frbs as probes of fundamental physicsaspen17.phys.wvu.edu/wu.pdf · 2017-02-18 · einstein’s...

FRBs as Probes of Fundamental Physics

Xue-Feng Wu

Purple Mountain Observatory, Chinese Academy of Sciences

1 2017.2.17

Einstein’s equivalence principle tests

Constraints on the rest mass of photon

Summary and prospect

2

Outline




3

Outline

100 anniversary of Einstein’s General Relativity

(1915.11.25-2015.11.25)

4

Einstein’s Equivalence Principle

Weak Equivalence Principle (WEP):

inertial mass = gravitational mass

(all the test particles have the same acceleration in the gravitational field, independent of their masses)

（Strong）Equivalence Principle (EP):

The result of a local non-gravitational experiment by a free-falling person in a gravitational field, is independent of the gravitational field。

“An alternative statement of WEP is that the trajectory of a freely falling “test” body (one not acted upon by such forces as electromagnetism and too small to be affected by tidal gravitational forces) is independent of its internal structure and composition.” —— Clifford M. Will, 2014, Living Reviews Relativity, 17, 4

5


Einstein’s happiest idea

Einstein’s Equivalence Principle (EEP):

1、WEP valid； 2、Local Lorentz Invariance（LLI）： The outcome of any local non-gravitational experiment is independent of the velocity of the freely-falling reference frame in which it is performed. 3、Local Position Invariance（LPI）： The outcome of any local non-gravitational experiment is independent of where and when in the universe it is performed.

Will, 2014, Living Reviews Relativity, 17, 4 6


Parametrized Post Newtonian formalism (PPN)：



PPN parameters：



SN1987A： Milky Way version of the Pisa tower experiment

Where：LMC，distance ~ 50 kpc When：（1）neutrino burst：Feb., 23.316UT, 1987 Kamioka、IMB （2）optical： Feb., 23.443UT, 1987 ~ 3 hrs later than neutrino burst

Masatoshi Koshiba Raymond Davis Jr. Riccardo Giacconi The Nobel Prize in Physics 2002 was divided, one half jointly to Raymond Davis Jr. and Masatoshi Koshiba "for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos" and the other half to Riccardo Giacconi "for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources“.

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Tests of post-Newtonian gravity in the Milky Way

(Courtesy by Longo, 1988, PRL)

Shapiro delay：

（1）d~50 kpc （2）b=12 kpc （3）MW’s U(r)=-GM/r （mass of LMC is <5% of MW）

Longo, 1988, PRL；Krauss & Tremaine 1988, PRL 11



Longo, 1988, PRL；Krauss & Tremaine 1988, PRL

（1）time delay between 2 neutrinos（7.5MeV, 40MeV）<10 s

（1）time delay between photons and neutrinos（<6 hours）

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(Courtesy by Longo, 1988, PRL)

13

b

Gao, Wu, Meszaros, 2015, ApJ

Testing WEP with cosmic transients

IceCube neutrinos GWB Blazar GRB

Gao, Wu, & Meszaros, P., 2015, ApJ, 810, 121

Constraint on the PPN gamma with GRBs： (1) GRB 090510 (z=0.90):

(2) GRB 080319B (z=0.94): (3) Hipparcos (Froeschle et al. 1997)： (1)-(3), eV – MeV – GeV,

Testing WEP with GRB eV–MeV–GeV photons

Abdo et al., 2009, Nature

GRB 090510 GRB 080319B

14


Racusin et al., 2008, Nature

Wei, Wang, Gao, Wu*, 2016, ApJL

Constraint on the PPN gamma with blazars： (1) Mrk 421 (z=0.031):

(2) Mrk 501 (z=0.034):

(3) PKS 2155-304 (z=0.117)

(4) GRB (Gao, Wu & Meszaros et al. 2015)：

eV – MeV – GeV，

therefore，from (1)-(4), eV – MeV – GeV – TeV,

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Mrk 421

Furniss et al., 2015, ApJ


Testing WEP with blazar keV–TeV photons

Abbott et al. 2016, PRL, 116, 061102

1. Merger phase t(150 Hz)- t(30 Hz) ~ 0.2 s 2. Ringdown phase t(100 Hz)- t(200 Hz) ~ ms

16

Wu,Gao,Wei,Meszaros,Zhang,Dai, Zhang,Zhu,2016,PRD,94,024061


GW150914: first GW event

Testing WEP with gravitational waves

1. First FRB（Lorimer 2007）

FRB 010724 Lorimer Burst 2. More FRBs (Keane et al. 2011; Thornton et

al. 2013; Burke-Spolaor & Bannister 2014; Spitler et al. 2014; Ravi et al. 2015, etc.)

