Igor Oya Vallejo UCM 1 MAGIC observations of Active Galactic Nuclei Igor Oya Vallejo UCM Madrid On behalf of MAGIC collaboration 1 VIII Reunión Científica de la Sociedad Española de Astronomía

Igor Oya Vallejo UCM 2 Multiwavelength Astronomy 2 2

Igor Oya Vallejo UCM 3 Satellites vs Ground Detectors EGRET (on Compton gamma ray observatory) GLAST satellite: was launched past month Expect sources !! Small detector area Low sensitivity for energies > 50 GeV GLAST 1 year MAGIC HESS 50h VERITAS 50h 3

Igor Oya Vallejo UCM 4 VHE  -ray targets > 60 sources above 100 GeV, rapid growth in recent years HESS galactic plane scan pulsar  -quasar shelltype SNR galactic center pulsar wind nebula GRBs AGN cold dark matter quantum gravity effects origin of cosmic rayscosmological  -ray horizon 4

Igor Oya Vallejo UCM 5 The MAGIC  -ray telescope Largest single dish Cherenkov Telescope: 17 m Ø mirror dish, mirror surface (241 m 2 ) 3.5° FoV Camera with 577 enhanced QE PMT’s Fast repositioning for GRBs: average < 40 s Low energy trigger threshold: GeV Sensitivity: < 2.0% Crab / 50 h  -PSF: ~ 0.1° Energy resolution: 20 – 30% Enhaced duty cycle : Moon + twilight Observations Major Atmospheric Gamma-ray Imaging Telescope Canary Island La Palma 2200 m asl 5

Igor Oya Vallejo UCM 6 Imaging Air Cherenkov Telescopes ~ 10 km Particle shower ~ 1 o Cherenkov light ~ 120 m Gamma ray Cherenkov light Image of particle shower in telescope camera reconstruct: arrival direction, energy have to reject hadron background 6

Igor Oya Vallejo UCM 7 Crab-Standard VHE Candle IC peak is estimated to be around 75 GeV Circle containing 64% of events at 250GeV >500GeV Circle Position of Pulsar IC peak? Point-like VHE emission (r < 2’) Coincident with Pulsar position Systematic uncertainty ~ 1’ 7

Igor Oya Vallejo UCM 8 Extragalactic VHE  -ray sources: AGN with relativistic jet aligned with observer’s line of sight of observer non-thermal emission, highly variable AGNs: sources of extragalactic CRs ? VHE gamma-rays: leptonic or hadronic origin ? Blazars: Jet Black Hole Obscuring Torus Narrow Line Region Broad Line Region Accretion Disk Urry & Padovani (1995) blazar 8

Igor Oya Vallejo UCM 9 Mrk501 (z=0.034) Precision studies of spectrum and variability possible now Flare on 30 th June and 9 July 2005 observed by MAGIC Doubling time less than 5 min Spectrum shape changes within minutes => Causality & speed of light limit size of emission region Quantum Gravity theories predict violation of Lorenz invariance (speed of light depends on photon energy) => use energy dependent time structure of flares to test Lorenz invariance Variable VHE gamma-ray emission from Markarian 501 J. Albert et al., ApJ 669 (2007) 862 9

Igor Oya Vallejo UCM 10 Mrk501 Flares on June 30 and July 9 in 2005 MAGIC X-Ray Optical Intra-night light curve in 2mins bin Light curve in May-July 2005 June 30July 9 Spectrum down to 100GeV =>IC peak ? TeV TeV TeV TeV

Igor Oya Vallejo UCM 11 EBL Cherenkov Telescope BL-Lac object Attenuation of VHE  -rays 11

Igor Oya Vallejo UCM 12 1ES (z=0.182) Whipple: F (>350GeV) <8% C.U. HEGRA: F (>750GeV) <12% C.U. MAGIC: DISCOVERY! Jan 2005, 8.2 h 6.4 σ, F (>120GeV) = 13% C.U., index: -3.0 ± 0.4 Support the evidence that in general HBL flux in X-RAY ~ flux in TeV TeV lightcurve  2 plot spectrum Discovery of VHE gamma-ray emission from 1ES J. Albert et al., ApJ Letters 642, L119 (2006) 12

Igor Oya Vallejo UCM 13 1ES (z=0.182) Is it possible to derive EBL constraints from the 1ES1218 spectrum? Assuming 6 different EBL realizations, all reconstructed de-absorbed spectra do not contradict the rising slope dN/dE  E - ,  >

Igor Oya Vallejo UCM 14 1ES (z=0.212) Optical trigger Distant source MAGIC: DISCOVERY! March-May 2007, 18.7 h 6.2 σ, F (>200GeV) = 10% C.U., index: -3.3 after deabsortion (model Kneise et al.(soft, no new constraint, confirm models) Second source successfully triggered by optical, after Mrk 180 Optical trigger valuable tool for VHE γ astronomy Discovery of VHE gamma-ray emission from 1ES J. Albert et al., ApJ Letters 642, L119 (2006) 14

