1. Gamma-Ray Bursts: The Most Brilliant Events in the Universe D. Q. Lamb (U. Chicago) PHYSICS for the THIRD MILLENNIUM: II Huntsville, AL 5–7 April 2005 High-Energy Transient ExplorerSwift

2. Electromagnetic Spectrum Universe, Freedman and Kaufmann, 7th edition (W. H. Freeman)

3. Serendipitous Discovery of Gamma-Ray Bursts Klebesadel, Strong, and Olson (1973)  Vela satellites built and flown to monitor partial nuclear test ban treaty (1962)  Mysterious events first noted in 1967  New Vela satellites built; additional data obtained in 1971-73  Discovery of “cosmic gamma-ray bursts” announced (1973)

4. Compton Gamma-Ray Observatory BATSE – Fishman, Meegan, Paciesas, et al. (1991)

5. Some Time Histories of Gamma-Ray Bursts Paciesas et al. (2000)

6. Durations of Gamma-Ray Bursts Kouveliotou et al. (1993) Long GRBs Short GRBs

7. Spectra of Gamma-Ray Bursts GRB Spectrum Peaks in Gamma - Rays XRF Spectrum Peaks in X-Rays

8. Sky Distribution of Gamma-Ray Bursts Paciesas et al. (2000) Distribution of GRBs is uniform (random) on sky

9. Discovery of X-Ray Afterglow of GRB Piro, Costa, Frontera, et al. (1997)

10. GRBs Lie at Cosmological Distances z = 0.83 Metzger et al. (1997) GRB 970508

11. Optical Afterglow and Host Galaxy of GRB 990123 Fruchter et al. (1999)

12. GRBs Occur in Star-Forming Regions of Starburst Galaxies Fruchter et al. (2004)

13. High-Energy Transient Explorer Ricker, Lamb, Atteia, Kawai, Fenimore, Woosley (2000) SXC FREGATE WXM

14. GRB 030329 (z = 0.167) Vanderspek et al. (2004)

15. GRB030329: Afterglow + SN Lightcurve Klose et al. (2003)

16. Long GRBs Come from Collapse of Massive Stars – Are (Possibly) Birth Cry of Black Holes Stanek et al. (2003)

17. GRBs Come From Narrow Jets et al. (1999)  Bulk motion of jet is v = 0.999 c, so special relativistic beaming is dramatic  Optical light decreases when jet slows down and we begin to see beyond edge of jet

18. GRBs Are Ultra-Relativistic Jets (v = 0.999 c) Universe, Freedman and Kaufmann, 7th edition (W. H. Freeman)

19. Schematic Picture of GRB Jets Peter Meszaros

20. Numerical Simulation of GRB Jet Zhang and Woosley (2004)

21. Spectra of Gamma-Ray Bursts GRB Spectrum Peaks in Gamma - Rays XRF Spectrum Peaks in X-Rays E peak

22. Density of HETE-2 Bursts in (S, E peak )-Plane Sakamoto et al. (2005)

23. Relation Between Spectral Peak Energy (E peak ) and Isotropic Radiated Energy (E iso )  Found by BeppoSAX for GRBs (Amati et al. 2002)  Confirmed for GRBs and extended to XRFs by HETE-2 (Sakamoto et al. 2004; Lamb et al. 2004)  Relation spans five decades in E iso GRB 980425 GRB 031203

24. Phenomenological Jet Models ● Power-Law Shaped Jet Diagram from Lloyd-Ronning and Ramirez-Ruiz (2002) ● Top-Hat Shaped Jet

25. Variable Opening-Angle Top-Hat Jet vs. Universal Power-Law Jet  VOA top-hat jet can account for both XRFs and GRBs  Universal power-law jet can account for GRBs, but not both XRFs and GRBs DQL, Donaghy, and Graziani (2004)

26. Launch of Swift Satellite 20 November 2004

27. Swift UVOT BAT XRT Gehrels et al. (2004) Swift’s Revolutionary Feature is Its Ability to Quickly (< 100 sec) Observer GRBs in X-Rays and UV/Optical

28. Swift Catching a GRB “On the Fly”

29. Properties of GRBs: HETE-2 and Swift GRB Spectrum Peaks in Gamma - Rays XRF Spectrum Peaks in X-Rays Even with the BAT’s huge effective area (~2600 cm 2 ), HETE can better determine the spectral properties of most bursts, especially XRFs

30. Value of the Scientific Partnership Between HETE and Swift  GRBs plus XRFs provide unique information about q structure of GRB jets q GRB rate q nature of Type Ic SNe qExtracting this information will require prompt q localization of many XRFs q determination of E iso and E peak q identification of X-ray and optical afterglows q determination of redshifts qHETE is ideally suited to do the first two, whereas Swift (with 15 < E < 150 keV) is not; Swift is ideally suited to do the second two, whereas HETE cannot qPrompt Swift XRT and UVOT observations of HETE bursts can greatly advance our understanding of GRBs and XRFs

31. XRF050215b: Example of Scientific Partnership Between HETE and Swift Sakamoto et al. (2005) HETE FREGATE Swift BAT

32. Dark Matter Dominates Mass of Galaxies Universe, Freedman and Kaufmann, 7th edition (W. H. Freeman) Kepler’s Law

33. Type Ia SNe Can Be Used As “Standard Candles”  Peak luminosities of Type Ia SNe range over a factor > 5  Using correlation between peak luminosity and rate of decline reduces range to ~ 10%

34. Observations of Type Ia SNe Imply An “Accelerating Universe”

35. Non-Euclidian Geometry of Space-Time Universe, Freedman and Kaufmann, 7th edition (W. H. Freeman)

36. Observations of Cosmic Micrrwave Background Imply Geometry of Space-Time is Flat Universe, Freedman and Kaufmann, 7th edition (W. H. Freeman)

37. “Concordance” Model of Cosmology Universe, Freedman and Kaufmann, 7th edition (W. H. Freeman)

38. GRBs Can Be Used As “Standard Candles” Ghirlanda, Ghisellini, Lazzati, and Firmani (2004) Measurement of E peak gives Energy (and L)

39. Hubble Diagram for Type Ia SNe and GRBs  Before “standard candle” calibration  After “standard candle” calibration

40. GRBs Plus XRFs Can Provide New Constraints on Cosmology GRBs GRBs Plus XRFs Ghirlanda, Ghisellini, Lazzati, and Firmani (2004)

41. GRBs in Cosmological Context Lamb (2002)

42. GRBs as Probes of Very High-Redshift Universe qMoment of “first light” qStar formation history of universe qMetallicity history of universe qReionization history of universe Lamb and Reichart (2000)

43. Conclusions Gamma-Ray Bursts:  were discovered serendipitously in 1967  occur at cosmological distances  are the most brilliant events in the universe  involve ultra-relativistic (v = 0.999 c) jets  provide important insights into nature of core collapse supernovae  can provide new constraints on key cosmological parameters  may be powerful probes of very high redshift (z > 5) universe  are a phenomenon that remains mysterious in many ways