Short bursts -an observational perspective
Sylvio Klose, Thüringer Landessternwarte Tautenburg, Germany
1
short afterglows:
the typical
light curve
• be fast
• go deep
4 mag
+/- 2 mag
Kann & Klose (2007)
long vs. short
afterglows:
typically
dm >~ 4 mag
2
3
Outline of the talk
• dust and gas
• the outflow geometry
• extra light
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Challenge 1
the GRB environment
(dust & gas)
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(A) long bursts
*** I. Photometry: GRB host extinctions ***
• inspired by GRB 970828 (Groot et al. 1998)
• starting with Ramaprakash et al. (1998)
Kann, Klose, & Zeh (2006)
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(A) long bursts
pre-Swift era
Kann, Klose, & Zeh (2006)
GRB 970828: Djorgovski et al. (2001)
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(B) short bursts
Multi-color data from short burst afterglows
GRB 050709
4.6?
Fox et al. (2005)
GRB 060121
050709
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mostly very bad sampled
de Ugarte Postigo et al. (2006);
Berger et al. (2006)
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(B) short bursts
GRB host extinctions
• GRB 050709: A_V = (0.67 +/- 0.19) mag (Ferrero et al. 2007a)
• GRB 060121: A_V = (0.5 +/- 0.2 ) mag
(de Ugarte Postigo et al. 2006)
current situation: not satisfactory
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in perspective: multi-color imaging
GROND
7 channels
ANDICAM
2 channels
Gamma-Ray Burst Optical Near-Infrared Detector
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***
II. Spectroscopy: early spectra ***
060418,
VLT, 10 min
060607A,
VLT, 8 min
30 min
5 min
061121,
Keck, 14 min
1 min
(A) long bursts
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Early spectra from short burst afterglows?
1 min
(B) short bursts
30 min
current situation:
not satisfactory
5 min
(no spectra at all)
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(B) short bursts
Observing with Integral Field Units
star
star
star
Calar Alto 3.5-m,
PMAS/PPak
GRB 060605
3D cube
Ferrero, Savaglio et al. (2007b)
74“ x 64“
in perspective:
ag
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Challenge 2
afterglow geometry,
jets
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(A) long bursts
***
I. Photometry
***
• starting with GRB 990123
(Castro-Tirado et al. 1999)
• and later GRB 990510
• first summarized by Frail et al. (2001)
• Panaitescu & Kumar (2001)
• Bloom et al. (2003)
• and others
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(A) long bursts
Light curve breaks in long burst afterglows
R band
B,V,R,I bands
GRB 990123
Castro-Tirado et al. (1999)
GRB 990510
Stanek et al. (1999)
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(A) long bursts
Light curve breaks in long burst afterglows
pre-Swift era
UBVRIJHK bands
GRB 030226
Klose et al. (2004)
Zeh, Klose, & Kann (2006)
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(B) short bursts
Light curve breaks in short burst afterglows
short
bursts
????
051221A, 061006, 061210
long
bursts
Watson et al. (2006)
Berger (2007)
see also Livio & Waxman (2000);
Rosswog & Ramirez-Ruiz (2003);
Janka et al. (2006)
4 mag
α=1
current situation: not satisfactory
in perspective:
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(A) long bursts
***
II. Polarimetry ***
Polarisation data for long burst afterglows
GRB 990123: Hjorth et al. (1999)
GRB 990510: Covino et al. (1999); Wijers et al. 1999
GRB 990712: Rol et al. (2000)
GRB 020813: Gorosabel et al. (2004); Lazzati et al. (2004)
GRB 021004: Rol et al. (2004)
GRB 030226: Klose et al. (2004)
GRB 030329: Greiner et al. (2003)
GRB 060218: Gorosabel et al. (2006)
list is incomplete
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GRB 020813
Lazzati et al. (2004)
Gorosabel et al. (2004)
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(A) long bursts
The best sampled polarimetric light curve
GRB 030329
R = 15.0
t = 2040 sec
dP= 0.09 %
Greiner et al. (2003)
VLT 8.2-m
R = 20.6
t = 9600 sec
dP= 0.48 %
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(B) short bursts
Polarimetric data from short burst afterglows?
R (t=0.01 days) = 19.5
R (t=1 day)
= 24.5
R (t=10 days) = 27.0
in perspective:
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Challenge 3
extra light, SNe
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(B) short bursts
I. Mini-supernovae (Li & Paczynski 1998) ***
***
z = 0.1
β = 1/3
3
6
1
4
5
(1)
(2)
(3)
(4)
(5)
(6)
2
f = E_rad / Mc**2
M = ejected mass
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Short bursts,
afterglows
and upper limits
D.A. Kann
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(B) short bursts
Observational constraints on the LP model
day 20
day 1
GRB 050509B (no detected afterglow)
current situation: strong constraints
see also Hjorth et al. (2005)
in perspective:
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(A) long bursts
***
II. SN 1998bw light
***
• starting with GRB 980326
(Bloom et al. 1998)
• inspired by GRB 980425/
SN 1998bw (Galama et al.,
Kulkarni et al. 1998)
Zeh, Klose, & Hartmann (2004)
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(A) long bursts
The GRB-SNe luminosity distribution
SN 1998bw
SN 1991D
extinction corrected
SN 1992ar
GRB 991208
GRB 000911
H_0 =71
Ω _m = 0.27
Ω_Λ = 0.73
GRB 060218
(SN 2006aj)
Ferrero et al. (2006), incl. data from
Richardson, Branch, & Baron (2006)
SN 1987K
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(B) short bursts
Constraints on SN 1998bw light
k = 0.60
k = 0.29
k = 0.0060
k < 0.001 ?
k = 0.0015
Kann & Klose (2007)
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(B) short bursts
What are the chances to detect SN light?
k=0.001
k=1.0
SN 1998bw peak magnitude (z)
VLT/FORS1, R-band,
exposure times (seconds), S/N = 10
current situation: deep limits
in perspective:
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Summary
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10 years
GRB afterglows
1997 - 2007
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Challenge 4
„How can I get so much observing time?“
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Short burst afterglows, an optical perspective
• obtaining multicolor imaging data (UBVRIJHK) is surely possible
z, gas • getting (early-time) spectra is possible
SNe
jets
• setting constraints on extra light down to deep flux limits is possible;
but the perspectives for detecting something are an open question
• detecting / constraining a light curve break in the optical bands might
be hard
more and more difficult
dust
• obtaining a polarimetric light curve might be impossible at all
Anyway,
we will try.
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