44 th Rencontres de Moriond - La Thuile, Valle d’Aosta, February 1-8, 2009 The MAGICextragalactic sky The MAGIC extragalactic sky Barbara De Lotto Università di Udine & INFN - Italy on behalf ot the MAGIC Collaboration The telescope MWL campaigns Recent results & discoveries Hints of new physics?

Imaging Air Cherenkov Technique ~ 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 - reject hadron background statistically in the analysis

The MAGIC site La Palma, IAC 28° North, 18°West ~2240 m asl

Currently the largest single-dish Cherenkov telescope (17 m diameter) In operation since fall 2004 ( starting AO-5 in Spring ’09) Sensitivity: 1.6% Crab in 50 h Angular resolution: 0.1 deg Energy resolution: ~ 20% Enhanced duty cycle (by 50%) thanks to moonlight & twilight observations Substantially lower energy threshold than other installations: 55 GeV nominal 25 GeV pulsar (“sum”) trigger Fast repositioning (~30 s) 2 nd telescope (MAGIC-II) first light this winter, ceremony on April 24th The MAGIC telescope ~150 physicists, 23 institutes Germany, Italy, Spain leading

Propagation of  -rays x x x Measured spectrum affected by attenuation in the EBL: For  rays, relevant background component is optical/infrared (EBL) different models for EBL: minimum density given by cosmology/star formation Measurement of spectral features permits to constrain EBL models Science 2008 ≈ ~ E -2  VHE  EBL  e + e - dominant process for the  absorption: maximal for: Heitler 1960  (  ) ~

Attenuation of  -rays  -ray horizon:  (E,z) = 1  (E,z) = 1 Importance of decreasing the energy threshold to look further away Blanch & Martinez 2005 region of opacity:  > 1 optical depth  Fazio & Stecker 1970

Extragalactic VHE  -ray sources 24 AGN discovered by IACTs: Ref.:

Extragalactic VHE  -ray sources: 23 blazars & 1 radio galaxy AGN with relativistic jet aligned with observer’s line of sight of observer non-thermal emission, highly variable Blazars:observer AGNs: sources of extragalactic CRs? VHE  -rays: leptonic or hadronic origin? E 2 dF/dE energy E  0 decay IC shape of spectrum Extragalactic Background Light Propagation mechanisms Lorentz Invariance e - (TeV) Synchrotron  (eV-keV)  (TeV) Inverse Compton  (eV) B leptonic acceleration -- 00 ++  (TeV) p + (>>TeV) matter hadronic acceleration

Highlights in MAGICextragalactic observations Highlights in MAGIC extragalactic observations Mrk421 (z=0.031) 1ES2344 (z=0.044) 1ES1959 (z=0.047) Mrk501 (z=0.034) Mrk180 (z=0.045) MAGIC discovery 1ES1218 (z=0.18) MAGIC discovery + 3 more in press … M87 (z=0.0043) S (z=0.31) BL-Lacertae (z=0.069) MAGIC discovery 1ES1011 (z=0.212) MAGIC discovery 3C279 (z=0.536) MAGIC discovery MAGIC J0223 (3C66B?) MAGIC discovery PG (z>0.25) MAGIC codiscovery MAGIC discovery PRELIMINARY

Bright Blazars Multiwavelength campaigns Simultaneous Multifrequency Observations covering 15 decades in photon energy: VHE: H.E.S.S., MAGIC, VERITAS HE: Agile, Fermi X-ray: Suzaku, Swift, Chandra, Integral Optical: KVA Radio: Metsahövi, … Some recent MWL campaigns: Mrk 421, Mrk 501, PG , 1ES , 1H , M87 Further under process, organized …

1ES ApJ 679 (2008) 1029 MWL campaign during May 2006 with Suzaku and Swift Two-peaked SED VHE emission (E>200 GeV) at one of the lowest ever observed states, no significant variability detected Modeled by a one-zone SSC model

Mrk 421 June ‘08 flare ApJ 691 (2009) L13 Mrk 421 June ‘08 flare Donnarumma+ ApJ 691 (2009) L13 Hard X-ray flare triggered MWL campaign: WEBT, Swift, Agile, MAGIC, VERITAS Time variability in TeV and X-ray comparable SSC modeling Interpretation paper under development

