Galactic sources in GeV/TeV Astronomy and the new HESS Results

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1 Galactic sources in GeV/TeV Astronomy and the new HESS Results Martin Tluczykont for the HESS Collaboration LLR Ecole Polytechnique Joint Symposium on GeV-TeV Astrophysics in the GLAST Era Stanford, September 2004 The era of the Next Generation has begun Results Crab Nebula Supernova remnants New source type : Binary pulsar system Unitentified sources

2 The Pioneering Era Whipple, HEGRA, CAT, CANGAROO,... Object Flux level (approx.) First detection Confirmation [Crab] Crab Nebula 1.00 Whipple Many Vela 0.50 CANGAROO PSRB CANGAROO SN CANGAROO Cas A 0.03 HEGRA RXJ CANGAROO Cen X Durham Sgr A* CANGAROO (Whipple) TeV J HEGRA RCW CANGAROO RX J ? CANGAROO Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 2/38

3 The Era of the Next Generation has begun HESS, VERITAS, MAGIC, CANGAROO III Object Flux level First detection Conf. Contradiction (HESS) [Crab] Crab Nebula 1.00 Whipple Many Vela 0.50 CANGAROO Flux PSRB CANGAROO Flux SN CANGAROO Flux Cas A 0.03 HEGRA RXJ CANGAROO HESS Cen X Durham Sgr A* CANGAROO HESS Spectrum TeV J HEGRA HESS J HESS PSR B /SS HESS RCW CANGAROO RX J ? CANGAROO currently: work to understand contradictions (simultaneous observations) Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 3/38

4 The beginnings: The Crab Nebula First TeV source (Weekes, T.C. et al. 1989, ApJ, 342, 379) Many subsequent detections in GeV/TeV Calibration source Spectral index Whipple: α = 2.49 ± 0.07 HEGRA: α = 2.62 ± 0.05 CAT: α = 2.76 ± 0.04 Flux Whipple: 2.15 ± m 2 s 1 HEGRA: 1.75 ± m 2 s 1 CAT: 1.78 ± m 2 s 1 Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 4/38

5 The Crab Nebula as seen by HEGRA dn/de [(cm 2 s TeV) -1 ] After 400 h of observations The spectrum : 500 GeV < E < 80 TeV The position : HEGRA data Crab nebula z.a.<45 deg z.a.>45 deg dn/de=(2.83 ± 0.04) (E/TeV) (-2.62±0.02) ph/(cm 2 s TeV) E [TeV] 1 st detection E>50 TeV (5 σ) 21:58 22: Centroid position of TeV excess Pulsar position 5:34:30 Upper Limit on TeV source extension systematic uncertainty Aharonian, F.A. et al., astro-ph/ (ApJ accepted) Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 5/38 20

6 The Crab Nebula as seen by HESS (preliminary) High zenith angle (E thr 325 GeV) Independent analyses give consistent results Spectral index: α = 2.62 ± 0.02 Compatible with previous results Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 6/38

7 Observation Campaigns Martin Tluczykont for the HESS Collaboration 7/38

8 Galactic Plane Scan Pointsource search (HEGRA): No detection E>1 TeV (<4.5 σ) Upper limits: 63 SNRs, 86 Pulsars, 9 un-id. GeV sources ( Crab) Diffuse emission (Whipple/HEGRA):... To come: similar campaigns by next generation... Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 8/38

9 Shell-type Supernova remnants Martin Tluczykont for the HESS Collaboration 9/38

10 The shell-type Supernova remnant Cas A (HEGRA) 210 h of observations pp π 0 + H γγ + H Cosmic-Ray acceleration? MAGIC/VERITAS spectral shape around GeV GLAST observations towards 70 MeV bump Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 10/38

11 The Shell-Type Supernova Remnant RXJ Discovery in X-rays ROSAT All-Sky survey source Non-thermal X-rays Distance: 1 kpc (CO survey) Angular extension: 1 deg First TeV-detection: CANGAROO II (Muraishi, A. et al. 2000; Enomoto, R. et al. 2002) 0.7 Crab Question of Cosmic ray acceleration controversial discussions (Pohl et al. 2002) Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 11/38

