Title: EELT and Gammaray bursts
1E-ELT and Gamma-ray bursts Frédéric
Daigne(Institut dAstrophysique de
Paris) Réunion E-ELT du Programme
National de Cosmologie, IAP, 31 mai 2007.
1. GRBs2. GRBs and cosmology3. E-ELT and GRBs
21. GRBs
3GRB prompt emission
4Duration
Spectrum
10 s
100 ms
keV ? MeV
Lightcurves
5(No Transcript)
6GRB 970228
GRB afterglows? temporal decay hours,
days? spectral evolution X,V,radio
7GRB 970508
Host galaxy z 0.835
8GRB 050904 z 6.29 !
TAROT detection _at_ 86 s I 16 (Quasar z 6.37,
I23.3)
Timescales are multiplied by 1z 7.3 (T90gt200 s)
9SWIFT redshift distribution of long GRBs
(Jakobsson et al.)
10Optical afterglows compilation by Zeh, Kann and
Klose
1 h
pre-SWIFT era
R 15-20
11Optical afterglows compilation by Zeh, Kann and
Klose
1 h
pre-SWIFT era
12Optical afterglows compilation by Zeh, Kann and
Klose
short GRBs
13Optical afterglows compilation by Zeh, Kann and
Klose
pre-SWIFT eraGRBs _at_ z1
14Optical afterglows compilation by Zeh, Kann and
Klose
short GRBs
15Long GRBs are associated with massive stars
GRB 980425 / SN 1998bwz0.008
GRB 030329 / SN 2003dhrz0.168
16Short GRBs NS-NS mergers ?
Weak optical afterglowsHost elliptical
4 irregular 1 starforming 1
z 0.266
17GRBs models
Energetics 1051 1054 erg (isotropic) 1051
erg (after correction for beaming)Redshift
0.008 ? 6.3
18Initial event Collapsar (long GRBs)Mergers
(short GRBs ?) ? Stellar black hole thick disc
R in meters
19R in meters
Transparency
Coasting phase Final Lorentz factor G ? 100 !
Relativistic ejection
20? Internal shocks ? Prompt g/X-rays / optical
?
R in meters
Transparency
Coasting phase
Relativistic ejection
21? Reverse shock ? Optical flash ?
Internal shocks
R in meters
Transparency
Coasting phase
Relativistic ejection
22? Forward shock ? Afterglow
Contact discontinuity
Reverse shock
Internal shocks
R in meters
Transparency
Coasting phase
Relativistic ejection
23? Lateral expansion Starts at late time.
Forward shock
Discontinuité de contact
Reverse shock
Internal shocks
R in meters
Transparency
Coasting phase
Relativistic ejection
242. GRBs and cosmology
25Host galaxy - source environment -
ISM Intergalactic medium
GRB 050730 z3.969 (Chen et al. 05)R17.7 4
hours after the burstISM N(HI)22.15 Z/Z?1/1
00IGM DLA _at_ z3.564 LLS _at_ 3.022 MgII abs. _at_
z2.253,1.773
26GRB 050904 _at_ z 6.3
Kawai et al. 2005 (Subaru)
27Host galaxy - source environment -
ISM Intergalactic medium ? Chemical evolution
(structures, IGM) ? QSOs vs GRBs some
differences (z distribution, initial luminosity,
angular size, impact on environment, )
28Host galaxy - source environment -
ISM Intergalactic medium ? Chemical evolution
(structures, IGM) ? QSOs vs GRBs some
differences Needs accurate spectroscopy at
early times, when the afterglow is still bright
(first hour after the burst).? GRB hosts new
sample of high z galaxies
29- Montecarlo simulations
- GRB rate follows SFR
- Powerlaw F(L)
- Instrumental thresholds BATSE, HETE2, SWIFT
- Constraints
- log N log P
- Epeak distribution
- XRF/GRB ratio
Data from Hopkins 2005
30GRB production by stars Higher efficiencyat
high z ?
(Daigne, Rossi Mochkovitch 2006)Metallicity
effect ? See e.g. E. Le Floch et al. 06One
needs to better understand the GRB progenitors.
31Very high redshift GRBs (zgt6) ?Probing the
reionization epoch (spectroscopy) ?Pop. III stars
?
