An infrared flash contemporaneous with the gamma-rays of GRB 041219a.
The explosion that results in a cosmic gamma-ray burst (GRB) is thought to produce emission from two physical processes: the central engine gives rise to the high-energy emission of the burst through internal shocking, and the subsequent interaction of the flow with the external environment produces long-wavelength afterglows. Although observations of afterglows continue to refine our understanding of GRB progenitors and relativistic shocks, gamma-ray observations alone have not yielded a clear picture of the origin of the prompt emission nor details of the central engine. Only one concurrent visible-light transient has been found and it was associated with emission from an external shock. Here we report the discovery of infrared emission contemporaneous with a GRB, beginning 7.2 minutes after the onset of GRB 041219a (ref. 8). We acquired 21 images during the active phase of the burst, yielding early multi-colour observations. Our analysis of the initial infrared pulse suggests an origin consistent with internal shocks.
Blake
C H
CH
Harvard College Observatory, Cambridge, Massachusetts 02138, USA.
Bloom
J S
JS
Starr
D L
DL
Falco
E E
EE
Skrutskie
M
M
Fenimore
E E
EE
Duchêne
G
G
Szentgyorgyi
A
A
Hornstein
S
S
Prochaska
J X
JX
McCabe
C
C
Ghez
A
A
Konopacky
Q
Q
Stapelfeldt
K
K
Hurley
K
K
Campbell
R
R
Kassis
M
M
Chaffee
F
F
Gehrels
N
N
Barthelmy
S
S
Cummings
J R
JR
Hullinger
D
D
Krimm
H A
HA
Markwardt
C B
CB
Palmer
D
D
Parsons
A
A
McLean
K
K
Tueller
J
J