Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France Axions Axions G. Raffelt, Max-Planck-Institut f G. Raffelt, Max-Planck-Institut f ür Physik, Mü ür Physik, Mü Motivation, Limits and Searches Motivation, Limits and Searches Axions Axions ONT d’Avignon, 21-25 April 2008, Avignon, Franc ONT d’Avignon, 21-25 April 2008, Avignon, Franc
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Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT dAvignon, 21-25 April 2008, Avignon, FranceAxions Georg G. Raffelt, Max-Planck-Institut.
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Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
AxionsAxionsGeorg G. Raffelt, Max-Planck-Institut fGeorg G. Raffelt, Max-Planck-Institut für Physik, Münchenür Physik, München
Motivation, Limits and SearchesMotivation, Limits and SearchesAxionsAxions
PONT d’Avignon, 21-25 April 2008, Avignon, FrancePONT d’Avignon, 21-25 April 2008, Avignon, France
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Axion Physics in a Nut ShellAxion Physics in a Nut Shell
CosmologyCosmology
CosmiCosmicc
StringString
In spite of small mass, axionsIn spite of small mass, axions are born are born non-relativisticallynon-relativistically (“non-thermal relics”)(“non-thermal relics”)
““Cold dark matter”Cold dark matter” candidate candidate
mmaa ~ 1 ~ 1--1000 1000 eVeV
Search for Axion Dark MatterSearch for Axion Dark Matter
CP conservation in QCD byCP conservation in QCD by Peccei-Quinn mechanismPeccei-Quinn mechanism
For fFor faa ≫≫ f f axions are “invisible” axions are “invisible”
and very lightand very light
AxionsAxions a a ~ ~ 00
mmff m maaffaa
aa
Solar and Stellar AxionsSolar and Stellar Axions
Axions thermally produced in stars,Axions thermally produced in stars, e.g. by Primakoff productione.g. by Primakoff production
• Limits from avoiding excessiveLimits from avoiding excessive energy drainenergy drain• SearchSearch forfor solarsolar axionsaxions (CAST, Sumico)(CAST, Sumico)
aa
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
StandardStandard QCD LagrangianQCD Lagrangian containscontains a CP violating terma CP violating term
GG~Tr)Mdetarg(
8L
20
qs
CP
GG~Tr)Mdetarg(
8L
20
qs
CP
The CP Problem of Strong InteractionsThe CP Problem of Strong Interactions
Induces a neutronInduces a neutron electric dipole momentelectric dipole moment (EDM) much in excess(EDM) much in excess of experimental limitsof experimental limits
cme10310
cme10d 26n2
16n
cme10310
cme10d 26n2
16n
Characterizes degenerateCharacterizes degenerateQCD ground state (QCD ground state ( vacuum) vacuum)
Phase of Quark Phase of Quark Mass MatrixMass Matrix
1010 1010 Why so smallWhy so small ??≲≲
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
30 Years of Axions30 Years of Axions
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
The Cleansing AxionThe Cleansing Axion
““I named them after a laundryI named them after a laundry detergent, since they clean updetergent, since they clean up a problem with an axial current.”a problem with an axial current.”(Nobel lecture 2004, written version)(Nobel lecture 2004, written version)
Frank WilczekFrank Wilczek
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Windows of OpportunityWindows of Opportunity
AxionsAxions AlternativesAlternatives
• Cosmic cold dark matter candidateCosmic cold dark matter candidate• Direct detection possibleDirect detection possible
• Supersymmetric particlesSupersymmetric particles• Superheavy particlesSuperheavy particles• Sterile Neutrinos Sterile Neutrinos • Many others … Many others … (but usually not experimentally(but usually not experimentally accessible)accessible)
Search for new physics at E Search for new physics at E ≫≫ TeV TeV in low-energy experimentsin low-energy experiments (Axions Nambu-Goldstone boson of(Axions Nambu-Goldstone boson of spontaneously broken symmetry)spontaneously broken symmetry)
