# Presentation: 194307

## The Swift Gamma Ray Burst Mission

**Neil Gehrels**
**NASA-GSFC**
**San Diego AAS Meeting**
**January 12, 2005**

## Swift Papers and Posters at AAS Meeting

## NASA MIDEX Mission selected in 1999Primary science is to study gamma-ray bursts throughout the UniverseInternational hardware participation from UK and ItalyLaunch on November 20, 2004 

- NASA MIDEX Mission selected in 1999Primary science is to study gamma-ray bursts throughout the UniverseInternational hardware participation from UK and ItalyLaunch on November 20, 2004

## Motivations for Swift

- Black Hole Birth
- Ultrarelativistic Outflows
- Early Universe Probes

## Swift Designed to Answer GRB Key Questions

**What causes GRBs?**

**What physics can be learned about BH formation and ultra-relativistic outflows?**

**What is the nature of subclasses?**

**What can GRBs tell us about the early universe?**

## Swift Instruments

**New CdZnTe detectors**
**Most sensitive gamma-ray                      imager ever**
**X-Ray Telescope (XRT)**
**Arcsecond GRB positions**
**CCD spectroscopy**
**UV/Optical Telescope (UVOT)**** **
**Sub-arcsec positions**
**Grism spectroscopy**
**24****th**** mag sensitivity (1000 sec)**
**Finding chart for other observers**
**Autonomous re-pointing, 20 - 75 s**
**Onboard and ground triggers**

**Instruments**

**Spacecraft**

## Multiwavelength observations on all time scales
>100 GRBs per year of all types
BAT sensitivity 2 - 5 time better than BATSE
Arcsec positions & counterparts for 100’s GRBs
Rapid GRB notifications via GCN 
Identification of host galaxies offsets
X-ray and UV/optical spectroscopy
Upload capability to slew to GRB and transients detected by other observatories

**>100 GRBs per year of all types**
**BAT sensitivity 2 - 5 time better than BATSE**
**Arcsec positions & counterparts for 100’s GRBs**
**Rapid GRB notifications via GCN **
**Identification of host galaxies offsets**
**X-ray and UV/optical spectroscopy**
**Upload capability to slew to GRB and transients detected by other observatories**

- Mission Capabilities

**BAT**

**XRT**

**UVOT**

## Supernova-GRB connection
Connections between SNe Ic and GRB are emerging.
Swift's rapid subarcsec positions and lightcurve monitoring will allow SN searches on 100's GRBs.  
Questions addressed:  								What fraction and what kinds of GRBs have underlying SN?   				What fraction and what kinds of SN have accompanying GRBs?

- SN1998bw  -   GRB 980425

- GRB
-  980326

**Supernova-GRB connection**
**Connections between SNe Ic and GRB are emerging.**
**Swift's rapid subarcsec positions and lightcurve monitoring will allow SN searches on 100's GRBs.  **
**Questions addressed: **** ****	****	****	****	****	****	****	****	****What fraction and what kinds of GRBs have underlying SN?   ****	****	****	****	****What fraction and what kinds of SN have accompanying GRBs?**

- Swift Science - Supernova Connection

## Swift sensitive to 
Normal     l   o   n   g   GRBs
Short   GRBs
X-Ray Flashes  
Weak GRBs
U l t r a - l o o o o n g GRBs
GRBs subclasses - example: short GRBs 
Not understood.  No counterparts detected.  Appears to be a separate class.  
Non-detection of GRB 020531 indicates afterglow is weak or rapidly declining.
Swift will perform rapid follow-up observations of ~100 short GRBs

**Swift sensitive to**** **
**Normal     l   o   n   g   GRBs**
**Short****   ****GRBs**
**X-Ray Flashes  ******
**Weak GRBs**
**U l t r a - l o o o o n g GRBs**
**GRBs subclasses - example: short GRBs**** **
**Not understood.  No counterparts detected.  Appears to be a separate class.  **
**Non-detection of GRB 020531 indicates afterglow is weak or rapidly declining.**
**Swift will perform rapid follow-up observations of ~100 short GRBs**

