The MAGIC Telescope MAGIC International School of Cosmic Ray Astrophysics Erice, 2-13. July 2004 MAGIC - talks in this session - Overview - F.Goebel Selected physics topics Pulsars - R. de los Reyes AGNs - R. Firpo Microquasars - N. Sidro GRBs - S. Mizobuchi First Analysis Analysis method - D. Mazin First results - E. Aliu Florian Goebel Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) München for the MAGIC collaboration Parlero’ telescopio MAGIC come esempio di “ground based experiment” per la gamma-astronomia. Da quando fu osservata la prima sorgente nel 1989 (wipple) i Ttelescopi cherenkov hanno raffinato tecnologie e metodologie. Ora gli IACT sono un maturo strumento di misura e osservazione per l’astronomia gamma delle alte energie Siamo giunti alla realizzazione di telescopi cherenkov di seconda generazione. Magic tra questi sara’ quello con la piu’ bassa soglia in energia Esistono altri progetti di esperimento “ground based” non imaging cherenkov telescopes come solar array (celeste) o rivelatori di particelle in alta quota (ARGO) ma, almenno finora, non hanno dimostrato di avere un ottimale strategia di reiezione del fondo. F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

Outline - MAGIC overview The MAGIC Telescope The aim for low energy threshold (the physics case) The key elements of the MAGIC telescope Outlook Nella prima parte del talk illustrero la tecnica IACT riassumendo le pricipali peculiuarità Di seguito’ parlero del telescopio MAGIC, della collaborazione e dello stato di avanzamento della realizzazione dello strumento Passero’ dunque ad illustrare gli obiettivi sceintifici di MAGIC Infine le conclusioni F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

The MAGIC Collaboration Major Atmospheric Gamma-Ray Imaging Cherenkov Telescope Barcelona IFAE, Barcelona UAB, Crimean Observatory, U.C. Davis, U. Lodz, UCM Madrid, INR Moscow, MPI München, INFN/ U. Padua, INFN/ U. Siena, HU. Berlin, Tuorla Observatory, Yerevan Phys. Institute, INFN/ U. Udine, U. Würzburg, ETH Zürich International collaboration of ~ 100 physicists 16 institutes 11 countries Il mio talk vertirà sul telescopio magic come esempio di “ground based sxperiment” di seconda generazione F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice The MAGIC telescope Largest Imaging Air Cherenkov Telescope (17 m mirror dish) Located on Canary Island La Palma (@ 2200 m asl) Lowest energy threshold ever obtained with a Cherenkov telescope Aim: detect –ray sources in the unexplored energy range: 30 (10)-> 300 GeV F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

Imaging Air Cherenkov Telescopes Gamma ray Cherenkov light Image of particle shower in telescope camera ~ 10 km Particle shower ~ 1o Cherenkov light ~ 120 m F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice Standard Analysis gamma shower Shower reconstruction and background rejection based on image shape analysis Hillas parameters: Length, width, distance, alpha raw image cleaned image hadron shower (background) F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

First source observations Mkn 421 (AGN) February 2004 (in flaring state) Source position Alpha distribution 1200 excess events 800 background events preliminary 100 minutes observation => Significance: 23 sigma F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

The unexplored spectrum gap Satellites give nice crowded picture of –ray energies up to 10 GeV. Effective area < 1 m2 Ground-based experiments show very few sources with energies > ~300 GeV. Effective area > 104 m2 Something must happen in the gap, and it’s interesting enough to have an instrument to measure in it. Also to confirm some of the EGRET catalogue sources at higher energies. And also to cross check the energy calibration and measurements between satellites and ground based experiments. Close gap with MAGIC expect discovery of many new sources F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

The MAGIC Physics Program Cosmological g-Ray Horizon AGNs Pulsars Origin of Cosmic Rays Tests of Quantum Gravity effects SNRs Cold Dark Matter GRBs F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

Absorption of extragalactic  - rays -rays travelling cosmological distances interact with the Extragalactic Background Light (EBL) For IACTs energies (10 GeV-10 TeV), the interaction takes place with infrared ’s (0.01 eV-3 eV, 100 m-0.5 m). MAGIC EBL Attenuated flux is function of g-energy and source distance (redshift z). F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice Gamma Ray Horizon The EBL absorption limits the maximum observable distance of g-ray sources. Gamma Ray Horizon A lower energy thresholds allows a deeper look into the universe MAGIC phase I MAGIC phase II F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

