Observation of GRBs with the MAGIC Telescope
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Transcript of Observation of GRBs with the MAGIC Telescope
7 March 2008 Nicola Galante, DPG - Freiburg 1
Observation of GRBs with the MAGIC Telescope
Nicola Galante (MPI für Physik - München)
for the MAGIC Collaboration
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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?
AGILE already in orbit, GLAST will be launched soon - GeV observations time!
GeV/TeV observation possible by new generation IACTs too
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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!
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Constraints on IACT
Band functionvalid up to GeVEbreak 300 keVhard-to-soft evolution
well described by Shock Synchrotron Model (SSM)
moreover…Tavani M., Ap.J. 466, 768-778 (1996)
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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&A 447, 897-903, 2006
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Interaction with EBL
cosmological horizon
Observed flux is attenuated
zmax 1for 50 GeV threshold
K. Mannheim et al., A&A, 413,807-815 (2006)
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GRB Alarm System
GCN
Alert System
Central Control
Communication:
•web
•Acoustic alarm
Outside
MAGIC systems
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The MAGIC Telescope
Analog signal transport via optical fibers IPE
IPEIPECENET
2-level trigger system& 2 GHz FADC system
Active mirror control
(PSF: 90% of light in 0.1o inner pixel)
high reflective diamond milled aluminum mirrorsLight weight
Carbon fiber structure for
fast repositioning
- 3.5o FOV camera - 576 high QE PMTs (QEmax= 30% 330 – 450 nm)
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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
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Sensitivity
Test on Crab Nebula:
measured sensitivity as a function of observation time
70 GeV < E < 300 GeV
~3.6 Crab in 20 s
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Observed GRBs 2005-2006GRB t0 talert toss t90 <ZA>
050421 04:11:52 58 s 108 s 10 s 50°
050502a 02:13:56 40 s 269 s 20 s 42°
050505 23:22:21 540 s 717 s 60 s 55°
050509a 01:46:29 16 s 131 s 12 s 50°
050713a 04:29:02 13 s 40 s 70 s 49°
050904 01:51:44 82 s 145 s 225 s 20°
060121 22:24:54 15 s 583 s 2 s 42°
060203 23:55:35 171 s 259 s 83 s 44°
060206 04:46:53 16 s 52 s 11 s 10°
Typical repointing40÷50 s
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Two Prompt Emissions
GRB 050713a
GRB 050904
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Flux Upper Limits 2005-2006GRB Eth Flux UL (30 min)
050421 212 GeV 0.2 CU
050502a 152 GeV 0.3 CU
050505 213 GeV 0.8 CU
050509a 215 GeV 0.4 CU
050713a 170 GeV 0.8 CU
050904 86 GeV 0.3 CU
060121 151 GeV 0.4 CU
060203 151 GeV 1.7 CU
060206 86 GeV 0.4 CU
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Flux Upper Limits 2006-2007GRB t0 talert toss t90 <ZA>
060825 02:59:58 19 s 57 s 8 s 28°
061028 01:26:22 140 s 169 s 106 s 38°
061217 03:40:08 13 s 786 s 0.4 s 56°
070412 01:27:03 674 s 701 s 34 s 35°
070920a 04:00:13 539 s 680 s 56 s 52°
GRB Eth Flux UL (30 min)
060825 80-125 GeV 0.7 CU
061028 100-125 GeV 0.8 CU
061217 300-500 GeV 0.5 CU
070412 80-125 GeV 0.2 CU
070920a 225-300 GeV 0.4 CU
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ConclusionsMAGIC features (TESTED!):Flux sensitivity: 3.6 Crab @ 5 LiMa in 20s @ 70 GeV < E < 300 GeVAngular resolution: 0.1°Slewing capabilities: 40÷50 s, ~20x than other CherenkovEth: 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 crucial but... ... need a near (but not so much) GRB!
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Fast Slewing Time!
QuickTime™ and aCinepak decompressor
are needed to see this picture.