Lecturer: Dr. Adi Zitrin Affiliation: Hubble Fellow, CALTECH Abstract: High-redshift science has been rapidly advancing in recent years on both theoretical and observational fronts. However, it is still vastly unclear whether galaxies could have reionized the universe, on what timescale, and what are the properties of these galaxies. I will review results from several recent projects we have been involved in, aimed to enhance our understanding of the first galaxies and the reionization process. In the first part of the talk I will review cluster lensing and recent advancements in lensing- related science, and in the second part I will concentrate on high-redshift galaxies. I will show that the crossroad of the two fields has been particularly useful to boost high-redshift science and our view of the reionization epoch. New efforts now underway with HST, Spitzer, and 10m ground-based telescopes will be overviewed, including some exciting results from Keck that potentially challenge our current understanding of reionization. Possible scenarios for reconciling this tension will be reviewed. 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=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.5j1k455mta6bbscq8s2pvl91hg&hs=121