eLearning Collaborative

Saturday was our first day of science research. The first day, we learned about the topic we are going to be doing research with. We're doing research on a specific type of galaxy, called an active galaxy, or AGN for short (standing for active galactic nuclei). Before I go into details about what we did with the AGNs, I would like to explain breifly what an AGN is.

It seems normal to think that the total amount of light being emitted from a galaxy is equal to all the light being emitted from its' stars. And this is indeed the case for most galaxies, however; in AGN this is not the case. The bolometric lumonisty (the total amount of light given off from a galaxy) is higher than the total amount of light given off from the galaxy's stars. The reason for this, is an active supermassive black hole within center of the active galaxy. Material surrounding is orbiting the black hole until it is eventually pulled in closer and closer from the black hole's strong gravity field. The material is called an accretion disk. In this material's final stage of life before passing the event horizon (the point of no return in a black hole) it emits a final surge of energy and light, which accounts for the extra brightness not provided by the stars.

Active Galaxy: an example picture

With AGN, Spitzer Space Telescope is studying the clouds of dust that surround the accretion disk. A quick interjection about Spitzer...it's an infrared telescope that is actually in outerspace right now. Anyways, this dust absorbs radiation (light emission) from the accretion disk and then reradiates it in a cooler temperature. By studying this reradiation, Spitzer can find the distance from the accretion disk to the dust which could be an important role in fueling the supermassive black hole.

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