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) 2 2 me! 7 3 n < ↵ 2 5 10 cm− e 3|− − | 4⇡e2 ⇡ ⇥ • Thus dispersing region must be sufficiently large R =DM/n > 1013 1014cm DM e − • Dispersing material must also be optically thin (Luan & Goldreich 2014; Katz 2016) 4 4 3/2 3 3 1 3 ne < 10 (T/10 K) (DM/10 pc cm− )− cm− • Potentially stricter, but depends on temperature • Consistent with supernova remnant? (Connor et al. ’16; Lyutikov et al. 16) Localization of FRB 121102 (Chatterjee et al. ‘17; Tendulkar et al. ‘17) Host of FRB 121102: SFR (Tendulkar et al. ’17; Metzger, Berger & Margalit ‘17; Perley et al. ‘16) 10uhf 101 ) -1 yr • O 100 -1 10 -1 -8 yr sSFR = 10 Star-formation rate (M 10-2 Type I/R Type II -1 -1 LVL -1 (area ~ SFR) yr yr -9 yr -10 -11 10-3 10 10 10 106 107 108 109 1010 1011 Stellar mass (MO • ) Host of FRB 121102: Metallicity (Tendulkar et al. ’17; Metzger, Berger & Margalit ‘17; Perley et al. ‘16) 9.5 10uhf 9.0 8.5 [O/H] 10 12+log 8.0 Type I/R Type II 7.5 (pale if from M-Z) LVL (area ~ SFR) 106 107 108 109 1010 1011 Stellar mass (MO • ) 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 3Mf 4 M f 3 DMSNR(t)= 2 =9.5 10 2 2 pc cm− 4⇡(vt) ⇥ M v9tyr ✓ ◆ • How do we eliminate these pesky unknown constants? Use the change in the DM! dDMSNR 5 M f∆tyr 3 ∆DMtotal ∆t 2 10 2 3 pc cm− ⇡ dt ⇡ ⇥ M v9tyr ✓ ◆ Comparing to FRB 121102 • Over the ~4 years these bursts have repeated, the DM is the same within a few pc/cm3 1/3 1/3 M f ∆tyr t & 60 2 yrs M v9 4 ✓ ◆ ✓ ◆ • 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 2 2 v9 tyr M . 8 M f 60 ✓ ◆ Is there sufficient rotational energy? Katz (2016) • For a spinning down dipole, the spindown time and available energy (in ~1 ms) are 3 Ic 2 2 t 10B− P yrs sd ⇡ 2(BR3)2⌦2 ⇡ 12 ms 3 2 4 (BR ) ⌦ 40 2 4 ∆E = ∆t 10 B P − erg c3 ⇡ 12 ms • If the neutron star spins down too fast, there won’t be enough rotational energy when remnant becomes optically thin Is there sufficient rotational energy? Piro (2016) • Favors quickly spinning (<2 ms) neutron stars with moderate B-field (<5x1011 G) 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 M 1/3 f 1/3 t 12 2 yrs ⇡ M v9 ✓ ◆ ✓ ◆ • But we can even get a more model independent constraint! DMSNR 2 +DMstu↵ 562.7 (t+3.2) = =0.596 DMSNR 944.4 t2 +DMstu↵ t2 < 0.596 (t +3.2)2 2 t<10.8yrs M<1.2(v9/f)M Stripped Envelope SN Light Curves Lyman et al. (2016) 21 1993J 2003jd 2005bf 2007C 2009bb − 1994I 2004aw 2005hg 2007Y 2009jf 1996cb 2004dk 2005kz 2007gr 2010bh 1998bw 2004dn 2005mf 2007ru 2011bm 20 1999dn 2004fe 2006T 2007uy 2011dh 43.5 − 1999ex 2004ff 2006aj 2008D 2011hs 2002ap 2004gq 2006el 2008ax iPTF13bvn 2003bg 2005az 2006ep 19 − 43.0 1/2 18 tp (M/vc) − ⇠ 42.5 17 1/2 − v (2E/M) 42.0 16 ⇠ Luminosity [erg/s] − 10 Absolute magnitude 15 41.5 log − 14 − 41.0 13 − 20 020406080100 − Phase from peak [days] Stripped Envelope SN Ejecta Masses Lyman et al. (2016) 1/2 Type IIP SNe M<1.1(E51/f) M IIb (9) Ib (13) f =0.1 Pejcha10 Ic (8)& PrietoIc-BL (2015) (8) ] ⊙ [M ej M 1 110 51 EK [10 ergs] (HakobyanNeutron et al. ‘08) Stars December 4, 2001 FRBs were 39 arcmin away :( 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 1 a − t Rtot LR ⇠ c 4⇡/c ✓ ◆ • Is the pair plasma surrounding the merger too dense for radio propagation? (Metzger & Zivancev 2016) 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? .