3. Event rate： ~several x 1,000 FRBs/sky/day

Lorimer et al., 2007, Science 17

Discovery of Fast Radio Bursts

Thorton, et al., 2013, Science (1.2GHz-1.5GHz)< 1 s

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Dispersion Measures (DM)

Advantages of FRBs in WEP tests

smaller difference in arrival times !!!

GRB 101011A GRB 100704A

6.2 sigma confidence level @ t=1076 s 6.6 sigma confidence level @ t=524 s

Bannister et al. 2012, ApJ：

z = (0.130, 0.246) for GRB 100704A

Deng & Zhang (2014) estimated the redshift of the two GRBs with DM:

z = (0.554, 0.687) for GRB 101011A

Possible associations of FRBs with GRBs

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FRB 131104: gamma-ray counterpart?

DeLaunay et al. (2016, ApJL): association probability: 3.2σ confidence

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FRB position

GRT position

FRB+GRT position

Possible associations of FRBs with GRBs

Keane et al., 2016, Nature, 530, 453 21

radio afterglow & host galaxy z = 0.492? radio flares from host AGN? (Williams & Berger, 2016, etc.) coincidence of this FRB and radio flares is quite low (Li & Zhang, 2016) cosmic comb model (Zhang 2017)

FRB 150418: first afterglow and redshift ?

Chatterjee et al., 2017, Nature, 541, 58; Tendulkar et al., 2017, ApJL

22

FRB 121102: first confirmed host galaxy and redshift

Gemini: Gillet (GMOS)

FRB 121102 (repeating): z=0.193 at least some FRBs are at cosmological distances

Constraint on the PPN gamma with FRBs： (1) FRB 110220 (z~0.81):

(2) FRB/GRB 101011A (z=0.246): (3) FRB/GRB 100704A (z=0.166)

FRBs vs. GRBs : 2 orders of magnitude better (Milky Way potential)

Testing WEP with FRBs

Wei, Gao, Wu, & Meszaros, P., 2015, PRL

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Uncertainty of FRB distance will NOT affect the constraint too much:

Red (from top to bottom): Δt(DM)=0.001Δt(obs) Δt(DM)=0.999Δt(obs)

Blue(from top to bottom): d=1Mpc, 0.5z, 2z, 3z


Tingay & Kaplan, 2016, ApJL, 820, 2, L31

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FRB 150418 vs. FRB 110220 (Wei et al. 2015): ~ 1 order of magnitude better Considering the span of the energies, introducing the constraint on instead

of , where is the ratio of high and low energies used in the limit.

Constraint on the PPN gamma by LSS： (1) FRB 110220 (z~0.81):

(2) FRB 150418 (z=0.492 ?):

(3) GRB 090510 (z=0.903): (4) GRB 080319B (z=0.937):

Large-scale structure vs. Milky Way potential : ~ 4 orders of magnitude better


Nusser, 2016, ApJL, 821, L2

25 see also Zhang, Shuang-Nan, arXiv:1601.04558

Testing WEP with Crab pulsar giant pulse

Hankins & Eilek, 2007, ApJ

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Testing WEP with Crab pulsar giant pulse

Yang & Zhang, 2016, PRD (rapid communications), 94, 101501 27

most stringent limit with MK




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Outline

Ultimate upper limit（uncertainty principle）: Upper limit adopted by the Particle Data Group: Olive et al. (2014): Most stringent limit: Chibisov (1976) : analysis of the mechanical stability of the magnetized

gas, however, depends on many assumptions.

