Search for Neutrino Emission from Fast Radio Bursts with IceCube

Transcription

1 Search for Neutrino Emission from Fast Radio Bursts with IceCube Donglian Xu Samuel Fahey, Justin Vandenbroucke and Ali Kheirandish for the IceCube Collaboration TeV Particle Astrophysics (TeVPA) 2017 August 7-11, 2017 Columbus, Ohio

2 Fast Radio Bursts - Discovery in Lorimer et al.,science 318 (5851): t delay = e 2 2 m e c 3 DM w 2 = s DM w 2 DM = Z n e dl = 375 ± 1cm 3 pc very compact extragalactic? SMC J (125) J (76) J (70) J (105)! t width =4.6ms ( 1.4GHz ) 4.8±0.4 Figure 2: Frequency evolution and integrated pulse shape of the radio burst. The survey data, collected on 2001 August 24, are shown here as a two-dimensional waterfall plot of intensity as a function of radio frequency versus time. The dispersion is clearly seen as a quadratic sweep across the frequency Z band, with broadening towards lower frequencies. From a measurement of the pulse delay across the receiver band using standard pulsar timing techniques, we determine the DM to be 375±1 dti cm 3! pc. ' The two 150 white± lines50jy separated by ms 15 that 1.4 boundghz the pulse show the expected behavior for the cold-plasma dispersion law assuming a DM of 375 cm 3 pc. The horizontal line at 1.34 GHz is an artifact in the data caused by a malfunctioning frequency channel. This plot is for one of the offset beams in which the digitizers were not saturated. By splitting the data into four frequency sub-bands we have measured both the half-power pulse width and flux density spectrum over the observing bandwidth. Accounting for pulse broadening due to known instrumental effects, we determine afrequencyscalingrelationship for the observed width W =4.6ms(f/1.4GHz) 4.8±0.4,wheref is the observing frequency. Apower-lawfittothemeanfluxdensitiesobtainedineachsub-band yields a spectral index of 4 ± 1. Inset:thetotal-powersignalafteradispersivedelaycorrection assuming a DM of 375 cm 3 pc and a reference frequency of GHz. The time axis on theinnerfigurealsospans the range ms. 12 A total of ~23 FRBs detected to date. Estimated FRB event rate is ~1,000/day J (205) Galactic DM: 25cm 3 pc Figure 1: Multi-wavelength image of the field surrounding the burst. Thegray contours respectively show Hα and HI emission associated with the SMC (8, 9). Cro the positionsofthe fiveknown radio pulsars in thesmc and are annotated with their

3 Fast Radio Bursts Emitting Neutrinos? 3 Blitzar Cataclysmic [H. Falcke and L. Rezzolla, A&A 562, A137 (2014)] Binary neutron star merger [T. Totani, Pub. Astron. Soc. Jpn. 65, L12 (2013)] Evaporating primordial black holes [Halzen et al., PRD 1995] MeV neutrinos Magnetar/SGRs hyperflares [S. B. Popov and K. A. Postnov, arxiv: ] [Halzen et al. (2005) astro-ph/ ] TeV neutrinos? this work No concrete neutrino production models yet

4 Goal: detecting TeV-PeV astrophysical neutrinos Construction completed in December 2010 IceCube Detector Donglian Xu High-E Neutrinos from Fast Radio Bursts Jan. 29,

5 Martin Rongen Martin Rongen Lake Baikal Lake Baikal September 2016 September 2016 Neutrino Signatures in IceCube vent signatures vent signatures (1) Track: charged current νμ <1o Angular resolution Event signatures Charged current νμ ν Charged current Factor ~ 2 energy resolution μ Factor ~2~2 energy resolution Factor energy resolution <1 angular resolution <1 angular resolution 2013 data (2) Cascade / Shower: all neutral current, charged current νe, low-e charged current ντ 10o Angular resolution above100 TeV 15% energy resolution on deposited energy 5 Neutral current, Charged current νe Neutral current, Charged current νe 15% resolution on the 15% resolution deposited energy on the deposited energy 10 angular resolution (above 100 TeV) 10 angular resolution (above 100 TeV) data Double Bang ντ high degeneracy Double Bang ν τ Vertex seperation ~50m/PeV Vertex seperation ~50m/PeV Not yet observed IceCube has detected a diffuse astrophysical neutrino flux, Not yet observed but no TeV neutrino point sources have been identified to4date. 4

6 All Sky Fast Radio Bursts with IceCube Coverage 6 Burst times cover IceCube data taking seasons from 2010 to 2015 (6 years) A total of 29 FRBs (11 unique locations). Repeated bursts are treated as unique bursts in space & time FRB repeated 26 times (17 times within our data sample) North South

