Unveiling the composition of plasma bubbles with the SZ-effect “The SZ Effect and ALMA” Institut ’Astrophysique Spatiale, Orsay (France)

Christoph Pfrommer (MPA) [email protected]

Unveiling the composition of plasma bubbles with the SZ-effect – p.1/15 Plasma bubbles (1)

Perseus cluster Abell 2052 (NASA/IoA/A.Fabian et al.) (Blanton et al., 2001)

Unveiling the composition of plasma bubbles with the SZ-effect – p.2/15 Plasma bubbles (2)

Hydra A cluster MS 0735 cluster (-ray: NASA/CXC/SAO; Radio: NRAO) (X-ray: NASA/CXC/Ohio U./ .McNamara et al.; Radio: NRAO/VLA)

Unveiling the composition of plasma bubbles with the SZ-effect – p.3/15 Why caring about plasma bubbles?

• minimum energy arguments show: εCRe 0.1εth where is the ‘missing’ pressure? ' → radio plasma bubbles ghost cavity transition: • ↔ 1. is there an influence on the dynamically dominant component? 2. inferring the magnetic field configuration, cross field diffusivity composition of AGN jets: hadronic leptonic scenario • ↔ • plasma bubble - cool core connection: cooling core cluster experienced only moderate accretion over the last Gyr (no major merger), cooling gas ‘triggered’ AGN activity detailed physical understanding of governing processes → This work: .P., Torsten Enßlin, & Craig Sarazin, 2005, A&A, 430, 799

Unveiling the composition of plasma bubbles with the SZ-effect – p.4/15 Idea Disadvantages of bubble X-ray observations: n2√kT X ∝ e

• hot dilute gas does barely contribute to X-ray luminosity • projected foreground and background emission contaminates weak signal

• projected substructure in outer regions could mock signal Advantages of bubble SZ observations:

kT dl = P dl ∝ e e e Z

• SZ effect measures directly the ‘missing’ quantity pressure

• possibility of bubble detections in outer cluster regions

Unveiling the composition of plasma bubbles with the SZ-effect – p.5/15 SZ effect (1) Planckian distribution function of the CMB I(x):

2(kT )3 x3 I(x) = i i(x) = CMB , 0 (hc)2 ex 1 − The relative change δi(x) in flux density as a function of dimensionless frequency x = hν/(kTCMB) for a line-of-sight through a galaxy cluster is given by

δi(x) = (x) y (x) + [(x) i(x)] τ gas − gas − rel thermal SZ effect relativistic SZ effect kinetic SZ effect

Unveiling the composition of plasma bubbles with the SZ-effect – p.6/15 SZ effect (2)

• Amplitude of the thermal SZ effect: σ y dl n kT gas ≡ c2 e,gas e e Z

• Amplitude of the kinetic SZ effect:

w β¯ τ = σ dl n β¯ , gas ≡ gas gas T e,gas gas Z

• Amplitude of the relativistic SZ effect:

τrel = σT dl ne,rel. Z Using the formalism of Enßlin & Kaiser (2000).

Unveiling the composition of plasma bubbles with the SZ-effect – p.7/15 Relativistic SZ effect We introduce a relativistic Comptonization parameter y˜:

δi (x) = [j(x) i(x)]τ = g˜(x)y˜, rel − rel where σ y˜ = T dl n kT˜ , m c2 e e e Z Pe kT˜e = , ne g˜(x) = [j(x) i(x)] β˜(kT˜ ) , − e 2 2 mec mec dl ne β˜(kT˜e) = = . kT˜ dl n kT˜ h ei Re e

Unveiling the composition of plasma bubbles with the SZ-effect – p.8/15 Spectral distortions

frequency ν [GHz] 0 200 400 600

6

4

2 distortion 0 g(x) PSfrag replacements spectral h(x) -2 g˜UCRe(x) g˜CRe(x) -4 g˜50 keV(x) g˜20 keV(x) -6 0 2 4 6 8 10 12 14 = dimensionless frequency x hν/kTCMB

Unveiling the composition of plasma bubbles with the SZ-effect – p.9/15 Bubble model: visual

Pressure of the cooling core cluster is described by a multi- ple β-model, radio plasma bubbles are spheres cutting out the thermal pressure.