32GRB ?
33GRBs cosmology measuring cosmological
parameters ?
Gamma-ray bursts are not standard candles?Eg,iso
1051 1054 erg ?Some correlations are used to
standardize GRBs Eg,iso vs Epeak large
dispersion Eg vs Epeak betterPBs
Eg is measured from the break time in the
afterglow
Epeak keV ? MeV
nFn
Amati et al. 2003
n
34q0
Obs
35q0
Obs
36Gamma-ray bursts are not standard candles?Eg,iso
1051 1054 erg ?Some correlations are used to
standardize GRBs Eg,iso vs Epeak large
dispersion Eg vs Epeak betterPBs Eg is
measured from the break time in the afterglow
difficult The physical interpretation is not
clear (chromatic/achromatic breaks) The number
of GRBs is too small to check the intrinsic
dispersion for a sample of GRBs at the same
redshift. ?Comparison to SNae Ia higher z ?
overcome the degeneracy pb
37Ghirlanda et al. 2005
383. E-ELT and GRBs
39- GRB detection t0 satellite with real-time
localization (1)t0 10s transmission to the
ground large spectral range (Epeak) - Afterglow detection t0 30s robotic telescope
localization (1)t0 1-2 min real-time
transmission infrared is needed
(high-redshift / dust) - (3) Afterglow follow-up t0 1-2min?weeks
photometry (early times small telescopes )t0
1-2min?hours minimal spectroscopy
redshift high-resolution spectroscopy (large
telescopes) infrared is needed
(high-redshift / dust)
SWIFT/XRT
40GRB 060418 Vreeswijk et al. 2007Trigger by
SWIFT/BAT t0 3 X-ray afterglow SWIFT/XRT
t01min 5 VLT/UVES using the rapid
response mode t010 min 1( a human
astronomer at t07 min to align theUVES slit
(1) on the afterglow)Spectra at t011, 16,
25, 41, 71 min resolving power 7 km/s S/N
10-15
41GRB 060418 Vreeswijk et al. 2007GRB z
1.490ISM time vaiability,better
understanding ofthe excitation mechanismof the
observed lines.
42GRB 060418 Vreeswijk et al. 2007GRB z
1.490ISM time variability,better
understanding ofthe excitation mechanismof the
observed lines.IGM three interveningMg II
systems z 0.603 z 0.656 z 1.107
43E-ELT proposed for 2020(1) which satellite
for the GRB detection SWIFT 2005 ? 2015
? GLAST 2008 ? 2018 ? (real-time localization
for HE only) SVOM 2012 ? 2022 ? (2) which
robotic telescopes for the afterglow detection
1 localization should not be an issue
44E-ELT proposed for 2020(1) which satellite
for the GRB detection(2) which robotic
telescopes for the afterglow detection 1
localization(3) E-ELT requirements ?
rapid pointing (lt 30 min) ? rapid
response (lt 30 min) ? spectroscopy alla
XSHOOTER UV?K (3 arms) R 4000-14000
fast response ? as far in infrared as
possible Without these requirements GRB
host galaxies
45E-ELT proposed for 2020(1) which satellite
for the GRB detection(2) which robotic
telescopes for the afterglow detection 1
localization(3) E-ELT requirements ?
rapid pointing (lt 30 min) ? rapid
response (lt 30 min) ? spectroscopy alla
XSHOOTER UV?K (3 arms) R 4000-14000
fast response ? as far in infrared as
possible(4) Impact of a large collecting area
? moderate-z GRBs excellent S/N ? high-z
GRBs detection of fainter sources ? study
of the host galaxy
46GRBs and cosmology ? ISM (host galaxy) ?
IGM (line of sight) ? SFR (biases ?) up
to z gt 6 (reionization epoch pop.
III) (expected GRB rate ?) ? cosmological
parameters (TBC) E-ELT and GRBs the large
collecting area improves the S/N and allows
to detected fainter sources. ? GRB detection
in space in 2020 ? Host galaxies no specific
requirements ? Afterglows - rapid
response / rapid pointing - fast
spectroscopy (VLT) (large spectral range
? IR) - location on Earth plays a
role
GRBs are a unique tool to probe the evolution of
the Universe from the first stars to the present
epoch.