Present and Future ACTs Jim Hinton 2 Contents ACT - PowerPoint PPT Presentation

1 Present and Future ACTs Jim Hinton

2 Contents » ACT results/potential discussed in many talks › T. Bringmann, W. Benbow, M. Kachelriess, Y. Gallant, S. Casanova, D. Giannios, M. Dalton, M. Vivier, R. Mukherjee, S. Sarkar, G. Morlino, S. Vincent, Q. Weitzel, R. Gilmore, C. Medina, D. Caprioli, I. Vovk, F. Aharonian, I. Puerto (Poster) ...  ACTs are a central part of TeV Particle Astrophysics  too many results/too much potential for 40 minutes! » I will try not to cover too much of the same ground again – I will focus on the experimental status, capabilities and plans for future ACTs

3 High Energy Sensitivity Space-based instruments only optical UV | X-ray | g -ray | VHE g -ray 10 -11 Integral n F n ( erg cm -2 s -1 ) 10 -12 More sensitive Fermi GST IACTs 10 -13 10 -14 XMM 10 -15 HST 10 -16 1 eV 1 keV 1 MeV 1 GeV 1 TeV 1 PeV Energy

4 High Energy Sensitivity Space-based instruments only optical UV | X-ray | g -ray | VHE g -ray 10 -11 Integral n F n ( erg cm -2 s -1 ) 10 -12 More sensitive Fermi GST IACTs 10 -13 Future IACTs 10 -14 XMM 10 -15 HST 10 -16 1 eV 1 keV 1 MeV 1 GeV 1 TeV 1 PeV Energy

5 High Energy Sensitivity Space-based instruments only optical UV | X-ray | g -ray | VHE g -ray 10 -11 Integral n F n ( erg cm -2 s -1 ) ? 10 -12 More sensitive Fermi GST IACTs 10 -13 ?  CTA 10 -14 XMM 10 -15  IXO HST 10 -16  1 MeV 1 GeV 1 TeV 1 PeV E-ELT Energy

Technique 6 Primary g -ray › Pair production › g → e + e - ~ 10 km › Bremsstrahlung › e - + ( g ) → e - + g Particle Shower › Cascade develops ~ 120 m

Technique 7 Primary g -ray › Pair production › g → e + e - ~ 10 km › Bremsstrahlung › e - + ( g ) → e - + g Particle Shower › Cascade develops » Cherenkov light produced › 1 ° angle at 10 km height → 100 m radius „light - pool‟ › few ns light „flash‟ ~ 120 m ~ 100 m

Technique 8 Primary g -ray ~ 10 km Particle Shower » Air-shower... Collection area ~10 5 m 2 ~ 120 m ~ 100 m

Technique 9 Detecting Very High Energy Gamma-Rays Primary g -ray with Cherenkov ~ 10 km Light Focal Particle Plane Shower Image Analysis gives  Shower Energy  Background rejection  Shower Direction » Air-shower... Collection area ~10 5 m 2 ~ 120 m Energy resolution ~ 20% ~ 100 m

Technique 10 Detecting Very High Energy Gamma-Rays Primary g -ray with Cherenkov ~ 10 km Light Focal Particle Plane Shower Image Analysis gives  Shower Energy  Background rejection  Shower Direction Stereoscopic views » Air-shower...  Improved angular / ~ 120 m energy resolution & background rejection ~ 100 m

11 Current ACTs HAGAR VERITAS MAGIC TACTIC Whipple 10m HESS CANGAROO-III Apologies if you have a currently operating ACT that I have missed!

12 Current ACTs ● HAGAR  Non-imaging array 7  7  1 m  Altitude 4300 m  Sensitivity ~35% Crab HAGAR ● TACTIC  3.5 m imaging telescope  Altitude 1300m TACTIC Whipple 10m  Sensitivity ~70% Crab ● Whipple 10m  Sensitivity ~15% Crab ● CANGAROO-III CANGAROO-III  Operating with 2 telescopes  Sensitivity ~15% Crab. (note that reanalysis of CANGAROO-I data clears up many old disagreements on southern sources ApJ 702, 631 (2009)

13 Current ACTs VERITAS MAGIC “The Big Three” HESS

14 VERITAS ● 4  12 m telescopes  3.5° Field of View ● 2009 Upgrade  Moved 1 telescope  Improved alignment  1%  0.7% Crab sen. ● Planned upgrade  Higher QE PMs (35% more light)  Improved trigger  Funded – complete mid-2012 Crab detected in ~70 s (~90 hrs in 1989 !)

15 MAGIC ● Two 17m telescope system operational, gives improved:  Energy & Angular res › ~30% better: <0.1° above 600 GeV  Sensitivity  1% Crab

16 HESS Status H.E.S.S. ● HESS phase-I (since 2004)  4  12m telescopes In Namibia, 5° FoV  0.7% Crab sens. (NB NGC 253, 0.3% Crab in 120 h)  recoating underway to restore original reflectivity (1 tel. done, others finished by end of next year) ● HESS phase-II  A single giant (30 m) telescope under construction in the centre array  ~20 GeV threshold  Construction on hold – changing contractor

17 What are ACTs good for? ● Short-timescale variability (better lower E) ● Imaging ( better higher E) *Current IACT ● Spectroscopy ( better higher E) arrays have factor ~2 better E-res and ang-res at 1 TeV ● NOT than at 100 GeV  Long-timescale variability/monitoring › Sparsely sampled light-curves (moon, sun, weather)  Very extended emission (>> 1°, limited FoV)  Precision measurements at <<100 GeV (shower fluc.)  Fermi can do these things better <100 GeV  HAWC will (hopefully) do them > a few TeV