• Neutrino masses (see-saw)Neutrino masses (see-saw)• Proton decayProton decay• Neutron electric dipole momentNeutron electric dipole moment• Deviation from Newton’s LawDeviation from Newton’s Law (e.g. large extra dimensions)(e.g. large extra dimensions)
Solve strong CP problemSolve strong CP problem by Peccei-Quinnby Peccei-Quinn dynamical symmetry restorationdynamical symmetry restoration
• Massless up-quarkMassless up-quark• Spontaneous CP violationSpontaneous CP violation• set at some high energy scaleset at some high energy scale (no radiative corrections)(no radiative corrections)
0 0
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Axions as a Research TopicAxions as a Research Topic
Papers in SPIRES that cite one of the two original Peccei and Quinn papers orPapers in SPIRES that cite one of the two original Peccei and Quinn papers or Weinberg’s or Wilczek’s paper or with “axion” or “axino” in their titleWeinberg’s or Wilczek’s paper or with “axion” or “axino” in their title (total of 3186 papers up to 2007) (total of 3186 papers up to 2007)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Axions as Pseudo Nambu-Goldstone BosonsAxions as Pseudo Nambu-Goldstone Bosons
• The realization of the Peccei-Quinn mechanism involves a new chiral The realization of the Peccei-Quinn mechanism involves a new chiral
U(1) symmetry, spontaneously broken at a scale fU(1) symmetry, spontaneously broken at a scale faa
• Axions are the corresponding Nambu-Goldstone modeAxions are the corresponding Nambu-Goldstone mode
E E f faa
• UUPQPQ(1) spontaneously (1) spontaneously
broken broken • Higgs field settles in Higgs field settles in “ “Mexican hat”Mexican hat”
Late-time signal most sensitive observableLate-time signal most sensitive observable
Emission of very weakly interactingEmission of very weakly interactingparticles would “steal” energy from theparticles would “steal” energy from theneutrino burst and shorten it.neutrino burst and shorten it.(Early neutrino burst powered by accretion,(Early neutrino burst powered by accretion, not sensitive to volume energy loss.)not sensitive to volume energy loss.)
Volume emissionVolume emission of novel particlesof novel particles
SN 1987A neutrino signalSN 1987A neutrino signal
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Axions as Pseudo Nambu-Goldstone BosonsAxions as Pseudo Nambu-Goldstone Bosons
• The realization of the Peccei-Quinn mechanism involves a new chiral The realization of the Peccei-Quinn mechanism involves a new chiral
U(1) symmetry, spontaneously broken at a scale fU(1) symmetry, spontaneously broken at a scale faa
• Axions are the corresponding Nambu-Goldstone modeAxions are the corresponding Nambu-Goldstone mode
E E f faa
• UUPQPQ(1) spontaneously (1) spontaneously
broken broken • Higgs field settles in Higgs field settles in “ “Mexican hat”Mexican hat”
by instanton effects by instanton effects • Mexican hat tiltsMexican hat tilts• Axions acquire a massAxions acquire a mass
aa
V(a)V(a)
=0=0__
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Series of Papers on Axion Cosmology in PLB Series of Papers on Axion Cosmology in PLB 120 (1983)120 (1983)
Page 127
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Series of Papers on Axion Cosmology in PLB Series of Papers on Axion Cosmology in PLB 120 (1983)120 (1983)
Page 133
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Series of Papers on Axion Cosmology in PLB Series of Papers on Axion Cosmology in PLB 120 (1983)120 (1983)
Page 137
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Killing Two Birds with One StoneKilling Two Birds with One Stone
Peccei-Quinn mechanismPeccei-Quinn mechanism• Solves strong CP problemSolves strong CP problem• May provide dark matterMay provide dark matter in the form of axionsin the form of axions
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Production of Cold Axion Population in the Production of Cold Axion Population in the Early UniverseEarly Universe
Approximate axionApproximate axion cold dark matter densitycold dark matter density
