The Transient Universe: AY 250 Spring 2007 The Transient Universe AY 250 Geoff Bower

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

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

The Transient Universe: AY 250 Spring 2007 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 Phenomena Transient Phenomena (Harwit 1984) 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

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

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

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

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

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

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

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

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

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

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

The Transient Universe: AY 250 Spring 2007 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

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 Course Overview

The Transient Universe: AY 250 Spring 2007

Course Details New time –TuTh 11:00-12:30 Office hours –621 Campbell No exams Reading (see syllabus) Student presentations