Spectroscopic Properties of the z=4.5 Lyman-alpha Emitters

We present Keck/LRIS optical spectra of 17 Lya-emitting galaxies and one Lyman break galaxy at z=4.5 discovered in the Large Area Lyman Alpha (LALA) survey. The survey has identified a sample of ~350 candidate Lya-emitting galaxies at z=4.5 in a search volume of 1.5 x 10^6 comoving Mpc^3. We targeted 25 candidates for spectroscopy; hence, the 18 confirmations presented herein suggest a selection reliability of 72%. The large equivalent widths (median W(rest)~80 A) but narrow physical widths (v < 500 km/s) of the Lya emission lines, along with the lack of accompanying high-ionization state emission lines, suggest that these galaxies are young systems powered by star formation rather than by AGN activity. Theoretical models of galaxy formation in the primordial Universe suggest that a small fraction of Lya-emitting galaxies at z=4.5 may still be nascent, metal-free objects. Indeed, we find with 90% confidence that 3 to 5 of the confirmed sources show W(rest) > 240 A, exceeding the maximum Lya equivalent width predicted for normal stellar populations. Nonetheless, we find no evidence for HeII 1640 emission in either individual or composite spectra, indicating that though these galaxies are young, they are not truly primitive, Population III objects.Comment: 12 pages, Accepted to Ap

Spectroscopic Confirmation of Three Redshift 5.7 Lyman-alpha Emitters from the Large Area Lyman Alpha Survey

Narrow-band searches for Lyman alpha emission are an efficient way of identifying star-forming galaxies at high redshifts. We present Keck telescope spectra confirming redshifts z = 5.7 for three objects discovered in the Large Area Lyman Alpha (LALA) survey at Kitt Peak National Observatory. All three spectra show strong, narrow emission lines with the asymmetric profile that is characteristically produced in high redshift Lyman alpha emitters by preferential HI absorption in the blue wing of the line. These objects are undetected in deep Bw, V, R, and 6600A narrow-band images from the NOAO Deep Wide-Field Survey and from LALA, as expected from Lyman break and Lyman alpha forest absorption at redshift z = 5.7. All three objects show large equivalent widths (>= 150A in the rest-frame), suggesting at least one of the following: a top-heavy initial mass function, very low stellar metallicity, or the presence of an active nucleus. We consider the case for an active nucleus to be weak in all three objects due to the limited width of the Lyman alpha emission line (< 500 km/s) and the absence of any other indicator of quasar activity. The three confirmed high redshift objects were among four spectroscopically observed targets drawn from the sample of 18 candidates presented by Rhoads and Malhotra (2001). Thus, these spectra support the Lyman alpha emitter population statistics from our earlier photometric study, which imply little evolution in number density from z=5.7 to z=4.5 and provide strong evidence that the reionization redshift is greater than 5.7.Comment: Submitted to AJ, June 2002. 15 pages, AASTe

A many-analysts approach to the relation between religiosity and well-being

The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N=10,535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β=0.120). For the second research question, this was the case for 65% of the teams (median reported β=0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

A Many-analysts Approach to the Relation Between Religiosity and Well-being

The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N = 10, 535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β = 0.120). For the second research question, this was the case for 65% of the teams (median reported β = 0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

On the canonical components of character varieties of hyperbolic 2-bridge link complements

textThis dissertation concerns the study of canonical components of the SL(2, C) character varieties of hyperbolic 3-manifolds. Although character varieties have proven to be a useful tool in studying hyperbolic 3-manifolds, very little is known about their structure. Chapter 1 provides background on this subject. Chapter 2 is dedicated to the canonical component of the Whitehead link. We provide a projective model and show that this model is isomorphic to P^2 blown up at 10 points. The Whitehead link can be realized as 1/1 Dehn surgery on one cusp of both the Borromean rings and the 3-chain link. In Chapter 3 we examine the canonical components for the two families of hyperbolic link complements obtained by 1/n Dehn filling on one component of both the Borromean rings and the 3-chain link. These examples extend the work of Macasieb, Petersen and van Luijk who have studied the character varieties associated to the twist knot complements. We conjecture that the canonical components for the links obtained by 1/n Dehn filling on one component of the 3-chain link are all rational surfaces isomorphic to P^2 blown up at 9n + 1 points. A major goal is to understand how the algebro-geometric structure of these varieties reflects the topological structure of the associated manifolds. At the end of Chapter 3 we discuss common features of these examples and explain how our results lend insight into the affect Dehn surgery has on the character variety. We conclude, in Chapter 4, with a description of possible directions for future research.Mathematic