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Maxwell’s equations/Einstein special relativity have a basic assumption: all electromagnetic radiation travels in vacuum at the constant speed c

The photon mass should be strictly zero Otherwise, the Maxwell’s equations changed to Proca equations

The most direct and model-independent method: Measuring the frequency dependence of the velocity of light

Upper limits on the photon mass

• Magnetic fields of Jupiter and Earth：

（Davis-jr et al. 1975,PRL；Fischbach et al.1994,PRL）

• Solar wind：

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Photon mass limit by the stability of the magnetized gas

adopted by

Particle Data

Group

• Magnetic fields of Jupiter and Earth：

（Davis-jr et al. 1975,PRL；Fischbach et al.1994,PRL）

• Solar wind：

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Photon mass limit by the stability of the magnetized gas

Massive photons have been evoked for (i.e., Retino et al., 2016, Astroparticle Physics,82, 49) (1) dark matter, (2) inflation, (3) charge conservation, (4) magnetic monopoles, (5) Higgs boson, etc., and in (a) applied physics, (b) superconductors, (c) “light shining through walls” experiments.

Physical Review D, 93(8)，id.083012

Massive photons and fundamental physics

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If the photon has a non-zero rest mass：

Dispersion of the group speed of photons in vacuum：

where，

If A can be constrained by observations， then the mass of photon is：

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Velocity dispersion from the nonzero photon mass

observer z=0

higher frequency photon

lower frequency photon

redshift z

If the source is not at cosmological distance

If the source is cosmological，the arrival time difference

lower frequency、 longer distance、 shorter arrival time

smaller A more stringent constraint

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The time delay induced by the nonzero photon mass

Tu, Luo, Gillies, 2005, Rep. Prog. Phys 35

Astronomical Constraints on the photon mass in History

36

Measurement of the frequency dependence of the velocity of light

（Warner & Nather,1969,Nature）

（Lovell et al. 1964,Nature）

（Schaerfer. 1999, PRL）

arrival time of optical and radio emission

dispersion in the arrival time of optical wavelengths of 0.35 and 0.55 μm

time delay between radio and the gamma-ray emissions

Astronomical Constraints on the photon mass in History

• radio – gamma-ray time delay, same as Schaefer (1999)；GRB 050416A

• different afterglow peak times between two radio frequency： – peak times fitted by models：GRB 991208

– peak times observed：GRB 000301C

• peak time difference excluding the astrophysical

“intrinsic” delay：δt is reduced but model (jet+synchrotron) dependent, e.g., GRB 980703

37 Zhang, Chai, Zou, & Wu, 2016, JHEAp, 11, 20

Upper limits on the photon mass with more GRBs

38

2-24

3

10410.2)(t ν

ν∝

×⋅

=∆ −

− pccmDMDM

degeneracy with the effect by the nonzero photon mass

Dispersion by plasma effect

Keane, et al., 2016, Nature, 530, 453

39

(1) difference in arrival times between 1.5 GHz and 1.2 GHz: Δt < 0.8 s； (2) Host galaxy redshift z=0.492 (?) FRB 121102 with host galaxy and z=0.193 measured (Tendulkar et al. 2017)



（Schaerfer. 1999, PRL）

（Wu, Zhang, Gao, Wei, Zou, Lei, Zhang, Dai, Meszaros, 2016, ApJL）

Cosmological origin:

Extragalactic origin: (d = 1 Mpc)

Upper limits on the photon mass with FRB 150418

40

Bonetti, et al., 2016, PLB （arxiv:1602.09135）


41 Bonetti, et al., arxiv:1701.03097


FRB 121102: first well localized FRB (Chatterjee et al. 2017, Nature) with redshift measurement of z=0.192 (Tendulkar et al. 2017, ApJL)

total DM

extragalactic DM

host galaxy+circumburst DM

1.77x10^(-47) g

Milky Way DM

IGM DM

42

The LMC and SMC are the only galaxies other than our own that have detectable pulsars:

LMC (~50 kpc): 21 radio pulsars

SMC (~60 kpc): 5 radio pulsars

(McCulloch et al. 1983; McConnell et al. 1991; Crawford et al. 2001; Manchester et al. 2006; and Ridley et al. 2013)

lower frequency longer distance shorter arrival time

more stringent constraint on the photon mass

Compared to the Crab pulsar (~2 kpc), radio pulsars in the LMC and SMC have two advantages:

1. Radio emission 2. Longer distance

Radio Pulsars in the Magellanic Clouds

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……

minimizing C1 = DM / DIST

Photon Mass Limits from Radio Pulsars

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(1) LMC : PSR J0451-67 L=49.7 kpc, DM=45 pc/cm^2

