Welcome to our Session!
New Constraints on
as Dark Matter
work in particular withBernard Carr
Katherine FreeseJens Jasche
Pavel NaselskyTommy OhlssonGlenn Starkman
Talk at 13. KosmologietagBielefeld, 4th of May 2018
Primordial Black Holes
Florian Kühnel
PBH Generalities
Black-hole (BH) formation for .
Astrophysical: From down to , but not lower.
Have a look at the density
To form smaller black holes we need higher density
Formation at early times; primordial black holes (PBHs)
Compare to cosmological density
Masses of primordial black holes:
PBH Formation Mechanisms
Formation of primordial black holes
http://www.damtp.cam.ac.uk/research/gr/public/cs_top.html
Cosmic string loops
PBH Formation Mechanisms
Formation of primordial black holes by
Cosmic string loops
PBH Formation Mechanisms
Formation of primordial black holes
Bubble collisions
by
http://www.damtp.cam.ac.uk/research/gr/public/cs_phase.html
Cosmic string loops
PBH Formation Mechanisms
Formation of primordial black holes
Pressure reduction
Bubble collisions
0.0 0.5 1.0 1.5 2.0
0.34
0.36
0.38
0.40
0.42
0.44
M/M⊙11
δc
by
Cosmic string loops
PBH Formation Mechanisms
Formation of primordial black holes
Pressure reduction
Bubble collisions
0.0 0.5 1.0 1.5 2.0
0.34
0.36
0.38
0.40
0.42
0.44
M/M⊙11
δc
by
More in Chris' talk
Cosmic string loops
PBH Formation Mechanisms
Formation of primordial black holes
Pressure reduction
Bubble collisions
by
Cosmic string loops
PBH Formation Mechanisms
Formation of primordial black holes
Pressure reduction
Large density perturbations
Bubble collisions
https://ned.ipac.caltech.edu/level5/Sept12/Kravtsov/Kravtsov3.htmlby
[Carr 1975]Simple estimate:
Jeans lengthscale of the over density
PBH —Probes of Scales
Probe a huge range of scales:Planck relics, Extra dimensions and higher-dimensional black holes, …
Quantum Gravity:
Early Universe: Baryogenesis, Nucleosynthesis, Reionisation, …
High-Energy Physics: Cosmological and galactic gamma-rays, …
Critical phenomena, Cold dark matter, Dynamical effects, Lensing effects, Gravitational waves, Black holes in galactic nuclei, …
Gravity:
PBH —Some Numbers
Mass range:
Size:
Number in our Galaxy:
Distance:
Consider an example of primordial black holes constituting all of the dark matter:
PBH Constraints at Formation
[Carr et al. 2010]
10-30
10-25
10-20
10-15
10-10
10-5
100
0 10 20 30 40 50
`’
log10(M/g)
Planck
LSP
Entropy
BBN
CMB
Galactic aEGB
21cm
1PBH
GRB
GW
WMAP3FIRAS
MACHOQSO
WBDF
LSS
Note that
and hence
PBH & Particle Dark Matter
If PBHs do not constitute the entirety of the dark matter, the latter must necessarily contain something else.
One possibility: a combined scenario, e.g. DM = PBHs + Particles
Halo profile does matter; enhancement of in density spikes.The annihilation rate .
�
� / n2
Let us now study WIMP annihilations in PBH halos:
PBH & Particle Dark Matter
Halo profile does matter; enhancement of in density spikes.The annihilation rate .
�
� / n2Let us now study WIMP annihilations in PBH halos:
Halo profile does matter; enhancement of in density spikes.
PBH & Particle Dark Matter
The annihilation rate . �
� / n2
1) We derive the density profile of the captured WIMPs, 2) calculate the annihilation rate, 3) and compare to data:
Let us now study WIMP annihilations in PBH halos:
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[Boucenna, FK, Ohlsson, Visinelli 2018]
PBH & Particle Dark Matter
1) We derive the density profile of the captured WIMPs, 2) calculate the annihilation rate, 3) and compare to data:
The annihilation rate . � / n2
Halo profile does matter; enhancement of in density spikes.�
Let us now study WIMP annihilations in PBH halos:
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[Boucenna, FK, Ohlsson, Visinelli 2018]
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HSC
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PBH & Particle Dark Matter
Let us now study WIMP annihilations in PBH halos:
Halo profile does matter; enhancement of in density spikes.1) We derive the density profile of the captured WIMPs, 2) calculate the annihilation rate, 3) and compare to data:
The annihilation rate . � / n2
�
[Boucenna, FK, Ohlsson, Visinelli 2018]
PBH & Particle Dark Matter
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KEG F NS
HSC
ML E WB
1) We derive the density profile of the captured WIMPs, 2) calculate the annihilation rate, 3) and compare to data:
[Boucenna, FK, Ohlsson, Visinelli 2018]
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������� ���� ���� ����
KEG F NS
HSC
ML E WB
h�vi = 3⇥ 10�26 cm3/s
PBH & Particle Dark Matter
1) We derive the density profile of the captured WIMPs, 2) calculate the annihilation rate, 3) and compare to data:
[Boucenna, FK, Ohlsson, Visinelli 2018]
��-�� ��-�� ��-� �����-��
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������� ���� ���� ����
KEG F NS
HSC
ML E WB
h�vi = 3⇥ 10�26 cm3/s
PBH & Particle Dark Matter
1) We derive the density profile of the captured WIMPs, 2) calculate the annihilation rate, 3) and compare to data:
[Boucenna, FK, Ohlsson, Visinelli 2018]
Primordial black holes are very interesting!
Conclusion
They are unique probes of their formation scenarios.
These scenarios (also those with sterile neutrinos) have distinct signatures and might be falsified or confirmed in the near future.
If PBHs do not constitute the entirety of the dark matter, the latter must necessarily contain something else, with combined dark-matter scenarios (PBHs + WIMPs) are amongst the most plausible ones.