1. IceCube: Multiwavelength Approach to
Transient Neutrino Point Source Candidates
Elisa Resconi, for the IceCube coll.
(Max-Planck-Institute for Nuclear Physics, Heidelberg)
TeV Particle Astrophysics II August Madison, WI

2. 106 : 1 n Fn (E, W) l 1. Construction of the Neutrino Sample
IceCube event
IceCube event n l
106 : 1
Fn (E, W)
Elisa Resconi

3. Fn (E, W) = Fatm + Fgalactic + Fextra- galactic
2. Extraction of Astronomical Information
Fn (E, W) = Fatm + Fgalactic + Fextra- galactic
Cosmic ray showers in
the Earth’s atmosphere:
p, K decay
 E-3.7
 20% uncertainty
“diffuse” flux:
CR interaction with
interstellar gas.
“point-like”:
galactic sources
 E-2  ?
“diffuse” flux:
p decay from pg interaction
with 2.7oK cosmic radiation
“point-like”:
extra-galactic sources
 E-2  ?
TeV-Blazar
discussed here
See also at this conference:
“Implications of neutrino flux limits” J. Becker for IceCube, talk
“Search for a Diffuse Flux of TeV to PeV Muon Neutrinos with AMANDA-II” J. Hodges for IceCube, poster

4. No significant excess found Blind analysis strategy
Fgalactic(E,W), Fextra-galactic(E,W) point-like sources
Ref. M. Ackermann, “The multimessenger approach ..”,
Barcelona, 07.06
On-Source
Off-Source
= 00-04
AMANDA-II preliminary: (1001 live days),
4282 n from northern hemisphere
No significant excess found
Blind analysis strategy
Variable sources ?
Elisa Resconi

5. dFatm(t)/dt = 1 / year 3o sky-bin
Multi-wavelength approach: photon light curves used for the improvement in identify
possible neutrinos emitted by astronomical sources
Synthetic light curve
Photon Rate
(counts/sec)
2000
2001
2002
2003 1
Nr of n
Time
dFatm(t)/dt = 1 / year 3o sky-bin
1 n / day sky-bin ~ 310 -3
How can we discriminate
these events ?
What can we learn from
photon observations?

6. 3. Transient Point Sources
The photon-neutrino link
Access to photon data
Analysis of photon data
Selection of neutrino “proxy” waveband
Availability / calibration / dead-time correction …..
WHAT IS A FLARE ?
Elisa Resconi

7. 3.1 The photon – neutrino link: HBL (LBL)
Synchrotron proton blazar model (ref. A. Mücke et al, Astroparticle Phy, 18 (2003) )
proton (highly magnetized environment) electron
γ synchr.
pγ γ synchr.
 ,  γ
γ synchr
e, 
γ synchr
casc. (e±)
γ synchr γ X
LBL
HBL
P.Giommi et al.,A&A 445, (2006)
Elisa Resconi

8. X- ray band γ- ray band X- AND γ-ray  emission Interpretation Data
HBL
X- AND γ-ray
 emission
X- ray band
γ- ray band C O R E L A T I N
Interpretation
primary electron AND
secondary electron (casc.)
only p,
if only synchrotron (no )
Data
huge amount of data,
monitor + high sensitivity
sporadic, no monitor,
difficult to combine
Strategy
Light curve interpretation
define “flares”
define periods of high activity
collect all the data available,
improve definition of “flare”
Elisa Resconi

9. 3.3 Photon data: WHAT IS A FLARE ?
Light Curve Interpretation:
characteristic flux level(s)
impulsive events (flares)
statistical studies on the timescales of variability
correlated activities across wavebands
periods of HE neutrino emission:
Construction of an hypothesis test
Maximum Likelihood Blocks applied to X- and -ray light curves
[E. Resconi, L. Costamante, D. Franco, E. Flaccomio, A. Gross, icecube/ ]

10. X-ray: an example All-Sky-Monitor (RXTE), Mkn 421
All-Sky-Monitor, RXTE, 10 years X-ray monitor zoom Mkn 421
Elisa Resconi

11. All-Sky-Monitor, Maximum-Likelihood-Blocks zoom Mkn 421
Elisa Resconi

12. All-Sky-Monitor, Maximum-Likelihood-Blocks, Characteristic level zoom Mkn 421
Rchar
Elisa Resconi

13. Hypothesis test: need to be blind!
 sample determined a priori
Time periods selected a priori
 in the time periods /  atmospheric expected
All-Sky-Monitor, Maximum-Likelihood-Blocks, Characteristic level zoom Mkn 421
Elevated levels or flares : ~ 15 %
+ 3
Rchar
Characteristic level (band)
Depends on: source + detector
Elisa Resconi

14. TeV -ray: preliminary
The light curves are very sporadic
Compilation of historical light curves: under construction
Mkn 421, Whipple public data, Maximum Likelihood Blocks
Elisa Resconi

15. Multi-wavelength: X- vs -ray
“Orphan” region
Correlated
corridor
-ray flux
“Anti-orphan” region
X-ray flux, PCA (MLB blocks)
Elisa Resconi

16. Future: … transition to a ‘multi-messengers’ approach
- IceCube as a ( half ) – All-Sky-Monitor in neutrino:
- Filed of view: northern sky
- High duty cycle
Idea: use neutrinos in order to trigger gamma-ray telescopes
(see E. Bernardini, “The multimessenger approach..” Barcelona, 07.06)
- Critical points under discussion:
- selection of the sources: the phenomenology is limited
- statistical interpretation of possible coincidences:
-ray flare rate, catalogue …
- blindness of the data:
minimal impact with off-line analysis
Status: TEST run between AMANDA and Magic of 3 months approved.
Elisa Resconi

17. Summary
Looking in the right direction and in the right moment is a good idea!
From existing models: selection of proxy wavebands (HBL discussed)
Photon light curves under compilation
Photon light curve analysis with a global method (MLB)
Selection of periods of possible neutrino emission:
global &
non arbitrary
Next: test on the data
Elisa Resconi