(2) SMC: PSR J0045-7042 L=59.7 kpc, DM=70 pc/cm^2

Manchester et al. 2006, ApJ, 649, 235

Wei, Zhang, Zhang & Wu, 2017,RAA, in press, arXiv:1608.07675

Photon Mass Limits from Radio Pulsars

45



（Schaefer. 1999, PRL）

（Wei et al.，2017, RAA）

extragalactic origin（d=1 Mpc）

（Wu, Zhang, Gao, Wei, Zou, Lei, Zhang, Dai & Meszaros, 2016, ApJL,）

Photon Mass Limits from GRBs/FRBs/pulsars

cosmological origin ( z=0.5 )




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Outline

Testing EEP with GRB photons eV – MeV – GeV, Δγ<10^(-3)

Testing EEP with FRB photons GHz, Δγ<10^(-7)

Testing EEP with Crab giant pulse photons GHz, Δγ<10^(-15)

Testing EEP with TeV blazar photons keV–TeV, Δγ<10^(-3) subTeV–TeV, Δγ<10^(-6)

Testing EEP with GW events 30 – 200 Hz gravitons, Δγ<10^(-9)

The constraint will be improved by 2-4 orders of magnitude with large-scale structure fluctuation /Laniakea supercluster of galaxies potential 47

Summary: WEP tests

Constraints by the dispersion (time of flight) method: photon mass limit by GRBs/radio pulsars mγ< ~10^(-45) g

photon mass limit by FRBs mγ < ~10^(-47) g one of most direct and conservative constraints.

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Summary: photon mass constraints

The CHIME (Canadian Hydrogen Intensity Mapping Experiment) radio telescope: four fixed 20- by 100-m semi cylinders

400-800 MHz

FoV: 200 square degrees

Operate in the latter half of 2017 could detect dozens of FRBs per day!

Kaspi, V. M., 2016, Science

Prospect: FRB observations

Radio facilities: Parkes, Arecibo, GBT, etc. CHIME, FAST, Tianma, SKA (ASKAP), etc.

More diverse FRB features are expected to be discovered: pulse duration: shorter (sub millisecond) or longer?

repetition: double-peaked? triple-peaked? etc.

counterparts: EM signals and afterglows?

associations: GRBs, GWs, neutrinos, pulsar giant pulses? Looking at the history of the GRB field, nature (the Universe) is more unexpected than we thought

Prospect: FRB observations

Wu,Gao,Wei,Meszaros,Zhang,Dai, Zhang,Zhu,2016,PRD,94,024061

Δγ =γ(GW)-γ(photon)

51

Prospect: WEP tests with FRBs

Multi-messenger Astronomy

WEP tests can use different species of particle (different internal structure and composition)

EM: from radio to gamma-ray GW: several 10 – 1000 Hz Neutrinos: MeV - TeV

FRBs-GRBs-GWs (macronovae) triple events?

FRBs with neutrinos, pulsar giant pulses?

The upper limit on the photon mass could be improved if a sample of FRBs with redshift measured time delay by plasma effect due to IGM/host can be extracted

lower frequency FRBs are discovered photon mass upper limit is proportional to frequency

Prospect: photon mass limit

Thank you

Back up

Tests of γ：I. The deflection of light

Will, 2014, Living Reviews Relativity, 17, 4

GR effect

54

Tests of post-Newtonian gravity in the Solar system

Will, 2014, Living Reviews Relativity, 17, 4

A radar signal from Earth to the Source, then back to Earth

（a planet or satellite）

The time delay by the Sun’s gravity：

55


Tests of γ：II. The (Shapiro) time delay of light

VLBI: quasars, 3C279 Hipparcos: optical starlight Viking: Mars lander Cassini: Saturn



Tests of γ：Results

• 广义相对论/电磁理论基本假设若不为零，麦克斯韦方程->Proca方程

• 光子质量限定方法： –实验室检验（安培定律、库伦定律）： Tu et al.2006： –天体物理检验：

• 等离子体波动（Ryutov 2007,PlasPhysControlFusion）： • 多波段光子时间延迟(Schaefer 1999,PRL)： • 引力透镜（Accioly & Pazszko 2004,PRD）： • 气体稳定性(Chibisov 1976,SovPhysUsp)：

• 国际粒子数据组PDG采用的上限: • 终极下限（测不准原理，时间不确定取宇宙时标）:

57

光子静止质量已有限制

= 1.783x10^-51 g

frbs as probes of fundamental physicsaspen17.phys.wvu.edu/wu.pdf · 2017-02-18 · einstein’s...

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