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8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
1/31
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
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
2/31
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
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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Whos afraid of Cold Dark Matter?
Missing satellites problem
Central density cusp vs flat core controversy
1/15
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
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
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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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
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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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!
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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(ste
rile
neutrino
production
rate)/H
Making sterile neutrinos in the primordial fireball
4/15
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
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
8/31
(ste
rile
neutrino
production
rate)/H
Making sterile neutrinos in the primordial fireball
4/15
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
/H T9
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
9/31
(ste
rile
neutrino
production
rate)/H
Making sterile neutrinos in the primordial fireball
4/15
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
/H T9 /H T3
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
10/31
(ste
rile
neutrino
production
rate)/H
Making sterile neutrinos in the primordial fireball
4/15
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
/H T9 /H T3
sh
2
0.13 sin2 (20)
108m
2
s,10 keV
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
11/31
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
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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Predictions of CDM recovered on Large Scales
Relativistic streaming erases structure on small length scales
Sterile neutrinos and small-scale large-scale structure
5/15
CDM Power Spectrum
Decreasingm
s
fs
1.
2 MpckeVms
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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Very small length scales!
Sterile neutrinos and small-scale large-scale structure
5/15
CDM Power Spectrum
Decreasingm
s
Galaxy Survey cutoffs
Predictions of CDM recovered on Large Scales
Relativistic streaming erases structure on small length scales
fs
1.
2 MpckeVms
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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Very small length scales!
Sterile neutrinos and small-scale large-scale structure
5/15
CDM Power Spectrum
Decreasingm
s
Galaxy Survey cutoffs
Predictions of CDM recovered on Large Scales
Relativistic streaming erases structure on small length scales
fs
1.
2 MpckeVms
Constraints from Ly- forest
ms 2
10 keV
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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Sterile Neutrino decays
X-rays! (keV photons)
huhifiuhiuhsiuehfiuehsfiushefiuhsefiuhseifuhseifuhseiufhsieufhisueh X-ray background constraint
(XMM)hhuiheiuhfiuewhfiuewhf Coma-Virgo Constraints
6/15
= 1026
s
7 keV
ms
5109
sin2
sin22 8 105m5.43
s,keV
sin22 1.15 104m5
s,keV
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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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
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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The tem erature evolution of a molecular cloud
8/15
dT
dz= ( 1)
T
np
dnp
dz+
T
d
dz+
T
1
d
Dz+
( 1)
npkH0 (1 + z)
+m (1 + z)
3
h
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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The tem erature evolution of a molecular cloud
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
h
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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The tem erature evolution of a molecular cloud
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
h l f l l l d
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
20/31
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
The tem erature evolution of a molecular cloud
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
h l f l l l d
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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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
The tem erature evolution of a molecular cloud
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
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
22/31
The (crude) chemistry of molecular clouds
Two formation chains for molecular
hydrogenfuhiuhsiufhsiuefhiueshfiusehfiusehfisuehfiusehfiusehfiusehfise Photo and collisional dissociation of
Photo and collisional ionization of H, recombination
9/15
e
+H H
+
H
+H H2 + e
H+ +H H+2 +
H+
2 +H H2 +H+
H2
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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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
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
24/31
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
10/15
zvir
Tvir
4 105M & 10
10M
zvir = 100 & zvir = 20
T (0.75zvir) 0.75T (zvir)
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
25/31
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
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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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
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
27/31
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
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
28/31
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
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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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
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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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
8/3/2019 Daniel Grin et al- Thermal Evolution of the primordial clouds in warm dark matter models with keV sterile neutrinos
31/31
Closing thoughts
Be afraid, be very afraid of sterile neutrinoparticipation in reionization, and enjoy the
Halloween party