6/7
a
6/7
12a
a meV1
4GeV10
f5.0
6/7
a
6/7
12a
a meV1
4GeV10
f5.0
Inflation after PQ symmetry breaking Inflation after PQ symmetry breaking
Homogeneous mode oscillates afterHomogeneous mode oscillates after T T ≲ ≲ QCDQCD
Dependence on initial misalignmentDependence on initial misalignmentangleangle ia ia
• Cosmic strings of broken UCosmic strings of broken UPQPQ(1)(1)
form by Kibble mechanismform by Kibble mechanism• Radiate long-wavelength axionsRadiate long-wavelength axions
• aa independent of initial conditions independent of initial conditions
Inhomogeneities of axion field large,Inhomogeneities of axion field large,self-couplings lead to formation of self-couplings lead to formation of mini-clustersmini-clustersTypical propertiesTypical properties• Mass Mass ~ 10~ 101212 M Msunsun
• Radius ~ 10Radius ~ 101010 cm cm• Mass fraction up to several 10%Mass fraction up to several 10%
• Isocurvature fluctuations from largeIsocurvature fluctuations from large quantum fluctuations of masslessquantum fluctuations of massless axion field created during inflationaxion field created during inflation• Strong CMBR bounds on isocurvature Strong CMBR bounds on isocurvature fluctuationsfluctuations• Scale of inflation required to beScale of inflation required to be very small very small II ≲≲ 10 101313 GeV GeV[Beltrán, García-Bellido & Lesgourgues[Beltrán, García-Bellido & Lesgourgues hep-ph/0606107]hep-ph/0606107]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Strings form by Kibble mechanism Strings form by Kibble mechanism after break-down of Uafter break-down of UPQPQ(1)(1)
Small loops form by self-intersectionSmall loops form by self-intersection
Axions from Cosmic StringsAxions from Cosmic Strings
Paul ShellardPaul Shellard
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Axion Mini ClustersAxion Mini Clusters
The inhomogeneities of the axion field are large, leading to bound objects,The inhomogeneities of the axion field are large, leading to bound objects,““axion mini clusters”axion mini clusters”. [Hogan & Rees, PLB 205 (1988) 228.] . [Hogan & Rees, PLB 205 (1988) 228.] Self-coupling of axion field crucial for dynamics.Self-coupling of axion field crucial for dynamics.
Typical mini cluster properties:Typical mini cluster properties:
Mass ~ 10Mass ~ 101212 M Msunsun
Radius ~ 10Radius ~ 101010 cm cmMass fraction up to several 10Mass fraction up to several 10%%
Potentially detectable with Potentially detectable with gravitational femtolensinggravitational femtolensing
Distribution of axion energy density. Distribution of axion energy density. 2-dim slice of comoving length 0.25 pc2-dim slice of comoving length 0.25 pc[Kolb & Tkachev, ApJ 460 (1996) L25][Kolb & Tkachev, ApJ 460 (1996) L25]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Inflation, Axions, and the Anthropic PrincipleInflation, Axions, and the Anthropic Principle
Late inflation scenario of axion cosmologyLate inflation scenario of axion cosmology
• Initial misalignment angle constant in our patch of the universeInitial misalignment angle constant in our patch of the universe
• Dark matter density determined by the initial random number Dark matter density determined by the initial random number i i
• Is different in different patches of the universeIs different in different patches of the universe• Dark matter fraction not calculable from first principlesDark matter fraction not calculable from first principles• Random number chosen by process of spontaneous symmetry breakingRandom number chosen by process of spontaneous symmetry breaking
Natural case for applying anthropic reasoning for the observed darkNatural case for applying anthropic reasoning for the observed darkmatter density relative to baryonsmatter density relative to baryons
