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The Transient Universe AY 250

The Transient Universe AY 250 Geoff Bower Bayeux tapestry commemorating SN of 1066 What is Transient Astronomy? What is Transient Astronomy? What isn’t? 20/43 astronomical phenomena (from Harwit 1984) involve or were discovered by transient or variable phenomena. Stars Planets Novae

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The Transient Universe AY 250

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  1. The Transient UniverseAY 250 Geoff Bower The Transient Universe: AY 250 Spring 2007

  2. Bayeux tapestry commemorating SN of 1066 The Transient Universe: AY 250 Spring 2007

  3. What is Transient Astronomy? The Transient Universe: AY 250 Spring 2007

  4. What is Transient Astronomy? • What isn’t? • 20/43 astronomical phenomena (from Harwit 1984) involve or were discovered by transient or variable phenomena. The Transient Universe: AY 250 Spring 2007

  5. Stars Planets Novae Comets Moons Rings Galactic clusters Clusters of galaxies Interplanetary matter Asteroids Multiple stars Variable stars with nebulosity Planetary nebulae Globular clusters Ionized gas clouds Giants/main sequence stars Cosmic rays Pulsating variables White dwarfs Galaxies Cosmic expansion Interstellar dust Novae/supernovae Galaxies with/without gas Supernova remnants Radio galaxies Magnetic variables Flare stars Interstellar magnetic fields X-ray stars X-ray background Quasars Microwave background Masers Infrared stars X-ray galaxies Pulsars Gamma-ray background Infrared galaxies Superluminal sources Gamma-ray bursts Unidentified radio sources PhenomenaTransient Phenomena(Harwit 1984) The Transient Universe: AY 250 Spring 2007

  6. What is Transient Astronomy? • What isn’t? • 20/43 astronomical phenomena (from Harwit 1984) involve or were discovered by transient or variable phenomena. • The study of variable and ephemeral phenomena in the sky… The Transient Universe: AY 250 Spring 2007

  7. What is Transient Astronomy? II • Where the timescale of variability is comparable to or less than a human graduate student timescale. • Giant pulses (nanoseconds) • Long wavelength radio afterglows (years) • Transient in flux • Undetectable to detectable • Gamma-ray bursts • Variable in flux • Exoplanet transits (milli) to a galactic supernova (mega-mega) • But solar variability? • Variable in position • Asteroids, KBOs • Astrometry? • Variable in spectrum, polarization • Exoplanet radial velocities? • Variable particle emission The Transient Universe: AY 250 Spring 2007

  8. Solar Transient Activity The Transient Universe: AY 250 Spring 2007 Nita et al 2004

  9. Solar Transient Activity Nita et al 2004 The Transient Universe: AY 250 Spring 2007

  10. What is Transient Astronomy? III • Answer is clearly human and telescope-dependent • The bigger the telescope, the longer the timescale the more transient phenomena • Critical from antiquity to the present in advancing our understanding of the Universe Bayeux tapestry commemorating SN of 1066 The Transient Universe: AY 250 Spring 2007

  11. Three Important Examples in Current Astronomy • Supernovae • Discovered in antiquity • Understood in modern era along with nucleosynthesis, stellar life cycle • Probes of the geometry of the Universe • Gamma-ray bursts • Discovered in modern era through military technology • Understood with advent of new telescopes • Probes of star formation at high redshift • Pulsars • Discovered in modern era with new telescope • Understood through accumulation of examples • Probes of general relativity, interstellar medium, nuclear equation of state The Transient Universe: AY 250 Spring 2007

  12. Examples of Transients That Will Become Critical • Killer asteroids • Exoplanets • Stellar transits as probe of size • Radio emission as probe of magnetic and stellar winds • Gravity waves • A generation of non-detections • Black hole & NS mergers • Neutrino sources • SN 1987A • SETI The Transient Universe: AY 250 Spring 2007

  13. Examples of Transients That Will Become Critical The Unknown The Transient Universe: AY 250 Spring 2007

  14. Expansion of Parameter Space  Discovery • Cosmic Discovery, Harwit 1984 • Parameter space • Sensitivity • wavelength • angular resolution • spectral resolution • time resolution • polarization • particle mode The Transient Universe: AY 250 Spring 2007

