Short Bursts

1
Short Bursts

• Daniel Perley
• Astro 250
• 9 November 2005

2
Title
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Subject
PBH flare merger collapsar 1036 1046 1050 1050 p
c Mpc Gpc Gpc too short OK OK too
long? invisible young NS old NS young
star nearby galactic star-forming galaxies outs
kirts regions repeats? possible Ib/c
supernova mini-SN
Daniel Perley
9 November 2005
Short Bursts
3
Long Bursts
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
GRB Classes
GRBs have long been known to fall into two
general categories
l o n g b u r s t
45 s
count rate (ct/s)
time (seconds)
Daniel Perley
9 November 2005
Short Bursts
4
Short Bursts
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
GRB Classes
GRBs have long been known to fall into two
general categories
0.8 s
short burst
count rate (ct/s)
time (seconds)
Daniel Perley
9 November 2005
Short Bursts
5
Burst Durations
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
GRB Classes
The separate populations are statsitcally robust,
although intersecting.
N
10-1
10-2
1
10
100
1000
T90 (seconds)
Daniel Perley
9 November 2005
Short Bursts
6
Burst Durations
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
GRB Classes
The separate populations are statsitcally robust,
although intersecting.
l o n g b u r s t s
N
short bursts
10-1
10-2
1
10
100
1000
T90 (seconds)
Daniel Perley
9 November 2005
Short Bursts
7
Duration/Hardness
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
GRB Classes
The two populations have different hardnesses
short bursts
Hardness (S3/S2)
l o n g b u r s t s
T90 (seconds)
Daniel Perley
9 November 2005
Short Bursts
8
Duration/Fluence
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
GRB Classes
Other intrinsic differences have also been
noticed.
10-4
l o n g b u r s t s
10-5
Ftot (erg/cm2)
10-6
10-7
short bursts
10-8
10-2
1
10
100
1000
10-1
T90 (seconds)
Figure 1, Balasz et al. 2004
Daniel Perley
9 November 2005
Short Bursts
9
Long Burst Localization
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Before Swift
First GRB (long burst) localized and first host
identified in 1997. Many have followed since
then. All long GRBs located in
star-forming galaxies All long GRBs located in
regions with massive stars Coincident type Ic
supernova observed in one case ? Long
bursts are associated with
supernovae. However, short GRBs long eluded
localization, and no similar conclusions could be
made.
Daniel Perley
9 November 2005
Short Bursts
10
Short Burst Localization
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Before Swift
The intrinsically short duration of a short burst
makes determining the position of the prompt
gamma emission even more difficult than usual.
"Best" localizations (5-50 square arcmin)
generally from Interplanetary Network.
5 '
Daniel Perley
9 November 2005
Short Bursts
11
Afterglow Nondetections
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Before Swift
Before thist year, no short burst afterglow had
been found in any IPN or burst detection error
box.
Daniel Perley
9 November 2005
Short Bursts
12
Galaxy Correlations
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Before Swift
(Recent) study computes correlation function of
BATSE short burst positions with nearby galaxies.
Result correlation significant to 2s No
correlation seen for long bursts. Estimate of
5-25 of GRBs from Daniel Perley
9 November 2005
Short Bursts
13
Burst Models
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
A large number of models had been proposed
mostly of the same which had been previously
proposed for GRBs in general.

• Black hole evaporation
• SGR (magnetar) giant flares
• Neutron star neutron star mergers
• Neutron star black hole mergers
• Collapsar
• Neutron star collapse (supranova)

