AstroPlasmas group June 14, 2010 Mike Baker

1. AstroPlasmas group June 14, 2010 Mike Baker

2. I have made several different analyses looking for timing structure for neutrino signals, I have a discussion of the IceCube part and then a bit more about the astrophysics in general * Search for periodic neutrino emission from binary systems * Search for neutrinos in coincidence with GeV-TeV photon flares * Search for generic clustering in time and space of neutrinos

3. Binary systems in the galaxy where one member is a compact object haven been posited as a source of cosmic rays. We search for clustering as a function of orbital period is a very similar analysis to searching for event clustering in MJD. We performed in AMANDA 7 yr, IC22 periodic searched where we used the period of binary X-ray stars and micro-quasars from stereoscopic information and fit the phase. We search for a best-fit Gaussian describing the events in phase. The discovery potential and AUL have the same trend as as a function of time as in the general (untriggered) flare search.

4. I ran the analysis over the 7 sources, and these are the best-fit parameters and pretrial p-values: Source | (Ra, Dec) Period |pretrialP| NSrc Gamma mean sigma_w Cygnus X3 | (308.107,40.958) 0.199679 | 0.00186 | 4.27 3.75 0.820 0.02 SS433 | (287.957,4.983) 13.0821 | 0.3523 | 2.15 2.89 0.601 0.02 Cygnus X1 | (299.591,35.202) 5.5929 | 0.0793 | 1.39 1.54 0.708 0.02 LS I +61 303 | (40.132,61.229) 26.498 | 0.2271 | 1.83 3.95 0.521 0.02 GRS 1915+105 | (288.798,10.946) 30.8 | 0.4266 | 2.03 3.95 0.986 0.045 XTE J1118+480 | (169.545,48.037) 0.16993 | 0.2784 | 2.40 2.35 0.872 0.131 GRO J0422+32 | (65.428,32.907) 0.21214 | 0.0373 | 2.95 3.06 0.800 0.02 Minimum P-value: 0.00186146 Best Source: Cygnus X3

5. Comparing to scrambled samples, the smallest p-value from all 7 objects is less than that found in data 1.8% of the time. I think the result is interesting, but it is still compatable with background.

6. Here is how the events look in phase for Cygnus X3 – the three highest-weight events come in 1/20 of the period, which corresponds to a 15-minute window of the 4.8 hour orbit. I took the phase=0 information from the Fermi paper from Science, and it looks like the maximum period is near 0.82. Phi=0 is at superior conjunction (x-ray minimum) and phi=0.5 is at inferior conjunction

7. One interesting thing about Cygnus X3 during the IC-40 period (April 2008 – May 2009) is that there was a series radio flares, with accompanying high states in GeV gamma rays. There is another analysis geared toward lower energies looking into neutrino coincidence also.

8. “Saxophone” plot: relation between ratio and soft x-ray fluxes varies depending on the flaring state.

9. Right are the periodic flux information from Fermi (top) and ASM (bottom). Fermi sees periodicity only when the source is in a high GeV state, we haven't looked at the raw times of our events yet.

10. I also managed to find a paper from the 1985 International Cosmic Ray Conference with a plot of muons seen from a 3 degree cone from the direction of Cygnus X-3. http://adsabs.harvard.edu/full/1985ICRC....9..445A

11. MWL Triggered Flare Search

12. Blazars are candidate sources for UHECRs, and hence neutrinos, and exhibit varibility in HE photon wavebands on the order of days. We use this MWL information on variability to motivate a cut in time for a point-source search.

