In the article, Hubble solves the mystery bulge at the center of the Milky Way on astronomy.com, author Alison Klesman enlightens us about the interesting bulges formed out of the center of the Milky Way galaxy. While looking at the Milky Way on its plane in visible light, it looks like a relatively flat structure with a central bulge. However, the gamma emission shows that there are two bubble looking structures that look like an hourglass around the center of the of the galaxy.
These structures are called Fermi Bubbles. They are a result from the supermassive black hole, in the central bulge, splurging on interstellar gasses and dust in the past. Compared to now, the black hole only has snacks. The Hubble was able to help astronomers figure out when these structures formed. Astronomers were able to map the motions of the cool gas in these bubbles to determine the age, which is 6 to 9 million years. These structures rise 23, 000 light-years above the plane of the Milky Way and contain enough cool gas to create 2 million sun-sized stars. The black hole at the center of the galaxy has a mass that is roughly equivilent to 4.5 million solar masses. Astronomers believed that our own supermassive black hole was a lot more active in the past. When the black hole was more active, not all the material always made it into the black hole. Some matter escaped along its spin axis forming outflows that span tens to thousands of light-years. The Fermi Bubbles are such outflows. All of the material that escaped emits gamma radiation that our Hubble telescope was able to capture an image of.
This article relates to our class and the conceptual objective, “I can describe the structure and size of the Milky Way Galaxy.” From our notes we have learned that the Milky Way galaxy is a spiral galaxy with a central bugle. It is roughly 150,000 light-years across and the stars reside in the arms. Like most other galaxies there is a supermassive black hole within the central bulge. This article informs us on new discoveries about our own Milky Way galaxy. These Fermi Bubbles are now a structural part of the galaxy.
Reading this article was fascinating. I didn’t think there would be more to the structure of the Milky Way. Looking at the images was amazing and really interesting. It makes me think about how the Milky Way must have acted 6 to 9 million years ago when the black hole was more active. Overall, I enjoyed this article.