Unveiling the composition of plasma bubbles with the SZ-effect – p.10/15 Bubble model: mathematical

• Unperturbed line-of-sight (not intersecting the bubble), the observed thermal Comptonization parameter reads

(3βy,i 1)/2 N 2 2 − − x1 + x2 ycl(x1, x2) = yi 1 + 2 ry,i ! Xi=1

2 1 3βy,i 1 1 where y = σ (m c ) P r − , . i T e − i y,iB 2 2   • In the case of a line-of-sight intersecting the surface of the bubble, the area covered by the bubble reads

(3βy,i 1)/2 N 2 2 − − x1 + x2 yb(x1, x2) = ycl(x1, x2) yi 1 + 2 − ry,i ! Xi=1 z+ sgn(z) 1 3βy,i 1 qy,i(z) , − × 2 I 2 2 z    − Unveiling the composition of plasma bubbles with the SZ-effect – p.11/15 A2052: SZE versus thermal X-rays

relative R.A. [arcsec] -40 -20 0 20 40 40

20

20 10 kpc] 1 − 70 h [ [arcsec]

0 0 Decl. e distance e v

-10 relati relati -20

-20

-40 -20 -10 0 10 20 PSfrag replacements −1 relative distance [h70 kpc]

2.7 2.9 3.0 3.2 3.3

simulated GBT observation Chandra: 7600 7600 × ν = 90 GHz, size: 8000 8000 (Blanton et al., 2001) ×

Unveiling the composition of plasma bubbles with the SZ-effect – p.12/15 Perseus: SZE versus thermal X-rays

relative R.A. [arcsec] -60 -40 -20 0 20 40 60

60 20

40

10 kpc]

1 20 − 70 h [ [arcsec]

0 0 Decl. e distance v e

v -20

-10 relati relati -40

-20 -60

-20 -10 0 10 20 PSfrag replacements −1 relative distance [h70 kpc]

11.8 12.2 12.6 13.0 13.3

simulated ALMA observation Chandra: 60 60 × ν = 144 GHz, size: 2.50 2.50 (NASA/IoA/A.Fabian et al.) ×

Unveiling the composition of plasma bubbles with the SZ-effect – p.13/15 Unveiling the composition of bubbles

relative angular displacement [arcsec] relative angular displacement [arcsec] 0 20 40 60 80 100 0 20 40 60 80 100 2.0 ultra-relativistic CRe power-law CRe, e−– p – composition − + 16 power-law CRe, e – e – composition 1.8 = thermal electrons (kTe 50 keV) −

] 1

] = υ = + thermal electrons (kT 20 keV) 2 2 e gas 300 km − − 1.6 arcmin arcmin 15 ultra-relativistic CRe − [mJy

[mJy − 1.4 power-law CRe, e – p – composition υ = + 1 − + gas 300 km s power-law CRe, e – e – composition = GHz) thermal electrons (kTe 50 keV) GHz) = 1.2 thermal electrons (kTe 20 keV)

14 217 144 ' =

0

0 -1.2 ν ν ( ( I I δ δ = −1 υgas 0 km s 13 -1.4 decrement

PSfrag replacements decrement PSfrag replacements flux

flux -1.6 − SZ 1 SZ υ = −300 km s 12 = − −1 gas υgas 300 km s -1.8

11 -2.0 0 10 20 30 40 0 10 20 30 40 −1 −1 relative distance [h70 kpc] relative distance [h70 kpc]

Unveiling the composition of plasma bubbles with the SZ-effect – p.14/15 Conclusions

• SZ effect offers suitable tool for studying plasma bubble composition (SZ effect more sensitive to cluster outskirts compared to X-rays)

• Observations of SZ cavities possible for non-thermal pressure supported bubbles: Perseus 5 hours exposure, A2052 30 hours exposure ∼ ∼ • Detailed observations will reveal the dynamically dominant composition (relativistic electrons, protons magnetic fields, hot thermal gas) Solving the cooling core riddle; indications how the heating mechanism→ proceeds by AGN bubbles Indications for AGN jet composition (leptonic versus → hadronic scenario)

Unveiling the composition of plasma bubbles with the SZ-effect – p.15/15