Next Generation Particle Astrophysics with GeV/TeV  -Rays D. Kieda University of Utah

Outline  Quick VERITAS Update  GeV/TeV  -rays and Dark Matter searches  GRBs GeV/TeV emission  Diffuse and point source angular/energy ranges  Roadmap for future  -ray observatories

499 PMT camera Steel OSS Control Room  Davies-Cotton f/1.0 Optics. Total area=110m 2  Operational at Whipple Basecamp at Mt. Hopkins (1275m) in February 2006 VERITAS Telescopes-1 & 2

Camera 1.8 m 3.5º FOV 499 PMTs Photonis XP º spacing

VERITAS:1-2 Stereo Observations of Mrk 421 April-May, 2006 Wobble mode: ~10 sigma/30 minutes

VERITAS Update VERITAS Update  2 VERITAS telescopes operational at Mt. Hopkins (Feb 2006)  T3, T4 additional telescopes under construction now (First light T3: 9/2006; T4: 10/2006)  Expect full 4 telescope array operation by end of T1 & T2 (Dec 2005) T3 assembly (June 9, 2006)

R. ONG 2005 ICRC

Santa Fe Updated of R. ONG 2005 ICRC

Physics/Astrophysics with GeV/TeV  -rays Active Galactic Nuclei Extragalactic Background Light Shell-type Supernova Remnants Gamma-ray Pulsars Plerions Gamma Ray Bursts Dark Matter (Neutralino) Galactic Diffuse Emission Unidentified Galactic EGRET Sources Lorentz symmetry violation (Quantum Gravity) SN Nucleosynthesis/Cosmic Ray Origin * * *

mSUSY Dark matter Search: Neutralino-antiNeutralino annihilation Integrate annihilation cross sections over Dark Matter Galactic Halo density/velocity profiles to predict gamma ray energy spectrum But: Galactic Halo density profile for r<1kpc mostly based upon N-body simulations -> Only see strong signal if cusp in DM profile ->large variations in predicted GeV/TeV gamma ray production rate ->Galactic Mergers may reduce/eliminate cusps -> Cusps may also form in Galactic Halo? But: Galactic Halo density profile for r<1kpc mostly based upon N-body simulations -> Only see strong signal if cusp in DM profile ->large variations in predicted GeV/TeV gamma ray production rate ->Galactic Mergers may reduce/eliminate cusps -> Cusps may also form in Galactic Halo?

Variations in central Cusp with recent mergers

HESS Sag A* Spectrum Profumo-Dark Matter Conf. UCLA 2006

Diffuse Emission in the GC Region (HESS 2006)

N-body simulations of DM Cusp formation in Halo Dieand,Kuhlen & Madan2006 DM cusps form in Halo as well as Galactic Center Cups region may persist & be dark (except for DM annhilation) High Galactic Latitudes may be easier to observe DM annhilation than GC Need unbiased all-sky survey with large detection area (>10 4 m 2 ) to detect. Unable to use optical, radio surveys to predict source regions DM cusps form in Halo as well as Galactic Center Cups region may persist & be dark (except for DM annhilation) High Galactic Latitudes may be easier to observe DM annhilation than GC Need unbiased all-sky survey with large detection area (>10 4 m 2 ) to detect. Unable to use optical, radio surveys to predict source regions

359° 330° The H.E.S.S. Survey Galactic Plane 30° 0° RX J HESS J HESS J HESS J G HESS J HESS J HESS J HESS J Gal. Centre HESS J h in 2004, 500 pointings; sensitivity 2% of Crab above 200 GeV 8 new > 6  post-trial (+3 known)

359° 330° The H.E.S.S. Survey Galactic Plane 30° 0° RX J HESS J HESS J HESS J G HESS J HESS J HESS J HESS J Gal. Centre HESS J h in new > 6  post-trial (+3 known) 6 new > 4  post-trial LS 5039 HESS J HESS J HESS J HESS J HESS J HESS J Aharonian et al, Science (2005) Aharonian et al, ApJ (2006)

359° 330° Classes of Objects / Counterparts 30° 0° SNR PWN X-ray binary

359° 330° Classes of Objects / Counterparts 30° 0° SNR PWN X-ray binary unknown At least 3 objects in the scan with no counterpart. As for  TeV J by HEGRA  HESS J

New Unidentified HESS Objects: In the Galactic Plane Extended (Diffuse) emission Are there More Sources at High Galactic Latitudes?

Dark accelerators?  TeV J : Recent 50 ks Chandra obs. reveals no compelling counterpart (Butt et al. astro-ph/ )  GRB remnant ?? (Atoyan, Buckley & Krawcynski astro-ph/ ) -TeV flux  huge E budget, yet no synchrotron… relativistic shock accel. of p +  not a single power law.  HESS J : Chandra, XMM) reveal no obvious counterpart. Archival ROSAT image, plus new Chandra image FOV (squares). Several pulsars - but none with sufficient spin- down flux for powering detectable TeV emission from a PWN. ~ 1  extent of HESS source. Mukherjee & Halpern astro-ph/ €

Microquasar Detected! LS 5039 The only point-like source in the HESS Galactic Plan scan. ~1.4% Crab (>100 GeV)

AGN/MicroQuasar/GRB GeV/TeV Unification?

