Fast Radio Burst Progenitor Models

Tony Piro Carnegie Observatories

Fast Radio Bursts: New Probes of Fundamental Physics and Cosmology, February 13, 2017

What could FRBs be? • Neutron stars collapsing to black holes, ejecting “magnetic hair” (Falcke & Rezzolla ‘14; Zhang ’14) • Merger of charged black holes (Zhang ‘16; Liu et al. ’16; Liebling & Panenzuela ‘16) • Magnetospheric activity during neutron star mergers (Totani ‘13) • Unipolar inductor in neutron star mergers (Hansen & Lyutikov ‘01; Piro ‘12; Wang et al. ‘16) • White dwarf mergers (Kashiyama et al. ‘13) • Pulses from young neutron stars (Cordes & Wasserman ’15; Connor et al. ‘15; Lyutikov et al. ’16; Popov & Pshirkov ’16; Kashiyama & Murase ‘17) • Magnetars (Popov et al. ’07; Kulkarni et al. ‘14; Lyubarsky ‘14; Katz ’15; Pen & Connor ‘15) • Sparks from cosmic strings (Vachaspati ‘08; Yu et al. ‘14) • Evaporating primordial black holes (Rees ’77; Keane et al. ‘12) • White holes (Barrau et al. ’14) • Flaring stars (Loeb et al. ‘13; Maoz et al. ‘15) • Axion stars (Tkachev ‘15; Iwazaki ‘15) • Asteroids/comets falling onto neutron stars (Geng & Huang ‘15) • Quark novae (Chand et al. ‘15) • Dark matter-induced collapse of neutron stars (Fuller & Ott ‘15) • Higgs portals to pulsar collapse (Bramante & Elahi ’15) • Planets interacting with a pulsar wind (Mottez & Zarka ’15) • Black hole superradiance (Conlon & Herdeiro ‘17) • Extragalactic light sails (Lingam & Loeb ‘17) • Schwinger instability in young magnetars (Lieu ‘17) • Neutron star-white dwarf binaries (Gu et al. ’16)

Repeating FRB 121102

• Spitler et al. (2016)

• Proves in at least one case FRBs are not cataclysmic events

Non-Cataclysmic FRB Progenitors 1. Radio emission accompanying magnetar giant flares (Lyutikov ‘02; Popov & Postnov ‘10; Keane et al. ‘12; Pen & Connor ’15; Kulkarni et al. ‘14; Lyubarsky ‘14; Katz ’15)

2. Giant pulse analogues emitted by young pulsars (Cordes & Wasserman ‘16; Connor et al. ‘16; Lyutikov et al. ’16; Popov & Pshirkov ’16; Kashiyama & Murase ‘17)

(Apologies if there are any missing references!)

Comparison to the SN rate Connor, Sievers, and Pen (2016)

Can DM be from the source? • Nearly quadratic dispersion implies plasma cannot be too dense (Katz 2016)

• Thus dispersing region must be sufficiently large

• Dispersing material must also be optically thin (Luan & Goldreich 2014; Katz 2016)

• Potentially stricter, but depends on temperature

• Consistent with supernova remnant? (Connor et al. ’16; Lyutikov et al. 16)

ne <2

3|� ↵� 2|me!2

4⇡e2⇡ 5⇥ 107cm�3

RDM = DM/ne > 1013 � 1014cm

ne < 104(T/104K)3/2(DM/103pc cm�3)�1cm�3

Localization of FRB 121102 (Chatterjee et al. ‘17; Tendulkar et al. ‘17)

106 107 108 109 1010 1011

Stellar mass (MO • )

10-3

10-2

10-1

100

101

Star

-form

atio

n ra

te (M

O • yr-1

)

sSFR =

10-8 yr

-1

10-9 yr

-1

10-10 yr

-1

10-11 yr

-1

10uhf

Type I/RType IILVL(area ~ SFR)

