P ! mor " al Black Hol et as Dark Ma $ er Florian Khnel - - PowerPoint PPT Presentation

P!mor"al Black Holet Dark Ma$er

work in particular with Bernard Carr Katherine Freese Glenn Starkman Talk at Rencontres de Moriond La Thuile, Italy - 20th of March 2019

as

Florian Kühnel

Stockholm University

Astrophysical black holes: From down to , but not lower.

PBH Generalitiet

1010M

1M

Astrophysical black holes: From down to , but not lower.

PBH Generalitiet

Have a look at the density 1010M

1M

Astrophysical black holes: From down to , but not lower.

PBH Generalitiet

Have a look at the density To form smaller black holes we need higher density. 1010M

1M

Astrophysical black holes: From down to , but not lower.

PBH Generalitiet

Have a look at the density To form smaller black holes we need higher density. Compare to cosmological density 1010M

1M

Astrophysical black holes: From down to , but not lower.

PBH Generalitiet

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 1010M

1M

Astrophysical black holes: From down to , but not lower.

PBH Generalitiet

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: 1010M

1M

PBH Formation Mechan%ms

Formation of primordial black holes

http://www.damtp.cam.ac.uk/research/gr/public/cs_top.html

Cosmic string loops

PBH Formation Mechan%ms

Formation of primordial black holes by

Cosmic string loops

PBH Formation Mechan%ms

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 Mechan%ms

Formation of primordial black holes Pressure reduction Bubble collisions by

0.001 0.100 10 1000 0.40 0.42 0.44 0.46 M/M⊙ δc

δc =0.453 Log(time)-averaged Time-averaged Turn-around time Horizon entry

[Byrnes et al. 2018]

[Carr 1975]

Simple estimate:

Jeans length scale of the over density

Cosmic string loops

PBH Formation Mechan%ms

Formation of primordial black holes Pressure reduction Large density perturbations

• f inflationary origin

Bubble collisions

https://ned.ipac.caltech.edu/level5/Sept12/Kravtsov/Kravtsov3.html

by

w > 0

δ > w

PBH Formation - Scalet

N Scale

PBH Formation - Scalet

Inflation Radiation Matter N Scale

Hubble Scale

Reheating

PBH Formation - Scalet

Inflation Radiation Matter N Scale

Hubble Scale Physical Scale

Collapse at Re-Entry if Reheating

δ > δc

PBH Formation - Scalet

Inflation Radiation Matter N Scale

Hubble Scale Physical Scale

Collapse at Re-Entry if Reheating

δ > δc

PBH Con&raints at Formation

[Carr et al. 2010]

10-30 10-25 10-20 10-15 10-10 10-5 100 10 20 30 40 50

’ log10(M/g)

Planck LSP Entropy BBN CMB Galactic EGB

21cm

PBH GRB GW

WMAP3 FIRAS

MACHO QSO WB DF LSS

Note that and hence

PBH —Probet of Scalet

Probe a huge range of scales: Planck relics, Extra dimensions and higher-dimensional black holes, … Quantum Gravity: Early Universe: 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 Con&raints

PBH Constraints

PBH Con&raints

PBH Constraints

Ω ≤ 1

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing Gravitational Waves

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing Evaporation Gamma-Rays, BBN, Entropy, ... Gravitational Waves

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing Evaporation Gamma-Rays, BBN, Entropy, ... Annihilation of Dark Matter Particles PBH + {WIMPs, ALPs, ...} Gravitational Waves

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing Evaporation Gamma-Rays, BBN, Entropy, ... Seismic Annihilation of Dark Matter Particles PBH + {WIMPs, ALPs, ...} Gravitational Waves

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing Evaporation Gamma-Rays, BBN, Entropy, ... "Disruption" Wide Binaries, Neutron Stars, White Dwarfs, ... Seismic Annihilation of Dark Matter Particles PBH + {WIMPs, ALPs, ...} Gravitational Waves

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing Evaporation Gamma-Rays, BBN, Entropy, ... CMB "Disruption" Wide Binaries, Neutron Stars, White Dwarfs, ... Seismic Annihilation of Dark Matter Particles PBH + {WIMPs, ALPs, ...} Gravitational Waves

PBH Con&raints

PBH Constraints

Ω ≤ 1

Lensing Evaporation Gamma-Rays, BBN, Entropy, ... CMB "Disruption" Wide Binaries, Neutron Stars, White Dwarfs, ... Seismic Annihilation of Dark Matter Particles PBH + {WIMPs, ALPs, ...} Gravitational Waves ...

2) Individual mergers (such as GW150914,(GW151226, ...?)

Gravitational Wavet form PBHs

PHBs can emit gravitational waves in various instances and times. Gravitational-wave emission from PBH binaries: 1) Stochastic GW background Gravitational waves from PBH formation.

