Neutrino Point Source Searches
with AMANDA-II m-DAQ
Jim Braun
IceCube Fall 2007 Collaboration Meeting
Progress Since Lake Geneva
• 2005 unblinded:
– http://www.icecube.wisc.edu/~jbraun/2005_point_source/
• 2006 unblinded:
– http://www.icecube.wisc.edu/~jbraun/2006_point_source/
• Improvements in methodology:
– http://www.icecube.wisc.edu/~jbraun/2006_point_source/sensitivity.html
• Internal report on methodology coming soon
IceCube Collaboration Meeting Fall 2007
Neutrino Point Source Searches with AMANDA-II m-DAQ: 2
Review: Sensitivity
Improvement:
~30%
IceCube Collaboration Meeting Fall 2007
Neutrino Point Source Searches with AMANDA-II m-DAQ: 3
Use of Energy Information
IceCube Collaboration Meeting Fall 2007
•
Mean number of signal events
required to reach 5s in 50% of
simulated experiments at d=42.5o
•
2006 data is background
•
Compare unbinned search with
and without using Nch
•
Utilizing Nch information
improves discovery potential for
spectral indices g < 3.3
•
Effect is 30% for E-2, representing
a 45% total improvement over the
binned search
Neutrino Point Source Searches with AMANDA-II m-DAQ: 4
2005 Unblinding
log10(p-value)
Highest Significance: 3.58s
Chance Probability: 69%
IceCube Collaboration Meeting Fall 2007
Object
P-value
MGRO J2019+37
0.152
Mrk 501
0.184
Mrk 421
~1
NGC 1275
0.064
Crab Nebula
~1
Cyg X-3
0.458
GRS 1915+105
0.581
80% Chance of observing
p = 0.064 given 26 sources
Neutrino Point Source Searches with AMANDA-II m-DAQ: 5
2006 Unblinding
Significance
Highest Significance: 3.58s
Chance Probability: 84%
IceCube Collaboration Meeting Fall 2007
Object
P-value
MGRO J2019+37
0.064
Mrk 501
~1
Mrk 421
0.227
NGC 1275
~1
Crab Nebula
0.456
Cyg X-3
0.012
GRS 1915+105
0.005
12% Chance of observing
p = 0.005 given 26 sources
Neutrino Point Source Searches with AMANDA-II m-DAQ: 6
2005 + 2006
Sensitivity of 2005-2006 analysis near
E2dF/dE = 7x10-11 TeV cm-2 s-1
5 year search: 5x10-11 TeV cm-2 s-1
3.82s
Significance
IceCube Collaboration Meeting Fall 2007
Object
P-value
m90*
MGRO J2019+37
0.065
12.83
Mrk 501
0.228
8.83
Mrk 421
~1
5.71
NGC 1275
0.106
10.98
Crab Nebula
0.438
6.67
Cyg X-3
0.033
13.37
GRS 1915+105
0.031
14.12
* 10-11 TeV cm-2 s-1
Neutrino Point Source Searches with AMANDA-II m-DAQ: 7
Plans for 2000-2006
• Expect to combine 2005+2006 with 2000-2004 Zeuthen
five year data set
– Will not reoptimize cuts for 2000-2004
• Expected sensitivity: ~3x10-11 TeV cm-2 s-1
• Finish by the end of the year
• Will not include 1997-1999 B10 data as previously
planned
– 465 total events in most recent 1997-1999 analysis
– Considering poorer angular resolution and 25% contamination,
equivalent to less than 40 days AMANDA-II livetime
IceCube Collaboration Meeting Fall 2007
Neutrino Point Source Searches with AMANDA-II m-DAQ: 8
The Crab
(Because Everyone Keeps Asking)
• 2000-2004: Excess (10 events, 6 expected)
• 2005-2006: Slight excess
• 2006 IC-9: Excess
• If the excesses are indeed a signal, we would
possibly observe ~3s for this source
– Significance reduced to ~2s with a catalogue of 26
sources
– Depends on Nch values of events observed in 20002004
IceCube Collaboration Meeting Fall 2007
Neutrino Point Source Searches with AMANDA-II m-DAQ: 9