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Gamma-Ray Bursts: The Most Brilliant Events in the Universe. D. Q. Lamb (U. Chicago). High-Energy Transient Explorer. Swift. PHYSICS for the THIRD MILLENNIUM: II Huntsville, AL 5–7 April 2005.
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Gamma-Ray Bursts: The Most Brilliant Events in the Universe D. Q. Lamb (U. Chicago) High-Energy Transient Explorer Swift PHYSICS for the THIRD MILLENNIUM: II Huntsville, AL 5–7 April 2005
Electromagnetic Spectrum Universe, Freedman and Kaufmann, 7th edition(W. H. Freeman)
Serendipitous Discovery of Gamma-Ray Bursts • 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) Klebesadel, Strong, and Olson (1973)
Compton Gamma-Ray Observatory BATSE – Fishman, Meegan, Paciesas, et al. (1991)
Some Time Histories of Gamma-Ray Bursts Paciesas et al. (2000)
Durations of Gamma-Ray Bursts Long GRBs Short GRBs Kouveliotou et al. (1993)
Spectra of Gamma-Ray Bursts GRB Spectrum Peaks in Gamma - Rays XRF Spectrum Peaks in X-Rays
Sky Distribution of Gamma-Ray Bursts Paciesas et al. (2000) Distribution of GRBs is uniform (random) on sky
Discovery of X-Ray Afterglow of GRB Piro, Costa, Frontera, et al. (1997)
GRBs Lie at Cosmological Distances GRB 970508 z = 0.83 Metzger et al. (1997)
Optical Afterglow and Host Galaxy of GRB 990123 Fruchter et al. (1999)
GRBs Occur in Star-Forming Regions of Starburst Galaxies Fruchter et al. (2004)
High-Energy Transient Explorer WXM FREGATE SXC Ricker, Lamb, Atteia, Kawai, Fenimore, Woosley (2000)
GRB 030329 (z = 0.167) Vanderspek et al. (2004)
GRB030329: Afterglow + SN Lightcurve Klose et al. (2003)
Long GRBs Come from Collapse of Massive Stars – Are (Possibly) Birth Cry of Black Holes Stanek et al. (2003)
GRBs Come From Narrow Jets • 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 et al. (1999)
GRBs Are Ultra-Relativistic Jets (v = 0.999 c) Universe, Freedman and Kaufmann, 7th edition(W. H. Freeman)
Schematic Picture of GRB Jets Peter Meszaros
Numerical Simulation of GRB Jet Zhang and Woosley (2004)
Spectra of Gamma-Ray Bursts Epeak GRB Spectrum Peaks in Gamma - Rays Epeak XRF Spectrum Peaks in X-Rays
Density of HETE-2 Bursts in (S, Epeak)-Plane Sakamoto et al. (2005)
Relation Between Spectral Peak Energy (Epeak) and Isotropic Radiated Energy (Eiso) • 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 Eiso GRB 031203 GRB 980425
Phenomenological Jet Models Diagram fromLloyd-Ronning and Ramirez-Ruiz (2002) • Power-Law Shaped Jet • Top-Hat Shaped Jet
Variable Opening-Angle Top-Hat Jet vs. Universal Power-Law Jet DQL, Donaghy, and Graziani (2004) • 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
Launch of Swift Satellite 20 November 2004
Swift XRT UVOT BAT Gehrels et al. (2004) Swift’s Revolutionary Feature is Its Ability to Quickly (< 100 sec) Observer GRBs in X-Rays and UV/Optical
HETE Passband Swift Passband Properties of GRBs: HETE-2 and Swift Even with the BAT’s huge effective area (~2600 cm2), HETE can better determine the spectral properties of most bursts, especially XRFs GRB Spectrum Peaks in Gamma - Rays XRF Spectrum Peaks in X-Rays
Value of the Scientific Partnership Between HETE and Swift • GRBs plus XRFs provide unique information about • structure of GRB jets • GRB rate • nature of Type Ic SNe • Extracting this information will require prompt • localization of many XRFs • determination of Eiso and Epeak • identification of X-ray and optical afterglows • determination of redshifts • HETE is ideally suited to do thefirst two, whereas Swift (with 15 < E < 150 keV) is not; Swift is ideally suited to do thesecond two, whereas HETE cannot • Prompt Swift XRT and UVOT observationsof HETE bursts can greatlyadvance our understanding of GRBs and XRFs
XRF050215b: Example of Scientific Partnership Between HETE and Swift HETE FREGATE Swift BAT Sakamoto et al. (2005)
Dark Matter Dominates Mass of Galaxies Kepler’s Law Universe, Freedman and Kaufmann, 7th edition(W. H. Freeman)
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%
Observations of Type Ia SNe Imply An “Accelerating Universe”
Non-Euclidian Geometry of Space-Time Universe, Freedman and Kaufmann, 7th edition(W. H. Freeman)
Observations of Cosmic Micrrwave Background Imply Geometry of Space-Time is Flat Universe, Freedman and Kaufmann, 7th edition(W. H. Freeman)
“Concordance” Model of Cosmology Universe, Freedman and Kaufmann, 7th edition(W. H. Freeman)
GRBs Can Be Used As “Standard Candles” Measurement of Epeak gives Energy (and L) Ghirlanda, Ghisellini, Lazzati, and Firmani (2004)
Hubble Diagram for Type Ia SNe and GRBs • Before “standard candle” • calibration • After “standard candle” • calibration
GRBs Plus XRFs Can Provide New Constraints on Cosmology GRBs GRBsPlusXRFs Ghirlanda, Ghisellini, Lazzati, and Firmani (2004)
GRBs in Cosmological Context Lamb (2002)
GRBs as Probes of Very High-Redshift Universe • Moment of “first light” • Star formation history of universe • Metallicity history of universe • Reionization history of universe Lamb and Reichart (2000)
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