Next Generation Observations Horan & Weeks 2003

Next Generation Observations  All-sky GeV/TeV survey with good sensitivity/ large area  Deep follow-up with high angular resolution/energy resolution  Ability to map large scale, diffuse structures  Lower energy threshold/faster response times for GRBs

GeV/TeV Observation Techniques GLAST Direct  -ray detection Energy Range: GeV Angular resolution: Energy Resolution: 10% Field of View: 2.4 sr Detection Area: 1 m 2 On-time efficiency : > 90% $>100 M US VERITAS/HESS Cherenkov Light Detector Energy Range: 50 GeV-50 TeV Angular resolution: Energy Resolution: 10% Field of View: sr Detection Area: >10 4 m 2 On-time efficiency : 10% $12 M US MILAGRO Particle Detector Energy Range: TeV Angular resolution: Energy Resolution: % Field of View: > 3 sr Detection Area: >10 4 m 2 On-time efficiency : >90% $3 M US

Energy Ranges GeV 100 GeV-10 TeV TeV Inaccessible to Particle detectors Cherenkov: low Cherenkv light density ->20-30 m diameter mirrors, high altitude? Satellite: only a few photons: difficult spectra Particle detectors ok Cherenkov: 10 m diameter mirrors; low gamma ray rate, 1 km 2 array, larger f.o.v. Satellite: very few photons: no spectra Particle detectors good Cherenkov: 6 m diameter mirrors, very low gamma ray flux- >>km 2 array, large f.o.v Satellite: too small

Future  -Ray Roadmap (2010+) HAWC Particle detector $40 M US Wide FOV >90% on time All-sky survey at 10 mCrab/year Moderate angular/energy resolution Major IACT Array $~100 M US narrow FOV 10% on time <1 mCrab point source/50 hours High angular/energy resolution 30 + IACT telescopes?

few 1000 m High-energy section ~0.05% area coverage E th ~ 1-2 TeV 250 m Medium-energy section ~1% area coverage E th ~ GeV 70 m Low-energy section ~10% area coverage E th ~ GeV Array layout: 2-3 Zones FoV increasing to 8-10 degr. in outer sections

Not to scale ! Option: Mix of telescope types

Point Source Sensitivity of CTA Crab 10% Crab 1% Crab GLAST MAGIC H.E.S.S. Current Simulations 20 wide-angle 10 m telescopes de la Calle Perez, Biller, astro-ph m stereo telescopes Konopelko Astropart.Phys. 24 (2005) 191 W. Hofmann CTA Talk (2006)

High Density Camera Stack-Up Need a to develop versitile, reliable, cheap camera/readout in Order for IACT array to be feasible.

Active base DC-DC converter V Last 4 dynodes active HV & current readout Current limit Analog Ring Sampler (ARS) Samples PMT signal at 1 GHz 128 samples ring buffer Serves to delay signal until trigger decision High/low gain channels for large dynamic range (> 2000 pe) Multiplexed ADC to digitize signal; FPGA Controls conversion and readout Optionally sums signals over readout window (16 ns) Parallel bus for readout, token-passing scheme Photonis PMT XP Dynodes Gain ~2 x 10 5

Particle Detector Layout Milagro: 450 PMT (25x18) shallow (1.4m) layer 273 PMT (19x13) deep (5.5m) layer 175 PMT outriggers Instrumented Area: ~40,000m 2 PMT spacing: 2.8m Shallow Area:3500m 2 Deep Area:2200m 2 HAWC: 5625 or PMTs (75x75x(1 or 2)) Single layer at 4m depth or 2 layers at Milagro depths Instrumented Area: 90,000m 2 PMT spacing: 4.0m Shallow Area:90,000m 2 Deep Area:90,000m 2 miniHAWC: 841 PMTs (29x29) 5.0m spacing Single layer with 4m depth Instrumented Area: 22,500m 2 PMT spacing: 5.0m Shallow Area:22,500m 2 Deep Area:22,500m 2 Andy Smith, Santa Fe Workshop 2006

Source Detectability Source Size < Angular resolution = Point Sources: Crab AGN M87 constant

Source Detectability Source Size > Angular Resolution = Diffuse Sources: SNR Tibet-Milagro UID Molecular Cloud n.b. if Source has internal structure you will do better

Diffuse Sensitivity Extended Sources: Molecular clouds SNR, PWN Point Sources: AGN Pulsar Diffuse Sources: Galactic Plane Galactic Arm Next Gen is 1 km 2 IACT, 5 deg f.o.v, 1 mCrab/50 hours

VHE Experimental World: 2010

Summary  DM detection probably requires wide fov survey in GeV/TeV energy band comnbined with pointed follow- up  New GeV/TeV sources at wide range of energies, angular scales.  GeV/TeV GRB emission requires all-sky capability  Next generation Instruments require balanced combination of complementary techniques  New Collaborations are being formed at the present time to develop/build next generation Instruments. Chinese participation is highly needed for these major new facilities.

Source Resolvability Source Size > Angular Resolution Just need some factor  >1 more S/N to resolve internal source structure

Source Resolvability Source Size < Angular resolution As F  increases, tails of Gaussian become detectable->resolve source size

Possible Emission Mechanisms Inverse Compton scattering stellar photons jet synchrotron photons disk photons “coronal” photons high-mass companionlow-mass companion OR hadronic origin

Hadron Gamma rayMuon Ring Hadron

Point Source All-sky Survey Sensitivity Andy Smith, Santa Fe Workshop 2006