2. Frank Krennrich*, for the VERITAS Collaboration (*Iowa State University) Results from VERITAS Results from VERITAS New Opportunities at the interface between particle physics and astronomy Tel 1 Tel 2 Tel 3 Tel 4 VERITAS

3. OutlineOutline VERITAS Instrument Performance Northern Sky seen in the first year Extragalactic science Summary

4. Very Energetic Radiation Imaging Telescope Array System E ~ 100 GeV - 50 TeV A area ~ 10 5 m 2 ang. Res. ~ 3’ - 6’ Energy Res. ~ 15% FOV ~ 3.5 0

5. VERITAS Collaboration U.S. Adler Planetarium Argonne Nat. Lab. Barnard College DePauw U. Grinnell College Iowa State U. Purdue U. Smithsonian UCLA UCSC U. Of Chicago U. of Delaware Univ. of Iowa U. of Massachusetts U. of Utah Washington U. Canada McGill U. U.K. Leeds U. Ireland Cork Inst.Tech. Galway-Mayo Inst. N. U. I., Galway U. College Dublin + 25 Associates Supported by: SI, NSF & DOE (US), PPARC (UK), NSERC (Canada), SFI (Ireland) Supported by: SI, NSF & DOE (US), PPARC (UK), NSERC (Canada), SFI (Ireland) VERITAS-4 Construction funded in 2003 VERITAS-4 Construction funded in 2003

6. VERITAS Observatory T1 Jan 2005 T1 Jan 2005 T2 Spring 2006 T2 Spring 2006 T3 Fall 2006 T3 Fall 2006 T4 Spring 2007 T4 Spring 2007

7. TeV Monitoring capability

8. VERITAS Telescope Control Room Davies-Cotton f/1.0 Optics. Total area=110m 2

9. Control Room Davies-Cotton f/1.0 Optics. Total area=110m 2 VERITAS Telescope

10. Stereoscopic Events

11. Angular Resolution o Courtesy Asif Imran

12. VERITAS Sensitivity 1% Crab in 47 hours 5% Crab in 2.5 hours 5 σ Detection Sensitivity Measured sensitivity to the Crab Nebula at high elevation (>65°) HESS ~ 1% Crab in 25 hours MAGIC ~ 2% Crab in 50 hours

13. TeV  -ray Sky W Comae IC 443 Crab Nebula Mrk 421 Mrk 501 Cas A 1ES 2344+514 LSI +61 303 1ES 0806+524 1ES 1218+304 M87

14. Key Science Questions Origin of Cosmic rays - galactic/Extragalactic Relativistic Jets & Black holes - leptonic vs. hadronic jets Dark Matter - Neutralino Annihil. Signature - LHC - direct detection - Storage TeV beam in extragalactic space - test dispersion relation of light - Q.G. - how far do we see? Opacity? - Probe Cosmic Infrared Background

15. Science Program Observations: ~ 800 hrs / year + ~ 200 hrs / year moonlight Discretionary (10%) Bulk Program (40%) ToO’s GRB’s (priority) etc. Sky Survey (Cygnus region) BLAZARS SNRs/PWNDark Matter Key Science Projects (50%) Science Groups: Astroparticle Physics Blazars Dark Matter Extragal. Sources Galactic Compact Galactic Diffuse GRB’s PWN & SNR’s Unidentifieds

16. recent discoveries Multiwavelength Science EBL Extragalactic Science

17. 1ES 0806+524 ATEL#1415 Preliminary P. Cogan, in preparation - “best candidate” TeV BL Lacs (Costamante & Ghisellini 2002) - HBL - z = 0.138 - 5.8  in ~ 40 hours - flux ~ 0.01 Crab - weakest VERITAS blazar - “best candidate” TeV BL Lacs (Costamante & Ghisellini 2002) - HBL - z = 0.138 - 5.8  in ~ 40 hours - flux ~ 0.01 Crab - weakest VERITAS blazar

18. W Comae Courtesy of M. Beilicke - radio 1971, X-ray 1980 - IBL (between LBL- HBL) - seen by EGRET: 0.1 -10 (27) GeV - z = 0.102 - 4.9  in ~ 40 hours - outburst March 08 (> 8  detection) - Quasi- simulataneous X-ray data (Swift) ATEL#1422

