The Physics and Cosmology of Tev Blazars

Physics of blazar heating The intergalactic medium Galaxy clusters

The Physics and Cosmology of TeV Blazars

Christoph Pfrommer1

in collaboration with

Avery E. Broderick2, Phil Chang3, Ewald Puchwein1, Volker Springel1

1Heidelberg Institute for Theoretical Studies, Germany 2Perimeter Institute/University of Waterloo, Canada 3University of Wisconsin-Milwaukee, USA

Aug 30, 2012 / ICM theory/computation workshop, Michigan

Christoph Pfrommer The Physics and Cosmology of TeV Blazars Physics of blazar heating The intergalactic medium Galaxy clusters Outline

1 Physics of blazar heating Propagation of TeV photons Plasma instabilities in beams Implications

2 The intergalactic medium Blazar luminosity density Thermal history of the IGM Properties of blazar heating

3 Galaxy clusters Bimodality of core entropies AGN feedback Challenges and Conclusions

Christoph Pfrommer The Physics and Cosmology of TeV Blazars Physics of blazar heating Propagation of TeV photons The intergalactic medium Plasma instabilities in beams Galaxy clusters Implications The TeV gamma-ray sky

There are several classes of TeV sources: Galactic - pulsars, BH binaries, supernova remnants Extragalactic - mostly blazars, two starburst galaxies

1 TeV photons can pair produce with 1 eV EBL photons:

+ − γTeV + γeV → e + e

mean free path for this depends on the density of 1 eV photons: → λγγ ∼ (35 ... 700) Mpc for z = 1 ... 0 → pairs produced with energy of 0.5 TeV (γ = 106) these pairs inverse Compton scatter off the CMB photons: → mean free path is λIC ∼ λγγ /1000 → producing gamma-rays of ∼ 1 GeV

2 E ∼ γ ECMB ∼ 1 GeV

each TeV point source should also be a GeV point source

Every TeV source should be associated with a 1-100 GeV gamma-ray halo – not seen! → limits on extragalactic magnetic ﬁelds?

TeV spectra

expected cascade TeV detections emission

Fermi constraints

Neronov & Vovk (2010)

How do beams of e+/e− propagate through the IGM? plasma processes are important interpenetrating beams of charged particles are unstable

wave-like perturbation with k||v beam, longitudinal charge oscillations in background plasma (Langmuir wave): initially homogeneous beam-e−: attractive (repulsive) force by potential maxima (minima) e− attain lowest velocity in potential minima → bunching up e+ attain lowest velocity in potential maxima → bunching up

p p

e− e −

wave-like perturbation with k||v beam, longitudinal charge oscillations in background plasma (Langmuir wave): beam-e+/e− couple in phase with the background perturbation: enhances background potential stronger forces on beam-e+/e− → positive feedback exponential wave-growth → instability

+ + Φ e e

p p e− e−

e− e −

particles with v & vphase: pair momentum → plasma waves: growing modes/instability

particles with v . vphase: plasma wave momentum → pairs: damping (Landau damping)

k oblique to v beam: real word perturbations don’t choose “easy” alignment = P all orientations greater growth rate than two-stream: ultra-relativistic particles are easier to deﬂect than to change their parallel velocities (Nakar, Bret & Milosavljevic 2011)

Bret (2009), Bret+ (2010)

excluded for collective consider a light beam plasma phenomena penetrating into relatively dense plasma maximum growth rate

nbeam ∼ 0.4 γ ωp oblique nIGM

oblique instability beats IC IC by factor 10-100 assume that instability grows at linear rate up to saturation Broderick, Chang, C.P. (2012)

 IC off CMB → γGeV + −  γTeV + γeV → e + e →  plasma instabilities → heating IGM

absence of γGeV’s has signiﬁcant implications for . . . intergalactic B-ﬁeld estimates γ-ray emission from blazars: spectra, background

additional IGM heating has signiﬁcant implications for . . . thermal history of the IGM: Lyman-α forest late time structure formation: dwarfs, galaxy clusters

Christoph Pfrommer The Physics and Cosmology of TeV Blazars Physics of blazar heating Blazar luminosity density The intergalactic medium Thermal history of the IGM Galaxy clusters Properties of blazar heating TeV blazar luminosity density: today

collect luminosity of all 23 TeV blazars with good spectral measurements account for the selection effects (sky coverage, duty cycle, galactic occultation, TeV ﬂux limit) TeV blazar luminosity density is a scaled version (ηB ∼ 0.2%) of that of quasars!