Host of FRB 121102: SFR (Tendulkar et al. ’17; Metzger, Berger & Margalit ‘17; Perley et al. ‘16)

Host of FRB 121102: Metallicity

106 107 108 109 1010 1011

Stellar mass (MO • )

7.5

8.0

8.5

9.0

9.5

12+l

og10

[O/H

]

10uhf

Type I/RType II

(pale if from M-Z)

LVL(area ~ SFR)

(Tendulkar et al. ’17; Metzger, Berger & Margalit ‘17; Perley et al. ‘16)

Supernova remnant

Supernova Remnant Evolution Piro (2016)

Total DM including SNR • Assuming we can subtract out the MW component, the remaining DM is

DMtotal(t) = DMSNR(t) + DMHost +DMIGM

�DMtotal

⇡ dDMSNR

dt�t ⇡ 2⇥ 105

✓M

M�

◆f�t

yr

v29

t3yr

pc cm�3

• How do we eliminate these pesky unknown constants?

Use the change in the DM!

DMSNR(t) =3Mf

4⇡(vt)2= 9.5⇥ 104

✓M

M�

◆f

v29t2yr

pc cm�3

Comparing to FRB 121102 • Over the ~4 years these bursts have repeated, the DM is the same within a few pc/cm3

• So not crazy. Can we keep checking the DM? How accurately can DM be measured?

• We also know that the total DM < 225 pc/cm3 (once MW and IGM is subtracted, Tendulkar et al. ‘17), which limits the mass to

t & 60

✓M

M�

◆1/3 ✓ f

v29

�tyr4

◆1/3

yrs

M . 8v29f

✓tyr60

◆2

M�

Is there sufficient rotational energy?

• For a spinning down dipole, the spindown time and available energy (in ~1 ms) are

• If the neutron star spins down too fast, there won’t be enough rotational energy when remnant becomes optically thin

Katz (2016)

�E =(BR3)2⌦4

c3�t ⇡ 1040B2

12P�4ms erg

tsd ⇡ Ic3

2(BR3)2⌦2⇡ 10B�2

12 P 2msyrs

Is there sufficient rotational energy?

• Favors quickly spinning (<2 ms) neutron stars with moderate B-field (<5x1011 G)

Piro (2016)

What about FRBs 110220 &140514? • Very different DMs:

FRB 110220, DM = 944.4 pc/cm3

FRB 140514, DM = 562.7 pc/cm3

• Similar positions within 9 arcmin:

FRB 110220, RA=22h34m38s, DEC= -12°24’

FRB 140514, RA=22h34m06s, DEC= -12°18’

• Could these be the same source? Maoz et al. (2016) conclude with 99% confidence that this is from the same repeating source based on location, FRB rate, and sky coverage

Assuming FRB 110220 &140514 are the same source

• Over the 3.2 years, DM has changed by 381.7 pc/cm3

t ⇡ 12

✓M

M�

◆1/3 ✓ f

v29

◆1/3

yrs

DMSNR(t+3.2)2 +DMstu↵

DMSNRt2 +DMstu↵

=562.7

944.4= 0.596

t2

(t+ 3.2)2< 0.596

t < 10.8 yrs M < 1.2(v29/f)M�

• But we can even get a more model independent constraint!

−20 0 20 40 60 80 100Phase from peak [days]

−21

−20

−19

−18

−17

−16

−15

−14

−13

Abso

lute

mag

nit

ude

1993J

1994I

1996cb

1998bw

1999dn

1999ex

2002ap

2003bg

2003jd

2004aw

2004dk

2004dn

2004fe

2004ff

2004gq

2005az

2005bf

2005hg

2005kz

2005mf

2006T

2006aj

2006el

2006ep

2007C

2007Y

2007gr

2007ru

2007uy

2008D

2008ax

2009bb

2009jf

2010bh

2011bm

2011dh

2011hs

iPTF13bvn

41.0

41.5

42.0

42.5

43.0

43.5

log 1

0Lum

inos

ity

[erg

/s]