Igor Oya Vallejo UCM 15 S ● Blazar clasiffied as LBL or IBL ● Very rapid variability from radio to X-rays ● Redshift unknown, but recent detection of the host galaxy suggests z=0.33±0.09 (Nilsson et al. 2008, submitted to ApJL) ● Discovery of VHE gamma-rays by MAGIC in April 2008 (Teshima et al. 2008, ATel #1500) ● Optical trigger MAGIC observations 15

Igor Oya Vallejo UCM 16 S March-May 2008, 2.6 h 6.8σ Analysis of the data ongoing, preliminary flux estimation: F(>400GeV)= ph/cm2/s~25% crab. On 28th of April SWIFT reported “X-ray and UV flux levels significantly larger than ever observed before” (Giommi et al, ATel#1495) 9/27/

Igor Oya Vallejo UCM 17 3C 279 (z = 0.538) Brightest EGRET AGN Flat Spectrum Radio Quasar Fast time variation ΔT ~ 6h in a flare in 1996 MAGIC OBS. 9.7 hours in 10 nights Marginal detection on 22 Feb 2006 Clear detection on 23 Feb 2006, 6.15 sigma Most distant object detected in these VHE All source classes on blazar sequence detected on VHE Very high energy gamma rays from a distant Quasar: How transparent is the Universe MAGIC Collaboration, Science, 320 (2008)

Igor Oya Vallejo UCM 18 3C 279 (z = 0.538) ● EBL influences observed spectrum ● Reconstruction of intrinsic spectrum using different EBL models: ● S07 fast-evolution: α *=0.5±1.2st±0.5sy ● Kneise (tuned): α *=1.5 ● P05: α *= 2.9 ± 0.9st ± 0.5sy ● If we assume α * = >1.5 (obs. and models support): ● Probe to z=0.538 ● Allowed region of EBL quite small ● HST and Spitzer may correctly estimate EBL 18 “Gamma ray horizon”

Igor Oya Vallejo UCM 19 Conclussions ● There are now 24 Blazars detected on VHE. 13 of them by MAGIC, 6 of them first time ● From the total, 20 are HBL and the other: BL Lac (LBL), 3c279(FSRQ), M87(Radio), S (LBL). ● Mrk 501 studies have implications on fundamental physics. ● 3C279 very distant--> Important input for EBL ● Optical triggers led to discover Mrk180(2006), 1ES (2007), S

Igor Oya Vallejo UCM 20 Backup Slides

Igor Oya Vallejo UCM 21 Origin of cosmic rays ? , apparent source direction charged particle  0 ->   ± ->  + nucleus + X ->  + X‘  -> e +

Igor Oya Vallejo UCM 22  -ray astronomy and cosmic rays (CR) -- 00 ++  (TeV) p + (>>TeV) matter hadronic acceleration Origin of CRs? (charged) CRs deflected by B-fields => search for  -rays produced by CRs close to source e - (TeV) Synchrotron  (eV-keV)  (TeV) Inverse Compton  (eV) B leptonic acceleration E 2 dF/dE energy E  0 decay IC discriminate hadronic vs leptonic acceleration => shape of spectrum

Igor Oya Vallejo UCM 23 Experimental Techniques ( E  10 GeV ) Instrumented Water / Ice Scintillator or Water Č   Č-Telescope Č Fluorescence Detector Hadron-Detector Fluorescence Primary (Hadron,Gamma) Air Shower Atmospheric (4  )  Primary (4  ) , e,  R&D Radio-Detection Acoustic-Detection

Igor Oya Vallejo UCM 24 Background Rejection hadron shower (background) gamma shower raw imagecleaned image Main Background: - Cosmic Ray (hadron) showers - >10 4 times more numerous than gamma-ray showers - Reject based on shower shape

Igor Oya Vallejo UCM 25 Standard “Hillas” Analysis Background rejection with multidimensional cuts on Hillas parameters: Length, Width, Dist, Alpha On data Off data Alpha Plot  WIDTH LENGTH DIST Hadron background: - isotropic - flat Alpha distribution Gammas: - excess in source direction

Igor Oya Vallejo UCM 26 First Generation telescope Whipple 1968 Detection of the Crab Nebula 1989: > 50 h observation time for 9  signal

Igor Oya Vallejo UCM 27 Current generation Cherenkov telescopes HESS CANGAROO III VERITAS MAGIC

Igor Oya Vallejo UCM 28 What is the strategy ? Observe Known Sources to make precision studies of spectrum, variability Discover new sources at high redshifts, test EBL models

Igor Oya Vallejo UCM 29 Extragalactic VHE  -ray sources: AGN with relativistic jet aligned with observer’s line of sight of observer non-thermal emission, highly variable AGNs: sources of extragalactic CRs ? VHE  -rays: leptonic or hadronic origin ? observer 12 blazars & 1 radio galaxy 12 blazars & 1 radio galaxy Blazars: redshift MAGIC observations: Mrk 421, z=0.030 Mrk 501, z= ES z=0.044 Mrk 180, z= ES ,z= ES ,z=0.182 PG ,z>0.09