Download discovery potential of KM3Net for the SNR Vela X

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ASTRONOMY SESSION: A
SUMMARY
R. Coniglione,
INFN - Laboratori Nazionali del Sud
Astronomy session
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Detector optimization: Kooijman for De Jong, Sapienza
 FoM for Galactic sources: Sapienza, Coniglione, Leisos

•The reference detector: 2 blocks of 310
strings (20 floors/string 40m distant) with
MultiPMT. Distance between strings 100m.
Total volume 3.8 km3
•MC inputs: same (WPD document)
•Codes: Sirene, HOU software, ANTARES
code modified for KM3NeT (LNS code)
P. Kooijman for M. de Jong
Sirene
 Sirene is yet another program that simulates the detector
response to muons and showers
 It uses a general purpose collections framework for PDF/CDF
tables
‒ allows for optimisation of accuracy and speed of interpolations
‒ facilitates I/O
 It runs about 10 x faster than km3
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NO reconstruction – no search analysis
Analysis at trigger level
number of events with ≥ 5 L1s from RXJ1713 per year (Kelner spectrum)
L1 corresponds to two (or more) hits on same optical module within 10 ns
procedure
scaling factor applied to absorption length (0.9, 1.0, 1.1, 1.2)
vary horizontal spacing 80‒130 m and vertical spacing 30‒50 m
determine optimal spacing for each absorption length
dependence of performance figure on scaling factor
P. Kooijman for M. de Jong
Module
• Scaling Factor: Absorption length wrt Km3 “standard” absorption length
• Number of lines  In a block events scaled to 640 lines (20 floors)
• Number of floors  Reduced floors gives more lines, 120 line blocks
events / year
scaling factor
scaling factor
=
number of lines in a block
number of floors
Building block = smallest detector with optimal efficiency
80<Lines<120 and 15<floors<19
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P. Kooijman for M. de Jong
Example
horizontal spacing
events / year
vertical spacing
scaling factor 1.1
horizontal spacing [m]
scaling factor 1.1
vertical spacing [m]
There is a clear maximum
For this scaling factor: 100m horizontal and 34-38 m vertical
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P. Kooijman for M. de Jong
Dependence on absorption length
events / year
optimal detector
scaling factor
For each absorption length optimize the detector
There is a clear linear dependence
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P. Kooijman for M. de Jong
Conclusions
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
From detector optimization with SIRENE
Typical numbers:
Blocks: 80-120 lines
 Floors: 14-18
 Horizontal distance: 80-110 m
 Vertical distance: 35-40 m



Numbers vary within these limits for different
absorption length
Optimizing at each absorption length yields a linear
dependence of number of events on absorption length.
P. Sapienza
The SNR RXJ1713
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




Event simulation performed with Antares code
adapted for km3 detector
Simulation for RXJ1713 with a Kelner spectrum
in a flat disk of 0.6°
RECO => Fit with a scanning procedure based
on a 3°x3° grid plus rotations + Aart strategy
Binned and unbinned search analysis
values of FoM (years for 5s discovery) and
sensitivity
RXJ1713
P. Sapienza
RXJ1713-39.46 sensitivity 1 y – DU distance
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


Two blocks of 310 strings
20 multi-PMT/string
40 m distance between multi-PMT
1.72


E
(E) 1.68 1014   e 
TeV 

Proposed as public plot
E
2.1TeV
GeV 1s1cm 2
• Better performance for a 100m string
distant detector
• In one year, if no statistically significant
excess will be found, upper limits lower
the kelner model can be set
P. Sapienza
RXJ1713-39.46 5s – DU distance
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Proposed as public plot
Official result to quote:
RXJ1713 5.8 years preliminary and binned
Binned
Significance
Unbinned estimated
5sigma
Years
5.8
Nsource
29.9
Nbackground
26.8
3sigma
2.1
10.1
8.5
100 m is a good distance for galactic sources
Unbinned calculations provide a rather good improvement of the FoM
P. Sapienza
RXJ1713-39.46 labs dependence
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L*abs = 1.1 Labs
String
Nsource/year
Distance (m)
Nback/year
F.O.M.
90
5.30
37.2
6.
100
5.40
34.2
5.6
130
5.10
24.1
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L*abs = 1 Labs
String
distance (m)
Nsource/yea
r
Nback/year
F.O.M.
90
5.01
34.4
6.3
100
5.04
30.0
5.8
130
4.66
20.9
6.5
Nsource and Nback = number of events in 1° around the
source position (no cut applied)
• 10% difference in Labs-> Difference
of about 5% between FOM
• Same string distance optimization at
different Labs
From A. Leisos
HOU codes
Unbinned search method
The unbinned analysis
and ANTARES code
simulation gives 4.8y
(estimated value)
Agreement at about
10%
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R. Coniglione
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The Pulsar Wind Nebula
Vela X
R. Coniglione
VelaX Gamma spectrum
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

New HESS paper appeared on ArXiv in October 2012 and now on Astronomy and Astrophysics
548 (2012) A38 with a higher flux measurement. (53h 2012/ 12h 2006 of observation)
Observation up to 50 TeV
d=-45.6°
Extension:
•Inner region 0.8°
•Total 1.2°
R. Coniglione
Gamma spectra
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
Ecut
(TeV)
>1TeV (s-1cm2)
2.13 10-14
2.04
17.9
1.68 10-11
VelaX 2006*
1.03 10-14
1.45
13.8
1.28 10-11
VelaX 2012 total
1.46 10-14
1.32
14.0
2.10 10-11  Astronomy & Astrophysics L43 448 (2006)
VelaX 2012 inner
1.16 10-14
1.36
13.9
1.6 10-11
N
(GeV-1s-1cm-2)
RXJ1713
dN
 N E   exp( E E cut )
dE
* F. Aharonian et al.,
R. Coniglione
Neutrino spectra
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R. Coniglione
Simulation results
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



Source at d=-45.6° with a flat disk distribution of 0.8° (inner part
of VelaX)
Reconstruction with scanning 3°x3°
Official value for public :
no morphology in simulation
VelaX about 3 years preliminary
no atmospheric muons
Years for discovery Years for discovery
5s 50%
3s 50%
Vela X 2006
Kappes
7.5
2.6
VelaX 2006
Vissani
5.2
1.8
VelaX 2012 inner
Vissani
2.8
1.1
A. Leisos
HOU codes
Unbinned search method
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3.8 years with HOU codes to be compared with 2.8 years with ANTARES code and binned analysis
Difference to be investigated.
R. Coniglione
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The SuperNova Remnant
Vela junior
Vela Junior gamma spectrum
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SNR Vela Junior d=-46.37°
F. Aharonian et al., Astrophys. Journal (2007) 236
data from December 2004 to May 2005 (33h of ON-source run)


Observation up to ≈20 TeV
no cut off observed
Radial profile
=2.24 N=1.9 10-14
Vela Junior gamma spectrum
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SNR Vela Junior d=-46.37°
Manuel Paz Arribas et al., ICRC 2011
Amount of data increased by a factor 2
data from 2004 to 2009 (72h of live time after data quality
selection)
Morphology analysis -> NO absolute flux values ->
*N extracted from 2007 values
N
(GeV-1s-1cm-2)

Ecut
(TeV)
>1TeV (s-1cm-2)
VelaJ 2007
*1.89 10-14
2.24
-
1.52 10-11
VelaJ ICRC
2011 single
region
*1.69 10-14
2.11
-
1.52 10-11
VelaJ ICRC
2011 whole
*1.86 10-14
2.22
-
1.52 10-11
Vela Junior neutrino spectrum
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* dN
dE
 N E   exp( (E E cut ))
** dN

dE
 N E   exp((E E cut ))

N
(GeV-1s-1cm-2)

Ecut
(TeV)
>1TeV (s-1cm-2)
VelaJ Vissani
2007**
6.6 10-15
2.24
-
5.30 10-12
VelaJ Vissani
ICRC 2011
single region**
2.64 10-15
2.11
-
5.71 10-12
VelaJ Kappes*
1.67 10-14
1.72
1.19
4.84 10-12
Simulation results Vela Junior
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



Source at d=-46.37° with a flat disk distribution of 1°
Reconstruction with scanning 3°x3°
no morphology
no atmospheric muons
Years for discovery
5s 50%
Vela Junior Vissani
2007
>10
VelaJ Vissani ICRC
2011
2.9
VelaJ Vissani ICRC
2011
+ cutoff 13 TeV
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VelaJ Kappes
>>10
No cutoff unrealistic
With a supposed cutoff (not measured)
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The Fermi bubbles
The Fermi bubble
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In the paper simulation for 2 x154 towers with multiPMT 180m spaced (≈6km3)
Paper appeared in Astroparticle Physics Vol. 42 (feb 2013) 7-14.
tower+multipmt detector @180m
Discovery for E-2 with a cutoff@100 TeV
spectrum in about 1 ÷1 ½ year
Discovery for E-2 with a cutoff@30 TeV
spectrum in about 5 ÷6 years
strings+multipmt detector @100m
(no muatm)
Discovery for E-2 with a cutoff@100 TeV
spectrum in about 1 ÷1 ½ year
Discovery for E-2 with a cutoff@30 TeV
spectrum in about 3÷4 years
To be confirmed
Summary
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
String distance optimization -> 100m

No different optimal string distance at different Labs


Discovery of RXJ1713 in about 5.8 years
(agreement at about 10% with HOU results)
Discovery of VelaX in about 3 years (difference
with HOU results to be understood)