluster 

B) kT = 12.8 kev (+2.1/-1.6) 

V = 3600 km/s (+3440/-2160) 

V = 3238 km/s (252/-242) 

C) kT = 34.0 kev (+11/-7.9) 

V = -3720 km/s (+2960/-2480) 

V = -733 k/s (+486/-478) 


V = 831 km/s (843/-700) 


V = 278 km/s (+295/-339)

MACS J07017.5+3745 


Cluster 

B) kT = 12.8 kev (+2.1/-1.6) 

V = 3600 km/s (+3440/-2160) 

V = 3238 km/s (252/-242) 

C) kT = 34.0 kev (+11/-7.9) 

V = -3720 km/s (+2960/-2480) 

V = -733 k/s (+486/-478) 


V = 831 km/s (843/-700) 


V = 278 km/s (+295/-339) 

E) Non-thermal component 

s=3.5, p1=0.1 

=5 10 -4 – 2 10 -2

MACS J07017.5+3745 

Comp. C 

[S.C. & 

Marchegiani 2013] 

Comp. C 

Comp. B

The Road to AstroPhysics 

Independent 

of astrophysics 

Strongly dependent 

on astrophysics 

I 

y 

th 

( kT ) 

( hc) 

3 

2 0 y g( 

x 

th 2 th 

 

kT 

e 

 

T 

dne 

2 

mec 

) 

Accessible 

from Space 

Need external priors 

• X-ray kT 

• GL M 

• O z 

for a proper use in 

• Cosmology 

• Astrophysics 

OVRO 

MUSTANG 

SPT 

kT= 7 keV 

kT=10 keV 

kT=15 keV 

kT=20 keV

Planck-Herschel Era: multi-n 

A2319 

THE PLANCK EARLY SZ SKY 

189 SZ sources (S/N > 6) 

‣ First SZE measure for 

~ 80% of known clusters 

‣ 37 new clusters 

PLANCK SZ Source CATALOG 

1227 SZ sources 

‣ 861 confirmed clusters 

- 683 known clusters 

- 178 new clusters 

‣ 366 cluster candidates

P-H Era: SZE spectrum 

Abell 2319: LFI-HFI PLANCK SZE spectrum 

Stacked SZ spectrum 

confirmed 

candidate 

IR and Radio source spectrum

The Planck take on SZE 

• Statistics 

• X-ray Luminosity 

• Optical 

• DM Mass 

• Massive 

• Luminous 

• Complex 

• Super-clusters 

• Intra-cluster Physics 

• Intensive quantities (P, kT, …)

DM 

P-H Era: towards AstroPhysics 

First evidence of SZE 

relativistic / non-thermal 

[Zemcov 250 mm et al. 2010] 

Herschel SPIRE 

view of the 

Bullet cluster 

Radio Halo 

non-relativistic 

350 mm 

500 mm 

n

SZE: probes of AstroPhysics 

Multi - Temperature 

kT 1 = 13.9 keV =3.5 10 -3 

kT 2 = 25 keV, =5.5 10 -3 

Thermal + non-thermal 

kT = 13.9 keV =1.1 10 -2 

n e ~E -2.7 , p 1 =1, =2.4 10 -4 

T2 

c 2 =1.27 

d.o.f.=1 

rms fom=1 

Thermal 

c 2 =0.44 

d.o.f.=2 

rms fom=0.35 

T1 

Non-thermal 

[S.C. et al. 2011] [S.C. et al. 2011] 

Evidence of non-gravitational activity in the cluster merging 

Shock acceleration or MHD acceleration 

Stochastic electron acceleration 

Continuous hadron acceleration

SZE: 3-d tomography 

Morphological SZE 

T standard deviation 

First measurement of the 

Temperature standard deviation 

in galaxy clusters: using the SZE 

[Prokhorov & Colafrancesco 2012] 

I 

I 

345 GHz Laboca 600 GHz Herschel 

600GHz 

345GHz 

A2219 

[Prokhorov, S.C. et al. 2011b] 

Shock 

hot 

Bullet 

cold 

Bullet Cluster 

~ 13.9 keV 

= 10.6 ± 3.8 keV 

• Measure of the temperature 

stratification in clusters 

• Measure of plasma in-homogeneity 

(th.+non-th.) along the line-of-sight

SZE: Radio Halo clusters 

RH vs thermal pressure 

RH vs total pressure 

Bimodality 

- active RHs 

- in-active RHs 

(Brunetti et al 2009) 

(Basu 2012) 

No Bimodality 

- all RH clusters have Y SZ

SZE 

Measuring P non-th : Y SZ - L X 

Self-similar G-only 

cluster formation 

Y SZ 

≈ L X 

5/4 

(1+x) 

Self-similar cluster formation + 

non-thermal pressure evolution 

X ≈ L X 

-0.81 

X-ray 

[S.C. et al. 2013] 

X=P non-th 

/P th 

evolution with L X 

X ≈ L X 

-0.81 

[S.C. et al. 2013]

Exploiting SZE information 

Different spectroscopic configurations 

for studying the SZE in cosmic structures 

EC2 

3m 

passive 

SZ kin 

Foreground 

EC3 

12m 

passive 

SZ th 

SZ non-th 

EC5 

12m 

active 

[DeBernardis, Colafrancesco et al. 2012]

Exploiting SZE information 

Different spectroscopic configurations 

for studying the SZE in cosmic structures 

EC2 

3m 

passive 

EC3 

12m 

passive 

SPT 

PLANCK 

Herschel 

EC5 

12m 

active 

[DeBernardis, Colafrancesco et al. 2012]

SZE spectroscopy: thermal plasma 

The relativistic kinetic theory 

(DF derivation) of astrophysical plasma 

is still unknown ! 