Broderick, Chang, C.P. (2012)

Quasars and TeV blazars are: regulated by the same mechanism contemporaneous elements of a single AGN population: TeV-blazar activity does not lag quasar activity → assume that they trace each other for all redshifts!

Broderick, Chang, C.P. (2012)

HI,HeI−/HeII−reionization

photoheating 103 standard blazar standard blazar fit ] 1 ¡ optimistic blazar 2 10 optimistic blazar fit blazar heating 10

0.1 10x larger

Heating Rates [eV Gyr heating

photoheating 10 2

10 5 2 1 1 +z

Chang, Broderick, C.P. (2012)

total power from AGN/stars vastly exceeds the TeV power of blazars 4 TIGM ∼ 10 K (1 eV) at mean density (z ∼ 2) kT ε = ∼ −9 th 2 10 mpc

radiative energy ratio emitted by BHs in the Universe (Fukugita & Peebles 2004)

−4 −5 εrad = η Ωbh ∼ 0.1 × 10 ∼ 10

fraction of the energy energetic enough to ionize H I is ∼ 0.1:

−6 εUV ∼ 0.1εrad ∼ 10 → kT ∼ keV

−3 2 photoheating efﬁciency ηph ∼ 10 → kT ∼ ηph εUV mpc ∼ eV (limited by the abundance of H I/He II due to the small recombination rate) −3 2 blazar heating efﬁciency ηbh ∼ 10 → kT ∼ ηbh εrad mpc ∼ 10 eV (limited by the total power of TeV sources)

105 only photoheating standard BLF optimistic BLF

[K] 10

103 20 10 5 2 1 1 +z

Chang, Broderick, C.P. (2012)

no blazar heating with blazar heating

Chang, Broderick, C.P. (2012)

blazars and extragalactic background light are uniform: → blazar heating rate independent of density → makes low density regions hot → causes inverted temperature-density relation, T ∝ 1/δ

no blazar heating with blazar heating

Chang, Broderick, C.P. (2012)

blazars completely change the thermal history of the diffuse IGM and late-time structure formation

Christoph Pfrommer The Physics and Cosmology of TeV Blazars Physics of blazar heating Bimodality of core entropies The intergalactic medium AGN feedback Galaxy clusters Challenges and Conclusions Entropy evolution

temperature evolution entropy evolution

105 only photoheating only photoheating 2 standard BLF 10 standard BLF optimistic BLF optimistic BLF ]

2 10

[K] 10

T [keV cm

K 1

0.1 103 20 10 5 2 1 20 10 5 2 1 1 +z 1 +z

C.P., Chang, Broderick (2012) −2/3 evolution of entropy, Ke = kTne , governs structure formation blazar heating: late-time, evolving, modest entropy ﬂoor

mass accretion history mass accretion rates

1015 5

z0.5 = 0.42 ) z 4 ( a 14 10 z0.5 = 0.55 ]

• O 3 / d log z0.5 = 0.70 200c [ M M 200c 2 M 13 10 z0.5 = 0.86 = d log z0.5 = 0.95 S 1

1012 0 1 1 1 + z 1 + z

C.P., Chang, Broderick (2012)

most cluster gas accretes after z = 1, when blazar heating can have a large effect (for late forming objects)!

