Radio relis (and halos) in galaxy clusters Matthias Hoeft Thringer - - PowerPoint PPT Presentation

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May 29, 2023 130 likes •394 views

Radio relis (and halos) in galaxy clusters Matthias Hoeft Thringer Landessternwarte Tautenburg Matthias Hoeft ICM physics and modeling Garching, 2015 - overall spectrum of

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Matthias Hoeft ICM physics and modeling Garching, 2015

Radio relis (and halos) in galaxy clusters

Matthias Hoeft Thüringer Landessternwarte Tautenburg

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Matthias Hoeft ICM physics and modeling Garching, 2015

overall spectrum of relics
relic statistics
an unusual radio halo

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Matthias Hoeft ICM physics and modeling Garching, 2015

Radio relic: the textbook example

CIZA2242, the “sausage” perfect aging profile intrinsic width ~ 55 kpc homogenous along relic perfect magnetic field alignment but: no projection effects?

[van Weeren+ 2010]

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Matthias Hoeft ICM physics and modeling Garching, 2015

trace merger shock fronts diffusive shock acceleration: power-law electron spec. (observed 𝜹 ~ 104 ) injection or seed electrons: thermal? accretion shocks? fossil AGN? shock drift accel? downstream advection and cooling (synchr. + IC)

dP(νobs) dν = 6.4 × 1034 erg s Hz A Mpc2 ne 10−4cm−3 ξe 0.05

νobs

1.4 GHz ⇥− s

× ⇤ Td 7 keV ⌅ 3

µG

⇥1+ s

BCMB

µG

⇥2 +

µG

⇥2 Ψ(M, T)

fraction of diss. energy

The canonical(?) model for radio relics

DSA cooling+synch injection+efficiency

[Ensslin+ 1998] [Hoeft & Brüggen 07]

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Matthias Hoeft ICM physics and modeling Garching, 2015

Does this work for any relic?

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Matthias Hoeft ICM physics and modeling Garching, 2015

Example: Double relic in Abell 1240

a typical, low lum double relic relic north 6.0 +/- 0.2 mJy (20cm) LSS 650 kpc relic south 10.1 +/- 0.4 mJy (20cm) LSS 1250 kpc polarized

[Bonafede+ 2009] VLA + ROSAT, Lx ~1044 erg/s

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Matthias Hoeft ICM physics and modeling Garching, 2015

Low frequency follow up: WSRT

relic north 35 mJy (90cm) alpha = - 1.2 relic south 10.1 +/- 0.4 mJy (20cm) alpha = - 1.1 no surprises

[Drabent+ in prep.]

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Matthias Hoeft ICM physics and modeling Garching, 2015

Low frequency follow up: WSRT

relic north 35 mJy (90cm) alpha = - 1.2 relic south 10.1 +/- 0.4 mJy (20cm) alpha = - 1.1 no surprises

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Matthias Hoeft ICM physics and modeling Garching, 2015

Radio relic ‘compilation’

most of ‘proper’ relics have a power-law spectrum with spectral index 1-1.6 consistent with DSA+cooling counter examples: A2256: too flat A2146: shock but no radio ...

[Feretti+ in 2012]

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Matthias Hoeft ICM physics and modeling Garching, 2015

Is there a high frequency cut-off?

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Matthias Hoeft ICM physics and modeling Garching, 2015

The “sausage” spectrum

102 103 104 frequency [MHz] 100 101 102 103 flux [mJy] γbreak = 104.5 105.0

indication for break >10 GHz but

not seen by lower

single dish obs

new Effelsberg [Stroe+ 2013]

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Matthias Hoeft ICM physics and modeling Garching, 2015

Does any shock-front hosts a relic?

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Matthias Hoeft ICM physics and modeling Garching, 2015

Shock fronts in the “Music” cluster sample

Mach number (slice) radio emission (slice) X-ray radio (projected)

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Matthias Hoeft ICM physics and modeling Garching, 2015

Simulat radio relic sample

aim: mimic NVSS appearance beam 45arcsec surface bright: ~ 1mJy/beam difficult: what is one relic? depends on surface brightness threshold measure flux and LLS

[Nuza, Gelszinnis in prep]

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Matthias Hoeft ICM physics and modeling Garching, 2015

Statistics: Luminosity - LLS relations

measure relics in NVSS in the same way reproduces Lum - LSS corr but: we habe introduced a detection bias for small relics

[Nuza, Gelszinnis in prep]

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Matthias Hoeft ICM physics and modeling Garching, 2015

Future prospects?

