160 likes | 291 Views
Observation of GRBs with the MAGIC Telescope. Nicola Galante (MPI für Physik - München) for the MAGIC Collaboration. Observations at VHE. BATSE: 2704 GRB up to ~2 MeV EGRET: 4 GRBs above 1 GeV (up to 18 GeV) No more detections above GeV (only 1 evidence of excess by MILAGRO)
E N D
Observation of GRBs with the MAGIC Telescope Nicola Galante (MPI für Physik - München) for the MAGIC Collaboration Nicola Galante, DPG - Freiburg
Observations at VHE • BATSE: 2704 GRB up to ~2 MeV • EGRET: 4 GRBs above 1 GeV (up to 18 GeV) • No more detections above GeV(only 1 evidence of excess by MILAGRO) • (too) Many emission models • New phenomenology recently discovered(GRB late X-ray flares 103 - 104 s later) • VHE observations necessary to constrain models • GeV/TeV emission present in late activity? GeV/TeV observation possible by new generation IACTs too AGILE already in orbit, GLAST will be launched soon - GeV observations time! Nicola Galante, DPG - Freiburg
Constraints on IACT Isotropic GRB distribution: IACT Duty-Cycle ~10% Duration Short T90 < 2s, T90 0.7s, 1/3 Tot Long T90 > 2s, T90 30s, 2/3 Tot Fast repositioning time required! Nicola Galante, DPG - Freiburg
Constraints on IACT Band function valid up to GeV Ebreak 300 keV hard-to-soft evolution well described by Shock Synchrotron Model (SSM) moreover… Tavani M., Ap.J. 466, 768-778 (1996) Nicola Galante, DPG - Freiburg
Afterglow and redshift GRB970228: first fading X-ray counterpart by Beppo-SAX. From X to O up to several days adjacent galaxies: red-shift measurement 0.01 ≤ z ≤ 6.29 Jakobsson P., Levan A., et al., A&A447, 897-903, 2006 Nicola Galante, DPG - Freiburg
Interaction with EBL cosmological horizon Observed flux is attenuated zmax 1 for 50 GeV threshold K. Mannheim et al., A&A, 413,807-815 (2006) Nicola Galante, DPG - Freiburg
GRB Alarm System Outside GCN MAGIC systems • Communication: • e-mail • web • Acoustic alarm Alert System Central Control Nicola Galante, DPG - Freiburg
Light weight Carbon fiber structure for fast repositioning high reflective diamond milled aluminum mirrors IPE IPE - 3.5o FOV camera - 576 high QE PMTs (QEmax= 30% 330 – 450 nm) IPE NET CE Analog signal transport via optical fibers 2-level trigger system& 2 GHz FADC system The MAGIC Telescope Active mirror control(PSF: 90% of light in 0.1o inner pixel) Nicola Galante, DPG - Freiburg
Sensitivity Since February 2007 a fast 2GHz Multiplexed FADC DAQ system is working improved sensitivity Current Sensitivity for E>300 GeV 1.57% Crab in 50 h Nicola Galante, DPG - Freiburg
Sensitivity Test on Crab Nebula: measured sensitivity as a function of observation time 70 GeV < E < 300 GeV ~3.6 Crab in 20 s Nicola Galante, DPG - Freiburg
Observed GRBs 2005-2006 Typical repointing 40÷50 s Nicola Galante, DPG - Freiburg
Two Prompt Emissions GRB 050713a GRB 050904 Nicola Galante, DPG - Freiburg
Flux Upper Limits 2005-2006 Nicola Galante, DPG - Freiburg
Flux Upper Limits 2006-2007 Nicola Galante, DPG - Freiburg
Conclusions MAGIC features (TESTED!): Flux sensitivity:3.6 Crab @ 5s LiMa in 20s @ 70 GeV < E < 300 GeV Angular resolution:0.1° Slewing capabilities:40÷50 s, ~20x than other Cherenkov Eth:50 GeV at zenith, lowest attained E at Cherenkov Publishing GCN circular within 1 week! Paper on 2005-2006 observations already published J. Albert, et al., Ap. J. 667, 358, 2007 Measurements in VHE crucialbut... ... need a near (but not so much) GRB! Nicola Galante, DPG - Freiburg
Fast Slewing Time! Nicola Galante, DPG - Freiburg