Very High Energy (VHE) γ-ray Astronomy: Status & Future

Transcription

1 6 th Rencontres du Vietnam: Particle Astrophysics Very High Energy (VHE) γ-ray Astronomy: Status & Future Rene A. Ong University of California, Los Angeles

2 OUTLINE Scientific Motivation Origin of cosmic rays A new Astronomy Beyond Standard Models. Experimental Technique Latest results from around the world Where do we go now? Next few years. Next decade. Conclusions Rene A. Ong (UCLA) Page 2

3 Cosmic Ray Origin 90 year old mystery! Galactic? Enormous E range Mostly charged particles E density ~ 1 ev/cm 3 Extragalactic? New component? Neutral messengers γ, ν required to directly observe cosmic accelerators. Diffuse, all particle spectrum (ν astronomy: DeYoung, Hoffman, Vernin, Weiler) Rene A. Ong (UCLA) Page 3

4 Galactic TeVatrons and PeVatrons Microquasars Pulsars Supernova Remnants (SNRs) Standard picture of SNRs: SN explodes into ISM. Diffusive shock acceleration. E, power-law form satisfied. Galactic Center Pulsar Nebulae But, no unambiguous evidence so far. Rene A. Ong (UCLA) Page 4

5 The VHE Sky sources Mrk421 Mrk501 Crab Pulsar Nebula SNR AGN Other, UNID R.A.Ong Aug 2005 Rene A. Ong (UCLA) Page 5

6 The VHE Sky sources Mrk421 H1426 M87 Mrk501 1ES1959 Cas A 1ES 2344 TeV 2032 RXJ 1713 GC Crab PKS 2155 Pulsar Nebula SNR AGN Other, UNID R.A.Ong Aug 2005 Rene A. Ong (UCLA) Page 6

7 The VHE Sky sources Mrk421 H1426 1ES ES1959 Cas A 1ES 2344 Cygnus Diffuse TeV 2032 Mrk501 SNR G0.9 LS 5039 PKS 2155 Pulsar Nebula M87 RXJ 1713 GC H2356 PSR B1259 MSH PKS 2005 AGN 1ES 1101 RXJ 0852 Vela X HessJ1303 Crab add. sources in galactic plane. SNR Other, UNID R.A.Ong Aug 2005 Rene A. Ong (UCLA) Page 7

8 Present Time: August sources G. Hermann Rene A. Ong (UCLA) Page 8

9 Source Counts Source Type* Pulsar Wind Nebula (e.g. Crab, MSH ) Supernova Remnants (e.g. Cas-A, RXJ 1713 ) Binary Pulsar (B ) Micro-quasar (LS 5039, LSI ) Diffuse (Cygnus region) AGN (e.g. Mkn 421, PKS 2155 ) Unidentified TOTAL * Includes likely associations of HESS unid sources Explosion in the number of VHE sources. Rene A. Ong (UCLA) Page 9

10 A New Astronomy New view of the Universe Many Surprises M87 Jet One example: Active Galactic Nuclei MAGIC Mrk 501 Central BH Supermassive BHs Jets beamed towards us Remarkable variability Rene A. Ong (UCLA) Page 10

11 Extragalactic Background Light (EBL) 2.7K M. Beilicke Determine cosmic IR/UV background Red shifted stellar light Red shifted dust light Rene A. Ong (UCLA) Page 11

12 Searching for Dark Matter Galactic Center Enhanced WIMP density in certain locations. WIMP annihilation γ, ν ν,ν γ continuum γ lines χ+χ p e d + Galactic Halo Galactic Satellites Extragalactic Sources Point back to source Search for excess components in cosmic rays (DIFUSION) γ-ray yields Rene A. Ong (UCLA) Page 12

13 Experimental Technique Rene A. Ong (UCLA) Page 13

14 HE and VHE γ-ray Detectors Satellite Detector Air Shower Detector Rene A. Ong (UCLA) Page 14

15 Cherenkov Telescopes γ ray θ ~ 1.5 o Rene A. Ong (UCLA) Page 15

16 MILAGRO Experimental World STACEE MAGIC TIBET MILAGRO CACTUS STACEE TACTIC TIBET ARGO-YBJ CACTUS PACT GRAPES TACTIC VERITAS HESS CANGAROO III Rene A. Ong (UCLA) Page 16

