Look at the spectra of a number of quasars at different redshifts. How do the spectra change as redshift increases? Make a graph of quasar color as a function of redshift. How do you explain what you see in the graph?
Things you might think about
- What does it mean to look at quasars at different redshifts?
- What features do quasar spectra have in common?
- What lines are most useful for classifying and comparing quasars?
- How do spectra change at increasing redshift?
Tools that might help you (all links open in new windows)
Explore: use this tool to get data, including spectra, when you know a quasar’s ID number or position
Image List: use this tool to get thumbnail images of quasars that meet your search criteria
Plate Browser: use this tool to browse through 640 spectra at a time, looking for quasars
Science background (new windows)
Hints and cautions (new windows)
If you write your own SQL query, be sure to include spectral classes 3 and 4.
Be careful that you correctly identify lines in the spectra – some lines are very close to other lines.
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