2 - 13 July 2004, Erice 1

The performance of MAGIC Telescope for observation of

Gamma Ray Bursts

Satoko Mizobuchi for MAGIC collaboration

Max-Planck-Institute for physics(Werner-Heisenberg-Institute)

Muenchen

2 - 13 July 2004, Erice 2

Low Energy Threshold

•GRBs originate in cosmological distances•High energy γ-rays are absorbed through the

interaction with infrared photon•Energy cutoff is expected

from 50GeV to 100GeV•Need a detector with low energy threshold!!

MAGIC Effective collection area 103m2～ 105m2 (10GeV-100GeV)

•Need a fast slewing telescope•GRB Duration time: few seconds - several minutes•SWIFT : 5 arc-minutes accuracy within 10 seconds

Fast slewing time

MAGIC Slewing time < 20s

Gamma-Ray Bursts detection by MAGIC

40GeV

10GeV

2 - 13 July 2004, Erice 3

The MAGIC sensitivity and expected prompt GRB spectra

10-10

10-11

MAGIC

10-6

10-7

10-8

10-9

Ref : Prompt GRB spectra : detailed calculations and the effect of pair production

Asaf Pe’er and Eli Waxman astro-ph/0311252 11 Nov 2003

ConditionL = 1052erg εe= εB = 10-0.5, p=3

∆t = 10-2s, Γ= 300 (l´ = 2.5)∆t = 10-3s, Γ= 600 (l´ = 0.8)∆t = 10-4s, Γ= 1000 (l´ = 0.6)

AssumptionLuminosity distance dL = (1+Z) r = 2×1

028

z = 1

10s

100s

2 - 13 July 2004, Erice 4

Epeak

α

β

Energy

Flu

x

BATSE GRB Current Catalog (2702 GRBs)- fluence - duration- light curve (64ms resolutio

n)The spectral catalog (95 bursts)

- amplitude(A), low-energy spectral index (α),high-energy spectral index (β),peak energy (Epeak)

Ref : http://www.batse.msfc.nasa.gov/batse/grb/catalog/current/ , http://cossc.gsfc.nasa.gov/batse/batseburst/sixtyfour_ms/,

Preece R.D., ApJ 496: 849- 862, April 1998, Preece R.D., ApJ Supp., 126, 19-36, Jan 2000

Epeak

β

Information of GRBs detected by BATSE

2 - 13 July 2004, Erice 5

300keV

α

β

Energy

Flu

x Normalize

90

)()300@(

T

FluenceCkeVflux

T90

Fluence

Expected spectrum of GRBs

2 - 13 July 2004, Erice 6

MAGIC (PMT)Index -2.2

10GeV – 20GeV 10.7σ20GeV – 40GeV 16.3σ

BG40Hz

MAGIC observation time

BG20Hz

Observation Start time

Significance > 5 σ Observation start time 15sec – 30sec

　10GeV-20GeV

20GeV-40GeV

-2.5 2.0% 3.0%

-2.2 24% 29%

-1.9 41% 42%

Detection capability with MAGIC Telescope

BATSE

2 - 13 July 2004, Erice 7

•With HPD Advanced CameraLarger observable sky x1.7Higher Detection efficiency x1.3

•Predicted number of GRBs by SWIFT Satellite : ～ 200 bursts/year

•Duty Cycle of observation time by MAGIC 14%•Observable sky by MAGIC 15% (zenith angle <45˚)•GRB detection efficiency by MAGIC: 　 >24%

≥1.0 bursts/year

Number of observable GRBs with MAGIC

Preliminary

2 - 13 July 2004, Erice 8

Thank you

2 - 13 July 2004, Erice 9

1. BATSE GRB Current Catalogue (2702 bursts)-Fluence -Duration time-Light curve (Time Profile)

2. Assume Power law index -1.9,-2.2 and -2.5 between 300keV and 40GeV energy, estimate Gamma Ray flux at 10-20 GeV, 20-40 GeV energy bins.

3. Convolute MAGIC acceptance with Gamma Ray flux at 10-20GeV, and 20-40GeV

4. Add Expected Hadron shower rates 40Hz, and 80Hz in 10-20GeV and 20-40GeV energy bin.

Estimation of gamma-ray rate at MAGIC energy

Gamma Ray flux at 300keV

Toy Simulation

2 - 13 July 2004, Erice 10

MAGIC

HETE2(2000-)SWIFT(2004.09-)

XMM(1999-)ASTRO-E (2005.02-)Ⅱ

ASCA(1993-2000)ROSAT(1990-1999)

RXTE(1995-)

BeppoSAX(1996-2002)Chandra(1999-)

CGRO(1991-2000)

GLAST(2007.02-)INTEGRAL(2002-)

MAGIC

The energy rangeINTEGRAL

HETE2

SWIFT

2 - 13 July 2004, Erice 11

Shock plasma conditions (6 free parameters)1. Related to the underlying source

• Total luminosity L [erg]• Lorentz factor of the shock plasma Γ• Variability time t∆ [s]

( assumption : thickness of shells is c t )∆2. Related to the microphysics

• Ratio of the magnetic field energy density to the total th

ermal energy• The fraction of the total thermal energy E

which goes into random motions of the electrons

• Power law index d log ne / d log εe = -p

E

UBB

E

Uee

Comoving compactness

∆R : comoving width :comoving number photon density : Thomson cross section

15 tLnRl eT

n

T

Plasma parameters

2 - 13 July 2004, Erice 12

Relevant physical processes1. Synchrotron emission 2. Synchrotron self absorption 3. Compton scattering (eγ→eγ)4. Inverse Compton5. Pair production (e+e-→γγ) 6. Annihilation (γγ→e+e-)

: magnetic field Uint : internal energy density

int4 UB B

Time dependent numerical model