A Unique Multi-Messenger Signal of QCD Axion Dark Matter Thomas D. - - PowerPoint PPT Presentation

A Unique Multi-Messenger Signal

• f QCD Axion Dark Matter

Thomas D. P . Edwards, Marco Chianese, Bradley J. Kavanagh, Samaya M. Nissanke, Christoph Weniger

1 1905.04686

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Multi-Messenger Astrophysics is Here

2

1710.05834

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Multi-Messenger Signal of QCD Axion

3

Time Radius Radio Amplitude Gravitational Wave Strain

IMBH − DM

NS

γ

a

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

QCD Axion Dark Matter

4

|θ| < 10−10

|θ| 6= O(1)

L = − g2

sθ

32π2 Gµν ˜ Gµν

• The strong interaction also admits a CP violating

term in its Lagrangian

• Promoting theta to a field allows the CP-violating term

to dynamically reach zero

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

QCD Axion Dark Matter

4

|θ| < 10−10

|θ| 6= O(1)

L = − g2

sθ

32π2 Gµν ˜ Gµν

• The strong interaction also admits a CP violating

term in its Lagrangian

• Promoting theta to a field allows the CP-violating term

to dynamically reach zero

λ = h mc

m > 10−7eV

1904.12803

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Intermediate Mass Black Holes and DM Spikes

5

1311.6918 1702.02149

fini(E, L) → ffin(E, L)

z = 20

z = 0

MDM = 106 [M]

9906391, 0501625, 1904.12803

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

108 107 106 105 104 103 102 101 Radius [pc] 104 107 1010 1013 1016 1019 1022 Density ⇥ M pc3⇤ Mini-Spike, α = 7/3 NFW BH-NS 1000 Mpc > Galactic NS BH-NS 10 Mpc > Galactic NS

Structure of the Mini-Spike

6

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

108 107 106 105 104 103 102 101 Radius [pc] 104 107 1010 1013 1016 1019 1022 Density ⇥ M pc3⇤ Mini-Spike, α = 7/3 NFW BH-NS 1000 Mpc > Galactic NS BH-NS 10 Mpc > Galactic NS

Structure of the Mini-Spike

6

• Density slope depends
• n initial slope
• 7/3 corresponds to an

initially NFW like density profile

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Dynamical Friction

7

fDF = 12πG2m2

NS

ρDM(r) v2

NS

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Dynamical Friction in a Binary System

8

GWs

Time

The smaller partner will reach merger faster than in a vacuum inspiral = Change in Phase evolution

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Dynamical Friction in a Binary System

8

GWs

Time

10−2 10−1 100 Frequency, f [Hz] 10−6 10−4 10−2 100 102 104 106 Phase difference, ∆Ψ α = 2.5 α = 7/3 α = 2.0

1408.353 The smaller partner will reach merger faster than in a vacuum inspiral = Change in Phase evolution

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Dephasing of the GW Signal

9

10−2 10−1 100 Frequency, f [Hz] 10−6 10−4 10−2 100 102 104 106 Phase difference, ∆Ψ α = 2.5 α = 7/3 α = 2.0

1408.3534

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Dephasing of the GW Signal

9

10−2 10−1 100 Frequency, f [Hz] 10−6 10−4 10−2 100 102 104 106 Phase difference, ∆Ψ α = 2.5 α = 7/3 α = 2.0

Majority of the phase difference occurs at large separations 1408.3534

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Dephasing of the GW Signal

9

10−2 10−1 100 Frequency, f [Hz] 10−6 10−4 10−2 100 102 104 106 Phase difference, ∆Ψ α = 2.5 α = 7/3 α = 2.0

Majority of the phase difference occurs at large separations Number of cycles low in the final stages of the evolution 1408.3534

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Gravitational Waves Constrain the Slope of the Density Profjle

10

3 4 5 6 7 8 10 12 14 Radius, r ⇥ 109 pc ⇤ 1020 1021 1022 1023 1024 DM Density, ρDM ⇥ M pc3⇤

3 days 10 days 30 days 100 days 1 year 4 years

Time to merger

α = 7/3

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Gravitational Waves Constrain the Slope of the Density Profjle

