1 / 37

OUTLINE

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

nessa
Download Presentation

OUTLINE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 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

  2. OUTLINE • All Optical: • Eye and Hand • Telescope and Hand • Photography • New Science: Equations for fun! • Mathematics of Invariance: Relativity+ QM • Bohr Atom • New Instruments: Seeing the Invisible • 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”

  3. Early Observations: Eye, HandCrab Supernova July 1054 AD • Anasazi • Japan • Chinese guest star “seen in the day like Venus”

  4. Armillary Sphere

  5. Grand Sweep of Stars and Planets:How to Infer 3D from meticulous 2D: Ptolemy, Hypatia, …

  6. Telescope: Galileo and onwardsAllows more meticulous precision

  7. Planetary Motions: 3D from 2D: Kepler, Brahe, Hooke, Newton…

  8. Statistics: • Least-Squares Fitting (LaPlace) • Periodic Motion (Fourier) • SKIPPING many interesting math techniques for orbits, etc.

  9. Quantum Mechanics & Relativity: Oh, Equations! Fun! • QUANTUM MECHANICS • E = h n ( Energy = Planck constant * frequency ) • n = c / l (frequency = light-speed / wavelength) • Wave properties for light AND matter! • Comes in lumps: • Particle properties for matter AND light! • RELATIVITY: • E = m c^2 • Electron ~ 0.5 MeV, Proton and neutron ~ 1 GeV

  10. Potential Energy balanced by angular momentum* Angular momentum quantized = nh* Result: Constructive interference: Integer l’s in each orbit Energy levels ~ 1/n^2

  11. Stellar Spectra: Annie Jump Cannon Women of Harvard College Observatory

  12. 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!

  13. New Instruments: Seeing the Invisible

  14. Jumping Over Whole Story of Radio:G. Reber, 1932 backyard; Present VLA(But Interferometry - very intersting!)

  15. Ionizing Radiation from the Sky Victor Hess flies with a gold-leaf electroscope like one at left; Measures decreasing discharge time as altitude increases

  16. Radio-Chemistry Skill of Curie Family:Supply Standards of Radioactive Materials Radium, purified

  17. 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

  18. 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?

  19. 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

  20. 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

  21. Pre-1975: Early G-Ray “Telescopes”Bin size>PSF; fewer counts; “Bin them up” SAS-2 satellite: charged particle shield covers spark chamberS • > 100 MeV G-ray profile of Galactic plane

  22. 1975-1990's: COS-B Gamma-Ray SatellitePreliminary imaging; Simple Gauss-Normal “fix it up at the end” • Galactic Anti-center region: Crab and Geminga pulsars + Diffuse emission • COS-B satellite (Aug '75 - Apr '82; 2 keV – 5GeV) Cutaway of spark-chambers, shielding

  23. 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” Einstein Observatory (Nov. '78-April '81; 0.15-3 keV) Mirror assembly Tycho Supernova Remnant (1572)

  24. 1990's and Beyond: Great Observatoriesneed to do it right; no longer can “fix it up at the end” Compton Gamma-Ray Observatory (Apr '91 – Jun '00; COMPTEL: 0.8-30 MeV; EGRET 20 MeV-100 GeV) Chandra X-Ray Observatory Jul 1999 and beyond; 0.1-10 keV)

  25. 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)

  26. 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

  27. CGRO/COMPTEL All-Sky 1.8MeV(Knödelseder, Dixon, Diehl, Strong, et al 1998)very non-diagonal instrument response; horrid background

  28. Mkn 501 at TeV: Whipple Observatory (Quinn et al. for Whipple collaboration, 1996, ApJL, 456, p83)1st AGN DISCOVERED at TeV; horrid background, response

  29. Chandra has it “easy” …BUT illustrates main principles

  30. CHANDRA Image of Tycho Supernova

  31. CHANDRA PSF on-axis: varies with energy

  32. CHANDRA PSF: spreads off-axis 5 arcmin off-axis

  33. CHANDRA PSF off- axis 10 arcmin

  34. CHANDRA ACIS BACKGROUND BI CCD FI CCD Effect of a Charged Particle Event

  35. 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!

  36. Pathway for Future: • Other instruments: Ground-based TeV • GLAST, Swift, … • CON-X, etc

  37. “Doing it right” in one area helps many overlapping areas

More Related