1. IceCube IceCube Neutrino-Trigger network of optical telescopes Anna Franckowiak 1, Timo Griesel 2, Lutz Koepke 2, Marek Kowalski 1, Thomas Kowarik 2, Anna Mohr 1, Alexander Piégsa 2 1 Institut für Physik, Humboldt Universität zu Berlin 2 Institut für Physik, Johannes Gutenberg-Universität Mainz Supernova detection with IceCube: From low to high energy neutrinos 1. G.G. Raffelt, astro-ph/0303226, 2003 2. A.S. Dighe et al. JCAP 06 005, 2003 3. T.Totani et al, Astrophys. J. 496 216, 1998 4. J. Janka et al. arXiv:astro-ph/0612072v1, 2006 5. S.Ando & J.Beacom, Phys. Rev. Lett. 95 061103, 2005 6.M.Kowalski & A.Mohr, Astroparticle Physics, 27, 553, 2007 References Detecting high energy neutrinos from Supernovae While core-collapse SNe are guaranteed sources of low energy neutrinos, they might also be powerful sources of high energy TeV neutrinos. High energy neutrinos from Supernovae, besides being a remarkable discovery by themselves, would prove the presence of internal jet production in Supernovae. Such jets are motivated by the recent association of Supernovae and Gamma-Ray Bursts [1]. By complementing IceCube with optical follow-up observations, one can increase its sensitivity by a factor of 2-3 [2]. Supernovae Sensitivity Sensitivity can be doubled by follow-up! Model: TeV neutrino emission from core collapse SNe is modeled according Ando & Beacom (2005) and used to project the sensitivity. SN Rate and jet kinetic energy are free parameters in our model. Configurations: 1)Neutrino doublets (or higher order multiplets) combined with an optical follow-up with a 1m class telecope. 2)Single neutrinos are correlated with optically detected SNe within 20 Mpc. This Figure shows the projected sensitivity (50% detection probability) of IceCube with optical follow-up (after a km 3 yr exposure). The star refers to the model of [6] Optical Neutrino Follow-up Method: Triggered by a burst of high energy neutrinos, a network of optical telescopes scans the corresponding part of the sky. By searching for rising SN lightcurves as well as Gamma-Ray Burst afterglows through optical follow-up observations, one can sig- nificantly improve the perspectives for the detection of selected transient sources. Neutrino Burst Trigger: Rate of two coincident atmospheric neutrino events: 250  a day for IceCube 2 o x 2 o GRB/SN time -window:100 sec single neutrinos average of two neutrinos Optical Telescope Requirements: 1.Large Field-of-View to match IceCubes pointing accuracy (~ 1 o ) (see left Fig.) 2.Limiting magnitude 20 (~1m diameter). 3.Observing time requirements ~20 hours a year 4.Fast response time and automated operation 5.Visibility of the northern hemisphere Telescopes which fulfill most of these requirements already exist (ROTSE-III, STELLA,…) and others become available soon (PTF,…). Supernova Optical Detection: first image later image image difference IceCube pointing accuracy Supernovae search with IceCube Due to the low noise rates of the IceCube DOMs (Digital Optical Modules) an incoming Supernova neutrino signal will lead to a significant rise in the noise rate of every single DOM. This excess can be detected with high significance. An online analysis monitors the rates and triggers Supernovae burst candidates. This will allow IceCube to participate in SNEWS (Super-Nova-Early-Warning-System). The online algorithm is well tested and understood. The method is being used in IceCube’s precursor AMANDA-II (Antarctic Muon And Neutrino Detector Array) and is now implemented in the new detector. Since IceCube will detect the neutrino light curve with unprecedented resolution, this experiment will provide precision information for neutrino science and Supernova modeling. We estimate Supernova signals in IceCube for several models. While the Cherenkov light emission was simulated, the dark noise was taken from measurements during the first IceCube runs. The predictions on luminosity and mean energy are taken from the Livermore group for long time scales up to about 10s and from the Garching group for short time scales ~25ms [1,2,3] to analyze the very first rise of the Supernova neutrino emission. The figure shows the generated Supernova signal for the final IceCube detector setup with 4800 DOMs based on the Livermore SN simulation [3]. IceCube‘s estimated significance is more than one magnitude higher than that of AMANDA-II as the detector will have twelve times more DOMs with a significant lower noise rate and corresponding fluctuations.The significance of a “Livermore- like“ Supernova at 10kpc is 160 , while at 52kpc (Large Magellanic Cloud) the significance is still about 6 standard deviations. The figure shows significance versus distance for a Supernova detection in IceCube and AMANDA-II. Locations of the Galaxy Center and the LMC are indicated. Galaxy Center (10kpc)  ~ 160 LMC (52kpc)  ~ 6 What can we learn ? A triggered Supernova event will provide a variety of new information. It will be possible to measure the full neutrino light curve and neutrino spectra of a Supernova explosion. This information is important for the phenomenology of Supernovae, as the neutrino driven heating inside the star is a crucial component of the explosion mechanism [1,4]. The measured data will also provide information on neutrino oscillation effects within star and earth matter. It may be possible to determine the neutrino mass hierarchy [2]. This chance will be improved by combining flux measurements of experiments with different earth matter effects. A trigger sent to SNEWS would allow for the observation of the full optical light curve beginning just after the time of explosion – an observation that has not yet been made, yet.