10

3 4 5 6 7 8 10 12 14 Radius, r ⇥ 109 pc ⇤ 1020 1021 1022 1023 1024 DM Density, ρDM ⇥ M pc3⇤

3 days 10 days 30 days 100 days 1 year 4 years

Time to merger

α = 7/3

Effect on GW small towards the end of the inspiral

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Gravitational Waves Constrain the Slope of the Density Profjle

10

3 4 5 6 7 8 10 12 14 Radius, r ⇥ 109 pc ⇤ 1020 1021 1022 1023 1024 DM Density, ρDM ⇥ M pc3⇤

3 days 10 days 30 days 100 days 1 year 4 years

Time to merger

α = 7/3

Effect on GW small towards the end of the inspiral Tight constraints at larger radii

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Radio Counterpart

11

γ

GWs

a

a

a

a

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Radio Counterpart

11

γ

GWs

a

a

a

a

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Radio Counterpart

11

γ

GWs

a

a

a

a

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Radio Counterpart

11

γ

GWs

a

a

a

a

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Radio Counterpart

11

γ

GWs

a

a

a

a

dP dΩ ∝ paγρDM(rc)vcr2

c

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Sensitivity of SKA

12

10−7 10−6 10−5 10−4 Axion Mass, ma [eV] 10−18 10−17 10−16 10−15 10−14 10−13 10−12 10−11 10−10 Axion-Photon Coupling, gaγγ [GeV−1]

ADMX ADMX projection

QCD axion

d = 1.00 Gpc d = 0.01 Gpc α = 7/3 P = 10 s B0 = 1012 G

r = 3 × 10−9 pc r = 6 × 10−9 pc

LISA Rates ∼ 3 − 10 Gpc−3 yr−1

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Sensitivity of SKA

12

10−7 10−6 10−5 10−4 Axion Mass, ma [eV] 10−18 10−17 10−16 10−15 10−14 10−13 10−12 10−11 10−10 Axion-Photon Coupling, gaγγ [GeV−1]

ADMX ADMX projection

QCD axion

d = 1.00 Gpc d = 0.01 Gpc α = 7/3 P = 10 s B0 = 1012 G

r = 3 × 10−9 pc r = 6 × 10−9 pc

Lower cut off - set by frequency range of radio telescopes

LISA Rates ∼ 3 − 10 Gpc−3 yr−1

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Sensitivity of SKA

12

10−7 10−6 10−5 10−4 Axion Mass, ma [eV] 10−18 10−17 10−16 10−15 10−14 10−13 10−12 10−11 10−10 Axion-Photon Coupling, gaγγ [GeV−1]

ADMX ADMX projection

QCD axion

d = 1.00 Gpc d = 0.01 Gpc α = 7/3 P = 10 s B0 = 1012 G

r = 3 × 10−9 pc r = 6 × 10−9 pc

Lower cut off - set by frequency range of radio telescopes Upper cut off - conversion to photons must happen

• utside of the NS

LISA Rates ∼ 3 − 10 Gpc−3 yr−1

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Two Messengers can be Combined for Robust Signal

13

10−7 10−6 10−5 10−4 Axion Mass, ma [eV] 10−18 10−17 10−16 10−15 10−14 10−13 10−12 10−11 10−10 Axion-Photon Coupling, gaγγ [GeV−1]

ADMX ADMX projection

QCD axion

d = 1.00 Gpc d = 0.01 Gpc α = 7/3 P = 10 s B0 = 1012 G

r = 3 × 10−9 pc r = 6 × 10−9 pc

3 4 5 6 7 8 10 12 14 Radius, r ⇥ 109 pc ⇤ 1020 1021 1022 1023 1024 DM Density, ρDM ⇥ M pc3⇤

3 days 10 days 30 days 100 days 1 year 4 years

Time to merger

α = 7/3

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Two Messengers can be Combined for Robust Signal

13

Difficult to set robust limits due to the uncertainty in the NS properties, magnetic field etc. If many are found, utilising NS population properties will allow for a more robust constraint

