Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos

8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos

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Thermal Evolution of the primordial clouds in warm darkmatter models with keV sterile neutrinos.

Jaroslaw Stasielak, Peter L. Biermann, Alexander KusenkoAp. J 654 (2007), astro-ph/0606435

&Relic keV sterile neutrinos and reionization.Peter L. Biermann & Alexander KusenkoPRL. 96 091301 (2006), astro-ph/0601004

Astronomy Journal Club 10/26/07Daniel Grin


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Outline:

Why WDM (Warm Dark Matter)?

Sterile Neutrinos:Basic physics, cosmological behavior, radiation backgrounds

Existing constraints

Sterile Neutrinos and reionization

Sterile Neutrinos and reionization: The model: Tegmark and friends (1996) + sterile neutrinos

Results

Caveats

2 and star formation


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Whos afraid of Cold Dark Matter?

Missing satellites problem

Central density cusp vs flat core controversy

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4/31

WDM patches up small-scale structure

Thermal streaming of WDM erasesstructure on smallest scales

King (cored) profile + phase-spaceboundsjfiseoifjseoifjosiefjosiejfosiejfosiejfoisejfosiejfsoeijfosiejfsoifjiosjfeoisejfoisejfijssioef

WDM seems to suppress number of smallhalos

WDM still produces cuspy cores!

WDM upends hierarchical structureformation

2/15

ms

32 pc

rc

1/2

10 km s1

1/4

keV 20 h1 Mpc

z=3 CDM 350 eV WDM


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Sterile Neutrinos: A natural keV WDM particle

Standard model has no masses uhiuhiuhiuhiuh Can add Dirac massnjkfneskjfnskejfnskejnfskjenfskejnfskejfnsekj Adding heavy can explain observed

masses.nvnkjvnkxjfnvkjnjknjknvkjxfnvkjxfnvkjxfnvxkjfnvxkfjnvxfkjvnxfnxjkvnfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvn

Lighter (keV) Majorana can still explain masses

Sterile does not directly interact with SM particles Sterile mixes with active

3/15

mD/mR

L,mass = mDRL

m1 m2

D/mR m2 mR

L,mass = mDRL +mRRR

as sin22

R


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Standard model has no masses uhiuhiuhiuhiuh Can add Dirac massnjkfneskjfnskejfnskejnfskjenfskejnfskejfnsekj Adding heavy can explain observed

masses.nvnkjvnkxjfnvkjnjknjknvkjxfnvkjxfnvkjxfnvxkjfnvxkfjnvxfkjvnxfnxjkvnfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvnxfkjvn

Lighter (keV) Majorana can still explain masses

Sterile does not directly interact with SM particles Sterile mixes with active

Sterile Neutrinos: A natural keV WDM particle

3/15

mD/mR

L,mass = mDRL

m1 m2

D/mR m2 mR

L,mass = mDRL +mRRR

as sin22

R

See-Saw!


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(ste

rile

neutrino

production

rate)/H

Making sterile neutrinos in the primordial fireball

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Sterile neutrinos produced by oscillation from SM neutrinos

Real mixing suppressed by leptons/hadrons in plasma

Full Boltzmann treatment yields:

Out of equilibrium!

Ordinary Neutrinosthermally produced

G2FT5 sin2 [0] /2


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(ste

rile

neutrino

production

rate)/H


4/15




Out of equilibrium!


G2FT5 sin2 [0] /2

/H T9


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(ste

rile

neutrino

production

rate)/H


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Out of equilibrium!


G2FT5 sin2 [0] /2

/H T9 /H T3


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(ste

rile

neutrino

production

rate)/H


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Out of equilibrium!


G2FT5 sin2 [0] /2

/H T9 /H T3

sh

2

0.13 sin2 (20)

108m

2

s,10 keV


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Sterile neutrinos and small-scale large-scale structure

Predictions of CDM recovered on Large Scales

Relativistic streaming erases structure on small length scales

5/15

CDM Power Spectrum

fs

1.

2 MpckeVms


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5/15

CDM Power Spectrum

Decreasingm

s

fs

1.

2 MpckeVms


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Very small length scales!


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CDM Power Spectrum

Decreasingm

s

Galaxy Survey cutoffs



fs

1.

2 MpckeVms


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Very small length scales!


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CDM Power Spectrum

Decreasingm

s

Galaxy Survey cutoffs



fs

1.

2 MpckeVms

Constraints from Ly- forest

ms 2

10 keV


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Sterile Neutrino decays

X-rays! (keV photons)

huhifiuhiuhsiuehfiuehsfiushefiuhsefiuhseifuhseifuhseiufhsieufhisueh X-ray background constraint

(XMM)hhuiheiuhfiuewhfiuewhf Coma-Virgo Constraints

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= 1026

s

7 keV

ms

5109

sin2

sin22 8 105m5.43

s,keV

sin22 1.15 104m5

s,keV


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Sterile neutrinos and reionization

Generic WDM scenario suppresseslow mass halos (Yoshida/Sokasian2003)

Decaying WDM (a sterile neutrino)would produce additional XRB

This could hasten reionization (Mapelli

and Ferrara 2005) but doesnt cut it!

An additional ionizing backgroundchanges star formation!

