GR3. GRB Imaging

Experience a small part of what GRB astronomers do in 5 easy steps

1.  Find out where GRBs are happening

Go to the Gamma-Ray Burst Real-Time Sky Map to see where the latest GRBs are located in the sky. You can see where bursts are located that are less than seven days old. Be patient, it may take a few seconds to load the sky map. Take some time to play with the application. Click on several bursts and compare the information given for each. Some of the newest ones may not have much information yet. The Burst Summary box may not scroll in Safari – it works in Firefox & Chrome.

2. Pick a GRB

When you feel you know how the application works, choose Swift from the “Select Mission” box. Pick out one GRB and take notes. Note its Burst ID, Burst date, Right Ascension and Declination. Record any details about your burst (What kind of light was in the afterglow; length of the burst; identification of source; how many peaks the light curve had; other detectors that saw this burst; etc). The higher the redshift z, the more distant the object should be.

3.  Get images

Go to SkyView Virtual Observatory (  Click on the SkyView Query Form. In the “Coordinates or Source” box, put your RA and Dec, with RA going first. Use a space between each pair of numbers and a comma between RA & Dec like this         03 44 48, -06 39 22

Choose the  type of images you want to see by clicking on the name in each type of light. Swift’s gamma-ray image is called BAT under Hard X-ray. DSS will give you a visible light image. You can leave all other choices as they are and Submit Request. Another window will open with your images.

4.  Analyze the images

Look through the images. How are they similar, how are they different? Each image should be centered on the position you entered. Is there a source visible at each waveband (wavelength)?

Your images came up with an image size of 300 pixels by 300 pixels. What does this mean in the sky though? Does each telescope take pictures of the same size of sky? Go back and look at the “Image Size (degrees)” and “Image size (pixels)” for each image. The image size in degrees tells you how much of the sky is shown in each image. The more degrees, the bigger the piece of sky the telescope was looking at. What do you see with each waveband? Are they the same? Is one bigger than the other? What does this say about the resolution or sharpness of the telescope?

5.  Take your own image in optical light

Go to Skynet and request an image of your GRB. Use your notes to help you figure out what filters to choose and what exposure time to use. When it comes back use image processing to make a good color image of your object. If you took three color images, add them to make a false colored image. You can print it and post it with an explanation page that describes this GRB using the notes you took from the Real Time Sky Map or any images from SkyView Virtual Observatory.





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