We present 36 spectroscopically confirmed Lyman-alpha emitting galaxies (LAEs) from follow-up observations with Keck/DEIMOS of high-redshift candidates behind 10 galaxy cluster lenses. High-redshift candidates were selected to be between 5 [less than or approximately equal to] z [less than or approximately equal to 7] from a variety of photometric data using HST and Spitzer imaging surveys including the Cluster Lensing And Supernova Survey with Hubble (CLASH), the Hubble Frontier Fields (HFF), and the Spitzer UltRa Faint SUrvey Program (SURFSUP). A subset of 27 of our targets were prioritized from the Grism Lens-Amplified Survey from Space (GLASS). After compiling a large sample of potential high-redshift candidates from our extensive spectroscopic program, we used photometric redshift information derived from accompanying photometric data to perform an integrated P(z) cut >1% between 5 z 7 in order to construct a sample of 198 high-redshift objects, 136 primary targets and 62 secondaries (serendipitous objects). Our high-redshift sample spans intrinsic UV luminosities from a few L* down to 0.001L* (where L* is the characteristic luminosity of galaxies in our redshift range). We identified 19 high-confidence detections of Ly[alpha] in our final sample and an additional 17 likely detections. Five of these detections have been previously reported spectroscopically. We divided our sample into a lower-redshift (z [approximately equal to] 5.5) and higher-redshift (z [approximately equal to] 6.5) sample and ran Monte Carlo trials, incorporating the strength of the Ly[alpha]emission, the photometric redshift of the non-detections, and different treatments of multiple images. Considering only objects where Ly[alpha]could be detected at EW(Ly[alpha])25Å at 3[sigma] at the fiducial depth of our survey, and considering only those galaxies with EW(Ly[alpha])25Å as true LAEs, and finally, considering only objects with m[subscript AB]

Here, we present a detailed gravitational lens model of the galaxy cluster RCS2 J232727.6-020437. Due to cosmological dimming of cluster members and ICL, its high redshift (z=0.6986) makes it ideal for studying background galaxies. Using new ACS and WFC3/IR HST data, we identify 16 multiple images. From MOSFIRE follow up, we identify a strong emission line in the spectrum of one multiple image, likely confirming the redshift of that system to z=2.083. With a highly magnified (? ≳ 2) source plane area of ̃0.7 arcmin2 at z = 7, RCS2 J232727.6-020437 has a lensing efficiency comparable to the Hubble Frontier Fields clusters. We discover four highly magnified z ̃7 candidate Lyman-break galaxies behind the cluster, one of which may be multiply-imaged. Correcting for magnification, we find that all four galaxies are fainter than 0.5L*. One candidate is detected at >10? in both Spitzer/IRAC [3.6] and [4.5] channels. A spectroscopic follow-up with MOSFIRE does not result in the detection of the Lyman-alpha emission line from any of the four candidates. From the MOSFIRE spectra we place median upper limits on the Lyman-alpha flux of 5 – 14 × 10–19 ergs–1cm–2 (5?).

One of the hottest debates in astronomy and cosmology today concerns the value of the Hubble constant. This constant is of paramount importance since it fixes the size and age of the Universe. At a symposium at the Space Telescope Science Institute, experts from around the world presented the latest results from a plethora of techniques for determining the Hubble constant. The value has always been controversial, but at this meeting experts' results agreed for the first time to within about 20%. Based on the meeting, this book presents twenty-three specially written review articles. They provide a comprehensive account of the Hubble-constant debate with the latest results from gravitational lensing, supernovae and novae, the Tully-Fisher relation, the Sunyaev-Zeldovich effect, globular clusters, planetary nebulae, light echoes, and the Hubble Space Telescope Key Project. This timely volume provides a standard reference for graduate students and researchers in astronomy and cosmology.

The dawn of the first stars, galaxies and black holes signaled a fundamental milestone in our Universe’s evolution: the Epoch of Reionization. The light from these galactic ancestors began spreading out, ionizing virtually every atom in existence. Our Universe transitioned from darkness to light, from cold to hot, from simple and boring to the wondrous cosmic zoo we see around us today. Despite its importance, observations of reionization have been few, and their interpretation has been highly controversial. Fortunately, this is rapidly changing. We will soon enter the "Big Data” era of this mysterious epoch, driven by an upcoming wave of observations with state-of-the-art telescopes as well as new sophisticated analysis tools. The aim of this volume is to summarize the current status and future outlook of the reionization field. We bring together leading experts in many sub-disciplines, highlighting the measurements that will illuminate our understanding of reionization and the cosmic dawn: (i) 21cm interferometry; (ii) high-redshift quasar spectra; (iii) high-redshift galaxy surveys; (iv) primary and secondary anisotropies of the Cosmic Microwave Background; (v) high-resolution studies of the metal content of early galaxies. We seek a roadmap to interpreting the wealth of upcoming observations. What is the best use of limited observational resources? How do we develop theoretical tools tailored for each observation? Ultimately, what will we learn about the epoch of reionization and our galactic ancestors?

A coherent introduction for researchers in astronomy, particle physics, and cosmology on the formation and evolution of galaxies.