Measurement of the IR background IR background light is result of history of the universe (Star formation, Radiation of stars, Absorption and reemission by ISM) Mkn 501 (z=0.034) By measuring AGN spectra up to z=1, MAGIC can help determining the IR background Absorption leads to cutoff in AGN spectrum Need several sources (@ similar z) to disentangle source intrinsic effects. F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice Pulsars 7 -ray pulsars seen by EGRET (E < 10 GeV) Only upper limits from present IACTs for pulsed emission (spectral cut-off) Where do g-rays come from? Outer gap or polar cap? 30 – 100 GeV decisive energy range F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice Gamma Ray Bursts Origin and acceleration mechanism not yet fully understood. Do GRBs have E > 10 GeV counterparts? GRBs are short (10 – 100 sec) => Need fast repositioning after GRB alert If GRB origin very far => High energy -rays will be absorbed by EBL => Need low energy threshold MAGIC can observe 1-2 GRB/year F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

Search for Dark Matter Particles Neutralino (lightest SUSY particle) is attractive Cold Dark Matter candidate g-flux from c annihilations: CDM density: g-ray flux ~ r2 => search for CDM clumps observe: galactic center (high diffuse g background), dwarf spheroidal and nearby galaxies, globular clusters g-line Eg = mc g-line Eg = mc- mZ2/4 mc g continuum Particle physics: g-continuum dominates g-lines suppressed F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

Key Elements of the MAGIC Telescope 17 m diameter reflecting surface (240 m2 ) Light weight Carbon fiber Structure for fast repositioning Active mirror control Diamond milled aluminum mirrors 3.5o FOV camera 577 high QE PMTs Analog signal transport via optical fibers 2-level trigger system & 300 MHz FADC system IPE CE NET F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice The Reflector overall reflector: parabolic (f/1), isochronous, maintain time structure of Cherenkov light flashes (~2 nsec) better bkg light rejection ~950 spherical mirror elements 49.5 x 49.5 cm2 All-aluminum, quartz coated, diamond milled, internal heating >85% reflectivity (300-650nm) 4 mirrors mounted on 1 panel mirror spot (after pre-alignment): d90%~1cm (pixelinner d=3cm) F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice The Frame carbon fiber structure lightweight dish & mirrors: 20 tons telescope: 65 tons Stiff allows fast slewing time (180º in both axes in 22s) Fast follow-up of a Gamma Ray Burst F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice

The Active Mirror Control PC controlled motors allow remote refocusing of all mirror panels anytime Correct for small deformations of telescope structure Panel orientation measured with laser beam Achievable Point Spread Function: R80 ~ 15mm  0.05°  0.9 mrad F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice The Camera Matrix of 577 PMTs Field of View: 3.50 Inner part: 0.10 pixel Outer part: 0.20 pixel Plate of Winston cones  Active camera area 98% F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice High QE PMTs Pixels: 6 stage PMTs ET 9116A (1”) ET 9117A (1,5”) Quantum Efficiency increased up to 30 % with diffuse scattering coating extended UV sensitivity by with wavelength shifter coating 239 m2 -> 284 m2 !!! F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice The Signal Processing Analog signals transmitted over 162 m long optical fiber: Signal still short Cable weight, noise immune. Max trig rate ~ 1 kHz data rate => 20 MB/s => 800 GB/night 2 level trigger Fast (5 nsec) next neighbor logic Slower (150 nsec) topological pattern recognition Stretch pulse to 6 nsec Split to high & low gain (dynamic range > 1000) Digitize with 300 MSamples/s 8 bit FlashADCs (testing 2GS/s) F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice M. Mariotti Padova 30-01-2003

Future of MAGIC observatory MAGIC I Second MAGIC type telescope under construction (more observation time, background rejection & better event reconstruction in coincidence mode) Plans for 34 m telescope for gamma astronomy down to E = 5 GeV ECO1000 F. Goebel, MPI München, 2-13 July 2004, ISCRA, Erice