Juttner 

Maxwell-Boltzmann 

Non-relativistic 

A method based on Fourier analysis 

to derive the velocity DF of electrons 

by using SZE observations at ≥ 4 

frequencies. 

[Prokhorov, Colafrancesco, et al. 20011a] 

SZE spectroscopy will allow to 

derive spatially resolved T-profiles for 

nearby clusters out to large radii: 

Perseus 

Inversion Technique SZE → T, , V p , T CMB 

T profile with uncertainties similar to 

those of X-ray observations 

T profile uniquely sampled in the outer 

parts of the cluster 


X-Ray 

[Colafrancesco & Marchegiani 2010]

SZE spectro-polarimetry: 3-d 

SZE intensity spectrum allow to measure the plasma temperature kT 

Polarization due to finite optical depth allow to measure the density 

and velocity distribution of the electron plasma → 3-d phase-space 

I 

 

T 

 

71.43 

g( 

x) 

f ( x) 

T 

1 

 

I 

 

g( 

x) 

1 1 

40 

f ( x) 

 

V 

t 

kT 

m c 

e 

2 

Measure independently 

of cluster parameters (T,V t ) 

Measure t given kT and 

BB spectrum 

5 keV 

8 keV 

13 keV 

20 keV

SZE: particle acceleration 

CIZAJ2242.8+5301 

8.2 keV 

SZE Quasi-Thermal 

E e a few GeV 

Shock acceleration 

SZE Thermal 

8.2 keV 

E e ~ keV 

Thermalized plasma 

13 keV 

20 keV

SZE: Cavities in Clusters 

[Colafrancesco 2005] 

Cavities are isolated from the 

surrounding cluster atmosphere at 

n ~ 220 GHz 

n > 800 GHz 

I ~ ∫dl۰U e,tot : advantage w.r.t. X-rays

X-rays 

g-rays 

SZE: Radio-Galaxy Lobes 

SZE spectrum 

for a typical 

RG lobe 

(3C 294) 



I E 

[S.C. 2008, S.C. & Marchegiani 2012] 

X-ray: rough misleading 

measure of Ue 

E min 

E 

I ( x) 

g( 

x) 

d 

U e , 

 

rel 

SZE: reliable unbiased 

measure of Ue

SZE: Galaxy Winds & Outflows 

NGC 253 

Combine SZE and Radio 

to study the wind composition & energetics 

Thermal wind 

Non-thermal wind 

[Colafrancesco et al 2013] 

[Colafrancesco et al 2013]

SZE: Clusters Cosmology 

SZE allows to derive an unbiased 

measure of cluster DM mass 

[Planck Coll. 2013] 

Astro Physics 

= rms density fluctuation at scale R 

d v = overdensity threshold for collapse 

36

SZE: Cluster Cosmology 

Tension (3-) between 

Cluster vs. CMB Cosmology 

… more general tension between 

different CMB analyses 

(Planck vs SPT)

SZE: Cluster Cosmology 

Getting higher 8 from Clusters 

• Change bias factor 

• Look for missing clusters 

• Improve physics (scaling Y SZ - M) 

(by using refined SZE studies) 

≥ 

Cluster missing energy 

Physics 

≤ 

Cosmology 

Getting lower 8 from CMB 

• Change initial power spectrum 

• Change transfer function

SZE Cosmology: spectro-pol. 

Clusters Π−(th) 

RG Π−(non-th) 

Clusters Π−(th) 

CMB 

n=2 

Quadrupole 

Measure the CMB multi-pole at the position of the cluster in the Universe 

CMB 

n=4 

Octupole 

RG Π−(non-th) 

S.C. et al. 

[2012-13]

2013 

2014 

~2016 

~2020 

~2028-34 

SZE in Space: a future outline 

PLANCK 

HERSCHEL 

OLIMPO 

SAGACE 

MILLIMETRON 

PRISM 

SAGACE 3m 

MILLIMETRON 12m 

3 m dish 

Passive cooling 

(50 K) 

Θ= 0.7-4.2 arcmin 

Noise=18 mJy/√Hz 

FTS spectroscopy 

12m dish 

3m dish 

12 m dish 

Active cooling 

(4 K) 

Θ< 0.1-1.0 arcmin 

Noise

THANKS 

for your attention

17.25 Sergio COLAFRANCESCO Multifrequency Study of the SZ ...

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