10−7 10−6 10−5 10−4 Axion Mass, ma [eV] 10−18 10−17 10−16 10−15 10−14 10−13 10−12 10−11 10−10 Axion-Photon Coupling, gaγγ [GeV−1]

ADMX ADMX projection

QCD axion

d = 1.00 Gpc d = 0.01 Gpc α = 7/3 P = 10 s B0 = 1012 G

r = 3 × 10−9 pc r = 6 × 10−9 pc

3 4 5 6 7 8 10 12 14 Radius, r ⇥ 109 pc ⇤ 1020 1021 1022 1023 1024 DM Density, ρDM ⇥ M pc3⇤

3 days 10 days 30 days 100 days 1 year 4 years

Time to merger

α = 7/3

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Conclusions

14

Multi-messenger Astrophysics can be used to probe fundamental physics in extreme astrophysical environments QCD Axion Dark Matter can potentially be discovered with future GW and radio

• bservations

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Constant Signal — Not Modulated by NS Spin

15

Time variations due to rotation

• f NS are averaged out

Cannot observe Doppler shift from rotation around the BH, since the velocity of the NS is slower than the DM

dP dΩ ∼ 2 × paγρDM(rc)vcr2

c ,

paγ ∝ g2

aγγB(rc)2

2vc

1804.03145

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Constant Signal — Not Modulated by NS Spin

15

Time variations due to rotation

• f NS are averaged out

Cannot observe Doppler shift from rotation around the BH, since the velocity of the NS is slower than the DM

dP dΩ ∼ 2 × paγρDM(rc)vcr2

c ,

paγ ∝ g2

aγγB(rc)2

2vc

1804.03145

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Increased Velocity of DM reduces the Signal

16

f(E) = 1 √ 8π2 "Z E dΨ √ E − Ψ d2ρ dΨ2 + 1 √ E ✓ dρ dΨ ◆

Ψ=0

#

E = Ψ(r) − 1 2v2

• The finite electron density in the

plasma gives the photon an effective mass

• Signal is dependent on the

velocity distribution of the DM

100 101 102 103 104 105

v [km/s]

10−8 10−7 10−6 10−5 10−4 10−3 10−2 10−1

f(v) [(km/s)−1]

r = 10−8 pc r = 10−6 pc r = 10−4 pc r = 10−1 pc

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Slope Dependence on GW Constraints

17

3 4 5 6 7 8 10 12 14 Radius, r ⇥ 109 pc ⇤ 1017 1018 1019 1020 DM Density, ρDM ⇥ M pc3⇤

3 days 10 days 30 days 100 days 1 year 4 years

Time to merger

α = 2.0

3 4 5 6 7 8 10 12 14 Radius, r ⇥ 109 pc ⇤ 1022 1023 1024 DM Density, ρDM ⇥ M pc3⇤

3 days 10 days 30 days 100 days 1 year 4 years

Time to merger

α = 2.5

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Sensitivity Dependence on Slope

18

10−7 10−6 10−5 10−4 Axion Mass, ma [eV] 10−18 10−17 10−16 10−15 10−14 10−13 10−12 10−11 10−10 Axion-Photon Coupling, gaγγ [GeV−1] P = 10 s B0 = 1012 G

ADMX ADMX projection

Q C D a x i

• n

α = 2.5 α = 7/3 α = 2.0

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Sensitivity Dependence on Magnetic Field

19

10−7 10−6 10−5 10−4 10−3 Axion Mass, ma [eV] 10−19 10−17 10−15 10−13 10−11 Axion-Photon Coupling, gaγγ [GeV−1]

ADMX ADMX projection

Q C D a x i

• n

α = 7/3 P = 10 s

B0 = 1015 G B0 = 1012 G B0 = 109 G

Thomas D. P . Edwards | TAUP 2019 | 1906.05800

Sensitivity Dependence on Spin Period

20

10−7 10−6 10−5 10−4 10−3 Axion Mass, ma [eV] 10−19 10−17 10−15 10−13 10−11 Axion-Photon Coupling, gaγγ [GeV−1]

ADMX ADMX projection

Q C D a x i

• n

α = 7/3 B0 = 1012 G

P = 10 s P = 1.0 s P = 0.1 s