17 Scientific Highlights I. HESS Galactic Plane survey. Discovery of many new sources, many unidentified. II. III. IV. Detailed studies of Galactic sources: Supernova remnants. Pulsars and pulsar wind nebulae. Binary systems microquasars. Diffuse sources. Extragalactic Sources. AGN and Radio Galaxies (M87). New constraints on EBL. Dark Matter Searches: Galactic Center and dwarf satellites. Rene A. Ong (UCLA) Page 17

18 HESS Survey Gal. Centre RX J Rene A. Ong (UCLA) Page 18

19 HESS Survey: New Sources HESS J HESS J HESS J HESS J HESS J G Gal. Centre Sources > 6 sigma (9 new, 11 total) HESS J HESS J RX J HESS J Rene A. Ong (UCLA) Page 19

20 HESS Survey: New Sources HESS J HESS J HESS J HESS J HESS J G Gal. Centre 30 0 LS 5039 HESS J HESS J HESS J HESS HESS J HESS J Sources > 6 sigma (9 new, 11 total) Sources > 4 sigma (7 new) HESS J HESS J RX J HESS J Rene A. Ong (UCLA) Page 20

21 Supernova Remnants RXJ SNR RXJ RX J Berezkho & Völk astro/ph ~B 2 d = 1 kpc E = erg M = 3.5 M ρ(r) = /cm 3 B ~ 10 µg e/p = 10-4 HESS Image ASCA (X-ray) contours Good fit for this proton model but electron models are still possible. (U. Schwanke, parallel sessions) Rene A. Ong (UCLA) Page 21

22 Pulsar Wind Nebulae: Vela Region W. Hofmann Chandra X-rays Vela (Rosat) Vela X PWN Vela Junior d 200 pc age 700 y Rene A. Ong (UCLA) Page 22

23 µ Quasars: LSI AU To observer µ-quasar model MAGIC High mass 2kpc. Eccentric orbit, probably NS. Radio, X-rays modulated by orbital period of 26.5d. Compact jets resolved. MAGIC: Pt-like source, bright at phase [0.5,0.7]. Rene A. Ong (UCLA) Page 23

24 LS I : the movie Albert et al Q: Are we seeing the jet or the disk? J. Rico Rene A. Ong (UCLA) Page 24

25 J. Hinton Diffuse VHE Sources Galactic Center and Cygnus HESS Galactic Center 1 degree H.E.S.S hours Milagro Cygnus Region EGRET GeV Map underlay Preliminary Contours of CS emission (molecular tracer) Subtracted Image G. Sinnis TeV emission along Gal. plane. CRs interacting with molecular clouds. Evidence for new source of diffuse TeV radiation. CR interactions! Rene A. Ong (UCLA) Page 25

26 Extragalactic TeV Sources Now 12 known AGN (& M87) AGN are Blazars relativistic jet beamed to us 2 peak spectra Highly variable! MAGIC Mrk 421 and model fit. Looking out further in redshift. Rene A. Ong (UCLA) Page 26

27 Extragalactic Background Light upper limits X measurements X HESS limits lower limits from galaxy counts Reference shape Universe is more transparent! Rene A. Ong (UCLA) Page 27

28 Dark Matter I? DM annihilation HESS Galactic Center. Results also from MAGIC. E 2 F(E) [TeV/cm 2 s] TeV Neutralino 20 TeV KK particle 0, E [TeV] Astrophysics dominates but we don t know what it is! Rene A. Ong (UCLA) Page 28

29 Dark Matter II New result from STACEE (preliminary) Draco Dwarf Satellite CACTUS (2005) Claim evidence for 100 GeV γ-rays from Draco. 2.4 hr data. Large γ-ray excess hr data, Apr-Jun No γ-ray signal. Rate, R < γ/min (95%). Flux (>200 GeV) < 1.9 x /cm 2 /s CACTUS also now sees no signal. (Tripathi, ICHEP 2006) Rene A. Ong (UCLA) Page 29

