1. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin on behalf of the MAGIC collaboration Max-Planck-Institut für Physik, Munich

2. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich outline Active Galactic Nuclei (AGN) and blazars Extragalactic Background Light (EBL) MAGIC  Markarian 421, z=0.030  Markarian 501, z=0.034  1ES2344+514, z=0.044  Markarian 180, z=0.045  1ES1959+650, z=0.047  1ES1218+304, z=0.182  PG1553+113, z>0.09 Conclusions, outlook redshift

3. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich TeV blazars TeV blazars: non-thermal emission, highly variable All but one are HBL (high peaked BL Lacertae) Models: leptonic vs. hadronic origin Kino et al, ApJ, 2002, 564, 97 See talk by Paolo Padovani on Tuesday

4. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich EGRET sky 273 sources above 100 MeV

5. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich TeV sky > 30 sources above 100 GeV, and this is factor 3 larger than before H.E.S.S and MAGIC went online

6. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Where are the sources? In the Galactic plane, it starts to be crowded above 100 GeV. Expectations fulfilled. Extragalactic sources: only 13: 12 blazars and M87 as radio galaxy. Expect many more if extrapolate from EGRET AGNs. Possible reasons:  Intrinsic cut-off  Extragalactic absorption

7. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Attenuation of GeV-TeV photons EBL Cherenkov Telescope BL-Lac object Cross section peaks at: Pair creation: See talk by Luigi Costamante

8. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich What is EBL? Unique imprint of the history of the universe Test of star formation and galaxy evolution models Cosmological evolution models have to explain current EBL Opacity source of GeV-TeV photons Red shifted stellar light Red shifted dust light Dwek&Krennrich 05, Kneiske et al. 04 2.7K

9. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Direct measurements Uncertainties due to strong foreground emission (e.g. zodiacal light) Galaxy counts provide robust lower limits

10. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich MAGIC The largest imaging atmospheric Cherenkov Telescope with 17m mirror diameter 3.5° FoV Camera with 576 enhanced QE PMT’s Trigger threshold: 50- 60GeV Sensitivity: 2.5% Crab Nebula in 50 hours  -PSF is about 0.1° Energy resolution 30% at 150 GeV Canarian Island La Palma, 2200 m asl

11. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Mkn 421 (z=0.030) Dec 2004 – Apr 2005 25.6 h, over 7000 excess events Energy threshold: 150 GeV spectru m TeV-X-ray- correlation ApJ submitted, astro- ph/0603478 TeV X-ray optica l lightcurv e TeV X-ray optica l

12. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Mkn 421 (z=0.030) In case of 1-day variability scale, the model provides similar parameters as from the 1994 flare: D=9, B=0.3G SE D SSC constraints ApJ submitted, astro- ph/0603478 B C A D E F log(D) log(B)

13. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Mkn 501 (z=0.034) June – July 2005 23.1 h, over 85 , over 14000 excess events Analysis threshold: 150 GeV TeV-optical- correlation TeV X-ray optica l TeV-X-ray- correlation

14. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Mkn 501 (z=0.034) Flare on 9 July 2005 Doubling time less than 5 min. Spectrum shape changes within minutes IC peak detected?

15. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich 1ES2344+514 (z=0.044) Whipple: Flare (20-12-95), F (>350GeV) = 63% Crab, (Catanese, 97) Whipple later upper limits only, F (>350GeV) < 8% Crab in 96/97 (Schroedter, 05) HEGRA 1997-2002: 4.4  F int (>970GeV) = 3.3% Crab (Tluczykont et al. 03) MAGIC. Aug 05 – Jan 06, 27.4 h: 8.1  ; F(>350GeV) = 6% Crab, no variability; index: - 2.96±0.12 Clear detection! Sky plot: TeV X-ray opt. Light- curve :

16. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Mkn 180 (z=0.045) Whipple: F (>300GeV) <10.5% C.U. HEGRA: F (>1.5TeV) <12% C.U. MAGIC: DISCOVERY! April 2006, 11.1 h Triggered by optical flare 5.5 , F (>200GeV) = 11%C.U., index: -3.3 ± 0.7  2 plot sky plot spectru m SED Subm. to ApJL, astro-ph/0606630

17. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich 1ES1959+650 (z=0.047) Blazar famous for the orphan flare in 2002 MAGIC: Significant signal in only 6h of effective obs. ApJ, 639 (2006), 761 Light curve: flaring or quiescent state? Simultaneous multiwavelength data not enough to distinguish between hardronic and leptonic models More is in pipeline Spectral index: 2.72 ± 0.14 3.2 ± 0.2 TeV X-ray opt.

18. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich 1ES1218+304 (z=0.182) Whipple: F (>350GeV) <8% C.U. HEGRA: F (>750GeV) <12% C.U. MAGIC: DISCOVERY! Jan 2005, 8.2 h 6.4 , F (>120GeV) = 13% C.U., index: -3.0 ± 0.4 TeV lightcurve  2 plot spectrum

19. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich 1ES1218+304 (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 - ,  > 1.5

20. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich PG1553+113 (z>0.09) spectru m lightcurve Alpha plot Observed 18.8h in 2005-06 H.E.S.S.: 4.0  evidence (A&A 448L (2006), 43) MAGIC: ApJL submitted, astro-ph/0606161 8.8 , firm detection.

21. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich PG1553+113 (z>0.09) HESS published spectrum MAGIC published spectrum HESS / MAGIC together HESS corrected by 7 % HESS/MAGIC joint Aim: derive constraint on the redshift of the source Assumptions: a) intrinsic slope not harder than 1.5 b) intrinsic spectrum has just one peak HESS MAGIC HESS corr. MAGIC HESS/MAGIC

22. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich PG1553+113 (z>0.09) Method 1: Loglikelihood test between power law and broken power law Method 2: modified run test; probability of the given distribution of points around the fitted power law Preliminary result, using the new method: z < 0.42 Published: HESS: z<0.74 MAGIC: z<0.78

23. MAGIC TeV blazars and Extragalactic Background Light Daniel Mazin, MPI, Munich Conclusions / Outlook There are 12 blazars above 100 GeV established MAGIC detected 7 of them; 2 of them discovered by MAGIC, 1 co-discovered with HESS Simple leptonic models usually work but there are exceptions (e.g. 1ES1959+650) De-absorbed spectra are the harder the further away the sources are. Observational bias or physics? Hard preliminary constraint on the redshift of PG1553+113 to z 0.42, first observation of multipeak structure of a blazar above 100 GeV.