12 RXJ as seen by HESS Recent GeV/TeV-confirmation: HESS 2004 (D. Berge, Gamma 2004 & Nature acc. f. publ.) High quality data 18.1 h >20 σ total remnant The first ever astronomical TeV-image Shown here: High resolution data subsample (E>800GeV) Superposition: ASCA X-ray data contours Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 12/38

13 RXJ The spectrum Spectrum: inconsistent spectral indices HESS: α = 2.19±0.09±0.15 consistent results in independent analyses CANGAROO II: α = 2.84±0.15±0.20 Further observations by HESS and CANGAROO III GLAST observations of 70 MeV bump? Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 13/38

14 Inconsistency: SN 1006 Hofmann, Gamma 2004 Martin Tluczykont for the HESS Collaboration 14/38

15 The Galactic Center (Sgr A*) CANGAROO: first detection 9 σ VERITAS: 3.7 σ HESS: 9.2 σ (slope and flux CANGAROO) Chandra X-ray image HESS superimposed: 68 % & 95 % confidence regions for source position 95 % upper limit on rms source size Steady state 0.05 % (E> 165 GeV) Power-law with α = 2.2 ± 0.09 ± 0.15 Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 15/38

16 A new (unique) type of GeV/TeV-emitter Martin Tluczykont for the HESS Collaboration 16/38

17 PSRB / SS 2883 The Binary Pulsar system PSRB / SS 2883 at 1.5 kpc 10 M Be star L = W dense stellar disk, high mass outflow 48 ms radio Pulsar L spindown = W Pulsar orbit around Be star 3.4 years Periastron : 23 R Apastron : 331 R Inclination : 35 deg Diameter: 350 R (Point-like) CANGAROO 3.8 m: 4.8 σ (1994), 10 m: Upper limits (2000), after periastron HESS-observations at last periastron passage : 7 th of March 2004 Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 17/38

18 PSRB / SS 2883 HESS Results (S. Schlenker, Gamma 2004) Pre-Periastron Post-Periastron High quality data : 7.8 h Significance : 9.1 σ High quality data : 17.4 h Significance : 6.3 σ Excess rate : 0.4 γ/min Overall > 10σ detection by HESS Excess rate : 0.2 γ/min Flux E>400 GeV 5 % Crab Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 18/38

19 PSRB / SS 2883 HESS Results (S. Schlenker Gamma 2004) Significance Skymap Energy Spectrum α = 2.8 ± 0.3 Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 19/38

20 PSRB / SS 2883 The Next Periastron passages July/August 2007 Christmas Simultaneous observations with GLAST already in 2007? Or nice Christmas present in 2010? Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 20/38

21 Non-identified GeV/TeV-Sources Martin Tluczykont for the HESS Collaboration 21/38

22 HESS J (M. Beilicke, Gamma 2004) Surprise in PSRB observations: Second signal in FoV! 0.7 deg from Pulsar position Steady state signal (18 σ) Calibration or Physics? High data quality Consistent results for different algorithms Declination [deg] HESS J PSR B Significance Skymap H.E.S.S. (preliminary) gal. plane excess events h m h m Right Ascension Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 22/38

23 HESS J (M. Beilicke, Gamma 2004) Surprise in PSRB observations: Second signal in FoV! 0.7 deg from Pulsar position Steady state signal (18σ) HESS : Gamma-ray signature entries χ / ndf / 25 Prob p R± p R± 32.4 p R± p R± HESS J excluding Dec i data (preliminary) mscw Declination [deg] Significance Skymap H.E.S.S. (preliminary) gal. plane HESS J PSR B h m h m Right Ascension excess events Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 23/38

24 HESS J : The 2 nd unidentified TeV-source Extended object ( 0.2 ) Powerlaw spectrum (α=2.2±0.2) entries HESS J (H.E.S.S., Feb.-May 2004, preliminary) signal region background region PSF (Crab) ], arb. units -1 TeV energy spectrum index: Γ = 2.2 R± 0.2 stat (H.E.S.S., preliminary) squared angular distance θ [deg ] Populated corner of the sky but... No obvious radio / optical / X-ray counterpart found -1-2 m flux [ph. s energy [TeV] Further HESS & Future GLAST observations Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 24/38

