Modern Observational/Instrumentation Techniques Astronomy 500

Andy Sheinis, Sterling 5520,2-0492 [email protected] MW 2:30, 6515 Sterling Office Hours: Tu 11-12 Class Website: Handouts, .ppt lectures and HW will be posted http://www.astro.wisc.edu/~sheinis/~500class Homework: There will be a 5-6 problem sets, one due approximately every other week. I will either post, or handout solutions. I encourage you to discuss the problems with your classmates, but you must each write up your own solution.

There will also be a Midterm and Final exam as well as an “Observational” project, which may or may not include a laboratory exercise. Grading: Approximate grading distribution will be: HW 40% Project 20% Midterm 20% Final 20% Texts:

Required: Walker, "Astronomical Observations", Cambridge Univ. Press. Schroeder, "Astronomical Optics", Academic Press

Recommended: Kitchin, "Astrophysical Techiques", Adam Hilger, Ltd Bevington&Robinson, "Data Reduction and Error Analysis for the Physical Sciences", McGraw-Hill Gray, “The Observation and Analysis of Stellar Photospheres”, Cambridge U. Press

Other Useful References: McLean, “Electronic Imaging in Astronomy”, Wiley Rybicki and Lightman, “Radiative Processes in Astrophysics”, Wiley Cox, “Allen’s Astrophysical Quantities”, Athlone Press chapters Date title W K S G R & L 1/22/06 Introduction to the course. Basic Observables 1 6 1/23/06 Photon Fluctuations, Fundamental noise sources, S/N 2 4 1/29/06 S/N in aperture photometry 2 4 1/30/06 Detection Limits/ Signal-to-noise/ time estimation 2 1.1 16 2/5/06 Planning an Observing run 2/6/06 Basic Processing 2/12/06 Basic Processing 2/13/06 Intro to Optics: Fundamentals/ radiometry 2 5 1 2/19/06 Intro to Optics: Paraxial Optics, Wave Optics 10 2/20/06 Detectors revisited 8 16 2/26/06 3 4, 7 ,8, 10 2/27/06 Telescopes 3 4, 7 ,8, 10 3/5/06 seeing, speckles and scintillation 4 5 3/6/06 seeing, speckles and scintillation 4 2 3/12/06 Direct imaging resolved and unresolved source photometry 2.1, 2.3, 3 3/13/06 Direct imaging resolved and unresolved source photometry 2.1, 2.3, 3 3/19/06 Spectrographs: Basics 7 4 13, 15 3 3/20/06 Spectrographs: Basics 7 4 13,15 3 3/26/06 Spectrographs: Specialized, MOS, IFU 4 3/27/06 Midterm 4/2/06 spring break 4/3/06 spring break 4/9/06 Spectoscopy: Processing techniques 7 4 4/10/06 Measureing spectral Continuum 7 10 4/16/06 Measureing spectral Lines 7 12 4/17/06 Student Presentations 4/23/06 Student Presentations 4/24/06 Polarimetry: Nordsieck 5.2 4/30/06 Fabry-Perot: Reynolds 5/1/06 Radio: Eric Wilcots 1.2 5/7/06 Radio: Eric Wilcots 5/8/06 Review.

* W=Walker K=Kitchin S=Schroeder G=Gray R&L=Rybicki and Lightman Astronomy is Different

• is the laboratory • We can only observe, no interaction • Limited to phenomena, occuring in the past • Must take interpret a “snapshot” • Have only the properties of light • Cannot measure directly, must infer from the measurement of light. Properties of light

• Intensity, flux, irradiance, amplitude • Angle of arrival, position, image • Wavelength, frequency, color • Angular momentum, spin, polarization • time variation (in some cases) • Phase (interferometry, radio, AO) LargeTelescopes

• Only two (Keck I and II) available in the 90’s • Several available at the turn of the century (the 4 VLT units, Gemini North and South, Subaru, HET) • One more in 2005, SALT! • others under construction (LBT, GTC) • and plans already for 30-100m telescopes... Telescopes

