Recent results and status of HEGRA Performance and Status of HEGRA Galactic Sources (st Unidentified TeV source, Gal. plane scan) Extragal. Sources (Mkn 4, H46+48, ES959+65) Summary Dieter Horns for the HEGRA collaboration MPI f. Kernphysik Heidelberg Dieter Horns, MPI-K, Heidelberg Status of the instruments CTSystem: Operation time: 997-9/7/ (since 998 5 telescope setup) Observation: >6 hrs of good data onß objects Upgrades: None after 998, HV-adjustments. CT : Operation time: 99- Observation: >6+(moon) hrs of good data on 6 objects Upgrades: New camera (7 pix) /994, alum. mirror ( m ) /997 Dismantling of CTs in this year. Telescopes will be operated by Brenda Dingus in Mexico at 4.4 km a.s.l. Dieter Horns, MPI-K, Heidelberg
Dieter Horns, MPI-K, Heidelberg 3 H46+48 (Aharonian et al. ) ES959+65 (Götting et al. ICRC ) Mkn 5 (Bradbury et al. 997, Aharonian et al. 997,999a,999b,999c,a,b,a,b,c) Mkn 4 (Petry et al. 996, Aharonian et al. 999,, and ) Unid. TeV source in Cygnus (Aharonian et al. ) Cas-A (Aharonian et al. ) Crab Nebula (Konopelko et al. 996, Aharonian et al. 999) HEGRA detected 7 sources (> discoveries) See talk by Gerd Pühlhofer HEGRA IACT Exposure Sky Map Above 5 GeV Dieter Horns, MPI-K, Heidelberg dieter.horns@mpi-hd.mpg.de ES344+54-9 PKS 55-34 3rd EGRET catalogue: Ground based detections: AGN Pulsars TeV sources (confirmed) Unidentified EGRET sources LMC TeV sources (not confirmed) solar flare Unidentified TeV source (not conf.) RXJ73.7-3946 PSR B76-44 Vela 3C 66A +8-8 Cas-A Crab Nebula ES959+65 TeV J3+43 Mkn 5 Mkn 4 SNR 6 Cen X-3 +9 H46+48 E> MeV The gamma-ray sky The Universe viewed in Gamma-Rays Sept. 4-8, Performance of the instruments Figures of merit: Ang. resol. Energy resol. Thresh. a γ-rate(crab) b CR-rate b Signal/ p hr c ffi [ ] E/E [GeV] [/hr] [/hr] [σ= p hr] CTSystem <. ffi >% 5-6 36 3.3 CT ß. ffi >5% 7-9 8 3.3 3.3 a In zenith b After cuts at z.a.<3 ffi c Calculated using Li&Ma Log-Likelihood Dieter Horns, MPI-K, Heidelberg 4
Galactic plane scan (CTSystem) astro-ph/936, A&A in press short exposure scan (Sensitivity >.3 Crab units) covers /4 of Galactic plane, 86 known pulsars, 63 known SNR, 9 GeV sources No signal seen (Upper limits >.5 Crab units). Dieter Horns, MPI-K, Heidelberg 5 st Unidentified TeV Source (CTSystem) astro-ph/758, A&A in press Cygnus Field: HEGRA CT-System Dec (J) [ deg ] 43 4 E dn/de [ erg cm - s - ] - ASCA GIS (- kev) 3EG J33+48 TeV Source HEGRA CT-System HEGRA-Airobicc 4 4-3 -9-8 -7-6 -5-4 -3 - - E [ TeV ] 4 39 - > 5σ excess discovered serendipitously ( hrs).5 ffi north of Cyg X-3 hard energy spectrum (α = :9) possibly extended 38.8.7.6.5.4.3 RA (J) [ hrs ] -4 follow-up observations confirm result (> 3 hrs) See talk by G. Rowell. Dieter Horns, MPI-K, Heidelberg 6