Cluster entropy proﬁles ICM entropy at 0.1R200:

Optically selected

X−ray selected

Cavagnolo+ (2009) Hicks+ (2008)

Do optical and X-ray/Sunyaev-Zel’dovich cluster observations probe the same population? (Hicks+ 2008, Planck Collaboration 2011)

Cluster entropy proﬁles Planck stacking of optical clusters

Cavagnolo+ (2009) Planck Collaboration (2011)

Do optical and X-ray/Sunyaev-Zel’dovich cluster observations probe the same population? (Hicks+ 2008, Planck Collaboration 2011)

varying formation time varying cluster mass

1000 1000

13 14 z = 0 M200 = 3 x 10 MO • M200 = 1 x 10 MO • , z = 0.5 13 z = 0.5 M200 = 3 x 10 MO • , z = 0.5 13 z = 1 M200 = 1 x 10 MO • , z = 0.5 z = 2 ] ] 2 2 100 100 [keV cm [keV cm e e K K

10 optimistic blazar 10 optimistic blazar

0.01 0.10 1.00 0.01 0.10 1.00 r / R200 r / R200 C.P., Chang, Broderick (2012) assume big fraction of intra-cluster medium collapses from IGM: redshift-dependent entropy excess in cores greatest effect for late forming groups/small clusters

Borgani+ (2005) greater initial entropy K0 2 → more shock heating K 0 = 25 keV cm → greater increase in K0 over entropy ﬂoor

net K0 ampliﬁcation of 3-5 expect:

preheated 2 median Ke,0 ∼ 150 keV cm no preheating + floor 2 max. Ke,0 ∼ 600 keV cm no preheating

Borgani+ (2005)

Christoph Pfrommer The Physics and Cosmology of TeV Blazars time-dependent preheating + gravitational reprocessing → CC-NCC bifurcation (two attractor solutions) need hydrodynamic simulations to conﬁrm this scenario

Physics of blazar heating Bimodality of core entropies The intergalactic medium AGN feedback Galaxy clusters Challenges and Conclusions Cool-core versus non-cool core clusters

cool hot

Cavagnolo+ (2009)

cool hot

early forming, late forming, t > t merger cool t merger < tcool

Cavagnolo+ (2009)

time-dependent preheating + gravitational reprocessing → CC-NCC bifurcation (two attractor solutions) need hydrodynamic simulations to conﬁrm this scenario

Christoph Pfrommer The Physics and Cosmology of TeV Blazars AGNs cannot transform CC to NCC clusters (on a buoyancy timescale)

Physics of blazar heating Bimodality of core entropies The intergalactic medium AGN feedback Galaxy clusters Challenges and Conclusions How efﬁcient is heating by AGN feedback?

E (kT = 5.9 keV) C.P., Chang, Broderick (2011) b, 2500 X 104 Eb, 2500(kTX = 3.5 keV)

Eb, 2500(kTX = 2.0 keV)

Eb, 2500(kTX = 1.2 keV) erg] 2

58 10

Eb, 2500(kTX = 0.7 keV) [10 tot PV 4 = 0

cav 10 E

cool cores non-cool cores 10-2

1 10 100 2 Ke,0 [keV cm ]

Christoph Pfrommer The Physics and Cosmology of TeV Blazars AGNs cannot transform CC to NCC clusters (on a buoyancy timescale)

Physics of blazar heating Bimodality of core entropies The intergalactic medium AGN feedback Galaxy clusters Challenges and Conclusions How efﬁcient is heating by AGN feedback?

E (kT = 5.9 keV) C.P., Chang, Broderick (2011) b, 2500 X 104 Eb, 2500(kTX = 3.5 keV)

Eb, 2500(kTX = 2.0 keV)

Eb, 2500(kTX = 1.2 keV) erg] 2

58 10

Eb, 2500(kTX = 0.7 keV) [10 tot PV 4 = 0

cav 10 E

cool cores non-cool cores 10-2

1 10 100 2 Ke,0 [keV cm ]

Christoph Pfrommer The Physics and Cosmology of TeV Blazars AGNs cannot transform CC to NCC clusters (on a buoyancy timescale)

Physics of blazar heating Bimodality of core entropies The intergalactic medium AGN feedback Galaxy clusters Challenges and Conclusions How efﬁcient is heating by AGN feedback?