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Matthias Hoeft ICM physics and modeling Garching, 2015

LOFAR observations: Abell 2069

Lx ~ 5 x 1044 erg/s WSRT 350 MHz contains a halo in A contains diffuse emission in B

[Drabent+ 2015]

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Matthias Hoeft ICM physics and modeling Garching, 2015

Abell 2069: a pre-merger?

a pre-merger system? cold front in B

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Matthias Hoeft ICM physics and modeling Garching, 2015

23 Core Stations and 14 Remote Stations Total observation time: 10 hours Frequency band: 120-180 MHz

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Matthias Hoeft ICM physics and modeling Garching, 2015

100/370 subbands used (27%) beam: 106'' × 103'' r.m.s.: 1.5 mJy/beam

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Matthias Hoeft ICM physics and modeling Garching, 2015

100/370 subbands used (27%) beam: 45'' × 35'' r.m.s.: 760 µJy/beam

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Matthias Hoeft ICM physics and modeling Garching, 2015

100/370 subbands used (27%) beam: 22'' × 18'' r.m.s.: 380 µJy/beam

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Matthias Hoeft ICM physics and modeling Garching, 2015

[Drabent in prep.]

in B: diffuse emission with similar morphology as X- ray ‘radio rim’ to South

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Matthias Hoeft ICM physics and modeling Garching, 2015

[Drabent in prep.]

extended emission coincides with hot ICM

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Matthias Hoeft ICM physics and modeling Garching, 2015

Summary

overall spectrum of sausage

power-law possible high frequency cut-off

relic statistics

consistent with populating merger shocks uniformly

Prospects with LOFAR

Radio relis (and halos) in galaxy clusters

Matthias Hoeft Thüringer Landessternwarte Tautenburg

Radio relic: the textbook example

CIZA2242, the “sausage” perfect aging profile intrinsic width ~ 55 kpc homogenous along relic perfect magnetic field alignment but: no projection effects?

trace merger shock fronts diffusive shock acceleration: power-law electron spec. (observed 𝜹 ~ 104 ) injection or seed electrons: thermal? accretion shocks? fossil AGN? shock drift accel? downstream advection and cooling (synchr. + IC)

The canonical(?) model for radio relics

DSA cooling+synch injection+efficiency

Does this work for any relic?

Example: Double relic in Abell 1240

a typical, low lum double relic relic north 6.0 +/- 0.2 mJy (20cm) LSS 650 kpc relic south 10.1 +/- 0.4 mJy (20cm) LSS 1250 kpc polarized

Low frequency follow up: WSRT

relic north 35 mJy (90cm) alpha = - 1.2 relic south 10.1 +/- 0.4 mJy (20cm) alpha = - 1.1 no surprises

Low frequency follow up: WSRT

relic north 35 mJy (90cm) alpha = - 1.2 relic south 10.1 +/- 0.4 mJy (20cm) alpha = - 1.1 no surprises

Radio relic ‘compilation’

most of ‘proper’ relics have a power-law spectrum with spectral index 1-1.6 consistent with DSA+cooling counter examples: A2256: too flat A2146: shock but no radio ...

Is there a high frequency cut-off?

The “sausage” spectrum

indication for break >10 GHz but

single dish obs

Does any shock-front hosts a relic?

Shock fronts in the “Music” cluster sample

Mach number (slice) radio emission (slice) X-ray radio (projected)

Simulat radio relic sample

aim: mimic NVSS appearance beam 45arcsec surface bright: ~ 1mJy/beam difficult: what is one relic? depends on surface brightness threshold measure flux and LLS

Statistics: Luminosity - LLS relations

measure relics in NVSS in the same way reproduces Lum - LSS corr but: we habe introduced a detection bias for small relics

Future prospects?

LOFAR observations: Abell 2069

Lx ~ 5 x 1044 erg/s WSRT 350 MHz contains a halo in A contains diffuse emission in B

Abell 2069: a pre-merger?

a pre-merger system? cold front in B

23 Core Stations and 14 Remote Stations Total observation time: 10 hours Frequency band: 120-180 MHz

100/370 subbands used (27%) beam: 106'' × 103'' r.m.s.: 1.5 mJy/beam

100/370 subbands used (27%) beam: 45'' × 35'' r.m.s.: 760 µJy/beam

100/370 subbands used (27%) beam: 22'' × 18'' r.m.s.: 380 µJy/beam

in B: diffuse emission with similar morphology as X- ray ‘radio rim’ to South

extended emission coincides with hot ICM

Summary

power-law possible high frequency cut-off

consistent with populating merger shocks uniformly

very well suited to identify diffuse emission Abell 2069 Halo in main component Minihalo in subcomponent (?) diffuse emission in compressed gas