• Linde, “Inflation and Axion Cosmology,” PLB 201:437, 1988Linde, “Inflation and Axion Cosmology,” PLB 201:437, 1988• Tegmark, Aguirre, Rees & Wilczek,Tegmark, Aguirre, Rees & Wilczek, “ “Dimensionless constants, cosmology and other dark matters,”Dimensionless constants, cosmology and other dark matters,” PRD 73, 023505 (2006) [arXiv:astro-ph/0511774]PRD 73, 023505 (2006) [arXiv:astro-ph/0511774]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Axion Hot Dark Matter from Thermalization Axion Hot Dark Matter from Thermalization after after QCDQCD
Freeze-out temperatureFreeze-out temperature
Cosmic thermal degrees ofCosmic thermal degrees offreedom at axion freeze-outfreedom at axion freeze-out
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Experimental Tests of the Invisible AxionExperimental Tests of the Invisible Axion
Primakoff effect:Primakoff effect:
Axions-photon transitions in externalAxions-photon transitions in externalstatic E or B fieldstatic E or B field(Originally discussed for (Originally discussed for 00 by Henri Primakoff 1951)by Henri Primakoff 1951)
Pierre Sikivie:Pierre Sikivie:
Macroscopic B-field can provide aMacroscopic B-field can provide alarge coherent transition rate overlarge coherent transition rate overa big volume (low-mass axions)a big volume (low-mass axions)
• Axion helioscope:Axion helioscope: Look at the Sun through a dipoleLook at the Sun through a dipole magnet magnet
• Axion haloscope:Axion haloscope: Look for dark-matter axions withLook for dark-matter axions with A microwave resonant cavityA microwave resonant cavity
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Search for Galactic Axions (Cold Dark Matter)Search for Galactic Axions (Cold Dark Matter)
PowerPower
FrequencyFrequency mmaa
Axion Axion SignalSignal
Thermal noise of Thermal noise of cavity & detectorcavity & detector
Power of galactic axion signalPower of galactic axion signal
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
ADMX (G.Carosi, Fermilab, May 2007)ADMX (G.Carosi, Fermilab, May 2007)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
ADMX (G.Carosi, Fermilab, May 2007)ADMX (G.Carosi, Fermilab, May 2007)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
ADMX (G.Carosi, Fermilab, May 2007)ADMX (G.Carosi, Fermilab, May 2007)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
ADMX (G.Carosi, Fermilab, May 2007)ADMX (G.Carosi, Fermilab, May 2007)
Renewed ADMXRenewed ADMXdata taking has begundata taking has begun
on 28 March 2008on 28 March 2008(Same day as CAST He-3 began)(Same day as CAST He-3 began)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
ADMX (G.Carosi, Fermilab, May 2007)ADMX (G.Carosi, Fermilab, May 2007)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Fine Structure in Axion SpectrumFine Structure in Axion Spectrum
• Axion distribution on a 3-dim sheet in 6-dim phase spaceAxion distribution on a 3-dim sheet in 6-dim phase space• Is “folded up” by galaxy formationIs “folded up” by galaxy formation• Velocity distribution shows narrow peaks that can be resolvedVelocity distribution shows narrow peaks that can be resolved• More detectable information than local dark matter densityMore detectable information than local dark matter density
P.SikivieP.Sikivie& collaborators& collaborators
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Tokyo Axion Helioscope (“Sumico”)Tokyo Axion Helioscope (“Sumico”) (Results since 1998, up again 2008)(Results since 1998, up again 2008)
CERN Axion Solar Telescope (CAST)CERN Axion Solar Telescope (CAST) (Data since 2003)(Data since 2003)
Axion fluxAxion flux
Alternative technique: Alternative technique: Bragg conversion in crystalBragg conversion in crystal Experimental limits on solar axion fluxExperimental limits on solar axion flux from dark-matter experimentsfrom dark-matter experiments (SOLAX, COSME, DAMA, ...)(SOLAX, COSME, DAMA, ...)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Tokyo Axion Helioscope (“Sumico”)Tokyo Axion Helioscope (“Sumico”)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Results and Plans of Tokyo Axion Helioscope Results and Plans of Tokyo Axion Helioscope (“Sumico”)(“Sumico”)