E (kT = 5.9 keV) C.P., Chang, Broderick (2011) b, 2500 X 104 Eb, 2500(kTX = 3.5 keV)

Eb, 2500(kTX = 2.0 keV)

Eb, 2500(kTX = 1.2 keV) erg] 2

58 10

Eb, 2500(kTX = 0.7 keV) [10 tot PV 4 = 0

cav 10 E

cool cores non-cool cores 10-2

1 10 100 2 Ke,0 [keV cm ]

E (kT = 5.9 keV) C.P., Chang, Broderick (2011) b, 2500 X 104 Eb, 2500(kTX = 3.5 keV)

Eb, 2500(kTX = 2.0 keV)

Eb, 2500(kTX = 1.2 keV) erg] 2

58 10

Eb, 2500(kTX = 0.7 keV) [10 tot PV 4 = 0 max K0

cav 10 E

cool cores non-cool cores 10-2

1 10 100 2 Ke,0 [keV cm ]

AGNs cannot transform CC to NCC clusters (on a buoyancy timescale)

Challenge #1 (unknown unknowns): inhomogeneous universe universe is inhomogeneous and hence density of electrons change as function of position could lead to loss of resonance over length scale spatial growth length scale (Miniati & Elyiv 2012) we have reasons to believe that the instability is not appreciably slowed in the presence of even dramatic inhomogeneities

plasma eigenmodes for the Lorentzian background case

Challenge #2 (known unknowns): non-linear saturation we assume that the non-linear damping rate = linear growth rate effect of wave-particle and wave-wave interactions need to be resolved Miniati and Elyiv (2012) claim that the nonlinear damping rate is linear growth rate

explains puzzles in high-energy astrophysics: lack of GeV bumps in blazar spectra without IGM B-fields unified TeV blazar-quasar model explains Fermi source counts and extragalactic gamma-ray background novel mechanism; dramatically alters thermal history of the IGM: uniform and z-dependent preheating rate independent of density → inverted T –ρ relation quantitative self-consistent picture of high-z Lyman-α forest significantly modifies late-time structure formation: group/cluster bimodality of core entropy values suppresses late dwarf formation (in accordance with SFHs): “missing satellites”, void phenomenon, H I-mass function

Puchwein, C.P., Springel, Broderick, Chang (2012): L = 15h−1Mpc boxes with 2 × 3843 particles one reference run without blazar heating three with blazar heating at different levels of efﬁciency (address uncertainty)

used an up-to-date model of the UV background (Faucher-Giguère+ 2009)

no blazar heating intermediate blazar heating 7.0 -7 -7 8 6.5 − ) = N HI H ( N 6.0 10 log -6 -8 -6

5.5 ) -5 -5 K / T

( 5.0

10 -4 -4 log 4.5

4.0 -3 -3 -2 -2

1 3.5 log10(Mpix/(h− M )) Viel et al. 2009, F=0.1-0.8 Viel et al. 2009, F=0-0.9 5 6 7 8 9 10 3.0 2 1 0 1 2 3 2 1 0 1 2 3 − − − − log (ρ/ ρ ) 10 h i

Puchwein, C.P., Springel, Broderick, Chang (2012)

1.0

0.8 τ − e

0.6

0.4 transmitted ﬂux fraction 0.2 no blazar heating intermediate b. h. 0.0 0.25 0.20

τ 0.15 − e

∆ 0.10 0.05 0.00 0 1000 2000 3000 4000 1 velocity [km s− ] Puchwein+ (2012)

no blazar heating no blazar heating 0.5 3.5 weak blazar heating weak blazar heating intermediate blazar heating intermediate blazar heating strong blazar heating

) Becker et al. 2011 eff

strong blazar heating K τ 0.4 Viel et al. 2004 4 10

( 3.0 /

Tytler et al. 2004 ) ∆ FG ’08 ( T 0.3 2.5 effective optical depth temperature 0.2

2.0

0.1 1.8 2.0 2.2 2.4 2.6 2.8 3.0 2.0 2.2 2.4 2.6 2.8 3.0 redshift z redshift z Puchwein+ (2012)

Redshift evolutions of effective optical depth and IGM temperature match data only with additional heating, e.g., provided by blazars!