Spectral variability Mkn 4 (&) Aharonian et al., A&A 393, 89 E dn/de [TeV/(cm s)] - H M L Mkn 4 HEGRA CT System E * average flux [TeV cm - s - ] - Mkn 4 - Energy spectrum - high state mean state low state Ratio Ratio - - - M/H α=.3+/-.4 L/H α=.9+/-. E/TeV Photon index -α -.8 - -. -.4 -.6 -.8-3 -3. -3.4 E [TeV] HEGRA CT System Mkn 4 L M - F(E>TeV) [(cm s) - ] H 999-997-998 MJD599/599 CT Dieter Horns, MPI-K, Heidelberg 7 Diurnal spectral variability (CTSystem) F(E> TeV) [ (cm s) - ] F(E> TeV) [ (cm s) - ] 5 a) MJD5989/599 5 Preflare Flare.6.3 : 3: :: : 3: UTC [h] 5 b) MJD599/599 March /3 5.6.3 Hardness Ratio.8.7.6.5.4.3. f b MJD 59.93-59. MJD 589.93-59. c a d. 3 4 5 6 7 8 9 Flux (E> TeV) [ (cm s) - ] 6 e 5 4 3 : 3: :: : 3: Dieter Horns, MPI-K, Heidelberg UTC [h] 8
Multi-wavelength observations Mkn4 6 5 RXTE PCU HEGRA Flux/average Flux 4 3-5987 5988 5989 599 599 599 5993 MJD Dieter Horns, MPI-K, Heidelberg 9 H46+48, 999& dφ/de [(cm s TeV) - ] - ±6 initial spectrum: E -.9 Extreme synchr. BLLac (Costamante et al.) 4 hrs of observation (999&): S=5.8 σ -3 absorbed spectrum 35±3 7±4 9± (a) z=.9 < τ(5 TeV)<5 Indication of absorption > hrs observations carried out in -4 HEGRA data H46+48-5 4± 6-6 Power law (fit to data) E [TeV] (b) Dieter Horns, MPI-K, Heidelberg
H46+48, 999- re-analyzed& data dφ/de [(cm s TeV) - ] - 3±3 ±6 Preliminary data-set init. spectrum: E -.9 Combining HEGRA, VERITAS,& CAT: correc- Absorption ted: α =.4-3 5±3 35±3 ± 9 7±4 9± 5 9± -4-5 -6 HEGRA data Re-analysed data 999/ Power law (fit to data) 6± 4± 6 E [TeV] Modeling with finite injection time SSC & external seed photons re-analysis confirms flattening data confirms flattening flux low Dieter Horns, MPI-K, Heidelberg ES959+65 & (CTSystem) SeealsoPosterS5: [deg] N W S E dn/de [TeV/(cm s)] - ES959+65 HEGRA CT System / Crab /h -3 α=3.3+/-.7 N =(4.+/-.) ph/(cm s TeV) E/TeV preliminary HEGRA CT-System ES959+65 (&) 94 hrs of good data in & Detection at S = 5:4σ ON-data OFF-data Integral flux 8 % of Crab-Nebula Photon index 3:3±:7 Dieter Horns, MPI-K, Heidelberg
ES959+65 (CTSystem) F(E> TeV) ph/(cm s).5.5 May June July Crab Flux E dn/de [TeV/(cm s)] - -3 ES959+65 prelim. HEGRA CT System May/July - 4 4 43 44 45 46 47 48 MJD-5 Strong variability & spectral hardening in For details see POSTER S5 E/TeV Dieter Horns, MPI-K, Heidelberg 3 ES959+65 (CT) ES 959+65 - Lightcurve ES959+65 - Energy spectrum TeV flux (E>.TeV) [ cm - s - ] 3.5.5.5 -.5 54 54 543 544 545 546 547 548 549 55 MJD average flux [cm - s - TeV - ] -3-4 df/de = f (E/TeV) -α χ / dof. =.3 / 4 f = (.85 ±.) cm - s - TeV - α = 3.3 ±.7 Similar results obtained with CT -5 E [TeV] Dieter Horns, MPI-K, Heidelberg 4
The Universe viewed in Gamma-Rays Sept. 4-8, Last light at HEGRA The Universe viewed in Gamma-Rays Sept. 4-8, Summary: Surveys.4sradsurveywith> 5 hrs of data (see later talk) Galactic plane survey Serendipitous discovery of unid. source in Cygnus region (see later talk) Extragal. sources Spectral variability observed for Mkn 4 Close correlation with flux H46+48: New data confirms flattening Indication for absorption ES959+65: Detection in low state flat spectrum in high state () (see poster S5) Early morning hours of Sep-7- End of shift, end of operation Dieter Horns, MPI-K, Heidelberg 5 Dieter Horns, MPI-K, Heidelberg 6