ASTR 402 Observational Astronomy 11 April 2006 Dr. H. Geller The
Dome Has Arrived Regarding Remaining Homework Assignment #3
2006:090:20:49: Discover and explain what each of the column
numbers represent (date, time, intensity, lat, long, etc.). In the
first column, define all of the parameters represented. 2. Describe
the differences between the different rows. Be specific. 3. Using
the intensities from one frequency (specify which one you are
using) develop a surface (colorized contour) map of the intensity
versus the location (RA, dec) of the center of the beam. You may
use either Excel or some other data visualization package.
Regarding Remaining Homework Assignment #4 Run the Virtual Radio
Interferometer Java applet from this site Using defaults, choose
the sources Point, Offset Point, Narrow Double, Wide Double, Wide
Gaussian, Narrow Gaussian, Disc, Crux, Radio Galaxy For each
different source describe the source and the FFT for each of the
sources For a defined configuration (you define what you like to
choose as your configuration of dishes) Set the hour-angle range to
zero (this is what is known as a "cut"). Accumulate cuts at hour
angles of 0, +4 and -4. Look at the uv- coverage for 6 antennas and
describe how the resultant image looks for a specified point as
compared to the radio galaxy source. Start with the declination set
to zero. Describe what happens on an east-west array. Now try
moving antennas off the E-W line and look at the new uv-coverage.
Review Chapter 10 Concepts Photon-electron interactions Rayleigh
Scattering Thomson Scattering Compton Scattering Photon Absorption
in the Cosmic Microwave Background Radiation Review Chapter 10
Concepts Photon-atom interactions Photon absorption Absorption
lines Emission nebulae Pair production Review Chapter 10 Concepts
Starlight Extinction Interstellar Medium (ISM) dust grains
Extinction Coefficient Extragalactic Sources Color Excess (aka
reddening) Frequency Dependence Dust-hydrogen association Review
Chapter 10 Concepts Cross sections Target cross section Mean
propagation distance Exponential absorption Mean free path Optical
depth Extinction coefficient cross section Review Chapter 10
Concepts Photoelectric absorption in the ISM Photoelectric Effect
Cosmic Abundances By number By mass fraction Propagation Distances
in the ISM Effective cross sections Survival distances Astronomical
gas calculations Review Chapter 10 Concepts