19. W Comae Courtesy of M. Beilicke

20. W Comae Courtesy of M. Beilicke

21. W Comae Courtesy of M. Beilicke

22. W Comae Quasi-simultaneous data March 14/15 2008 from AAVSO, UVOT, XRT, VERITAS - one-zone SSC/ weak B-field - EC model/ B ~ 0.3 G - GeV/TeV obs. critical

23. M87M87 HST M87 - Giant elliptical Galaxy - D ~ 16 Mpc - Misaligned jet ( E >10 TeV electrons - close up view of a jet! 4  evidence (HEGRA 03) M87

24. - UHE cosmic rays? - Synchr. Proton Blazar? - Synchr. Self Compton - inv. Compton in kpc jet (no time variations) - annihilation of SS dark matter - Where do TeV photons originate? p π0π0   +  M87M87

25. - M87 under the “microscope” in radio-optical-X-ray - variable in X-rays - TeV “image” is not resolved - M87 under the “microscope” in radio-optical-X-ray - variable in X-rays - TeV “image” is not resolved 15 “ 80 pc M87M87

26. 15 “ 80 pc M87M87 - M87 under the “microscope” in radio-optical-X-ray - variable in X-rays - TeV “image” is not resolved - M87 under the “microscope” in radio-optical-X-ray - variable in X-rays - TeV “image” is not resolved

27. VHE/X-ray Long-Term Correlation Acciari et al. (VERITAS collaboration), ApJ, 679, 1427 (2008) M87M87 VHE/X-ray Short-Term Correlation Hui et al 2008 (VERITAS collaboration), in preparation

28. M87M87 VHE/X-ray Long-term Light Curve Hui et al 2008 (VERITAS collaboration) Joint campaign HESS/MAGIC/VERITAS > 120 h in 2008 Stay tuned!

29. 1ES 2344+514 - HBL - z = 0.044 - discovered 1995 by Whipple - 0.07 Crab - VERITAS Observations Oct. 07 - Jan. 08 - 20.5  detection - Swift: highest known X-ray flux on Dec. 8 07 - VHE flux on Dec. 6/7 07: 0.41 Crab

30. Mrk 421 ATEL#1506 - HBL - z = 0.031 - “old faithful” - Early 2008: 0.3 - 10 Crab - TeV monitor of transients

31. 1ES 1218+30.4 Courtesy of M. Beilicke Courtesy of P. Fortin z=0.182

32. Probing Cosmology Blazar: DN/DE ~ E -2 Absorption: exp (-  (E   )) exp (-  (E   )) E ~ 1 TeV E ~ 1 TeV  ~ 1 eV Nikishov, JETP, 14, 2 (1962) Gould & Schreder, Phys. Rev. 155, 1408 (1967) 155, 1408 (1967) Stecker, de Jager & Salamon, ApJ, 390, L42 (1992) 390, L42 (1992) Measured Spectrum: dN/dE ~ E -2 exp(-  (E   )) dN/dE ~ E -2 exp(-  (E   )) e-e-e-e- e+e+e+e+

33. TeV Data VERITAS HESS - blazars with sufficient redshift - good spectral data - sensitive to near and/or mid-IR 1ES1218+30.4 (HBL) Z = 0.182 E ~ 0.2 - 1.5 TeV 1ES1101-232 (HBL) Z = 0.186 E ~ 0.2 - 2.9 TeV 1ES0229+200 (HBL) Z = 0.1396 E ~ 0.5 - 11.2 TeV Aharonian et al. 2006, 2007. 3o3o

34. Constraints to Intrinsic Spectra New Lower limit from galaxy counts Taking into account Fuzzy fringes of galaxies Levenson & Wright 2008 For a given measured Blazar spectrum a Higher EBL implies a Harder intrinsic spectra! Slope of EBL spectrum is Critical for constraining Intrinsic spectrum! Levenson & Wright, arXiv:0802.1239v2

35. Constraints to Intrinsic Spectra

39. EBL Lower Limits & Blazar Spectra TeV blazars seem to exhibit extremely hard spectra dN/dE ~ E -1.28+-0.20 or harder! FK, Dwek & Imran, submitted to ApJ

40. SummarySummary VERITAS Performs well! 0.01 Crab (47 hr); ang. Res. ~ 0.1deg. Seen ~ dozen sources in the Northern Sky Broad Science program Detailed studies of M87 Discovery of W Comae; study of IBLs Hard spectra of distant blazars EBL studies