S. Inoue at TAUP 07S. Inoue at TAUP 07
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Extending to higher mass values with gas Extending to higher mass values with gas fillingfilling
2qL
sinq
BgP 2
2a
a
2qL
sinq
BgP 2
2a
a
E2
mmq
22a
E2
mmq
22a
Axion-photon transition probabilityAxion-photon transition probability
Axion-photon momentum transferAxion-photon momentum transfer
Transition suppressed for qL Transition suppressed for qL ≳≳ 11
Gas filling: Give photons a refractiveGas filling: Give photons a refractivemass to restore full transition strengthmass to restore full transition strength(~ MSW effect)(~ MSW effect)
ee
2 nm4
m
ee
2 nm4
m
(n(nee electron density) electron density)
GasAZ
eV9.28m GasAZ
eV9.28m
HeHe44 vapour pressure at 1.8 K vapour pressure at 1.8 K33 cmg102.0 33 cmg102.0 eV26.0m eV26.0m
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
LHC Magnet Mounted as a Telescope to Follow LHC Magnet Mounted as a Telescope to Follow the Sunthe Sun
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
CAST at CERNCAST at CERN
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
One spare mirror system from the failed Abrixas x-rayOne spare mirror system from the failed Abrixas x-raysatellitesatellite
• From 43 mm From 43 mm (LHC magnet aperture) to ~3 mm (LHC magnet aperture) to ~3 mm • Signal/background improvement > 100Signal/background improvement > 100• Signal and background simultaneously measuredSignal and background simultaneously measured
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Sun Spot on CCD with X-Ray TelescopeSun Spot on CCD with X-Ray Telescope
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Limits from CAST-I and CAST-IILimits from CAST-I and CAST-II
CAST-I results: PRL 94:121301 (2005) and JCAP 0704 (2007) 010 CAST-I results: PRL 94:121301 (2005) and JCAP 0704 (2007) 010 CAST-II results (He-4 filling): preliminaryCAST-II results (He-4 filling): preliminary
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Limits on Axion-Photon-CouplingLimits on Axion-Photon-Coupling
PVLAS expectedPVLAS expected
Tokyo HelioscopeTokyo Helioscope
HelioHelioseisseismologymology
Tele
scop
eTele
scop
e
LaserLaser
KSVZ model
KSVZ model
DFSZ model
DFSZ model
Axion LineAxion Line
PVLASPVLASSignaturSignaturee
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
AlpsAlpsAxion-like particles (ALPs)Axion-like particles (ALPs)(Pseudo)-scalar particles with a two-photon vertex(Pseudo)-scalar particles with a two-photon vertex
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Particles with Two-Photon CouplingParticles with Two-Photon Coupling
Particles with two-photon vertex:Particles with two-photon vertex:• Neutral pions (Neutral pions (00), Gravitons), Gravitons• Axions (a) and similar hypothetical particlesAxions (a) and similar hypothetical particles
aBEgL aa aBEgL aa
Two-photonTwo-photondecaydecay
64
mg 3a
2a
a
64
mg 3a
2a
aPhotonPhotonCoalescenceCoalescence
PrimakoffPrimakoffEffectEffect
Conversion of photons intoConversion of photons into pions, gravitons or axions, pions, gravitons or axions, or the reverseor the reverse
In addition to QED In addition to QED Cotton-Mouton-effectCotton-Mouton-effect
PVLAS experiment recently PVLAS experiment recently measured anmeasured aneffect ~ 10effect ~ 1044 larger than QED larger than QED expectationexpectation(Signal now disproved)(Signal now disproved)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany PONT d‘Avignon, 21-25 April 2008, Avignon, France
Dimming of Supernovae without Cosmic Dimming of Supernovae without Cosmic Acceleration?Acceleration?
Axion-photon-oscillations in intergalactic Axion-photon-oscillations in intergalactic B-field domainsB-field domains dim photon flux dim photon flux Effect grows linearly with distanceEffect grows linearly with distance Saturates at equipartition between photons and axions (unlike grey dust)Saturates at equipartition between photons and axions (unlike grey dust)