30 Upcoming Projects Rene A. Ong (UCLA) Page 30

31 VERITAS 12 m diameter reflector 499 PMT camera Event in Camera Steel OSS Control Room VERITAS Arizona, USA Similar to HESS: 4 x 12m Telescopes 500 element cameras, 3.5 o 500 MHz FADC on each pixel. Rene A. Ong (UCLA) Page 31

32 VERITAS: 2 Telescope Operation γ-rays VERITAS Event April 2006 Strong γ-ray signal: Mrk 421, 4 hr data, 30 σ, ~6 γ/min (not optimized) (Whipple 10m: 1.8 γ/min) Mrk 421 Image Rene A. Ong (UCLA) Page 32

33 VERITAS: Array Completion Tel 3 Tel 4 110m Tel 1 80m Tel 2 Telescope 4 July 2006 Whipple Base Camp July m, dark site Oct 2006: 3 Telescope operation: Science observations begin. Feb 2007: 4 Telescopes! Rene A. Ong (UCLA) Page 33

34 MAGIC II and HESS II MAGIC-I MAGIC-II II MAGIC-II (2007) 85m Second 17m telescope. High-QE camera. (F. Goebel, parallel session) HESS-II (2008) New 28m telescope pixel camera. Lower energy ~50 GeV. (J.P. Tavernet, next talk) Rene A. Ong (UCLA) Page 34

35 GLAST Satellite Telescope GLAST LAT: Si strip tracker. CsI calorimeter. Energy range GeV Simulated sky map from 1 year survey. Scheduled launch: Sept GLAST will have a huge impact on the field. Rene A. Ong (UCLA) Page 35

36 Future Directions GLAST A. Konopeloko GeV 100 GeV 10 TeV TeV AGNs Pulsars & PWN Cosmology HESS, VERITAS CANGAROO III MAGIC SNRs Origin of cosmic rays Dark matter Better sensitivity! Wider FOV GRBs There is a wide variety of opinion on what direction(s) to pursue. Rene A. Ong (UCLA) Page 36

37 Future Concepts mini-hawc mini-hawc: Air shower detector: wide FOV and good duty cycle. Moderate sensitivity & resolution. Energy E > 500 GeV. minihawc: 841 PMTs (29x29) 5.0 m spacing Single layer with 4m depth Instrumented Area: 22,500 m 2 PMT spacing: 5.0 m Rene A. Ong (UCLA) Page 37

38 Future Concepts Large Cherenkov Tel. Arrays S. Fegan Field of view [π sr] Field of view [deg] Collecting Area [km 2 ] HE-ASTRO: 217 Telescopes (ø10m), 80m separation. 1.1 km 2 collection area & 12 o FOV. Challenging! Also, detailed work in Europe and Japan. Cherenkov Telescope Array (CTA) concept well underway. Rene A. Ong (UCLA) Page 38

39 The VHE γ-ray Science Program M. Martinez SNRs Origin of Cosmic Rays Pulsars Microquasars AGNs Cold Dark Matter cosmological γ-ray Horizon Test of the speed of light invariance GRBs Rene A. Ong (UCLA) Page 39

40 SUMMARY New generation of Cherenkov telescopes has yielded outstanding results many new sources discovered in last two years an unprecedented increase. Galactic Plane is rich in the number and type of VHE sources. Pulsar nebulae and SNRs are both firmly established in the TeV band. Origin of CR s is still an important question. New discoveries increase the number of known TeV blazars and push further out in redshift. Universe is more transparent than expected. No real evidence for DM from TeV γ-ray measurements, but technique is a key complement to direct and LHC. Upcoming experiments on ground (VERITAS) and in space (GLAST) should continue the rapid development of VHE astrophysics. Others will follow! Rene A. Ong (UCLA) Page 40

41 Acknowledgements Much thanks to: D. Driscoll, W. Hofmann, S. Fegan, A. Jarvis, A. Konopelko, R. Mirzoyan, M. Punch, G. Sinnis, J.P. Tavernet, M. Teshima, & M. Tripathi Rene A. Ong (UCLA) Page 41