7/15

max 0.05

F i g u r e 8 . top panel

bottom panel

s ol id l in e dot ted l in e dot -da shed l in e

dashed line soli d thi n li ne top panel

bottom

panel


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The tem erature evolution of a molecular cloud

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dT

dz= ( 1)

T

np

dnp

dz+

T

d

dz+

T

1

d

Dz+

( 1)

npkH0 (1 + z)

+m (1 + z)

3

h


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dT

dz= ( 1)

T

np

dnp

dz+

T

d

dz+

T

1

d

Dz+

( 1)

npkH0 (1 + z)

+m (1 + z)

3

PdV work

h


19/31


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dT

dz= ( 1)

T

np

dnp

dz+

T

d

dz+

T

1

d

Dz+

( 1)

npkH0 (1 + z)

+m (1 + z)

3

PdV work Ionization/Composition

h l f l l l d


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Compton Cooling

Recombination Cooling

Collisional excitation of H lines

Collisional excitation of

Bremsstrahlung

Heat of formation of

Photo-ionization by CMB

Collisional ionization by electrons


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dT

dz= ( 1)

T

np

dnp

dz+

T

d

dz+

T

1

d

Dz+

( 1)

npkH0 (1 + z)

+m (1 + z)

3

PdV work Ionization/Composition Heating/Cooling

Heating Cooling

H2 transitions

H2

h l f l l l d


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Compton Cooling

Recombination Cooling

Collisional excitation of H lines

Collisional excitation of

Bremsstrahlung

Heat of formation of

Photo-ionization by CMB

Collisional ionization by electron

Photo-ionization of H by neutrinoproduced photons

Collisional ionization by secondaries


8/15

dT

dz= ( 1)

T

np

dnp

dz+

T

d

dz+

T

1

d

Dz+

( 1)

npkH0 (1 + z)

+m (1 + z)

3

PdV work Ionization/Composition Heating/Cooling

Heating Cooling

H2 transitions

H2


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The (crude) chemistry of molecular clouds

Two formation chains for molecular

hydrogenfuhiuhsiufhsiuefhiueshfiusehfiusehfisuehfiusehfiusehfiusehfise Photo and collisional dissociation of

Photo and collisional ionization of H, recombination

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e

+H H

+

H

+H H2 + e

H+ +H H+2 +

H+

2 +H H2 +H+

H2


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Two formation chains for molecular

hydrogenfuhiuhsiufhsiuefhiueshfiusehfiusehfisuehfiusehfiusehfiusehfise Photo and collisional dissociation of

Photo and collisional ionization of H, recombination

Neutrino decay products included in photoionizing background

The (crude) chemistry of molecular clouds

9/15

+H H +

+H H2 + e

H+ +H H+2 +

H+

2 +H H2 +H+

H2

with sterile neutrinos


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Other ingredients

Model stolen adapted from Tegmark, Silk, Rees 1997

Spherical top-hat collapse until shortly before

Temperature rapidly ramped up to

halos

Halo `fragments if

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zvir

Tvir

4 105M & 10

10M

zvir = 100 & zvir = 20

T (0.75zvir) 0.75T (zvir)


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10-12

10-11

10-10

10-9

10-8

10-7

sin2

1

10

ms

(keV)

dark matter

excluded (x rays)

produced via mixing

for

xray

limit

=s

dm

(allowed)

pulsar kicks

Lyman

WDM1

WDM2

WDM3

The big picture

11/15


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Results: Gas temperature

101

102

103

104

1 10 100 1000

T

[K]

z

M = 4 105

Msun, zvir = 20

CDMWDM3WDM2WDM1

101

102

103

104

1 10 100 1000

T

[K]

z

M = 4 105

Msun, zvir = 100

CDMWDM3WDM2WDM1

101

102

103

104

105

106

1 10 100 1000

T

[K]

z

M = 1010

Msun, zvir = 100

CDMWDM3WDM2WDM1

101

102

103

104

105

106

1 10 100 1000

T

[K]

z

M = 1010

Msun, zvir = 20

CDMWDM3WDM2WDM1

12/15


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Results: Ionization Fraction

13/15

10-6

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xe

z

M = 4 105

Msun, zvir = 20

CDMWDM3WDM2WDM1

10-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

1 10 100 1000

xe

z

M = 4 105

Msun, zvir = 100

CDMWDM3WDM2WDM1

10-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

1 10 100 1000

xe

z

M = 1010

Msun, zvir = 100

CDMWDM3WDM2WDM1

10-6

10-5

10-4

10-3

10-2

10-1

100

1 10 100 1000

xe

z

M = 1010

Msun, zvir = 20

CDMWDM3WDM2WDM1


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Results: H2 abundance

14/15

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 4 105

Msun, zvir = 20

CDMWDM3WDM2WDM1

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 4 105

Msun, zvir = 100

CDMWDM3WDM2WDM1

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 1010

Msun, zvir = 100

CDMWDM3WDM2WDM1

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 1010

Msun, zvir = 20

CDMWDM3WDM2WDM1


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Results: H2 abundance

14/15

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 4 105

Msun, zvir = 20

CDMWDM3WDM2WDM1

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 4 105

Msun, zvir = 100

CDMWDM3WDM2WDM1

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 1010

Msun, zvir = 100

CDMWDM3WDM2WDM1

10-5

10-4

10-3

10-2

10-1

1 10 100 1000

xH2

z

M = 1010

Msun, zvir = 20

CDMWDM3WDM2WDM1

P

PUNCHLINE: DECAYING STERILE NEUTRINOS

ENABLE LOW MASS HALOS TO COOL


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but.....

No modeling of actual star formation and ionizingbackground from stars

No realistic assessment of how this changes ionization

history of universe

Actual halo population/effect of free-streaming not modeled

Unrealistic modeling of virialization (shock-heating/cooling

ignored)

Enhanced local radiation field not included

15/15


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Closing thoughts

Be afraid, be very afraid of sterile neutrinoparticipation in reionization, and enjoy the

Halloween party

Documents

Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos