Neutrinos from the Milky Way 18th Symposium on Astroparticle Physics in the Netherlands 23-10-2013 Erwin Visser
Outline How are these neutrinos produced? Why look for them? How to look for them The ANTARES neutrino telescope ANTARES sensitivity 23-10-2013 18th APP symposium - Erwin Visser 2/21
The Milky Way NASA NASA Neutrinos NASA 23-10-2013 18th APP symposium - Erwin Visser 3/21
Neutrino signal from the Milky Way CR p / He / Fe p 23-10-2013 18th APP symposium - Erwin Visser 4/21
Neutrino signal from the Milky Way CR p / He / Fe p π +/- π 0 ϒ ϒ µ +/- ν µ ν ν e +/- µ e 23-10-2013 18th APP symposium - Erwin Visser 5/21
Neutrino signal from the Milky Way CR p / He / Fe p π +/- π 0 ϒ ϒ µ +/- ν µ ν ν e +/- µ e Guaranteed signal Only limit known: (Amanda-II) IceCube excess could be caused by CR interactions 23-10-2013 18th APP symposium - Erwin Visser 6/21
Estimating the flux Theoretical models Using experimental observations Need a lot of assumptions Matter density Cosmic ray flux Magnetic field configuration 23-10-2013 18th APP symposium - Erwin Visser 7/21
Estimating the flux Theoretical models Need a lot of assumptions Matter density Cosmic ray flux Magnetic field configuration Using experimental observations CR p π +/- π 0 ϒ ϒ µ +/- ν µ ν ν e +/- µ e 23-10-2013 18th APP symposium - Erwin Visser 8/21
Estimating the flux Theoretical models Need a lot of assumptions Matter density Cosmic ray flux Magnetic field configuration Using experimental observations CR p π +/- π 0 ϒ ϒ µ +/- Fermi satellite measures γ-rays: E = 3.4 GeV ν µ ν ν e +/- µ e Photons 23-10-2013 18th APP symposium - Erwin Visser 9/21
Estimating the flux Theoretical models Need a lot of assumptions Matter density Cosmic ray flux Magnetic field configuration Using experimental observations CR p π +/- π 0 ϒ ϒ µ +/- E = 10.4 TeV ν µ ν ν e +/- µ e Neutrinos 23-10-2013 18th APP symposium - Erwin Visser 10/21
The ANTARES neutrino telescope Cherenkov light from muon γ č 43 µ +/- ν µ GC: 68% visibility 23-10-2013 18th APP symposium - Erwin Visser 11/21
The background 1. Atmospheric neutrinos Irreducible background 2. Atmospheric muons Reducible background Consider high quality events ν µ µ CR CR Earth Earth 23-10-2013 18th APP symposium - Erwin Visser 12/21
Reducing atmospheric muon background Use UPgoing events ANTARES Data MC: atm. muons MC: atm. neutrinos 23-10-2013 18th APP symposium - Erwin Visser 13/21
Reducing atmospheric muon background PRELIMINARY ANTARES Data MC: atm. muons MC: atm. neutrinos Make use of the event topology 23-10-2013 18th APP symposium - Erwin Visser 14/21
Neutrino fluxes In GC direction ν µ CR Earth Use high energy events 23-10-2013 18th APP symposium - Erwin Visser 15/21
My analysis Model independent approach Determine background using 5 background regions 5 4 1 2 3 23-10-2013 18th APP symposium - Erwin Visser 16/21
My analysis Need a sufficient angular resolution to distinguish events from the background regions Check systematics of background regions Optimise reconstruction quality and R parameter to find optimum MRF Compare number of events in signal region with average in background regions 23-10-2013 18th APP symposium - Erwin Visser 17/21
Angular resolution Angular resolution median of the angle between true neutrino track and reconstructed muon Sub degree angular resolution is good for a neutrino telescope 23-10-2013 18th APP symposium - Erwin Visser 18/21
Systematics of background regions Loose cut applied Region 1 2 3 4 5 # of events 13258 ± 115 13483 ± 116 13354 ± 116 13385 ± 116 13321 ± 115 23-10-2013 18th APP symposium - Erwin Visser 19/21
ANTARES sensitivity N signal N background = 1.09 = 61.25 PRELIMINARY NoDrift_simple NoDrift_advanced Drift AMANDA-II limit scaled ANTARES sensitivity (2007-2011) 23-10-2013 18th APP symposium - Erwin Visser 20/21
Conclusions and outlook Guaranteed signal Galactic plane is also an interesting region Model independent approach Background obtained from data using background regions A difficult measurement ANTARES can only set a limit Need bigger neutrino telescope for detection (KM3NeT) 23-10-2013 18th APP symposium - Erwin Visser 21/21
Backup 23-10-2013 18th APP symposium - Erwin Visser
References to theoretical papers 23-10-2013 18th APP symposium - Erwin Visser
Sources 23-10-2013 18th APP symposium - Erwin Visser
Visibility 23-10-2013 18th APP symposium - Erwin Visser
The Antares detector 23-10-2013 18th APP symposium - Erwin Visser
Detector performance Angular resolution: cumulative distribution of the angle between the true neutrino track and the reconstructed muon event that passes the selection criteria (assuming E -2 spectrum). Acceptance: (neutrino) effective area, i.e. the equivalent area of a 100% efficient detector, as a function of the neutrino energy (three different declinations band considered). The median is 0.46. 83% of the events are reconstructed better than 1 23-10-2013 18th APP symposium - Erwin Visser
Full sky search 23-10-2013 18th APP symposium - Erwin Visser
Matter density in the galaxy # particles / cm 3 23-10-2013 18th APP symposium - Erwin Visser
Column density # particles / cm 2 23-10-2013 18th APP symposium - Erwin Visser
Theoretical models C R p π 0 Assumption 1: cosmic ray flux ϒ ϒ π +/- µ +/- ν µ ν ν e +/- µ e Assumption 2: matter density Assumption 3: magnetic field 23-10-2013 18th APP symposium - Erwin Visser
Theoretical models C R p π 0 Assumption 1: cosmic ray flux ϒ ϒ π +/- µ +/- Simplest model ν µ ν ν e +/- µ e Simple CR parameterisation Neglect magnetic field Advanced model + Take CR composition into account Drift model + Magnetic field gives drift of CRs to GC Assumption 3: magnetic field 23-10-2013 18th APP symposium - Erwin Visser