• Name Diameter Nationality of Sponsors Site Built • (SALT) 11.0 m South Africa, USA, UK, Germany, Poland, New Zealand South African 2005 • (GTC) 10.4 m Spain Roque de los Muchachos Observatory, Canary Islands 2005 • Keck 1 9.8 m USA Mauna Kea Observatory, 1993 • Keck 2 9.8 m USA Mauna Kea Observatory, Hawaii 1996 • (HET) 9.2 m USA, Germany McDonald Observatory, Texas 1997 • (LBT) 2x8.4 m USA, Italy, Germany Mount Graham Arizona 2004 • Subaru (NLT) 8.3 m Japan Mauna Kea Observatory, Hawaii 1999 • VLT 1 (Antu) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 1998 • VLT 2 (Kueyen) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 1999 • VLT 3 (Melipal) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 2000 • VLT 4 (Yepun) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 2001 • Gemini North 8.1 m USA, UK, Canada, Chile, Australia, Mauna Kea Observatory, Hawaii 1999 • Gemini South 8.1 m USA, UK, Canada, Chile, Australia, Cerro Tololo Observatory, Chile 2001 • (MMT) 6.5 m USA Fred Lawrence Whipple Observatory, Arizona 1999 • Magellan 1 6.5 m USA Las Campanas Observatory, Chile 2000 • Magellan 2 6.5 m USA Las Campanas Observatory, Chile 2002 • BTA-6 6 m Russia Zelenchukskaya, Caucasus 1976 • Large Zenith (LZT) 6 m Canada, France Maple Ridge, British Columbia 2003 • Hale Telescope 5 m USA , 1948 SALT Telescope PIC: SALT outside now

WIYN Telescope

Total E/t= Luminosity, L dE = L(t)dt

dE = L" (t)d" dt

dE = L# (t)d# dt

Ln = specific luminosity

! Flux

dE = f" dA d" dt 2 dE = f" (4#R )d" dt = L" d" dt L $ f = " " (4#R2)

Flux is energy incident on some area dA of the Earths surface. Flux is not conserved and falls of as R-2. ! Flux

• Flux is measured in Janskys in the radio • 1Jy=10-26 W m-2 Hz-1 • In the visible flux is measured in apparent magnitudes # & f1 m1 " m2 = "2.5log10% ( $ f2 ' # & f1 m = "2.5log10% ( $ f0 '

! Flux: absolute magnitude

m M = 5log10 d 5 + A() 2 f1 d2 Q = f2 d1

• Absolute magnitude is the apparent magnitude that would be observed at 10 pc. • A is the total extinction due to intersetllar dust in magnitudes For small changes in flux

m = 2.5(log10( f + f )/(ln10) =1.086f f / f =1 f and f <<1 Q 1 2

Standard choices for reference flux

• Vega system: apparent Magnitude of Vega = 0 in all bands. • Convenient, but non-physical • A-B magnitude system: -23 -2 -1 • F0=3.63e10 W m Hz , flat spectrum • Agrees with Vega at 548nm (center of V-band) Interesting magnitudes (V-band)

• Sun: m=-26.7 • Full moon: m=-12.6 • Sirius: m=-1.5 • Naked eye limit: m=6 • Brightest stars in Andromeda: m=19 • Present day limit: m~29 • Night sky: m=21.5 (best sites, dark time) • Night sky: m=18 (bright time) Intensity

• Finite size source (subtends a real angle) • Specific intensity • Brightness, surface brightness • Specific brightness • Units: (Jy sr-1) or (W m-2 Hz-1sr -1) or (erg cm-2 Hz -1) or (m arcsec-2) • What happens when the source is not resolved? Intensity

dE = I" (#,",t, p)d#d" dt dA

Where I will depend on: • Omega measured in RA and Dec • v= frequency ! • t= Integration time • P=polarization • Location where you are receiving the light. Observation

E = " I# ($,#,t, p)r($)F(#)d$d# dt dA

E = A%t " I# ($,#,t, p)r($)F(#)d$d#

• E=energy received during measurement • R=energy from the sky ! • F= filter function 1.1µ silicon 3100Å is the UV bandgap atmospheric cutoff