M81 (NGC 3031) as seen in the infrared

Professional astronomical images and other data are freely available on the web in many places, but most of the general public is unaware that they can download these images and perform their own science. This webpage features both a guide about using the DS9 image viewer to view and examine these images and several computer-based experiments that could be performed by secondary school or undergraduate university students.

Related to this, my image gallery webpage features many images in jpg format that I have created from professional astronomy data. The gallery also includes links to the professional astronomy data used to create the gallery images.


A screenshot of DS9
Introduction to Astronomy Images and the DS9 Image Viewer
Guide (PDF)

DS9 is a program designed to display and analyze images in the FITS format, which is a specific image file format used by professional astronomers. An example screenshop it visible on the left. Information about the program as well as downloads for Windows, Mac, and Linux are available from the official DS9 website.

I have written a guide for using this program that includes a brief introduction to computer images and FITS images, information on getting started with DS9, an overview of the program's features, and instructions on using some of the features in DS9. The end of the guide also has some information on where people can find FITS images that they can freely download.

M5 (NGC 5904) as seen in ultraviolet, blue, and near-infrared light
Analysis of Globular Clusters Using Colour-Magnitude Diagrams
Lab Script (PDF)
Model Data (text format)
Model Data (Excel format)

The ages of clusters of stars as well as the amount of heavy elements present in the stars can be determined by plotting the relation between the stars' colours and brightnesses (or magnitudes). This experiment guides students through using this approach to identify the ages and heavy element content of a globular cluster.

To perform this experiment, students will not only need the lab script but also the model data, which is provided in plain text and Excel formats from links up above.

The image on the left is a near-ultraviolet (3543 Angstrom) / blue (4770 Angstrom) / near-infrared (7625 Angstrom) image of M5 (NGC 5904) based on data from the Sloan Digitized Sky Survey (SDSS) Collaboration. The images are available from these links: u-band image, g-band image, i-band image.

M74 (NGC 628) as seen in ultraviolet and infrared emission
Comparing Ultraviolet and Infrared Star Formation Tracers
Lab Script (PDF)

The places where stars are forming can be identified by looking for the emission assocated with bright, hot stars that use up the hydrogen in their cores soon after forming. In this experiment, students can compare ultraviolet light emitted from these hot stars and infrared light emitted by dust around the young stars to examine the effectiveness of each of these star formation tracers.

The image on the left shows the near-ultraviolet (2267 Angstrom) emission in blue and the mid-infrared (24 micron) emission in red from the spiral galaxy M74. The star forming regions appear bright in one or both bands. The ultraviolet image was published by M. Brown et al. (2014, ApJS, 212, 18) and can be downloaded from this link. The mid-infrared image is one that I created myself and is available from this link.

M100 (NGC4321) as seen in ultraviolet, infrared, and millimeter emission
The Relation Between Gas Density and Star Formation Rate in the Spiral Galaxy M100
Lab Script (PDF)

Astronomers have found an important relation between the rate at which stars form and the amount of interstellar molecular gas that is available for forming stars. This experiment provides instructions on how to measure this relation in the center of the spiral galaxy M100.

The multicolor image on the left shows the data used in this experiment. The near-ultraviolet (2267 Angstrom) emission is shown in blue, the millimeter (2.6 mm) emision is in green, and the mid-infrared (24 micron) emission is in red. The star forming regions appear red, blue, or magenta in this image, while the molecular gas appears green or white. The ultraviolet image was published by M. Brown et al. (2014, ApJS, 212, 18) and can be downloaded from this link. The mid-infrared image is one that I published myself (Bendo et al., 2012, MNRAS, 423, 197) and is available from this link. The millimeter image is available from this ALMA website.