25 1 st non-identified TeV-source TeV J (HEGRA) Steady state, serendipituous discovery ( ) confirmation 2002 Dec (J2000) [ deg ] Cygnus OB2 Field: HEGRA CT-System GeV J TeV J GeV J EG J Excess significance Significance 7 σ (279 h) Flux 5% Crab (E>1 TeV) Spectral index -1.9±0.1 stat ± 0.3 sys Position 0.5 N of Cyg X3 Extension 6.2 ±1.2 stat ± 0.9 sys Cyg X-3 Cyg-OB2 Core Circle RA (J2000) [ hrs ] Identification with Cyg-OB2? Cosmic Ray acceleration in stellar winds? Link with Cyg X3? Jet termination shock / e synchrotron / IC Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 25/38

26 TeV J and Cosmic Ray Acceleration Hypothesis: Association of 3EG J & TeV J & Cyg OB2? E 2 dn/de [ erg cm -2 s -1 ] ASCA GIS (2-10 kev) 3EG J TeV Source HEGRA CT-System H-A dn/de, [photons cm s MeV ] EGRET data 3EG J Fit: stellar to HEGRA α E max 2 χ = 2.70 = GeV / d.o.f = / 13 Fit: stellar to EGRET + HEGRA HEGRA data TeV J E [ TeV ] energy, [MeV] Aharonian et al. 2002, A&A, 393, L37 Tluczykont 2003 Incompatibility (?) of observed EGRET & HEGRA spectra Contributions from different particle populations? Different sources? Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 26/38

27 ] TeV J by GLAST dn/de, [photons cm s MeV EGRET data 3EG J GLAST? HEGRA data TeV J HESS? energy, [MeV]... Future observations in the MeV/GeV/TeV regime... GLAST: 2 sources or only one? Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 27/38

28 General: Future Multi Wavelength campaigns GeV/TeV : HESS & HESS 2, VERITAS, MAGIC & MAGIC 2, CANGAROO III GLAST How do the spectra change towards 70 MeV? Straight Powerlaw? Other wavelengths than γ-rays Counterparts & Correlations Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 28/38

29 Summary New generation : more than the top of the iceberg more and more (unexpected) objects many more sources below 0.05 Crab, it seems New HESS results 1 st time two sources resolved in one VHE field of view 1 st VHE γ-ray image Some contradictions to CANGAROO Soon: Spectral Imaging Future: Physics from 30 MeV to 30 TeV Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 29/38

30 Backup Transparencies Martin Tluczykont for the HESS Collaboration 30/38

31 The Crab Nebula Modelling: IC with synchrotron & other soft seed photons log 10 (ν/hz) log 10 (νf ν /erg/(cm 2 s)) : IC from sync. 2: IC from mm rad. 3: IC from FIR(dust) 4: IC from CMB 5: IC from mm emitting electrons log 10 (E/eV) Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 31/38

32 S. Schlenker, Gamma 2004 Martin Tluczykont for the HESS Collaboration 32/38

33 Spectrum of the Crab Nebula HESS & HEGRA Spectral index α = 2.62 ± 0.02 Whipple: α = 2.49 ± 0.07 HEGRA: α = 2.62 ± 0.05 CAT: α = 2.76 ± 0.04 Flux (E>1 TeV): 2.16 ± m 2 s 1 Whipple: 2.15 ± m 2 s 1 HEGRA: 1.75 ± m 2 s 1 CAT: 1.78 ± m 2 s 1 Martin Tluczykont for the HESS Collaboration Martin.Tluczykont@poly.in2p3.fr 33/38

34 TeV J by Whipple Archival data ( ) σ 0.12 Crab Martin Tluczykont for the HESS Collaboration 34/38

35 PSR B by HESS Hofmann, Gamma 2004 Martin Tluczykont for the HESS Collaboration 35/38

36 Vela by HESS Hofmann, Gamma 2004 Martin Tluczykont for the HESS Collaboration 36/38

37 Calibration Laser (Flatfielding) single p.e. (gain) µ (verification) Absolute Flux Calibration depends on Shower Simulation: Well-known particle interactions Athmospheric profile Detector Simulation Main uncertainty: Athmospheric profile Martin Tluczykont for the HESS Collaboration 37/38

38 HESS J Checks Different (independent) Reconstruction methods used Different Background estimations used Checks for broken Pixels Variation of observation modes (wobble in RA) Excluded individual telescopes one by one Characteristic distributions checked (mscw,...) True Signal Martin Tluczykont for the HESS Collaboration 38/38