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    I am an astronomer, cosmologist, and data scientist. I am currently a NSF funded Assistant Research Scientist at the UC San Diego Center for Astrophysics & Space Sciences (CASS profile) and a Research Affiliate in the MIT Program in Science, Technology and Society (STS). I work on several theoretical and observational cosmology projects to devise and implement fun experiments that leverage cosmology to help test fundamental physics. These include a series of experiments with colleagues to test quantum theory with astronomical observations as well as Infrared and Optical observations of Type Ia Supernovae with ground and space based telescopes, which can be used to measure the expansion history of the universe, cosmic acceleration, and dark energy. Before UCSD, I was an NSF Postdoctoral Fellow at MIT, a NSF Funded Research Associate at MIT, and a Visiting Research Scientist at the MIT Center for Theoretical Physics. I completed my PhD in Astronomy & Astrophysics from the Harvard University Department of Astronomy and I received my BA in Physics & Astrophysics from UC Berkeley. I am very interested in projects at the intersection between observational astronomy, astrophysics, data analysis, and the philosophy of science, especially the philosophy of cosmology. I am excited to explore a range of fascinating scientific questions through research, science writing, art, animation, public outreach, and working with the science media. For more, see my Bio, Resume, and CV.
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(a) Animation 6a corresponds to Fig. 2a of Friedman+2013 for the case α = 180 degrees where the redshift of event A is fixed to zA=0.5 and the redshift of event B is allowed to vary in the range 0.5 < zB < 71.91. For zB < zB ~ 50, events A and B have intersecting past lightcones and a shared causal past. For zB > zB ~ 50, the events do not have a shared causal past. This corresponds to fixing zA and α = 180 degrees and increasing zB until the point (zA, zB) lies in the light gray region in Fig 3b of Friedman+2013. For zA <= zB <= 3.65, events A and B both have shared causal pasts with Earth's worldline, whereas event B does not when zB > 3.65. The critical redshift zB is computed from Eq. 30 of Friedman+2013 (substituting labels A <--> B), and using Eq. 12 of Friedman+2013 to determine redshift for a given comoving distance.

(b) Animation 6b corresponds to Fig. 2a of Friedman+2013 for the case α = 180 degrees with symmetric redshifts zA=zB, where both redshifts are increased in the range 1 <= zA=zB <= 24.47. The symmetric case illustrates the role of the causal independence redshift zind=3.65. For zA=zB <= zind=3.65, events A and B have intersecting past lightcones and shared causal pasts with each other and Earth's worldline. For zA=zB > zind=3.65, events A and B have no shared causal past with each other or our worldline. The finite redshift resolution of the movie shows a frame with zA=zB=3.62 where the past lightcones of A and B clearly intersect (green circles), while the next frame with zA=zB=3.67 clearly shows that the past lightcones of the events no longer intersect.

University of California, San Diego UCSD Center for Astrophysics & Space Sciences Massachusetts Institute of Technology MIT Center for Theoretical Physics Institute for Quantum Optics and Quantum Information, Vienna Harvard University Astronomy Harvard-Smithsonian Center for Astrophysics UC Berkeley Astronomy National Science Foundation National Aernautics & Space Administration
Last Updated: Andrew Samuel Friedman, 2/2017

University of California, San Diego, 9500 Gilman Drive
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This material is based upon work supported by the National Science Foundation under NSF Award #1056580 (2012-2014) through an NSF Science, Technology, and Society Postdoctoral Fellowship at MIT and the NSF INSPIRE program via NSF Award #1541160 (2015-2018).

Original animations are shared under a
Creative Commons Attribution-NonCommercial-ShareAlike 3.0 US License