## Lamb & Reichart (2000)

**Early Universe**** **
**GRBs are the brightest events in universe.**
**Afterglow is detectable to z~15 by Swift (3 to15 per year at z>10)**
**Topics addressed:**
**Epoch of first stars (GRB may be unique probe of Pop III stars)**
**Star formation history**
**Re-ionization of IGM**
**Metallicity history**
**Dust and gas content of early galaxies**
**Large-scale structure of universe **

## Swift Observatoryin GoddardClean Room

**Swift Observatory****in Goddard****Clean Room**

## Arrival at KSC

## Swift Observatoryat KSC

**Swift Observatory****at KSC**

## Slide 14

## Slide 15

## Slide 16

## Swift Launch video

## Following launch, 1.5 months activation and 3 months verification.  Observatory will be fully operational on April 5, 2005
Public data and GI program start after verification phase.  
Any GRB reliably detected during verification will be distributed on GCN (non-realtime, after BAT-team checking)
35 proposals selected for Cycle 1 of Guest Investigator program.  Cycle 2 proposals due July 2005.
Swift follow-up team coordinated by K. Hurley
EPO team coordinated by L. Cominsky

**Public data and GI program start after verification phase.  **
**Any GRB reliably detected during verification will be distributed on GCN (non-realtime, after BAT-team checking)**
**35 proposals selected for Cycle 1 of Guest Investigator program.  Cycle 2 proposals due July 2005.**
**Swift follow-up team coordinated by K. Hurley**
**EPO team coordinated by L. Cominsky**

- Swift Activation

## Scientific Findings To Date

**9 GRBs detected since Dec. 17**
**Large GRB detected on Dec. 19**
**	**** ****(GRB 041219)  **
** ****XRT pointed at GRB 041223 via ground command at ~4.5 hours.  Afterglow detected.**
**Giant flare detected from **
**	****soft gamma repeater SGR 1806-20 on Dec. 27**
**BAT is performing sensitive monitoring of hard x-ray sky**
** **

## Light Curves of BAT GRBs

- • = detected by other gamma-ray instrument
- • = slewed to and imaged by XRT
- • = detected by ground-based optical/IR

- •

- •

- •

- •

- •

- •

- •

- •

## GRB 041219

- Long duration GRB lasting 500 s
- Fluence of ~10-4 erg cm-2
- Fluence in top 1% of CGRO/BATSE bursts
- Duration in top 2% of CGRO BATSE bursts
- Imaged by INTEGRAL & Swift

- IR fast-fading counterpart ("flash") discovered at early time
- Real-time (RAPTOR) optical detection
- Radio counterpart
- Campaign underway to determine host and redshift

## GRB 041223

- First XRT GRB Afterglow

## GRB 041223 Decay Lightcurve

## SGRs are galactic neutron stars with huge magnetic fields (~1015 G) that have occasional active periods and outbursts. 
SGR 1806-20 discovered in 1986.  Four known SGRs
Detected on Dec. 27, 2004 by all non-occulted gamma-ray detectors in space
Huge main peak lasting 0.5 sec followed by 400 sec of pulsations
Estimate (Boggs et al. GCN 2936) puts fluence greater than ~0.1 erg cm-2, 1-2 orders of magnitude greater than SGR 1900+14 1998 and SGR 0526-66 1979 flares.
Radio transient detected.  Slightly extended source.  Polarization detected.

**SGR 1806-20 discovered in 1986.  Four known SGRs**
**Detected on Dec. 27, 2004 by all non-occulted gamma-ray detectors in space**
**Huge main peak lasting 0.5 sec followed by 400 sec of pulsations**
**Estimate (Boggs et al. GCN 2936) puts fluence greater than ~0.1 erg cm****-2****, 1-2 orders of magnitude greater than SGR 1900+14 1998 and SGR 0526-66 1979 flares.**
**Radio transient detected.  Slightly extended source.  Polarization detected.**

- Giant Flare from SGR 1806-20

## Slide 25

## BAT Detection of 7.6 sec Pulsations

## Swift Non-GRB Capabilities

- Transient monitoring
- Multiwavelength response to transients detected by others

## Swift Team

**GSFC**