  15. Trends of Discovery(Harwit) • Most important discoveries result from substantial technological innovation • Following a new technique, discovery follows quickly • Novel instrument soon exhausts its capacity for discovery • New discoveries are often made by physicists or engineers from outside astronomy • Many discoveries involve military technology • Instruments used in the discovery were often constructed by the discoverer • Discoveries often occur by chance The Transient Universe: AY 250 Spring 2007

  16. How Much Is Left to Be Discovered? • Harwit 1984 makes counting arguments that suggest 10 – 30% of all discoveries have been made • Time scale for discoveries are centuries to millenia The Transient Universe: AY 250 Spring 2007

  17. A New Generation of Telescopes Gamma-ray Radio Optical Swift GLAST LOFAR MWA LWA ATA EVLA ALMA SKA Pan Starrs LSST KAIT PAIRITEL ROTSE III The Transient Universe: AY 250 Spring 2007

  18. Radio • MWA • LWA • LOFAR • ATA • EVLA • ALMA • SKA The Transient Universe: AY 250 Spring 2007

  19. New Radio Characteristics • Powerful survey capacity • Orders of magnitude in sensitivity increase • Rapid slewing • All sky view • Re-play mode • High time resolution • Increased frequency domain The Transient Universe: AY 250 Spring 2007

  20. Radio Survey Speed SKA ATA-350+ The Transient Universe: AY 250 Spring 2007

  21. Optical • KAIT • PAIRITEL • ROTSE III • Raptor • Pan Starrs • LSST • Kepler The Transient Universe: AY 250 Spring 2007

  22. Robotic Telescopes • Robotic follow-up telescopes • KAIT, PAIRITEL, ROTSE • Follow-up on time scale • Wide field of view search telescopes • Raptor (>1000 sq deg FOV) The Transient Universe: AY 250 Spring 2007

  23. Monster Survey Telescopes • SDSS • Pan Starrs • LSST The Transient Universe: AY 250 Spring 2007

  24. High Energy • Swift • GLAST The Transient Universe: AY 250 Spring 2007

  25. New High Energy Capabilities • Rapid, accurate localization • 1 deg  <1 arcmin • Much greater sensitivity • 50 times sensitivity of EGRET The Transient Universe: AY 250 Spring 2007

  26. Particle & Gravity Wave Telescopes • LIGO-II • LISA • Auger • IceCube The Transient Universe: AY 250 Spring 2007

  27. Issues in Transient Discovery • How to find transients • Telescope/wavelength specific search strategies • What is the optimal telescope for transient discovery? • What is the optimal search strategy? • Matched filter analysis • How does discovery change in the era of the VO? • Dealing with volume of data (10 PB/year for LSST) • How to identify/classify transients • Multi-wavelength coordination • Decision making strategies • What response should be made • Machine-to-machine communication • Number of transients will be large • Is it useful to me? The Transient Universe: AY 250 Spring 2007

  28. The Transient Universe: AY 250 Spring 2007

  29. Example of Flare Star/Asteroid/Optical Flash Confusion • Flare stars and asteroids dominate the foreground in the optical • Rejection of foregrounds by motion, optical color, spectral feature, multiwavelength behavior, catalog identification, parallax • LSST will catalog all s.s. objects > 200 m Vestrand et al The Transient Universe: AY 250 Spring 2007

  30. Course Overview The Transient Universe: AY 250 Spring 2007

  31. The Transient Universe: AY 250 Spring 2007

  32. The Transient Universe: AY 250 Spring 2007

  33. The Transient Universe: AY 250 Spring 2007

  34. The Transient Universe: AY 250 Spring 2007

  35. The Transient Universe: AY 250 Spring 2007

  36. Course Details • New time • TuTh 11:00-12:30 • Office hours • 621 Campbell • No exams • Reading (see syllabus) • Student presentations • http://astro.berkeley.edu/~gbower/TU_S07 The Transient Universe: AY 250 Spring 2007

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