Stripped Envelope SN Light Curves Lyman et al. (2016)

tp ⇠ (M/vc)1/2

v ⇠ (2E/M)1/2

Stripped Envelope SN Ejecta Masses

1 10EK [1051 ergs]

1

10

Mej[M

⊙]

IIb (9)Ib (13)Ic (8)Ic-BL (8)

Lyman et al. (2016)

M < 1.1(E51/f)1/2M�Type IIP SNe

Pejcha & Prieto (2015)

f = 0.1

Neutron Stars

FRBs were 39 arcmin away :(

(Hakobyan et al. ‘08)

December 4, 2001

Persistent radio source! Chatterjee et al. (2017)

Young Magnetar FRB Model Metzger, Berger & Margalit ’17

Synchrotron from either SN shock or pulsar nebula

Argues for long term monitoring of persistent radio source.

Don’t forget cataclysmic scenarios! • Neutron stars collapsing to black holes, ejecting “magnetic hair” (Falcke & Rezzolla ‘13; Zhang ’14)

• Merger of charged black holes (Zhang ‘16; Liu et al. ’16; Liebling & Panenzuela ‘16)

• Magnetospheric activity during neutron star mergers (Totani ‘13)

• Unipolar inductor in neutron star mergers (Piro ‘12; Wang et al. ‘16)

• White dwarf mergers (Kashiyama et al. ’13)

Probably cannot produce the majority of FRBs, but we should keep them in mind

“Blitzar” NS collapsing to BH Falcke & Rezzolla (2014); Zhang (2014)

• NS accretes and spun up above usual maximum mass

• When spun down (magnetic braking?) NS collapses to BH, expelling B-field, producing FRB

• Lots of potential scenarios (NS mergers, fast spinning SNe, HMXBs, AIC)

Many potential E&M and GW counterparts, but how will we uniquely know it’s a blitzar?

Unipolar inductor during NS mergers Goldreich & Lynden-Bell ‘69; Hansen & Lyutikov ’01;

Lai ’12; Wang et al. ‘16

Piro (2012)

Unipolar inductor emission • Take ~1% of dissipation and put into radio as curvature radiation (Mingarelli, Levan, & Lazio ‘15)

• Large currents expected to repeatedly break circuit (Lai ‘12)

• Treating as an LR circuit (Piro, unpublished) flaring timescale is

• Is the pair plasma surrounding the merger too dense for radio propagation? (Metzger & Zivancev 2016)

tLR

⇠ a

c

✓R

tot

4⇡/c

◆�1

E&M counterparts to NS mergers Metzger & Berger (2012) • GRB and afterglow

• Shattering of the NS crusts (Tsang et al. ‘12)

• Kilonova (~1041 erg/s infrared to optical transient)

• Pulsar wind nebulae in radio (Piro & Kulkarni ‘13)

• Radio from ejecta-ISM shock (Nakar & Piran ‘11)

Relative timing of counterparts to FRB also important

Summary and Conclusion • Repeating FRB argues for non-cataclysmic scenario unless strong evidence for multiple FRB progenitors

• Young neutron stars are attractive for producing rate and DM

• Rotational powering requires modest B-fields (<1012 G) short P

• Host galaxy, DM constraints, suggest connection with stripped envelope supernovae

• Are FRBs 110220 and 140514 the same source? A 3rd burst from this location would provide amazing constraints

• Cataclysmic scenarios are likely to have E&M and/or GW counterparts but probably cannot produce all FRBs

Questions • How well can DMs be measured to look for changes? What are the limiting factors?

• How long do we have to stare at the location of FRBs 110220 and 140514 to rule out repeated bursts?

• What is the best strategy (cadence, targets, etc) for finding repeating bursts?

• When looking for E&M counterparts, are we searching parameter space to actually rule out models?

• Many of the counterparts (E&M, GW, etc) require nearby FRBs to be seen. Are we able to recover low DM FRBs?