The Cosmic Distance Scale + Galaxy Properties
Freshman Seminar Project
The primary goal of this project is to produce a Hubble diagram
and an estimate of the Hubble Constant using diameters of
more distant spiral galaxies as compared to the diameters
of galaxies whose distances are known from HST measurements
of their distances (especially Andromeda, M81, M101 and M33,
but others as well).
The secondary goal is to examine some of the properties of
galaxies by plotting various interesting properties of galaxies
against others. Examples:
1. apparent magnitude versus redshift
2. apparent diameter versus redshift (see above!)
3. absolute size versus absolute luminosity
4. Surface brightness versus absolute luminosity
early.spirals.dat a file containing all the early type spiral
galaxies in the first CfA Redshift survey (about 475).
dist.dat a file containing good distance measurements
(estimates) for nearby galaxies. Some are early
type spirals, ignore the rest.
1. look at all these galaxies on the digitized Palomar
sky survey --- see utilities directory for how to
extract images using 'getimage'
2. measure their apparent diameters -- do this yourself,
don't just look them up! (and it might be worth
measuring both major and minor axis diameters). Pictures
of galaxies can be greated using
getimage , a canned routine on CfA computers
tat allows you to access the image database of scanned images of the Palomar
digital Sky Survey.
3. plot apparent diameter versus redshift (see supermongo
or use your own)
4. estimate the absolute diameters for those galaxies that
have non-redshift distances
After that, try plotting up some of the other quantities
you see above in this sample.
Here are the links to the data files:
early spirals tab file