A Morphological and Multicolor Survey for Faint QSOs in the Groth-Westphal Strip

Quasars representative of the populous faint end of the luminosity function are frustratingly dim with m~24 at intermediate redshift; moreover groundbased surveys for such faint QSOs suffer substantial morphological contamination by compact galaxies having similar colors. In order to establish a more reliable ultrafaint QSO sample, we used the APO 3.5-m telescope to take deep groundbased U-band CCD images in fields previously imaged in V,I with WFPC2/HST. Our approach hence combines multicolor photometry with the 0.1" spatial resolution of HST, to establish a morphological and multicolor survey for QSOs extending about 2 magnitudes fainter than most extant groundbased surveys. We present results for the "Groth-Westphal Strip", in which we identify 10 high likelihood UV-excess candidates having stellar or stellar-nucleus+galaxy morphology in WFPC2. For m(606)<24.0 (roughly B<24.5) the surface density of such QSO candidates is 420 (+180,-130) per square degree, or a surface density of 290 (+160,-110) per square degree with an additional V-I cut that may further exclude compact emission line galaxies. Even pending confirming spectroscopy, the observed surface density of QSO candidates is already low enough to yield interesting comparisons: our measures agree extremely well with the predictions of several recent luminosity function models.Comment: 29 pages including 6 tables and 7 figures. As accepted for publication in The Astronomical Journal (minor revisions

A MULTI‐GENE ESTIMATE OF HIGHER‐LEVEL PHYLOGENETIC RELATIONSHIPS AMONG NIGHTJARS (AVES: CAPRIMULGIDAE)

ABSTRACT ∙ The higher‐level phylogenetic relationships of the nightjars and nighthawks (Caprimulgidae) have been challenging for traditional systematics due to their cryptic plumage and conservative morphology. We explored these relationships by combining two previously published molecular datasets with new data to generate a complete matrix (7,104 bp) of evolutionarily disparate sequence elements from four genes for 36 taxa. We analyzed each of the genes separately for base composition heterogeneity and heterozygosity. We analyzed the concatenated matrix in a likelihood framework using seven different partitioning schemes. As the number of subsets in a given partitioning scheme increased, tree length and likelihood score also increased; however, the branching topology was little affected by increasingly complex partitioning schemes. Our best maximum likelihood tree has increased bootstrap support at 13 of 30 ingroup nodes compared with previous analyses, a result likely due to doubling the length of the sequence data. Coalescent‐based species tree inference produced a tree congruent with all strongly supported nodes in the maximum likelihood tree. This topology agrees with previous molecular studies in identifying three small, early branching Old World genera (Eurostopodus, Lyncornis, and Gactornis) and four more speciose terminal clades, representing the New World nighthawks (genus Chordeiles) and three nightjar radiations centered in South America, Central America and the Old World, respectively. Increased node support across the tree reinforces a historical scenario with origins in the region surrounding the Indian Ocean, followed by diversification in the New World and subsequent recolonization and radiation in the Old World. Future work on this group should incorporate additional members of the genera Lyncornis and Eurostopodus, to determine which is the basal lineage of Caprimulgidae.RESUMEN ∙ Relaciones filogenéticas de más alto nivel de los atajacaminos (Aves: Caprimulgidae) en base a un análisis multigénico Las relaciones filogenéticas de más alto nivel de los atajacaminos y añaperos (Caprimulgidae) son un reto para la sistemática tradicional, debido a que el grupo posee morfología poco variable y plumajes crípticos. Exploramos relaciones filogenéticas en el grupo combinando dos conjuntos de datos moleculares ya publicados con nuevos datos. La matriz completa (7,104 bp) se generó con cuatro genes y 36 taxones, incluyendo marcadores con distintos modelos de evolución. Se examinó cada uno de los genes por separado para determinar heterocigosidad y heterogeneidad de la composición de bases. Se analizó la matriz concatenada en un marco de máxima verosimilitud utilizando siete particiones diferentes. La longitud de los árboles filogenéticos y su verosimilitud aumentaron a la par del número de subconjuntos en una partición particular; sin embargo, la topología del árbol varió poco entre particiones. En comparación con topologías publicadas, nuestro árbol de máxima verosimilitud tuvo mejor soporte para 13 de los 30 nodos internos, resultado que podría deberse al uso del doble de los datos de secuencias. El método de árboles de especies basado en coalescencia produjo una topología congruente con la obtenida por máxima verosimilitud. Esta topología concuerda con previos estudios moleculares, identificando tres pequeños géneros del Viejo Mundo como basales en la filogenia (Eurostopodus, Lyncornis y Gactornis), y cuatro clados terminales con más especies. Estos clados terminales representan los atajacaminos del Nuevo Mundo del género Chordeiles, y otras tres radiaciones de América del Sur, Central y del Viejo Mundo. Nuestros resultados sugieren un escenario histórico con orígenes del grupo en la región circundante al Océano Indico, seguido por la diversificación en las Américas y la posterior recolonización y radiación en el Viejo Mundo. Futuros estudios en este grupo deben incorporar miembros adicionales de los géneros Lyncornis y Eurostopodus, lo que permitirá estudiar cuál es el linaje basal de Caprimulgidae

