2000-2006 AMANDA-II Point Source Search Results Jim Braun IceCube Spring 2008 Collaboration Meeting
m-DAQ Point Source Searches AMANDA-II complete Hauschildt, Steele: Phys.Rev.Lett.92:071102 2004 2000 2001 2002 2003 2004 2005 2006 This Analysis Combine all years for best possible sensitivity Final sample will also be utilized by John K. and others Y.-R. Wang: Phys.Rev.D71:077102 2005 M. Ackermann: Phys.Rev.D75:102001 2007 Unblinded in 2007 by J. Braun Unblinded in 2007 by J. Braun m-DAQ decommissioned
Data Overview Year Livetime 2000 197 d 2001 193 d 2002 204 d 2003 213 d 2004 194 d 2005 199.3 d 2006 187 d Total 3.8 Yr. 2000-2004 unified filtering done in Zeuthen by Ackermann et al. 2005-2006 filtered in Madison with a very similar configuration. Data and neutrino simulation available in Madison
Event Selection Much more information available on analysis web page: 20M events at L3 Use cuts from 5 year analysis Smoothness Paraboloid error Up/down likelihood ratio Use an SVM-based cut for d < 1.5o 6595 total events Much more information available on analysis web page: http://www.icecube.wisc.edu/~jbraun/combined_point_source
Event Selection
Search Method Apply unbinned maximum likelihood search method Use paraboloid error estimate as a measure of reconstruction uncertainty Use event energy (Nch) to separate signal from atmospheric neutrinos Method details described in internal report: http://internal.icecube.wisc.edu/reports/data/icecube/2008/04/001/icecube_200804001_v2.pdf
Search Method
Sensitivity
Unblinded Skymap Short, short summary: We see nothing
Analysis What did we do with the data? 1. All-sky search 2. Search based on a list of candidates 3. Milagro stacking search 4. Search for autocorrelation
All-Sky Search Max Significance Significance 3yr max significance: 3.73s 1.5s Max Significance d=54o, a=11.4h 3.38s 5yr max significance: 3.74s 2.8s 95 of 100 data sets randomized in RA have a significance ³ 3.38s
Source List Search The Crab: Upward Fluctuations: Selected Sources The Crab: Significance decreases Still a minor upward fluctuation Upward Fluctuations: LS I +61 303 Geminga Downward Fluctuations: Mrk 421 Source m90 P-value Crab 4.62 0.10 MGRO J2019+37 4.14 0.077 Mrk 421 0.67 0.82 Mrk 501 2.97 0.22 LS I +61 303 9.62 0.03 Geminga 10.72 0.0086 Compute limits with feldman-cousins procedure The probability of obtaining p £ 0.0086 for at least one of the 26 sources is 20%
Experimental Limits Energy Range (90%): 1 TeV – 3 PeV
Milagro Stacking Search A. Abdo et al. Proc. First Glast Symposium Apply stacking search to 6 Milagro sources with >5s pretrial significance Exclude PWN sources (Crab, Geminga) Use method developed by HiRes* to perform our likelihood search simultaneously for all Milagro source locations Improves per-source flux sensitivity and discovery potential by a factor of 4 compared to a fixed-point search for any of the six sources * R.U. Abbasi, et al. Astrophys. J., 636 680 (2006)
Milagro Stacking Search Halzen, Kappes, O’Murchada [arXiv:0803.0314]
Milagro Stacking Search Potential IC40 Sensitivity Halzen, Kappes, O’Murchada [arXiv:0803.0314]
Autocorrelation Search Search for event clustering at angular scales comparable to detector resolution Signal scenario: A number of small event clusters Method: Count the number of event pairs given a maximum angular separation and minimum Nch and compare to distributions from data with randomized RA Significance Max significance: 1.6s 99 out of 100 sets of randomized data have a max significance of 1.6s or greater If result went the other way, I’m sure the discussion would be somewhat different
Systematics Systematics will be similar to those from the 5 year analysis ANIS predicts 8% fewer atmospheric neutrino events compared to NUSIM Include nt muon contribution? Systematics of unbinned analysis
Publication Rapidly address systematics and get manuscript to collaboration as soon as possible
Conclusions This analysis is a factor of 2 more sensitive than previous point source analysis We didn’t see anything IC22, IC40 will yield substantial improvements