Lecturer: Dr. Ely Kovetz Affiliation: Johns Hopkins University Abstract: The standard model of cosmology, encapsulated by a handful of parameters to describe the energy content of the universe, its rate of expansion, and the amplitude and scale- dependence of primordial perturbations, has been immensely successful when confronted with cosmological observations hitherto. However, this simple picture masks the extent of our ignorance regarding several fundamental questions in cosmology, such as what are the properties of inflation, what is the nature of dark matter, what is the form of dark energy and how did galaxies form and evolve? Looking forward, a guiding principle for where to look for answers is the amount of information that can be gathered by different types of observations. With this in mind, I will briefly survey the different epochs in the history of the observable Universe and motivate our focus on high-redshift observations. I will then present recent work on several probes which could shed light on the questions above, including the quest for CMB B-modes from inflationary gravitational waves, heating effects on the dark-ages 21-cm signal from weak interactions between dark matter and baryons, measurement of star-formation rates using carbon-monoxide intensity mapping and tests of evolving dark energy models using clustering- based redshift estimation in radio continuum surveys. I will describe the unique motivation behind each measurement, the obstacles, possible solutions, and the prospects for detection in light of the vast number of ambitious cosmological experiments that are planned for the next few decades. Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/astrophysics?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.f1japs3dbcb6a3dnq2k0r4a4ek&hs=121