PG MWL campaign during July 2006 with H.E.S.S., Suzaku and KVA Simultaneous MWL campaign during March- April 2008 with Agile, XTE/ASM and KVA [paper in preparation] Differential spectrum compatible with H.E.S.S. and previous measurements Reimer+ ApJ 682 (2008) A&A 493 (2009) Spectral Energy Distributiom: homogeneous one-zone SSC model PRELIMINARY KVA AGILE U.L. MAGIC XTE/ASM

M87 constant flux >350 GeV GeV day-scale : 5.6 σ α=–2.2 α=–2.6 (Crab nebula) VERITAS/MAGIC/H.E.S.S. monitoring 8  on 2008 Feb 1 → Trigger issued to VERITAS and H.E.S.S. 9.9  in overall sample (22.8 hours) between 2008 Jan 30-Feb 11 Flux variable between 3-15% Crab High variability > 350 GeV Confirming day-scale variability (5.6  ). No intra-night variability Compatible with constant between GeV ApJ Lett. 685 (2008) L23 The first non-blazar radio galaxy observed to emit VHE  -rays

Optical triggers  new discoveries Mkn 180 z = ToO trigger MAGIC 12.1 h S=5.5 σ March 2006 ToO trigger 1ES z = MAGIC 18.7h S=6.2 σ March-May 07 ApJ, 667 (2007) L21 S MAGIC PRELIMINARY Significance 6.8 σ S z = 0.31 KVA optical telescope at la Palma ApJ, 648 (2006) L105

The 3C 66A/B region B: radio Galaxy A: distant Blazar, VHE candidate (EGRET, Crimea, VERITAS, Fermi) MAGIC observations triggered by optical outburst in 2007 ApJ Lett. 692 (2009) 29 3C 66B is more likely the source of emission ( MAGIC J )

flat-spectrum radio-quasar at z=0.536 brightest EGRET source. Highly variable, fast variability (~6 hours) MAGIC observed it in 2006 during WEBT campaign for 9.7 hours in 10 nights Clear detection 23 rd Feb 2006 (6.2  ) First FSRQ in TeV  -rays Major jump in redshift 3C279 the most distant Science 320 (2008) 1752 skymap

Energy spectrum of 3C279 Measured and EBL-corrected spectrum:

3C279 and the  -ray horizon Test of the transparency of the universe extended to z = 0.536!

Is there a new land just behind the horizon?

Spectral characteristics of observed AGN observed spectral index redshift Selection bias? New physics? adapted from De Angelis, Mansutti, Persic, Roncadelli MNRAS 2009

Limits on 3C454.3 We have also searched farther out: during summer 2007 intense emission of 3C a well known z = detected by AGILE Upper limits derived from MAGIC data together with nearly simultaneous multifrequency data allow to constrain the SED

Quantification of the delay: (0.030±0.012) s/GeV Probability of no delay: 2.6% Possible explanations: Astrophysical: intrinsic source effects photons at different energies were emitted simultaneously Propagation effect due to Lorentz invariance violation:  Probing the Planck energy scale ApJ 669 (2007) 892 Phys Lett B 668 (2008) 253 Energy-delayed flare of Mrk501: IF Flares: a way to new physics? July 9 ‘05 Opens the way to future population AGN studies at different z

MAGIC is producing high quality astrophysics after ~3.5 observation cycles: MAGIC is producing high quality astrophysics after ~3.5 observation cycles: Lowest energy threshold => deepest horizon We have discovered 8 new extragalactic sources, detected and studied 5 known We have discovered 8 new extragalactic sources, detected and studied 5 known Important contributions to the understanding of AGN, EBL Important contributions to the understanding of AGN, EBL Now reaching out much further in redshift: high energy photons (often traveling through large distances) are a powerful probe of fundamental physics under extreme conditions Now reaching out much further in redshift: high energy photons (often traveling through large distances) are a powerful probe of fundamental physics under extreme conditions MAGIC-II starts operations on April 24 th MAGIC-II starts operations on April 24 th CONCLUSIONS

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