Gabriel Reineck | Understanding How Cosmological Parameters Affect the Observations

Gabriel Reineck

By Gabriel Reineck
(B.S. Astrophysics, Class of 2017)

I began my 2015 internship in Physics & Astronomy by reading parts of Barbara Ryden’s book, Introduction to Cosmology, suggested to me by Dr. Hee-Jong Seo. This is where I learned the basics of cosmology. The book showed me how to view the universe – like on large scales the universe is isotropic and homogeneous, which means there is no special point that the universe prefers on large scales. Some things I learned from that book helped me understand a program called CAMB (Code for Anisotropies in the Microwave Background).

I also read about the temperature of the CMB, CMB photons and how the change of the photons’ temperature is related to the expansion of the universe in the past. What we know about the CMB and how it has changed over time can be explained by the Hot Big Bang model, which the author says explains our universe the best based on the CMB observations. I also learned about curvature of space and how it changes the universe from our point of view. All of that could be changed in CAMB to see how the universe would behave in response.

I learned to code in Python and plot using matplotlib. From the book we went into detail about the relationship of Hubble parameter, luminosity distance, angular – diameter distance, redshift, and proper distance. I wrote a code in Python integrating the proper distance in terms of the Hubble parameter and from a 0 to 10 redshift. The last thing we did was have me plot cosmological constant versus other models to see what value dark matter density or baryonic matter density should be for a flat universe.

I proceeded in a self-study manner with help from Dr. Seo, who guided me in the right direction. I certainly learned a lot about cosmology and some of the programs that I might use in the future, so the experience from that alone was worth it. I definitely feel more comfortable with programming as a result.

Gabriel Reineck – 2015 Intern with Dr. Hee-Jong Seo– junior at Ohio University – College of Arts & Sciences – astrophysics major