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1Sylvio Klose, Thüringer Landessternwarte Tautenburg, Germany
Short bursts -- an observational perspective
2
4 mag
+/- 2 mag
Kann & Klose (2007)
short afterglows: the typical light curve
long vs. shortafterglows:typically dm >~ 4 mag
• be fast• go deep
3
4
• dust and gas
• the outflow geometry
• extra light
Outline of the talk
5
Challenge 1
the GRB environment(dust & gas)
6
(A) long bursts
Kann, Klose, & Zeh (2006)
• inspired by GRB 970828 (Groot et al. 1998)• starting with Ramaprakash et al. (1998)
I. Photometry: GRB host extinctions*** ***
7
(A) long bursts
Kann, Klose, & Zeh (2006)GRB 970828: Djorgovski et al. (2001)
pre-Swift era
8
Fox et al. (2005)
GRB 050709
GRB 050709GRB 060121
(B) short bursts
de Ugarte Postigo et al. (2006);Berger et al. (2006)
4.6?
Multi-color data from short burst afterglows
mostly very bad sampled
1
9
(B) short bursts
• 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)
GRB host extinctions
current situation: not satisfactory
10
ANDICAM
GROND
in perspective: multi-color imaging
2 channels
7 channels
Gamma-Ray Burst Optical Near-Infrared Detector
11
5 m
in
30 m
in
1 m
in
(A) long bursts II. Spectroscopy: early spectra*** ***
060607A, VLT, 8 min
060418, VLT, 10 min
061121, Keck, 14 min
12
(B) short bursts Early spectra from short burst afterglows?
(no spectra at all)
current situation: not satisfactory
1 m
in
5 m
in
30 m
in
13
Calar Alto 3.5-m, PMAS/PPak
(B) short bursts Observing with Integral Field Units
in perspective:
GRB 060605
Ferrero, Savaglio et al. (2007b)
star
star
star
ag
74“ x 64“
3D cube
14
Challenge 2
afterglow geometry, jets
15
(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
*** ***
16
(A) long bursts Light curve breaks in long burst afterglows
Castro-Tirado et al. (1999) Stanek et al. (1999)
GRB 990123
R band
B,V,R,I bands
GRB 990510
17
Zeh, Klose, & Kann (2006)
(A) long bursts Light curve breaks in long burst afterglows
pre-Swift era
Klose et al. (2004)
GRB 030226
UBVRIJHK bands
18
long bursts
short bursts
Watson et al. (2006)
α = 1
see also Livio & Waxman (2000); Rosswog & Ramirez-Ruiz (2003); Janka et al. (2006)
(B) short bursts
0512
21A
, 061
006,
061
210
????4 mag
Light curve breaks in short burst afterglows
Berger (2007)
in perspective:
current situation: not satisfactory
19
GRB 990123: Hjorth et al. (1999)GRB 990510: Covino et al. (1999); Wijers et al. 1999GRB 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
Polarisation data for long burst afterglows
(A) long bursts II. Polarimetry*** ***
20
Lazzati et al. (2004)Gorosabel et al. (2004)
GRB 020813
21
Greiner et al. (2003)R = 15.0t = 2040 secdP= 0.09 %
R = 20.6t = 9600 secdP= 0.48 %
VLT 8.2-m
GRB 030329
(A) long bursts The best sampled polarimetric light curve
22
(B) short bursts
R (t=0.01 days) = 19.5R (t=1 day) = 24.5R (t=10 days) = 27.0
Polarimetric data from short burst afterglows?
in perspective:
23
Challenge 3
extra light, SNe
24
I. Mini-supernovae (Li & Paczynski 1998)
z = 0.1β = 1/3
1
2
3
4
5
6
f = E_rad / Mc**2M = ejected mass
(B) short bursts *** ***
(1)(2)
(3)(4)
(5)(6)
25
Short bursts, afterglows and upper limits
D.A. Kann
26
GRB 050509B (no detected afterglow)
Observational constraints on the LP model
day 20
see also Hjorth et al. (2005)
(B) short bursts
in perspective:
day 1
current situation: strong constraints
27
II. SN 1998bw light
Zeh, Klose, & Hartmann (2004)
(A) long bursts
• starting with GRB 980326 (Bloom et al. 1998)• inspired by GRB 980425/ SN 1998bw (Galama et al., Kulkarni et al. 1998)
*** ***
28Ferrero et al. (2006), incl. data fromRichardson, Branch, & Baron (2006)
The GRB-SNe luminosity distribution(A) long bursts
extinction corrected
SN 1991D SN 1992ar
SN 1987K
GRB 991208
SN 1998bw
GRB 060218(SN 2006aj)
GRB 000911H_0 =71Ω _m = 0.27Ω_Λ = 0.73
29
Kann & Klose (2007)
k = 0.0060
k = 0.0015
k = 0.60
k = 0.29
(B) short bursts Constraints on SN 1998bw light
k < 0.001 ?
30
SN 1998bw peak magnitude (z)
k=0.001
k=1.0
VLT/FORS1, R-band, exposure times (seconds), S/N = 10
(B) short bursts What are the chances to detect SN light?
in perspective:
current situation: deep limits
31
Summary
32
10 yearsGRB afterglows 1997 - 2007
33
„How can I get so much observing time?“
Challenge 4
34
Short burst afterglows, an optical perspective
• obtaining multicolor imaging data (UBVRIJHK) is surely possible
• getting (early-time) spectra is possible
• 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
• obtaining a polarimetric light curve might be impossible at all
z, gas
dust
jets
mor
e an
d m
ore
diffi
cult
SNe
Anyway, we will try.