13. Two kinds of alerts, one from sources providing lightcurves with sporadic data. 1ES1218+304 has a strong flare seen with VERITAS → Markarian 501 also has a short flare ← seen with VERITAS

14. Start out with a Maximum Likelihood Blocks reconstruction of the Fermi LAT lightcurve. The other kind of alert we have is from satellite sources with comprehensive coverage in a waveband

15. Instead of making a guess of what the best cut on the flux is, we maximixe with respect to the threshold, to find the best answer to the question: ”At what flux of the lightcurve does neutrino emission turn on?” threshold Resulting Pdf

16. Here is the discovery potential for the lightcurve of PKS 1510-089. I compare several methods, all using the lightcurve: In blue is the hypothetical case where we know the best cut on threshold and any lag. In red is the case used in the analysis, where we fit the threshold and allow a short lag as a method of interpolating the lightcurve. I also tested a case where we fit the threshold and allow a search for a long lag between photons and neutrinos, this is shown in black.

17. The most significant source found was one high-energy event during a GeV flare of PKS 1502+106, but it wasn't very strong, the overall p-value of the analysis is 29%

18. We've picked out most of the highly-variable sources for the triggered analysis, but it still could be interesting to include weaker flares in a stacking analysis, like in GRB searches

19. Fermi also finds two distinct kinds of flaring behavior: for many of the brighter sources the lightcurve displays complicated rising and lowering, others have relatively simple, discrete flares. This means that there very different things going on in the jet for different flares from different sources. ← 3C279 PKS 1454-354 →

20. Fermi also has their own method of fitting flares with 3-day binned LC, while I used 1-day binned LC.

21. Untriggered All-Sky Flare Search

22. We know of transient astrophysical phenomena with timescales of milliseconds-seconds (GRB) to minutes-days (AGN flares, SN afterglow). Observations in photons give us candidates to test for correlations in triggered searches, but these observations are not always continuous depending on the energy range tested. We have an interest in performing a general search which covers many orders of magnitude of flare duration to find occurrences undetected or undetectable with photon emission. We fit for the best mean and sigma of a Gaussian in time to find the strongest flare from a given source location. Here background events are in blue, with 5 injected signal events in red. The height of the line corresponds to S/B ratio of the event in the time-integrated analysis.

23. We find that by looking for a clustering of events in time we can dramatically reduce the number of events needed to see a discovery compared to a time-integrated search, and can make a detection which is below the upper limit in the general search.

24. The method's performance is similar to that of the time-integrated analysis even for long flares, opening up the possibility of looking from GRB timescales to steady sources. For flat emission, only 10% more signal is needed for discovery than a PS search even when we add two degrees of freedom to the likelihood. ~Time-Integrated GRBs AGN

25. Another possible outcome is that we see something completely unexpected, some sort of burst of neutrinos with no counterpart in photons. ?????????

26. I also had a look at what the Discovery potential and upper limit looks like in terms of fluence. A dedicated GRB analysis which looks at a widening time window near the burst reports the average fluence needed from 117 bursts as a function of the time window around the burst.

27. Skymap (with all fit parameters) is available for download as a root file: http://www.icecube.wisc.edu/~mfbaker/IC40/flares_g/tAllSkyBatch_UnblindFix.root

28. Hottest Spot: -log10(estp): 4.67768 at 254.75 RA and 36.25 dec. The mean is at: 54874.7 MJD and the flare width is 15 seconds. The spectral index fit is: 2.15 and the fit nsrc is: 2

29. Fifteen seconds doesn't stand out on year-long timescales, so we zoom in on the flare time to see both events.

30. Comparing to scrambled skymaps, the hottest spot is in the bulk of the distribution of the pretrial p-value at the hottest spot. The final p-value is ~58%.

31. The hottest flare corresponds to two events which are 22 seconds apart. There is a spatial separation of 2.01 degrees between the events. Paraboloid sigma = 0.60 deg Nch 65 Mue En = 3.33e4 Paraboloid sigma = 1.96 deg Nch 17 Mue En = 2.43e3

32. There may be more information about the flare – IceCube has a program with ROTSE to take optical images of close doublets of events, and this met the trigger criteria.

33. Finally, here is a zoom-in of the hottest flare, with both events. The higher-energy event is closer the best p-value. Markarian 501 is marked as the black star.