[Saito, Yokoyama 2009; Nakama, Silk, Kamionkowski 2017]

G W 1 7 8 1 7 G W 1 7 6 8 G W 1 5 1 2 2 6 G W 1 5 1 1 2 G W 1 7 1 4 G W 1 7 8 1 4 G W 1 7 8 9 G W 1 7 8 1 8 G W 1 5 9 1 4 G W 1 7 8 2 3 G W 1 7 7 2 9

−1.0 −0.5 0.0 0.5 1.0 χeff

[LIGO Scientific, Virgo 2018]

Gravitational Wavet form PBHs

PHBs can emit gravitational waves in various instances and times. Gravitational-wave emission from PBH binaries: 1) Stochastic GW background 2) Individual mergers (such as GW150914,(GW151226, ...?) Gravitational-wave emission from hyperbolic PBH encounters.

[Garcia-Bellido & Nesseris 2017]

Gravitational waves from PBH formation.

[Saito, Yokoyama 2009; Nakama, Silk, Kamionkowski 2017]

OGLE detected a populations of microlensing events:

OGLE - Microlensing

1- 300 days light-curve timescale - origin known. Should be brown dwarfs, MS stars, white dwarfs and neutron stars.

... but OGLE detected also another population of microlensing events:

Did OGLE Detect PBHs?

10−1 100

ML LC timescale: tE [days]

100 101 102

Number of events per bin

OGLE data

besft-fit PBH model

(MPBH = 9.5 × 106M, fPBH = 0.026) [Niikura et al. 2019]

0.1 - 0.3 days light-curve timescale - origin unknown! Could be free-floating planets... or PBHs!

Did OGLE Detect PBHs?

1026 1027 1028 1029

MPBH [g]

103 102 101 100

fPBH = ΩPBH/ΩDM

O G L E a l

• n

e OGLE+HSC allowed region (95% CL)

HSC excl. region

108 107 106 105 104

MPBH [M]

[Niikura et al. 2019]

Planck E v a p

• r

a t i

• n

FL WD K HSC NS EROS M WB S e g I Eri II

• 15
• 10
• 5
• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log10(Mc/M⊙) log10fPBH monochromatic

Con&raints —Words of Caution

[Carr et al. 2017]

May constraints rely on rather on uncertain, restrictive, simplistic or even incorrect assumptions!

Planck E v a p

• r

a t i

• n

FL WD K HSC NS EROS M WB S e g I Eri II

• 15
• 10
• 5
• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log10(Mc/M⊙) log10fPBH monochromatic

Con&raints —Words of Caution

[Carr et al. 2017]

Validity of Hawking radiation May constraints rely on rather on uncertain, restrictive, simplistic or even incorrect assumptions!

Planck E v a p

• r

a t i

• n

FL WD K HSC NS EROS M WB S e g I Eri II

• 15
• 10
• 5
• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log10(Mc/M⊙) log10fPBH monochromatic

Con&raints —Words of Caution

[Carr et al. 2017]

Validity of Hawking radiation May constraints rely on rather on uncertain, restrictive, simplistic or even incorrect assumptions! Assumes a far too large DM density in globular clusters

Planck E v a p

• r

a t i

• n

FL WD K HSC NS EROS M WB S e g I Eri II

• 15
• 10
• 5
• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log10(Mc/M⊙) log10fPBH monochromatic

Con&raints —Words of Caution

[Carr et al. 2017]

Validity of Hawking radiation Accretion models uncertain May constraints rely on rather on uncertain, restrictive, simplistic or even incorrect assumptions! Assumes a far too large DM density in globular clusters

Planck E v a p

• r

a t i

• n

FL WD K HSC NS EROS M WB S e g I Eri II

• 15
• 10
• 5
• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log10(Mc/M⊙) log10fPBH monochromatic

Con&raints —Words of Caution

[Carr et al. 2017]

Validity of Hawking radiation Accretion models uncertain May constraints rely on rather on uncertain, restrictive, simplistic or even incorrect assumptions! Assumes a far too large DM density in globular clusters Finite sources

Planck E v a p

• r

a t i

• n

FL WD K HSC NS EROS M WB S e g I Eri II

• 15
• 10
• 5
• 3.0
• 2.5
• 2.0
• 1.5
• 1.0
• 0.5

0.0 log10(Mc/M⊙) log10fPBH monochromatic

Con&raints —Words of Caution

[Carr et al. 2017]

Validity of Hawking radiation Accretion models uncertain May constraints rely on rather on uncertain, restrictive, simplistic or even incorrect assumptions! Ignores "Wave effect" Assumes a far too large DM density in globular clusters Finite sources

Conclusion

Primordial black holes are very interesting! A detailed understanding of their formation is crucial. Most of the primordial black-hole constraints rely

• n assumptions whose validity is hard to quantify.

They could be (a significant fraction of) the dark matter! They potentially influence physics on many different scales, and could manifest themselves via a plethora of different signatures.