Astro 430/530

Problem Set #1 Due Wednesday September 4, 2019

This first assignment is to acquaint you with the variety of types by visually examining images of nearby galaxies.

The (SDSS) has fundamentally changed how we view and analyze galaxies. Galaxy studies have moved from samples of a few hundred to a few hundred thousand objects, allowing far more quantitative and statistical analysis. However, it is still crucial to look at individual images of nearby galaxies, since detailed studies of them are the foundation for understanding galaxy structure and evolution.

Examine the SDSS images of the following galaxies from the Third Reference Catalogue of Bright Galaxies (RC3, deVaucouleurs et al. 1991), a well-known sample of nearby galaxies, from the following website: http://cosmo.nyu.edu/hogg/rc3/

NGC 4406 NGC 3377 NGC 309 NGC 1068 NGC 5850 NGC 7814 NGC 936 NGC 1055 NGC 660 NGC 3227 NGC 4438 NGC 3034 (M82) NGC 4449 Leo A (next to NGC3034) Plus pick out 2 other galaxies that you find interesting.

Create 1 (or 2) powerpoint (or equivalent) slide(s) for each galaxy. Submit a .pdf document of the slide set. Each slide should include the SDSS color image of the galaxy (any of the 3 provided on the Hogg website), with labelling and associated text that address the following points:

Describe what you see – in terms of morphology, structure, color, and symmetry. Provide observations & description, rather than interpretation. Which features originate from dust or other ISM components rather than ? Comment on older versus younger stars. Comment on how the 2D projected shape relates to the likely 3D shape. You may compare to other galaxies on the list to help describe features.

For each of the galaxies, give the “NED homogenized” galaxy classification from http://ned.ipac.caltech.edu/ and describe the features on which the classification is based. Are there other features apparent in the image which are not captured in the classification?

Extra Credit: Can you guess an approximate mass of the galaxies from the images? (Give your reasoning.)