Cnts/s!

Time (s)!

GRB Discoveries with Swift
Neil Gehrels
NASA/GSFC

Kyoto GRB Conference
November 11, 2013

Outline	→ Swift mission	

→ GRB background	→ Swift discoveries	→ Swift performance	→ Open questions for the future	041120	

Swift – Time Domain Observatory	• GRBs	UVOTXRT– 95 GRBs/yr with arcsec positions	– Hard X-ray prompt detection	

– Multiwavelength rapid (100 s) follow-up	

• Non-GRBs	

– >700 TOOs per year	

– AGN, SNe, novae, CVs, LMXBs, stars, ...	

– Multiwavelength rapid (1 hr) response	– BAT hard X-ray survey	• Instruments	

– BAT (2 sr): 15-300 keV,
– XRT:
0.3-10 keV,
– UVOT:
170-600 nm,

2 arcmin,2 arcsec,<1 arcsec,

BAT5000 cm2	120 cm2	30 cm mirror	

5

GRB Variability 	Swift Short GRB

GRB 061121 = brightest long GRB
GRB 061210 = brightest short GRB
Gehrels, Norris +06	The GRB	

Phenomenon	

GRB 990123 - HST	

GRB	

⇒

GRBs in distant galaxies	

⇒ Distance z ~ 2	

⇒ Energy ~ 1051 ergs in γ-ray flash	⇒ Gamma rays in ~5˚ beams	

Short⇒ Millisecond time structure	Kouveliotou+ 93 	Long

Long GRBs

Star Formation Rate from GRBs	

Ishida+ 11	

Robertson & Ellis 12	

GRB Rate / SFR	GRBs

Kistler+ 13	z	

Trenti+ 13	

GRB Follow-up Spectroscopic Capabilities
Facility

Location

Aperture

Date

Wavelength Range

Resolution

VLT/XShooter

Chile

8.2

Current

320-2500 nm

5100/8800/5100

VLT/UVES

Chile

8.2

Current

300-1100 nm

80000

VLT/ISAAC

Chile

8.2

Current

1000-5000 nm

2000

VLT/SINFONI

Chile

8.2

Current

1100-2400 nm

2000-5000

VLT/KMOS

Chile

8.2

Current

8000-2500 nm

2000-4000

Gemini/GMOS

Hawaii/Chile

8.1

Current

3600-1100 nm

1100-4000

Gemini/GNIRS

Hawaii

8.1Current

900-2500 nm

1700-18000

Gemini/Flamingos-2

Chile

8.1

Current

900-2400 nm

1200-3000

SUBARU/IRCS

Hawaii

8.2

Current

900-2500 nm

200-1000

Magellan/MagE

Chile

6.5

Current

310-1000 nm

4000

Magellan/FIRE

Chile

6.5

Current

800-2500 nm

6000-8000

Magellan/LDSS3

Chile

6.5

Current

360-1000 nm

500-3000

TNG/DOLoRes

La Palma

3.5

Current

310-1000 nm

500-6000

GTC/OSIRISLa Palma

10Current

3500-1000nm

300-2500

WHT/ISIS

La Palma

4.2

Current

310-1100 nm

800-7000

Keck/LRIS

Hawaii10Current

300-1000 nm

1200-4000

Keck/HIRES

Hawaii10Current

310-1000 nm

25000-85000

Keck/MOSFIRE

Hawaii10Current

900-2400 nm

2300-4700

MMT/BCS/RCS

Arizona

6.5

Current

320-1000 nm<5000

LBT/LUCI2

Arizona

2x8.4

Current

850-2400 nm

2000-8000

NOT/ALFOSCLa Palma

2.5

Current

320-1100 nm

600-4500

DCT/RIMAS

Arizona

4.2

2014-

900-2400 nm

25-5000

NOT/Heidi

La Palma

2.5

2014-

350-1600 nm

5000

Sho" GRBs

No Supernovae with Short GRBs	

GRB 050709	

GRB 050509B	

Hjorth+ 2005			

Contrast with Long GRBs:	

