Gamma Ray BurstsBart Giethoorn en Jeroen Snijdewint

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

Index

1. Introduction to GRBs

2. What are GRBs?

3. Current & future GRB research

4. Relevance for galactic evolution & formation

5. Summary

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

1. Introduction to GRBs

• discovered in the 1960s• ~1ms < t < ~100s• ~1keV < E < ~1GeV• some sources repeating, some not• some had an afterglow

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

1. Introduction to GRBs

• GRBs close or far away?

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

2. What are GRBs?

• Jet theory • Short-hard and long-soft GRBs • Hypernovae -> long GRBs• Binary merging -> short GRBs

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

2. What are GRBs? - hypernova theory

• Mstar > 40 solar masses collapse• γ-photons & material propelled along an axis• indications:- long GRBs on spots supernova' s- optical spectrum nearly identical to supernova

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

2. What are GRBs? - hypernova theory

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

2. What are GRBs? - merger theory

• Binary systems merge• Neutron stars and black holes• Produce short-hard GRBs• Indications:• 050509b in old galaxy -> no supernova

-> more neutron stars

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

2. What are GRBs? - merger theory

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research

• Observating GRBs: - On earth? No!- Only in space!

• Gamma-burst coordinates network (GCN)• GRB hunters; - Swift and HETE-2.- Soon joined by GLAST

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – HETE-2

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – HETE-2

• HETE-2 observes in the X-ray and gamma ray energy ranges (0.5 – 400 keV)

• Localization accuracy 10 arcsec. to 10 arcmin.• Three main components- The French Gamma Telescope (FREGATE)- The wide-field X-ray Monitor (WXM)- The soft X-ray camera (SXC)

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – HETE-2

FREGATE

WXM

SXC

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – HETE-2

• HETE-2 observes in the X-ray and gamma ray energy ranges (0.5 – 400 keV)

• Localization accuracy 10 arcsec. to 10 arcmin.• Three main components- The French Gamma Telescope (FREGATE)- The wide-field X-ray Monitor (WXM)- The soft X-ray camera (SXC)

• Recent discovery discussed in Nature

- Short GRB with optical afterglow

- Argument in favour of merging binaries

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – Swift

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

• Multiwavelength observations (γ, x-ray, UV & optical)• Localizes a GRB with an accuracy of 0.3 – 5 arcsec.• Quick reaction time when detecting GRBs• Also three main components• Burst Alert Telescope (BAT)• X-ray Telescope (XRT)• UV/Optical Telescope (UVOT)

3. Current & future GRB research – Swift

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – Swift

BAT

UVOT

XRT

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – Swift

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – Swift

• Most distant GRB recently detected by Swift• GRB 050904 has a redshift of z = 6.29• Very usefull to learn about stellar evolution

• Multiwavelength observations (γ, x-ray, UV & optical)• Localizes a GRB with an accuracy of 0.3 – 5 arcsec.• Quick reaction time when detecting GRBs• Also three main components• Burst Alert Telescope (BAT)• X-ray Telescope (XRT)• UV/Optical Telescope (UVOT)

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – GLAST

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – GLAST

• Many unsolved questions about GRBs• Gamma-Ray Large Area Space Telescope (GLAST)

satellite launch sheduled for august 2007• Can GLAST bring answers? Yes!• It has two components;• GLAST Burst Monitor (GBM) (~1keV – 25 MeV)• Large Area Telescope (LAT) (20 MeV- 300 GeV!)

• GLAST will also detect AGNs, help to understand dark matter, deal with particle astrophysics, detect gamma-ray pulsars and maybe discover new gamma-ray sources.

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

3. Current & future GRB research – GLAST

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

4. Relevance for galactic evolution & formation

•GRBs backlight Lyman-α forest for z>4.8•Many GRBs from AGNs called blazars•Large sample -> study evolution

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

5. Summary

• GRBs contain enormous amounts of energy• GRBs are spread out across the universe• Long GRBs -> hypernova theory• Short GRBs -> merger theory• HETE-2 and Swift are today’s GRB hunters• GLAST Research will bring new insight• GRBs useful for galaxy formation and evolution

11-11-2005

Gamma Ray Bursts

Bart Giethoorn en Jeroen Snijdewint

6. List of resources• J. S. Villasenor et. al. Discovery of the short g-ray burst GRB 050709. Nature vol.

437 (6 October 2005).• http://swiftsc.gsfc.nasa.gov/docs/swift/about_swift/objectives/cosmology.html• http://www-glast.sonoma.edu/science/where.html• http://imagine.gsfc.nasa.gov/docs/science/know_l1/grbs.html• http://universe.nasa.gov/press/2003/030220a.html• http://space.mit.edu/HETE/• http://www.astro.caltech.edu/• http://www.astro.psu.edu/• http://www.astro.uio.no/ita/• http://www.swift.psu.edu/xrt/• http://www.nasa.gov/vision/universe/starsgalaxies/2005_distant_grb.html