Senior IU scientist discusses formation of Milky Way

On Monday, October 15, the Department of Physics and Optical Engineering hosted a guest speaker in the Myers Presentation Room, focusing on the spiral structure of the Milky Way Galaxy and the various approaches to finding the actual dimensions of it. The speaker was a senior scientist from Indiana University, Thomas Steiman-Cameron.

Steiman-Cameron’s lecture on Monday began with an introduction on the basic history of the theory of galaxy formation and the shapes that such galaxies were believed and later proven to take on. He spoke about four basic galaxy types: elliptical, lenticular, spiral, and irregular, and the basic attributes of each structure including general shape, star age, and various emissions from these galaxies.

Photo: Matt Virgo Thomas Steinman-Cameron, a senior scientist from Indiana University, discusses the theory of spiral galaxy formation this past Monday. Steinman-Cameron was hosted by the Physics and Optical Engineering Department.

Following this, Steiman-Cameron’s lecture proceeded into the various methods of observing our own galaxy, since we have the inability to get far enough away to be able to observe the actual shape. The processes that have been used were then analyzed, showing their various strengths and weaknesses, such as low spatial resolution and percent errors of up to 25%.

The discussion then led into the various designs that had been suggested throughout time for the Milky Way Galaxy and how these various concepts interpreted the available data. Due to the nature of the data used in the earlier postulations, Steiman-Cameron and his colleagues, along with many other independent teams, came to the conclusion that a better model could be found.

Steiman-Cameron went on to postulate based upon new data collected from the recent COBE (Cosmic Background Explorer) satellite. This satellite provided information on the [C II] 128 micron spectrum and the [N II] 205 micron spectrum that allowed for a “galactic thinness,” or an ability to see through to almost any point on the galaxy without much diffusion. This information then allowed computer simulations to be run that would match each section of data and then compare them, allowing for the closest fit for the available COBE data. This analysis then led to an image of the Milky Way that very closely matched the available data.

This entire event, hosted by the Physics and Optical Engineering Department, provided many students an informative glimpse at what by many students was assumed to be already known. The attendance for the event proved to be good in nature, with approximately forty to sixty students in attendance. The general feel from the students who attended was that Steiman-Cameron provided a “pretty good presentation that gave a background of the topic, used the different methods in making models, gave a good description of his model and how he got it without a language that was too technical,” as summed up by Jennifer Pint, a junior mechanical engineering student.