980425 - 98bw
030329 - 03dhc
091127 - 09nz
120422A -12bz

021211 - 02lt
050525A -05nc
100316D -10bh
130427A -13cq	031203 - 03lw 	

060218 - 06aj 	

101219B -10ma	Short Burst HST Images	

Fong+ 10, 13
FruchterLong GRB	

Short vs Long GRBs	

GRB 050724 - Swift	

elliptical host	

GRB 020903 - SAX	SF dwarf host	

Cnts/sCnts/sShort GRB	

ChandraGRB

XRTIn non-SF	

and SF galaxies	

In SF	galaxies	

No SNe detected	

Accompanied bySNe	

Merger model	

is likely	

BH

Collapsar model
well supported	Short GRB 130603B	

Multiwavelength Afterglow	

Count / s

BAT Prompt	-0.5

00.5Time (s)Fong+ 13	jet break at 0.5 day implies opening angle of 4 – 8 degrees	

1.0FireballOutflow

Flux [erg /s /cm 2]

-9

10-9

10-1110-1110

grb 050826

grb 051210-15

grb 051221a-15

1010

1310

1510

3

1010-7Flux [erg /s /cm 2]

grb 050724

grb 050502b

-9-9

10-9

10-11-11

10

10-1110

grb 050826
grb 051210

grb 051210-1310-13-13

1010

grb 051221a-15

1010-15

510

short

10

short	

grb 050724
grb 050315

1010-7longshort-7

7

10time [s]1010510time [s]longGRB 131103A XRT	-1310-1310b 050502bs]

grb 050724

grb 050502b15

3short10long	

grb 050315-7

10Afterglows	

-7

long

110

110310310510

grb 051221a-15

10510

710time [s]
[s]
time

Gehrels, Ramirez-Ruiz & Fox 09

110351010710time [s]see also Zhang +06, Nousek+ 06, Kann+ 11	Hints of Magnetar Engine	Rapid fall-off after plateau phase in some short GRBs	

Rowlinson+ 13	

LookingAhead

Senior Review	• NASA's review of operating missions every 2 years	

• Missions under review	

– Fermi	– Kepler	– NEOWISE	

– NuSTAR	– Planck	– Spitzer	

– Suzaku	– Swift	– XMM	• HST and Chandra is separate review	• Proposals due January 15, 2014 with presentation in March 	Senior Review	• NASA's review of operating missions every 2 years	

• Missions under review	

– Fermi	– Kepler	– NEOWISE	

– NuSTAR	– Planck	– Spitzer	

– Suzaku	– Swift	– XMM	• HST and Chandra is separate review	• Proposals due January 15, 2014 with presentation in March 	

BAT & XRT Rapid Positions	

BAT	BAT Position Error (arcmin)	

Sakamoto 07	

XRT	

on-board	

corrected	

on-board	raw	XRT Position Error (arcsec)	

Evans+ 09	

UVOT Performance	

Typical Sensitivities

Offset (arcsec)	

Median position accuracy for
583 stars is 0.33 arcsec

V=19 first GCN (<1 hr)
V=22 2nd GCN (~3 hr)
Distance from Image Center (arcsec)	

Number of GRB OT Detections	

87% of GRB redshifts are from Swift	

following Strom+ 12	

Swift Discovery Areas	

Tidal Disruption
EventsLong GRBs

Ultralong GRBs

2006aj

SN Shock Breakout
Short GRBs

based on Levan+ 13	

Swift Transient - Sw J1644+57	

28 March 2011	

XRT Light Curve	

Flux (erg cm-2 s-1)	

HST Imaget-4/3

2 daysTransient at center of dwarf 	

non-AGN galaxy at z=0.35	

Time (seconds) 	

Lx ~ 1048 erg s-1	E ~ 1051 ergs	

MBH ~ 106 – 107 MO	

•Bloom+, Burrows+, Levan+, Berger+ 11	GW Electromagnetic Counterparts	

- Advanced era for LIGO/Virgo: 2015+	

- Great importance to finding EM counterparts	

- GW error boxes will be 10's to 1000 sq deg	- Galaxy strategy used in Swift in LIGO S6	Large Error Boxes – Galaxy Strategy	1000 deg2 2015100 deg2 2017

tiling - XRT•• •10 deg2 2020

galaxies# galaxies to cover 50% of light	

XRT FoV = 0.11 deg2	

Kanner, Gehrels+ 2012