Internet Resources for the Nelson Project

My research focuses on a class of objects known as Active Galactic Nuclei (or AGN) in which material in the center of a large galaxy falls into a massive black hole in its nucleus, releasing very large amounts of energy in the form of radiation across the electromagnetic spectrum, collimated jets of high energy particles, and winds of ionized gas. Although we believe they are all powered by roughly the same central engine, there is a veritable zoo of particular species, including Seyfert galaxies, quasars, radio galaxies, blazars, and many others. Below are some links to web pages about AGN.

  • My presentation slides (kind of a big file sorry!)
  • An essay by Bill Keel on AGN (a bit long but readable and thorough)
  • Bill Keel's Quasar page
  • Alan Bridle's Radio Galaxies
  • A nice page on AGN from George Rieke's Natural Sciences class at the University of Arizona
  • Some work I did some years ago on the Seyfert galaxy NGC 4151
  • Slides from a DUSCI talk I gave a couple years ago

    AGN are of course found in the centers of galaxies, large collections of stars, gas, dust, clusters and perhaps most importantly dark matter, ultimately containing several hundred billion or a trillion solar masses of material. There are three basic types of galaxies: elliptical, spiral and irregular, but the variety of morphological detail never ceases to amaze me. Here are some galaxy atlases, demonstrating the range of galaxy shapes and sizes. Many of the galaxies in the Arp atlas are the result of interactions and mergers between galaxies, a process that can be modeled using computer simulations. It is believed that these interactions drive material into the center ultimately fueling the central black hole and stoking up a quasar.


  • The Revised Shapley-Ames Catalog of Bright Galaxies (see especially Part V The Illustrations)
  • The Arp Atlas of Peculiar Galaxies
  • Models of interacting galaxies by Joshua Barnes at the University of Hawaii.

    The Sloan Digital Sky Survey is an attempt to digitally photograph a large section of the sky and obtain spectra and redshifts for a million or so galaxies. The data are made available on-line for the world to use for research, education and general enjoyment. Check out the navigator tool to go exploring this large piece sky in whatever direction you like.

  • The Sloan Digital Sky Survey Home Page
  • SDSS Navigator Tool
  • Instructions for exploring the SDSS

    Last but not least, my favorite web site.

    Astronomy Picture of The Day


  • ... ok one more The James Nevin Band soon to be known as Disco Boy.


    (Background image: a portion of the Hubble Deep Field)