Ancillary Data on Done & Talk pages

When classifying galaxies, if you select "Done & Talk" you can find additional information about each object below the spectrum in the sections called "Ancillary Data." When available, the left image is a cutout from JWST (NASA’s Webb Space Telescope), which observes in infrared light. Observing at longer wavelengths allows JWST to detect fainter and more distant galaxies, peer through cosmic dust, and reveal structures from the early Universe with high sensitivity. The right image is from HST (the Hubble Space Telescope), which observes in optical and ultraviolet light. Most subjects should include both images, but some may be missing one or the other.

Credits: JWST and HST cutouts are generated using data from the Dawn JWST Archive (DJA), produced by the Cosmic Dawn Center (DAWN) using the grizli pipeline. The imaging is part of the COSMOS-Web survey, and we gratefully acknowledge the COSMOS-Web team for producing and sharing this high-quality sruvey (Casey et al. 2023; Shuntov et al. 2025).

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More Resources

To learn more about astronomical spectra:

https://webbtelescope.org/contents/articles/spectroscopy-101--introduction

• This series of articles from Webb includes helpful infographics and examples of the information we can gather from different types of astronomical spectra.

https://imagine.gsfc.nasa.gov/science/toolbox/spectra1.html

• This page from the NASA Goddard Space Flight Center provides another explanation of light and the visible spectrum.

https://science.nasa.gov/mission/hubble/science/science-behind-the-discoveries/hubble-spectroscopy/

• This overview of Hubble spectroscopy describes the different kinds of information carried in light.

A short video series on what we can learn by studying light:

https://www.youtube.com/playlist?list=PLm0MBdI3VlBW1Eh4s-zOVhICiWebU-5uw

• Reading the Rainbow shows, in a few short videos, the power of spectroscopy in teaching us about the distance, speed, temperature, and more behaviors of cosmic objects.

To learn more about redshift and spectral features:

https://mosdef.astro.berkeley.edu/for-the-public/public/measuring-redshifts/

• This UC Berkeley article describes the use of MOSFIRE, an instrument on the Keck I Telescope in Hawaii that measures spectra, and shows some of the specific emission lines that we look for in galaxy spectra.

To learn more about the Early Universe:

https://jwst.nasa.gov/content/science/firstLight.html

• NASA's site dedicated to the Webb Space Telescope goes into more detail on the cosmic timeline, connecting distance and time and visualizing the evolution of our universe following the Big Bang.

To learn more about how we collect data with the DEIMOS instrument:

https://www.youtube.com/watch?app=desktop&v=syu4qyixAA0

• Watch this example of an observing run with DEIMOS (DEep Imaging Multi-Object Spectrograph), one of the instruments we use to observe galaxy spectroscopy. They show an example of a slit mask, talk through some of the tools and instruments used by astronomers, and demonstrate the process of data collection.

Visit the observatory websites to learn more about science goals and discoveries of the telescopes from which we get our data:

• Keck Observatory, DEIMOS instrument
• Gemini Observatory (GMOS instrument)
• Subaru Telescope (FMOS instrument)

Read more about our datasets in these publications:

• DEIMOS 10k

To learn more about NASA Citizen Science Projects:

http://science.nasa.gov/citizenscience

Additional Resources for those who want to dive deeper:

https://docs.google.com/document/d/16vGWmicjxkZm8BOc9sG5DKY3At8C0AooomE1xmtZtuc/edit?tab=t.0