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Explore the next generation ultimate gamma ray observatory, CTA, focusing on physics objectives, AGNs, pulsars, cosmological gamma-ray horizon, cosmic rays, quantum gravity, and more. With data from the Teshima and Max-Planck-Institute, uncover insights on the origin of cosmic rays, cold dark matter, GRBs, and SNRs. Discover the importance of extending galactic plane surveys to the entire sky and the significance of an all-sky observatory. Learn about the strategies for low and high-energy observations, the potential for observing up to 1000 sources by 2020, and the impact of multi-messenger observations on understanding high-energy sources.
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CTAThe next generation ultimate gamma ray observatory M. Teshima Max-Planck-Institute for Physics
Physics Objectives AGNs Pulsars Cosmological g-Ray Horizon Origin of Cosmic Rays Quantum Gravity SNRs Cold Dark Matter GRBs
Galactic Sources HESS Galactic plane Survey Survey in 2-3% Crab unit Astro-ph/0510397 17 sources + Several PWNs Shell type SNRs X-Ray Binary Un-ID sources
Extragalactic sources PKS2005 PG1553 Spectral Indices of new sources range 3~4 New Sources
PG 1553(z>0.25) Very Soft energy spectrum the attenuationby pair creation X-Ray Intensity =6.5μJy Mrk421 9.9 μJy Mrk501 9.4 μJy
Absorption of gamma rays in the universe Pair Creation; γ+γ e+ + e-
The SSC framework Higher Z Higher source luminosity Lower IC peak softer spectrum X-ray intensity at 1keV PG 1553 6.5 μJy z~0.3 Mrk421 9.9 μJy z=0.03 Mrk501 9.4 μJy z=0.03 PG1553’s source luminosity ~100 x Mrk 2005 1553 2344 Fossati et al. 1998
From HESS & MAGIC to CTA • About 30 sources are now identified as VHE gamma sources. • GLAST will see ~3000 of GeV sources around 2010 • Our target in VHE Energy • ~100 VHE sources in 2010 by HESS-II and MAGIC-II • ~1000 VHE sources in 2020 by CTA • CTA Sensitivity must be 10 times better than HESS, and MAGIC • Importance of all sky observatory full sky survey relatively large FOV is favored • Extend HESS galactic plane survey to entire sky
By W.Hofmann ∝Ntel 50hrs ∝Area Background Limited Signal Limited
Kifune’s Plot (my optimistic expectation) ~1000 sources by CTA ~3000 sources by GLAST, AGILE GLAST AGILE
VHE Log(S)-Log(N) plot HESS-I ~30 sources MAGIC-I ~20 sources Log(N) ~ -1.0 Log(S) ??? HESS-II ~60 sources MAGIC-II ~40 sources CTA South ~300 sources CTA North ~200 sources CTA HESS-II MAGIC-II
Option: Mix of telescope types ~10 central huge telescopes ~100 small telescopes outside Picture: Courtesy of W.Hofmann
Strategy in Low Energy~10GeV Eth • Image quality is limited by the number of photons and air shower fluctuations • Increase photo-collection efficiency • Increase telescope density (gain x 4) • ~100m spacing ~50m spacing • Many sampling points reduce shower fluctuation effect • Increase telescope diameter (gain x 3) • 12m-17m φ 20-30m φ • Increase Q.E. of photo-detectors (gain x 3) • Q.E. 20% 60-80% • Timing between telescopes may help S. Biller • Total gain 30~40 in photo collection efficiency could be realistic • 10GeV threshold energy with reasonable sensitivity • Photon sampling rate: HESS, MAGIC ~ 1/1000 • Photon sampling rate in CTA should be ~1/30 (10% mirror area, 50% Q.E.) • Significant improvement in data quality intensive M.C. is necessary
Strategy in High energyup to 100TeV • Extension of the sensitivity up to 100TeV to study galactic cosmic ray source CTA south only • Current IACTs’ sensitivity is just limited by the number of gamma events • Emax ~10TeV Emax ~100TeV • ~105 m2 (300m x 300m) ~107 m2 (3km x 3km)
Multi-Messengers observationAll sky observatory (N,S stations) Gamma Rays Gamma Ray & X-Ray Satellites Neutrinos CTA North CTA South IceCube: 2010 Completion of the construction
HESS-II and MAGIC-II can be good R&Ds for CTA March 2006 HESS-II 28m diameter telescope Lower threshold energy In 2008 MAGIC-II 2x17m, High Q.E. detectors Lower threshold energy High Precision In 2007
Summary • We definitely need CTA for the development of VHE astrophysics after HESS-II and MAGIC-II • 500~1000 sources will be observed in 10-20 years operation 10-20 hrs/source (time limited) • CTA could be an ultimate ground based gamma ray observatory and we should consider north & south stations (All sky observatory) • The number of galactic sources may be limited • Multi-wavelength and multi-messenger observation are very important to understand the nature of high energy sources • New advanced photon detector development will have a strong impact in the design of CTA (HPD, SiPM)