Daniel Perley
9 November 2005
Short Bursts
14
Primordial Black Holes
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
An early suggestion GRBs may be the evaporation
of black holes produced in the early universe.
Mass 7 1014 g (mc2 5 1035 erg) ?
Distance few parsecs Burst duration
cannot explain most short bursts
Daniel Perley
9 November 2005
Short Bursts
15
Magnetar Giant Flare
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
Massive flare on the surface of highly magnetized
neutron star. Catastrophic magnetic field
reorganization. Some previous flares - 5 March
1979 event 4 1044 ergs (SGR 0526-66, LMC)
0.2 s - 27 August 1998 event 8 1043 ergs
(SGR 190014) 0.2 s
Duration and hardness consistent with short
GRBs. Distance for GRB 4 Mpc (Virgo
cluster 20 Mpc) But could there be much
larger flares?
Daniel Perley
9 November 2005
Short Bursts
16
Magnetar Giant Flare
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
- 5 March 1979 event 4 1044 ergs
(SGR 0526-66, LMC) 0.2 s - 27 August
1998 event 8 1043 ergs (SGR 190014)
0.2 s - 27 December 2004 event
2 1046 ergs (SGR 1806-20)
0.5 s
Most energetic Galactic event since Tycho.
0.8 erg/cm2 over 0.5s
Sirius 10-4 erg/cm2/sFull Moon 1 erg/cm2/s
Daniel Perley
9 November 2005
Short Bursts
17
Magnetar Giant Flare
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
- 5 March 1979 event 4 1044 ergs
(SGR 0526-66, LMC) 0.2 s - 27 August
1998 event 8 1043 ergs (SGR 190014)
0.2 s - 27 December 2004 event
2 1046 ergs (SGR 1806-20)
0.5 s
Duration and hardness consistent with short
GRBs. (long ringing 'tail' would not be
detectable at great distance) Distance for GRB
30 Mpc (Virgo cluster 20 Mpc) Magnetars all
young 104 year lifetime
(restricted to star-forming
galaxies/regions) Repetition possible over long
time scales
Daniel Perley
9 November 2005
Short Bursts
18
Neutron Star-Neutron Star Merger
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
Closely orbiting neutron stars (d radius) lose energy from gravitational
radiation. Systems known to exist (binary
pulsars) Must eventually merge. Post-merger
object quickly collapses to black hole Very
high angular momentum of system accretion
disk forms falls onto black hole.
G M2 R
Gravitational binding energy 1053 erg
? Mpc/Gpc distances Timescale for collapse

Daniel Perley
9 November 2005
Short Bursts
19
Neutron Star-Black Hole Merger
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
Closely orbiting neutron star / black hole pair
also loses energy to gravitational radiation and
merges. Neutron star is tidally disrupted into
accretion disk falls onto black hole.
Gravitational binding energy MNSc2 1054
erg ? Mpc/Gpc distances Timescale for
accretion
Supernovae can 'kick' binary out of Galaxy.
Daniel Perley
9 November 2005
Short Bursts
20
Compact Object Mergers
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
Either type of merger Inspiral takes 1
Gyr. Star formation may have ceased. System
may have migrated from point of origin
supernova explosions cankick the binary well
outside galacticinterior Possibility of
"mini-supernova" due to production of radioactive
elements in ejected matter.
Daniel Perley
9 November 2005
Short Bursts
21
Collapsar
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models
Collapsar (hypernova) model highly successful in
describing long bursts. Collapse of iron core of
highly massive star to black hole accretion of
material (0.1-5 Msun). Relativistic jet
penetrates stellar envelope Energies 1050 erg
cosmological distances Fallback time for
stellar core few seconds too slow for short
GRBs. Significant uncertanties in calculation
Breakout flash could be shorter? Massive stars
short-lived would be bound to star-forming
regions (like long GRBs)
Daniel Perley
9 November 2005
Short Bursts
22
Model Summary
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
Burst Models

