Download Observation of GRBs with the MAGIC Telescope

Observation of GRBs with the
MAGIC Telescope
Nicola Galante
(MPI für Physik - München)
for the MAGIC Collaboration
7 March 2008
Nicola Galante, DPG - Freiburg
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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!
7 March 2008
Nicola Galante, DPG - Freiburg
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!
7 March 2008
Nicola Galante, DPG - Freiburg
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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)
7 March 2008
Nicola Galante, DPG - Freiburg
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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
7 March 2008
Nicola Galante, DPG - Freiburg
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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)
7 March 2008
Nicola Galante, DPG - Freiburg
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GRB Alarm System
GC
N
Outside
MAGIC
systems
Communication:
•e-mail
•web
•Acoustic alarm
7 March 2008
Nicola Galante, DPG - Freiburg
Alert
System
Central
Control
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The MAGIC Telescope
high reflective diamond milled
aluminum mirrors
Active mirror
control
(PSF: 90% of light in
o inner pixel)
0.1
o
Light weight
Carbon fiber
structure for
fast repositioning
- 3.5 FOV camera
- 576 high QE PMTs
(QEmax= 30% 330 – 450 nm)
Analog signal
transport
via optical fibers
7 March 2008
IPE
IPE
IPE
NET
CE
2-level trigger system
& 2 GHz FADC system
Nicola Galante, DPG - Freiburg
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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
7 March 2008
Nicola Galante, DPG - Freiburg
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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
7 March 2008
Nicola Galante, DPG - Freiburg
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Observed GRBs 2005-2006
GRB
t0
Dtalert
Dtoss
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 repointing
131 s
12 s
Typical
050713a
04:29:02
050904
01:51:44
82 s
060121
22:24:54
060203
060206
7 March 2008
13 s
40 s
s
40÷50
50°
70 s
49°
145 s
225 s
20°
15 s
583 s
2s
42°
23:55:35
171 s
259 s
83 s
44°
04:46:53
16 s
52 s
11 s
10°
Nicola Galante, DPG - Freiburg
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Two Prompt Emissions
GRB 050713a
GRB 050904
7 March 2008
Nicola Galante, DPG - Freiburg
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Flux Upper Limits 2005-2006
GRB
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
7 March 2008
Nicola Galante, DPG - Freiburg
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Flux Upper Limits 2006-2007
GRB
t0
Dtalert
Dtoss
t90
<ZA>
060825
02:59:58
19 s
57 s
8s
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
7 March 2008
Nicola Galante, DPG - Freiburg
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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 crucial but...
... need a near (but not so much) GRB!
7 March 2008
Nicola Galante, DPG - Freiburg
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Fast Slewing Time!
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
7 March 2008
Nicola Galante, DPG - Freiburg
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