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Results On VHE Gamma Ray Sources from ACTs and Air Shower Arrays • • • • • • HESS CANGAROO STACEE CELESTE MILAGRO TIBET – III Future Case Study from Other Sources Results from Northern Sources from HESS Object Crab Nebula Mkn 421 H.E.S.S. status ~50 s (3 h), flux and spectrum agree ~80 s (12 h), flux and spectrum ok Index 1.8 Cutoff 2.4 TeV Mkn 501 not seen (~2 h); not detected by Whipple either at that time CELESTE Bussons Gordo 2004 Energy calibration under review! H.E.S.S. Significance Map PSR 1706-44 • Spindown lum. ~ 1% of Crab • X-ray lum. Crab • TeV emission detected by Durham and CANGAROO-I,II Kifune et al. 1995 Chadwick et al. 1998 Kushida et al., ICRC 2003 Kifune, ICRC 2003 ~ 0.01% of IC prediction ~0.001 Crab Sefako & de Jager 2003, 2004 Preliminary ICRC 2003 E -1.2 Crab Flux E –2.2 PSR 1706-44 preliminary Signal region q2 (Degr.2) 14 h 2-telescope data taken during commissioning phase H.E.S.S. assuming point source preliminary VELA -10 10 Integral Flux E-1.5 CANGAROO Yoshikoshi et al. 1997 -2 -1 F [cm s ] -11 10 Durham Chadwick et al. 2000 Chandra • CANGAROO source 0.13o off pulsar • H.E.S.S. limits similar for both CANGAROO and pulsar location H.E.S.S. 2004 -12 10 assuming point source -13 10 0,1 1 E [TeV] 10 Classical southern SNRs CANGAROO SN 1006 Kifune ICRC 2003 Tanimori et al., ApJ 497 (1988) L25 3.8 m telescope + conference proceedings H.E.S.S. significance map preliminary H.E.S.S. flux limits Time dependence ? -11 CANGAROO 1996/97 -2 Integral Flux [cm s-1] 10 -12 10 HEGRA CT1 1999-2001 -13 10 o with CANGAROO psf (0.23) 1 Problem with theory ? (Berezhko, Völk) H.E.S.S. 99% UL 2003 Data for CANGAROO hotspot 0,1 Size of SNR ~50 LY But small scale shocks < 1 LY (Chandra) Need O(mG) fields to cool electrons quickly enough 10 Energy [TeV] 100 Fields > 100 mG reduce IC below limit Density < 0.1 cm-3 reduces po component below limit Classical southern SNRs CANGAROO RXJ1713.7-3946 Kifune ICRC 2003 H.E.S.S. RJX1713 Spectrum, HESS analysed 18 hrs of 2003 data, Hard Cuts and No Background Subtraction H.E.S.S.: full remnant CANGAROO: hotspot Index 2.2±0.07±0.1 Index 2.84±0.15±0.20 preliminary TeV gamma rays from GC Tsuchiya et al. 2004 67 h on Kosack et al. 2004 26 h H.E.S.S. 17 h data tight cuts no backgr. subtraction CANGAROO 2001/2002 > 10 s Whipple 1995 – 2003 3.7 s CANGAROO Results on GC Comparison of Spectrum from Different Experiments none of the individual experiments sees variability on off H.E.S.S. psf Point source (size < 3‘ or 7 pc) CANGAROO (80%) Whipple (95%) HESS and WHIPPLE see less flux than extrapolated EGRET flux H.E.S.S. PSR B1259-63 / SS 2883 System Outline Star ► Bright and massive Be-star: L* = 3 .1030 W, M = 10 M . ► Stellar disk, mass outflow Pulsar ► Radio pulsar with P = 48 ms ► Spin down luminosity Lp = 8 .1028 W Only known object of this class in our galaxy! (not really true ????) (see Tavani’s talk in HD’04) Orbit ► ► ► ► ► ► Period 3.4 years Periastron 23 R* Apastron 331 R* Inclination 35° Distance 1.5 kpc point source Last periastron 7th of March 2004 TeV gamma ray production via Inverse Compton Scattering of the star’s photon field and accelerated particle populations from: 1) Unshocked pulsar wind 2000 Ball, Kirk 2) Pulsar wind termination shock induced by star’s photon field Ball, Dodd 2001 3) Interaction region of star mass outflow and pulsar wind Kawachi et al. 2004 CANGAROO Observations HESS Observations Schedule Pre-periastron: ► ► ► ► ► 26.2. - 2.3.2004 Livetime: 7.8 h 3 telescopes only Zenith angle: 42 deg Threshold: 360 GeV Post-periastron: ► ► ► ► 19.3. - 29.3.2004 Livetime: 17.4 h Zenith angle: 44 deg Threshold: 380 GeV Preliminary Analysis Results - Signal Pre-periastron, 7.8 h: ► Significance: 9.1 σ ► Excess rate: (0.39 ± 0.04) /min Post-periastron, 17.4 h: ► Significance: 6.3 σ ► Excess rate: (0.22 ± 0.03) /min Significance Skymap: ► FoV = 2 deg radius ► Clear excess at pulsar position Spectrum Fit: ► Spectral index: -2.8 ± 0.3 (stat) ► Flux level: 5% Crab ► Spectral index of postperiastron spectrum is compatible ► HESS sees variability with RXT Observations log(Flux [a.u.]) Lightcurve Shape – Data vs. Models unshocked pulsar wind ► Data does not favour continuous flux decrease within 21 days after periastron ► Systematics still under investigation shocked pulsar wind aligned stellar disc days Looking For Other Sources in the Field of View Results from the CELESTE Experiment Results from the STACEE Experiment Results from Air Shower Arrays MILAGRO and TIBET-III DEC. Mrk421 TIBET-III (88.8,30.2) Crab List of sky cells with clustered directions (24)having statistic significance larger than 4.0 Crab and MKn421 seen at significance of 4.9 and 5.3 sigma resp. Upper limits for several sources given Large scale anisotropy of CR intensity with a magnitude of 0.1% has been observed R.A. All Sky Coverage by MILAGRO Old story we know Full (northern) sky surveys Energy Threshold ~ 1 TeV Crab and Mkn421 seen For more details see the Milagro Talk at Heidelberg, 04 MILAGRO Observations Contd……. Galactic Plane Survey Galactic Centre obs showed 91 objects that accounts for 90% of > 20 KeV bgd towards the centre of galaxy For more details, see talk by R.Much at HD’04 Some Thoughts for the Future Sources High Energy Processes from Microquasars Radio Emitting X-ray binaries A few sources detected simultaneously in X-ray/radio bands Merck et al ( 1996) studied spectral characteristics of unidentified galactic EGRET sources Most of them have hard spectrum and extend to GeV energies Could be Pulsar like !!!!!! Spectra does not seem to be identical to the identified pulsars High galactic diffuse background make analysis difficult Be Binary system LS I +61deg 303 (associated with GT 0236 +610) Possible emission with 100 MeV gamma ray source, 2CG135 +01 Simultaneous radio and RXTE obs Radio bursts on 26.5 day orbital circle Modulation of X-ray emission on orbital timescales confirmed Most likely IC of stellar photons off electrons accelerated at the shock boundary bet. relativistic wind of young pulsar and Be star wind. Multiwavelength Studies of AGNs There were quite a few talks, but no new results or theories as such People still want more data and more co-ordinated observations to distinguish between ‘hadronic’ and ‘leptonic’ model (see papers by Costamante and Ghisellini, A&A, 384, 56-71(2002) High Energy Components of GRBs • • • • • GRB association with SNe is confirmed in at least a few cases ( GRB0300329-Sn2003dh ) Physics of jet creation, acceleration, propagation and evolution to be understood Correlations of MeV energy with global jet parameters imply MeV to be dominant However in the standard scenario a large fraction of energy is expected in the afterglow phase And in several GRBs powerful >> MeV components are observed Hurley et al. 1994 discover high energy component with EGRET High energy photons last much longer than MeV emission Also Gonsalez et al(2003) discovered in EGRET archive a GRB whose prompt Energy emission is dominated by E>> 200 MeV, MILAGRO discovered a TeV burst at 3.0 sigma level Can one do cosmography with GRBs ? Check for possible evolution of cosmological constant??