7 Event Samples & Background Modeling 7 North (DEC >= -5 o ) South (DEC < -5 o ) Background PDF derived from off-time data 842,597 events (collected from ) 379,261 events (collected from ) dominated by atmospheric neutrinos dominated by atmospheric muons A total of 1.2 million events in 6 years 2015 ApJ 805 L5 arxiv:

8 Analysis Method: Unbinned Maximum Likelihood 8 The likelihood for observing N events with properties expected number of events is: {x i } for (n s + n b ) L(N,{x i }; n s + n b )= (n s + n b ) N N! exp( (n s + n b )) NY i=1 P (x i ) The normalized probability of observing event i is P (x i ): P (x i )= n ss(x i )+n b B(x i ) n s + n b T := ln L(N,{x i}; n s + n b ) L 0 (N,{x i }; n b ) S i = S time (t i ) S space (~x i ) B i = B time (t i ) B space (~x i ) temporal + spatial T := ˆn s + NX i=1 ln(1 + ˆn s S i <n b >B i )

9 Search Strategy 9 Stacking Distributed fluence test Source 1 Source 2 Source 3 declination STACKING r.a Max-burst Single bright neutrino source test declination Source 3 Source 1 Source 2 r.a Model independent Expanding time windows centered at burst times 25 time windows from 10 ms to 2 days, expanding as 2 i x10 ms (i =0,, 24)

10 Sensitivity & Discovery Potentials - Stacking 10 North South E 2 sensitivity E 2 5 E 2 sensitivity E 2 5 E 2.5 sensitivity E 3 sensitivity E E 3 5 E 2.5 sensitivity E 3 sensitivity E E 3 5 E TeV (GeV cm 2 ) IceCube Preliminary E TeV (GeV cm 2 ) IceCube Preliminary T(s) T(s) 25 time windows from 10 ms to 2 days, expanding as 2 i x10 ms (i =0,, 24) One coincident event can be discovery in the short time windows

11 Sensitivity & Discovery Potentials - Max-burst 11 North South E TeV (GeV cm 2 ) E 2 sensitivity E 2.5 sensitivity E 3 sensitivity IceCube Preliminary E 2 5 E E 3 5 E TeV (GeV cm 2 ) 10 0 E 2 sensitivity E 2.5 sensitivity E 3 sensitivity IceCube Preliminary E 2 5 E E T(s) T(s) 25 time windows from 10 ms to 2 days, expanding as 2 i x10 ms (i =0,, 24) One coincident event can be discovery in the short time windows

12 Results - Most Significant Bursts & Events 12 North Max-burst Most optimal time window: T = s South Max-burst Most optimal time window: T = s

13 Results - Upper Limits 13 North Stacking North Max-burst E 2 sensitivity E 2.5 sensitivity E 2 upper limit E 2.5 upper limit E 2 sensitivity E 2.5 sensitivity E 2 upper limit E 2.5 upper limit E 3 sensitivity E 3 upper limit E 3 sensitivity E 3 upper limit E TeV (GeV cm 2 ) IceCube Preliminary T = s E TeV (GeV cm 2 ) IceCube Preliminary T = s T(s) T(s)

14 Results - Upper Limits 14 South Stacking South Max-burst E 2 sensitivity E 2 upper limit E 2 sensitivity E 2 upper limit E 2.5 sensitivity E 2.5 upper limit E 2.5 sensitivity E 2.5 upper limit E 3 sensitivity E 3 upper limit E 3 sensitivity E 3 upper limit E TeV (GeV cm 2 ) 10 1 IceCube Preliminary E TeV (GeV cm 2 ) 10 0 IceCube Preliminary T(s) T(s)

15 Conclusion & Outlook 15 Fast radio bursts (FRBs) could emit high energy neutrinos A maximum likelihood analysis has been established to search for spatial and temporal coincidence between IceCube neutrinos and FRBs No significant correlations between IceCube neutrinos and FRBs were found in 6 years of data. Most stringent limits on neutrino fluence from FRBs have been set to be ~0.04 GeV cm -2. Publication is in preparation. IceCube can now quickly follow up on the FRBs to be detected in the forthcoming future, adding a multimessenger window to help untangle the FRB mystery

16 Back up slides 16

17 Neutrino vs Photon Arrival Times 17 Assume the same escape time t0: t = D 1 c 1 v = D ( 1 q (1 12 ) 1) s = E m,c=1 t ' 1 2 D (m E ) 2 t ' 1 2 (m ev )2 ( MeV ) 2 D ( E 10 kpc )

18 Neutrino vs Photon Arrival Times 18 For z ' 0.5, D light ' 2Gpc For 10 MeV neutrinos: t ' 1 2 (1 ev ev )2 ( MeV 10 MeV )2 ( 2Gpc 10 kpc ) ' 1000 s For 1 TeV neutrinos: t ' 1 2 (1 ev ev )2 ( MeV 1 TeV )2 ( 2Gpc 10 kpc ) ' s Photon trapped time unknown