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Astronomy Instruments from the Quantum Age: Do New Instruments, or New Ideas, Drive New Science? Alanna Connors, for the AstroStatistics Working Group at Harvard Smithsonian Center for Astrophysics “Processing of some sophistication is needed, rather than being just a fixup at the end.” Tim Cornwell OUTLINE All Optical: Eye and Hand Telescope and Hand Photography New Science: Equations for fun! New Instruments: Seeing the Invisible Mathematics of Invariance: Relativity+ QM Bohr Atom Below the Visible: Radio, Infrared (skip) ** Above the visible: Ionizing Radiation Background or signal: Cosmic rays Old Instruments, New Instruments: Chandra has it easy, but illustrates main principles Tougher Instruments; still, “Do It Right” Early Observations: Eye, Hand Crab Supernova July 1054 AD Anasazi Japan Chinese guest star “seen in the day like Venus” Armillary Sphere Grand Sweep of Stars and Planets: How to Infer 3D from meticulous 2D: Ptolemy, Hypatia, … Telescope: Galileo and onwards Allows more meticulous precision Planetary Motions: 3D from 2D: Kepler, Brahe, Hooke, Newton… Statistics: Least-Squares Fitting (LaPlace) Periodic Motion (Fourier) SKIPPING many interesting math techniques for orbits, etc. Quantum Mechanics & Relativity: Oh, Equations! Fun! QUANTUM MECHANICS Comes in lumps: E = h n ( Energy = Planck constant * frequency ) n = c / l (frequency = light-speed / wavelength) Wave properties for light AND matter! Particle properties for matter AND light! RELATIVITY: E = m c^2 Electron ~ 0.5 MeV, Proton and neutron ~ 1 GeV Potential Energy balanced by angular momentum * Angular momentum quantized = nh * Result: Constructive interference: Integer l’s in each orbit Energy levels ~ 1/n^2 Stellar Spectra: Annie Jump Cannon Women of Harvard College Observatory Cecelia Payne-Gaposchkin: Old Astronomy + New QM for 1st Time Huge amount of careful observations of spectra QM tells ionization balance Startling thesis result: Most of the visible universe made of Hydrogen! New Instruments: Seeing the Invisible Jumping Over Whole Story of Radio: G. Reber, 1932 backyard; Present VLA (But Interferometry - very intersting!) Ionizing Radiation from the Sky Victor Hess flies with a gold-leaf electroscope like one at left; Measures decreasing discharge time as altitude increases Radio-Chemistry Skill of Curie Family: Supply Standards of Radioactive Materials Radium, purified New Instruments •Scintillators (right; also reading) •Cloud chamber DEMO (tracing tracks by hand from photographs!) •Geiger Counter DEMO •Photographic / emulsion •Basics same as many modern ones Take a minute to think about Statistics, I Historical notes on watching for scintillations in a dark room Tracks: tracing by hand (!) until very recently (some HEP still do!) Historical note: for some reason, most technicians who do this are women -- Claudia Brevard and CGRO EGRET Any thoughts on statistics? Take a minute to think about Statistics, II Optical “culture”: What can I see? Invisible light “culture”: m = e * R * i + b <counts>=Eff. Area*Inst.Redist.*Source intensity +Sky+Inst. Bkg Measured counts = Y ~ Poisson (m) Poisson(m) ~ Normal(m,sqrt(m)) Least-squares, c^2 minimization, CC w/ R Pre-1975: Early X-Ray Telescopes: Bin size>PSF; Many counts/bin; NO processing SKYLAB: Solar – very large bright source Copernicus, ANS; sky, but only point sources Pre-1975: Early G-Ray “Telescopes” Bin size>PSF; fewer counts; “Bin them up” SAS-2 satellite: > 100 MeV G-ray charged particle shield profile of Galactic plane covers spark chamberS 1975-1990's: COS-B Gamma-Ray Satellite Preliminary imaging; Simple Gauss-Normal “fix it up at the end” Galactic Anti-center region: COS-B satellite (Aug Crab and Geminga pulsars '75 - Apr '82; 2 keV – 5GeV) Cutaway of spark+ Diffuse emission chambers, shielding 1975-1990s: Einstein X-Ray Observatory (HEAO2) First medium energy X-ray point sources+diffuse imaging; G-N approximation; “fix it up at the end” Tycho Supernova Remnant (1572) Einstein Observatory (Nov. '78-April '81; 0.15-3 keV) Mirror assembly 1990's and Beyond: Great Observatories need to do it right; no longer can “fix it up at the end” Compton Gamma-Ray Chandra X-Ray Observatory Jul Observatory (Apr '91 – Jun '00; COMPTEL: 0.8-30 MeV; EGRET 20 MeV-100 GeV) SvOutPlaceObject 1999 and beyond; 0.1-10 keV) CGRO/EGRET All-Sky Map diffuse glow; significantly non-Gaussian statistics Log Counts per time per 05 degree pixel: Four years of data (ranges from zero to thousands per pixel) SvOutPlaceObject CGRO/EGRET All-Sky Map Log Inferred flux per 0.5 degree pixel: Four years of data (known point and diffuse sources modelled out) Haar wavelet basis: Dixon, Hartman, Kolaczyk et al CGRO/COMPTEL All-Sky 1.8MeV (Knödelseder, Dixon, Diehl, Strong, et al 1998) very non-diagonal instrument response; horrid background Mkn 501 at TeV: Whipple Observatory (Quinn et al. for Whipple collaboration, 1996, ApJL, 456, p83) 1st AGN DISCOVERED at TeV; horrid background, response Chandra has it “easy” … BUT illustrates main principles CHANDRA Image of Tycho Supernova CHANDRA PSF on-axis: varies with energy CHANDRA PSF: spreads off-axi 5 arcmin off-axis CHANDRA PSF offaxis 10 arcmin CHANDRA ACIS BACKGROUND FI CCD BI CCD Effect of a Charged Particle Event Higher Energy: More Extreme! Dim, BKG, Rate… Hurley et al GRB940210: “The diffuse background in this direction results in about one photon above 30 MeV detected by EGRET in 7 minutes. On the subsequent Compton Observatory orbit, 1.5 hours later, EGRET had 20 minutes of livetime, and 10 gamma rays were detected from the region around the annulus, one with energy 26 GeV.” * ABOUT 2 DOZEN PAPERS on 1! Pathway for Future: Other instruments: Ground-based TeV GLAST, Swift, … CON-X, etc “Doing it right” in one area helps many overlapping areas