Title: The Radio Afterglow of GRB 030329
1The Radio Afterglow of GRB 030329
- Greg Taylor, Dale Frail (NRAO)
- Edo Berger, Shri Kulkarni (Caltech)
- Future Directions in VLBI, A Celebration of the
10th - Anniversary of the VLBA Socorro, June 9, 2003
2The first gamma ray-burst
Vela satellite
3Fireball Calorimetry
Frail, Waxman Kulkarni (2000)
- Long-lived radio afterglow makes a transition to
NR expansion - no geometric uncertainties
- can employ robust Sedov formulation for dynamics
- compare with equipartition radius and cross check
with ISS-derived radius - At z 0.835
4(No Transcript)
5The Fireball Model
Model Predictions
for burst at z0.2
Size0.05 to 0.1 mas No proper motion
The Cannonball Model
Cannot be resolved Motion0.05 mas/day
6GRB 030329 The Burst of the Decade
- World-wide armada of optical telescopes (60)
observed this burst 24/7 - A very bright burst (mv12.5). In radio it is 50
times brighter than any previous GRB! - Better yet at z0.168 it is only 740 Mpc away.
7The Gamma Ray Burst on March 29, 2003
8The Optical Transient (OT)
9OT Fades
10VLA Observations 1.4 to 43 GHz and OVRO 100 GHz
11VLA Light Curves (Berger et al 2003, submitted)
12VLBA on April 1 (t2.4 days)
A Scintillating Result
13April 1
April 6
5 GHz data not yet reduced
Modest Scintillation
Scintillation quenching
14Testing the Cannonball Model
Phase reference VLBI
gives accurate absolute
positions (0.1
-
0.3
mas
)
dominated by
systematics
can be improved
Already sufficient to rule
out predictions of
cannonball model (motion shown by arrow)
15Resolving the Afterglow
3rd Epoch April 22 VLBA EB Beam is 0.45 x
0.15 mas Estimated size is 0.1 /- 0.05
mas Consistent with standard model size of 0.07
mas average expansion velocity of 8c
16model 0 mas model
0.1 mas model 0.2 mas
17Resolving the Afterglow
4th Epoch May 19 VLBAEBGBTY27 Beam is 0.67
x 0.24 mas Jet component at 0.28 /- 0.05
mas Not consistent with standard
model prediction of 0.12 mas expansion average
expansion velocity of 19c
18Summary
GRB Afterglows
- Scintillate
- Expand
- Have jets?
Cannonball model is ruled out by current limits
on proper motion
19The Details Four Epochs
US VLBA 10 antennas April 01, 2003 5 8 GHz
US VLBA 10 antennas April 06, 2003 5, 8, 15 22 GHz
US VLBA Bonn 100-m April 22, 2003 15 22 GHz
VLBABonn GBTVLA May 19, 2003 15 22 GHz
20Jet Signatures Optical/X-ray
Piran, Science, 08 Feb 2002
21Broad-band Synchrotron Spectrum