Art of astronomy worksheet: Multiwavelength universe
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In this Exploration, you will create two images from multiwavelength data for the galaxy NGC 5055 (Messier 53, AKA the “Sunflower Galaxy). NGC 5055 is a spiral galaxy of about the same mass as the Milky Way, but with many short spiral segments. It is part of the same galaxy group as the Whirlpool galaxy, and lies at a distance of about 37 million light years.
Images for NGC 5055 are available from 21 cm radio data through infrared, optical, and UV wavelengths.
Below is a “natural color” optical wavelength image of NGC 5055 using the B, R, and H-alpha images.
Create a long wavelength image and a short wavelength image of NGC 5055 to compare to the optical image.
- Use the neutral hydrogen, 160 micron, 4.5 micron, and 3.5 micron images to create a false-color image showing what the galaxy would look like if we had radio/infrared eyes.
- Use the B, near-UV (NUV), and far-UV (FUV) to create a false-color image showing what the galaxy would look like if we had ultraviolet eyes.
Upload your images to the Canvas assignment.
In the Word document, describe what aspects of the galaxy are highlighted in each of the three images. For example, does the image show the presence of star formation or hot stars, the old stellar population, the presence of gas and dust. How does the size of the galaxy appear in each image?
Finally, explain why access to the full electromagnetic spectrum makes it possible to study the various aspects and components galaxies.
Below is a shorthand guide to creating images with Photoshop. You may wish to refer back to the more detailed Photoshop Guide used in Exploration 3.
- Load the images you need into Photoshop.
- Save one image to a new file name as a .psd file (for example, newimage.psd)
- For each of the other images, assign them as a duplicate layer to your newimage.psd image Layer/Duplicate layer and then close them.
- Convert newimage.psd from a grayscale image to an RGB image using Image/Mode.
- Colorize each layer of newimage.psd using the Image/Adjustments drop down menu at the top of the Photoshop window to adjust the brightness/contrast and the hue/saturation for that layer. Make sure you have completed these steps for each image layer!
- At this point, each of the four color layers should be adjusted and colored. Make sure you save your data at this point! Click the drop down menu File and then Save yourname.psd.
- Make the top layers transparent using the pull down menu in the toolbox on the right side of the Photoshop window that reads “normal.” Change “normal” to “screen.”
- Save the final result as a jpg file. A jpg option menu will appear when you save your image. Change the quality to 10 using the slide bar, then hit ok. The saved image should be in the folder with your original monochrome images.