18 Angular resolution ● ~1‟ resolution achievable with next 1 ° MILAGRO generation IACT arrays HAWK 0.1 ° ● Fundamental limit is ~10” 1’ 0.01 ° SF+JH sims. Limit above a few (WH) TeV

19 Source Numbers 10000 Adapted from Tadashi Kifune Fermi ? 1000 X-ray Satellites Sources 100 HE g -ray Satellites 10 Ground-based VHE g -ray obs. 1 1960 1970 1980 1990 2000 2010 Year

July 2010: 20 113 TeV sources 109 ACT discoveries 72 Gal. / 41 EG

21 The High Energy Sky ● >1 GeV (Fermi) ● >5 GeV (Fermi) cf >200 GeV (HESS)

22 Molecular cloud Massive star No acceleration expected until… Supernova SNR shell e.g. RX J1713

23 Active cloud Yes Molecular cloud Nearby accelerator? e.g. Sagittarius B No Passive cloud (e.g. EGRET galactic clouds) Massive star In cluster? Collective wind Yes No interactions Binary? No No acceleration Yes expected until… Compact Yes No companion? Supernova Neutron star e.g. Westerlund 2? Massive companion? companion? Yes Neutron star remains? No Binary PWN Yes No SNR shell Yes Radio jets? Composite SNR e.g. RX Yes J1713 PWN outlasts or e.g. PSR escapes SNR B1259-63 Colliding wind sys. Microquasar PWN e.g. G 21.5-0.9 (e.g. Eta Carinae) e.g. LS 5039? e.g. HESS J1825

24 Active cloud Yes Molecular cloud Nearby accelerator? e.g. Sagittarius B No Passive cloud (e.g. EGRET galactic clouds) Particle Acceleration is common Massive star In cluster? in nature and TeV emission can Collective wind Yes No interactions Binary? No be used to probe a wide range No acceleration Yes expected until… of astrophysical systems! Compact Yes No companion? Supernova Neutron star e.g. Westerlund 2? Massive companion? companion? Yes Neutron star remains? No Binary PWN Yes No SNR shell Yes Radio jets? Composite SNR e.g. RX Yes J1713 PWN outlasts or e.g. PSR escapes SNR B1259-63 Colliding wind sys. Microquasar PWN e.g. G 21.5-0.9 (e.g. Eta Carinae) e.g. LS 5039? e.g. HESS J1825

25 Supernova Remnants ● SNRs  Tycho (VERITAS)  HESS J1731-347A › New shell-like TeV SNR (1 st VHE Discovery)  New SNR/cloud interaction candidates › G22.7-0.2 (HESS) › g -Cygni (VERITAS) ● Expect many ACT + Fermi results in the near future for gal. sources

26 Starburst Galaxies » NGC 253 z=0.0008 ● M 82 z=0.0008 HESS Discovery 2009 VERITAS Discovery 2009 Enhanced star formation / supernova rate in a high density starburst region 1’ TeV implies CR density ~ SFR , but TeV emission from p 0 inside starburst or IC in superwind, …

27 Blazars PKS 2155-304 × 10 -9 HESS 28 th July 2006 (see also MAGIC Mrk 501 flare, VERITAS Mrk 421) Crab Nebula Flux >2 order of magnitude flare 2-3 minute variability timescale Crab Nebula Flux Quiescent Flux ● Variability timescale is ~1% R S c  Can be used to constrain Lorenz Invariance Violation – but not quite as good as Fermi GRBs (need more distant/faster objects)

28 A flood of new VHE AGN » Mostly Fermi triggered/motivated

29 ACTs + Fermi ● Better sensitivity match Crab Nebula  w.r.t EGRET ● No more “10 -100 GeV gap”  For strong TeV sources ● Lots of science potential e.g.  B EG lower limit › Neronov & Vovk (2010)  Blazars PKS 2155-302, PG 1553+113 › › MAGIC/HESS/VERITAS +Fermi collaborations  Binaries, PWN, SNR › LS I +61303 Vela X › › RX J1713-3946

30 TeV Astronomy: Highlights ● Microquasars : Science 309, 746 (2005), Science 312, 1771 (2006) ● Pulsars : Science 322, 1221 (2008) ● Supernova remnants : Nature 432, 75 (2004) ● Galactic Centre : Nature 439, 695 (2006) ● Galactic Survey : Science 307, 1839 (2005) ● Starbursts : Nature 462, 770 (2009), Science 326,1080 (2009) ● AGN : Science 314,1424 (2006), Science 325, 444 (2009) ● EBL : Nature 440, 1018 (2006), Science 320, 752 (2008) ● DM: Phys Rev Letters 96, 221102 (2006) ● LIV : Phys Rev Letters 101, 170402 (2008) ● Cosmic Ray Electrons : Phys Rev Letters (2009) Results from HESS, MAGIC and VERITAS

31 Photon Statistics -10 10 RX J1713-3946 HESS E 2 F(E) (erg cm -2 s -1 ) -11 10 Signal Background -12 10 limited limited 0.01 0.1 1 10 100 Energy (TeV)

32 Photon Statistics -10 10 RX J1713-3946 1 km 2 hour HESS E 2 F(E) (erg cm -2 s -1 ) 10 photons in: -11 10 10 km 2 hours Signal Background -12 10 100 km 2 hours limited limited 0.01 0.1 1 10 100 Energy (TeV)