Lecture 5 Observations
measure objects' properties
Its relation with us: distances
how can we evaluate the measurements
kinematic properties
position
motion
mass
compare with reference stars
photometric redshifts
spectroscopic redshifts
Newton II law: gravity and rotation
viral theotem
dynamic properties
size
angular size and distance
flux and distance for unresolved stars/exoplanets
mass and period for orbit
luminosity:flux and distance
temperature
kinetic
effective
color
excitation
ionization
age:population
environment
composition
atomic and molecular: spectrum
sturcture
magnetic field
time evolution:difficult
dark matter and central blackhole
parallax
trigonometry
angular size to actural size
use sun-earth distance as a ruler
require velocity
luminosity and standard candles
period and brightness
other methods:Hubble constant
two principles
errors always occur
measurement is to improve SNR
two groups of concepts
accuracy vs precision
systematic vs random errors
two way to simulate errors
Poisson
Guassian
error propagation
do partial differential