Short Blazar Flares for Current Neutrino Telescopes

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1 for Current Neutrino Telescopes Michael Kreter, Matthias Kadler, Felicia Krauss, Roopesh Ojha, Sara Buson, Karl Mannheim, Joern Wilms on behalf of the Fermi-LAT presentation 7th International Fermi Symposium 2017 October 20th, / 17

2 Blazars as promising neutrino sources Neutrino output of blazars estimated based on Mannheim 1993, A&A 269, Mannheim 1995, Astroparticle Physics, 3, 295 p + nucleus π + X (π = π ±, π 0 ) { p + γ + π 0 + p π + + n. Resulting pions decay: π 0 γ + γ π ± µ ± + ν µ ( or ν µ) µ + e + + ν µ + ν e µ e + ν µ + ν e Credit: Katz & Spiering / 17

3 Coincidence of a high-fluence blazar outburst with a PeV neutrino event Kadler et al. 2016, Nat Phys 12, 807 Calorimetric Output in BigBird field dominated by PKS B But: Chance Coincidence 5% 3 / 17

4 Test neutrino detection potential for short blazar flares are highly variable Choose sources that: show extreme bright short flares 4 / 17

5 Choose flares that fulfill: σ indi = (Flux 3 Flux err) A eff G σ indi 3 σ G: Flux Ground Level σ indi : individual flux variation of each bin σ: Intrinsic source variation A eff : Effective area 5 / 17

6 Choose flares that fulfill: σ indi = (Flux 3 Flux err) A eff G σ indi 3 σ G: Flux Ground Level σ indi : individual flux variation of each bin σ: Intrinsic source variation A eff : Effective area 6 / 17

7 Which flares to select? Start from Fermi s public bright-blazar list Identify flares according to flare selection method Run daily 6 year (Pass 8) light curves on sources responsible for 100 brightest short flares Re-run flare selection method on Pass 8 light curves Select the best 50 flares according to their fluence Calculate a neutrino expectation for all 50 flares 7 / 17

8 Estimate maximum neutrino output Pion Photoproduction: Maximum Neutrino Output: F γ = 1 3 F π F π = 1 2 F π F ν = F π = 1 2 F π See Krauss et al. 2014, A&A 566, L7 Kadler et al. 2016, Nat Phys 12, 807 Credit: Mücke et al ( ) N max Fγ ν,pev = A eff,eν t E ν Credit: Krauss et al. 2014, A&A 566, L7 8 / 17

9 Estimate maximum neutrino output Scaling Factor: N pred ν,pev = f Nmax ν,pev f = (1) Things to consider: Different neutrino flavors UV seed photons needed (FSRQs) PeV peaks might be smeared out to ( ) PeV See Kadler et al for details 9 / 17

10 3C279 Halzen & Kheirandish 2016, ApJ. 831,12 Suggestion of promising neutrino candidate 10 / 17

11 3C279 Halzen & Kheirandish 2016, ApJ. 831,12 Suggestion of promising neutrino candidate Identify flare duration of 6 days 11 / 17

12 3C279 Time resolved SED of 2015 flare Simultaneous Swift/XRT and Fermi/LAT observations 12 / 17

13 3C279 N pred ν,pev months of non flaring activity 13 / 17

14 . 50 best flares are generated by a group of only seven different sources: 3C 279, PKS , PKS , CTA 102, 3C 454.3, PKS , PKS C 279 and PKS responsible for 42 flares 14 / 17

15 probability shows saturating tendency Extending the sample size does not substantially increase the detection probability Highest fluence flares provide by far the largest contribution 15 / 17

16 TXS First track like IceCube EHE event consistent with a LAT source 16 / 17

17 Short blazar flares yield only a small neutrino detection probability No substantial improvement by adding more (fainter) flares Top-ranked flares produced by only a handful of individual blazars 17 / 17

18 Backup 18 / 17

19 Light curve ground level calculation 19 / 17

20 Light curve of 3C / 17

21 Light curve of 3C / 17

22 Light curve of PKS / 17

23 Light curve of CTA / 17

24 Light curve of PKS / 17

25 Light curve of PKS / 17

26 Light curve of PKS / 17