Geeks, rebels and prom queens : the risky business of perpetuating the capitalist family in 1980s high school genre films

When I was growing up, I wanted nothing more in the world than to be a character in a 1980s high school film. The characters in these films had the coolest of everything: cars, clothes, dance moves. Their parents went away on European vacations and left them at home. They trashed huge mansions without a second thought. Of course, all of that was only true on one side of the deeply divided socio-economic landscape. Onthe other side, cute rebels worked on their motorcycles while pouty girls designed clothesthat were cooler than what the rest of the kids were wearing. I was willing to exist on either side of this great divide. I could have been friendly with the rich kids, with their parties and sports cars, but I was equally enticed by the creativity, honor and drive that the working class kids seemed to represent. It is only now, as I look back to the characters I so admired, that I begin to ask some questions about my favorite films. Why were so many teenagers in these films virtually abandoned by their parents? Why were so many cars destroyed and dresses mangled? Why was romance, but only heterosexual romance, such an essential component to every film? Why did working class characters have different rules for success than their middle class counterparts? In essence, why are the rules of a 1980s high school genre film set the way that they are

Tuning Electrogenerated Chemiluminescence Intensity Enhancement Using Hexagonal Lattice Arrays of Gold Nanodisks

7 pags., 4 figs.Electrogenerated chemiluminescence (ECL) mi- croscopy shows promise as a technique for mapping chemical reactions on single nanoparticles. The technique¿s spatial resolution is limited by the quantum yield of the emission and the diffusive nature of the ECL process. To improve signal intensity, ECL dyes have been coupled with plasmonic nano- particles, which act as nanoantennas. Here, we characterize the optical properties of hexagonal arrays of gold nanodisks and how they impact the enhancement of ECL from the coreaction of tris(2,2¿-bipyridyl)dichlororuthenium(II) hexahydrate and tripro- pylamine. We find that varying the lattice spacing results in a 23- fold enhancement of ECL intensity because of increased dye-array near-field coupling as modeled using finite element method simulations.This work was primarily supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, CPIMS Program under Award #DE-339SC0016534. We also acknowledge funding from the Robert A. Welch Foundation (Grant C-1787 to C.F.L. and Grant C-1664 to S.L.) We would like to thank support from the U.S. National Science Foundation (Grant ECCS-1710697) and Ministerio de Ciencia, Innovación y Universidades of Spain (Grant TEM-FLU PID2019-109502GA-I00), as well as the UNM Center for Advanced Research Computing, for providing the part of the computational resources used in this work. We also thank Grants-in-Aid for Scientific Research (JP 16H06506) from MEXT, and the Photoexcitonix Project of Hokkaido University

High-Throughput Screening of Optical Properties of Glass-Supported Plasmonic Nanoparticles Fabricated by Polymer Pen Lithography

Optical applications of plasmonic nanoparticles depend critically on particle properties such as relative proximity, composition, crystallinity, and shape. The most common nanoparticle fabrication techniques, colloidal synthesis and electron beam lithography, allow the tailoring of some of these parameters, yet do not provide control over all of them. Scanning probe block copolymer lithography (SPBCL), a technique that grows nanoparticles on substrates from precisely deposited precursor droplets, merges the advantages of colloidal synthesis and electron beam lithography, and offers high throughput, precise particle positioning, and composition control. A few challenges with the SBCL method remain: fabrication of optically relevant particle sizes on optically transparent supports, and detailed correlation of their optical and morphological properties. Here, we adapt SPBCL to fabricate large arrays of gold nanoparticles on glass supports. The resulting nanoparticles have varying shapes, and at ∼100 nm in diameter, they support strong plasmon resonances. In order to fully exploit the high-throughput fabrication method, we designed an automated dark-field microscope and correlated the optical behavior to the mechanical properties as determined through electron and pump–probe microscopy. We find that the SPBCL-synthesized nanoparticles are highly crystalline, supporting both plasmon oscillations and mechanical vibrations with lifetimes comparable to colloidal nanospheres. Our work highlights SPBCL as a promising and versatile synthesis approach for plasmonic nanoparticles, leading the way toward extensive screening capabilities for optical properties and hence improved potential applications