tuned UV background 101 no blazar heating weak blazar heating intermediate blazar heating strong blazar heating 100 Kim et al. 2007

z = 2.52

1 10− 101 PDF of transmitted ﬂux fraction

100

z = 2.94

1 10− 0.0 0.2 0.4 0.6 0.8 1.0 transmitted ﬂux fraction

Puchwein+ (2012)

decomposing Lyman-α forest into individual Voigt proﬁles allows studying the thermal broadening of absorption lines

0.08 13 2 NHI > 10 cm− no blazar heating 0.07 2.75 < z < 3.05 weak blazar heating intermediate blazar h. strong blazar heating 0.06 Kirkman & Tytler ’97 ] 1

− 0.05 skm [

b 0.04

0.03 PDF of 0.02

0.01

0.00 0 10 20 30 40 50 60 1 b[kms− ] Puchwein+ (2012)

improvement in modelling the Lyman-α forest is a direct consequence of the peculiar properties of blazar heating: heating rate independent of IGM density → naturally produces the inverted T –ρ relation that Lyman-α forest data demand recent and continuous nature of the heating needed to match the redshift evolutions of all Lyman-α forest statistics magnitude of the heating rate required by Lyman-α forest data ∼ the total energy output of TeV blazars (or equivalently ∼ 0.2% of that of quasars)

thermal pressure opposes gravitational collapse on small scales characteristic length/mass scale below which objects do not form hotter IGM → higher IGM pressure → higher Jeans mass:

!1/2 c3 T 3 M T 3/2 M ∝ s ∝ IGM → J,blazar ≈ blazar 30 J 1/2 & ρ ρ MJ,photo Tphoto

→ depends on instantaneous value of cs “ﬁltering mass” depends on full thermal history of the gas: accounts for delayed response of pressure in counteracting gravitational collapse in the expanding universe apply corrections for non-linear collapse

1 + δ = 1, z = 10 blazar heating 1012 reion only photoheating M ~ 1011 M linear theory F o

] 10 10 • O 10 MF ~ 10 Mo M -1 h [ F non−linearlinear theorytheory 8 M 10 non-linear theory optimistic blazar standard blazar only photoheating 106 F

M / 10

F, blazar 1 M 10 1 1 + z

C.P., Chang, Broderick (2012)

mean density void, 1 + δ = 0.5

δ 1 + δ = 1, z = 10 12 1 + = 0.5, z = 10 1012 reion 10 reion

] 10

] 10 • O • O 10 10 M M -1 -1 h h [ [ F F linear theory linear theory 8 8 M M 10 non-linear theory 10 non-linear theory optimistic blazar optimistic blazar standard blazar standard blazar only photoheating 6 only photoheating 106 10 F F M M / / 10 10 F, blazar F, blazar 1

1 M M 10 1 10 1 1 + z 1 + z C.P., Chang, Broderick (2012) blazar heating efﬁciently suppresses the formation of void dwarfs 11 within existing DM halos of masses < 3 × 10 M (z = 0) may reconcile the number of void dwarfs in simulations and the paucity of those in observations

Springel+ (2008)

Dolphin+ (2005)

Substructures in cold DM simulations much more numerous than observed number of Milky Way satellites!

10 Myr M110

100 Myr 10 Gyr

1 Gyr

Dolphin+ (2005)

isochrone ﬁtting for different metallicities → star formation histories

Dolphin+ (2005)

τ red: form > 10 Gyr, z > 2

satellite formation time satellite luminosity function

Maccio & Fontanot (2010)

no blazar heating: linear theory non−linear theory late forming satellites (< 10 Gyr) not observed!

Maccio+ (2010) blazar heating suppresses late satellite formation, may reconcile low observed dwarf abundances with CDM simulations

Mo+ (2005)

H I-mass function is too flat (i.e., gas version of missing dwarf problem!) photoheating and SN feedback too inefficient IGM entropy floor of K ∼ 15 keV cm2 at z ∼ 2 − 3 successful!

Christoph Pfrommer The Physics and Cosmology of TeV Blazars