Daniel Perley
9 November 2005
Short Bursts
23
GRB 050509B
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
First Swift short burst. First X-ray afterglow
XRT provided 2.8' localization This position is
very close to large elliptical at center of low-z
cluster.
T90 0.040 S 1 10-10 E 3 1048
Large ellipticalz 0.2248
XRT
all units CGS
blue
Daniel Perley
9 November 2005
Short Bursts
24
GRB 050509B
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
Is the burst associated with the elliptical?
Chance alignment probability very small. inside
galaxy cluster 3 within 45" of center
0.07
(no long GRB ever seen in a cluster)
T90 0.040 S 1 10-8 E 3 1048
Large ellipticalz 0.2248
XRT
40 kpc
blue
Daniel Perley
9 November 2005
Short Bursts
25
GRB 050509B
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
Is the burst associated with the elliptical?
Chance alignment probability very small. inside
galaxy cluster 3 within 45" of center
0.07
(no long GRB ever seen in a cluster)
Additional arguments Extremely short duration
even for short GRBs putting at high redshift
(z2) requires unrealistically short intrinsic
duration. Energetics of putting at high-z
similarly difficult for very short durations.
T90 0.040 S 1 10-8 E 3 1048
Daniel Perley
9 November 2005
Short Bursts
26
GRB 050509B
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
No counterpart seen at other wavelengths. Cannot
be a supernova (if in cluster). No mini-supernova
observed.
T90 0.040 S 1 10-8 E 3 1048
SNIapeak
Daniel Perley
9 November 2005
Short Bursts
27
GRB 050709
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
HETE-II short burst. X-ray afterglow seen.
Unambiguously in low-z galaxy. Optical transient
(first ever for short GRB) detected coincident
with X-ray position.
T90 0.070 S 3 10-7 E 2 1049
Star-forming irregularz 0.160
XRT
3.8 kpc
HST Transient
Daniel Perley
9 November 2005
Short Bursts
28
GRB 050709
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
Optical light curve power-law decay with jet
break (like long burst no supernova bump)
Radio
T90 0.070 S 3 10-7 E 2 1049
Optical
X-ray
Daniel Perley
9 November 2005
Short Bursts
29
GRB 050724
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
Optical and radio (first for short GRB)
transients seen. Unambiguously associated with
non star-forming galaxy (within last Gyr) at
low-z. Not in a cluster.
T90 3 S 6 10-7 E 1 1050
Early-typez 0.258
2.6 kpc
XRT
Transient
Daniel Perley
9 November 2005
Short Bursts
30
GRB 050813
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
X-ray afterglow, but no optical/radio
transient. Inside a cluster - numerous possible
hosts.
Ellipticalz 0.722
XRT
T90 0.6 S 6 10-7 E 1 1050
Ellipticalz 0.719
Ellipticalz 0.73
Daniel Perley
9 November 2005
Short Bursts
31
GRB 050906
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
No X-ray afterglow detected. BAT position
consistent with IC 326.
p 0.1
BAT
IC 326 z 0.0308
T90 3 S 6 10-8 E 1 1047 at
133 Mpc
IC 327
Daniel Perley
9 November 2005
Short Bursts
32
GRB 050925
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
Soft, thermal spectrum. Galactic latitude b
- 0.1 Strong radio source no optical or X-ray
detections. SGR flare ('new' SGR)
T90 0.13 S 8 10-8 E 1 1040 at
20 kpc
Daniel Perley
9 November 2005
Short Bursts
33
GRB 051103
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
IPN detection of bright short GRB. Consistent
with outer regions of M81.
M 82Irr z 0
p 0.5
M 81Sb z 0
T90 0.17 S 2 10-5 E 5 1046 at 4
Mpc (M81) 1051 at 500 Mpc
Daniel Perley
9 November 2005
Short Bursts
34
GRB 051105A
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
No X-ray afterglow detected.
BAT
T90 0.13 S 2 10-8 E ?
Daniel Perley
9 November 2005
Short Bursts
35
Recent Short Bursts
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era
energy (erg)
Daniel Perley
9 November 2005
Short Bursts
36
Conclusions
Classes of GRBs Long Bursts Short Bursts
Durations Duration vs. Hardness Duration vs.
Fluence Short Bursts before Swift Long Burst
Localization Short Burst Localization
Afterglow Nondetections Galaxy
Correlations Short Burst Models Primordial
Black Holes Magnetar Giant Flare NS-NS
Merger NS-BH Merger Collapsar Summary Short
Bursts since Swift GRB050509B GRB050709
GRB050724 GRB050813 GRB050906 GRB050925
GRB051103 GRB051105A Summary Conclusions
The Swift Era

• Most short bursts are due to compact object
  mergers.
• Short bursts are beamed.
• Some short bursts may be due to magnetar giant
  flares in other galaxies, but a definitive
  example is still lacking.
• Short bursts occur more frequently per volume
  than long bursts (or are beamed less), but are
  intrinsically fainter.

Daniel Perley
9 November 2005
Short Bursts