Warm dark matter at small scales: peculiar velocities and phase space density

We study the scale and redshift dependence of the power spectra for density perturbations and peculiar velocities, and the evolution of a coarse grained phase space density for (WDM) particles that decoupled during the radiation dominated stage. The (WDM) corrections are obtained in a perturbative expansion valid in the range of redshifts at which N-body simulations set up initial conditions, and for a wide range of scales. The redshift dependence is determined by the kurtosis $\beta_2$ of the distribution function at decoupling. At large redshift there is an enhancement of peculiar velocities for $\beta_2 > 1$ that contributes to free streaming and leads to further suppression of the matter power spectrum and an enhancement of the peculiar velocity autocorrelation function at scales smaller than the free streaming scale. Statistical fluctuations of peculiar velocities are also suppressed on these scales by the same effect. In the linearized approximation, the coarse grained phase space density features redshift dependent (WDM) corrections from gravitational perturbations determined by the power spectrum of density perturbations and $\beta_2$. For $\beta_2 > 25/21$ it \emph{grows logarithmically} with the scale factor as a consequence of the suppression of statistical fluctuations. Two specific models for WDM are studied in detail. The (WDM) corrections relax the bounds on the mass.Comment: 22 pages, 9 figs, more explanations. Published versio

Snarky Signatures: Minimal Signatures of Knowledge from Simulation-Extractable SNARKs

We construct a pairing based simulation-extractable SNARK (SE-SNARK) that consists of only 3 group elements and has highly efficient verification. By formally linking SE-SNARKs to signatures of knowledge, we then obtain a succinct signature of knowledge consisting of only 3 group elements. SE-SNARKs enable a prover to give a proof that they know a witness to an instance in a manner which is: (1) succinct - proofs are short and verifier computation is small; (2) zero-knowledge - proofs do not reveal the witness; (3) simulation-extractable - it is only possible to prove instances to which you know a witness, even when you have already seen a number of simulated proofs. We also prove that any pairing based signature of knowledge or SE-NIZK argument must have at least 3 group elements and 2 verification equations. Since our constructions match these lower bounds, we have the smallest size signature of knowledge and the smallest size SE-SNARK possible

A single atom detector integrated on an atom chip: fabrication, characterization and application

We describe a robust and reliable fluorescence detector for single atoms that is fully integrated into an atom chip. The detector allows spectrally and spatially selective detection of atoms, reaching a single atom detection efficiency of 66%. It consists of a tapered lensed single-mode fiber for precise delivery of excitation light and a multi-mode fiber to collect the fluorescence. The fibers are mounted in lithographically defined holding structures on the atom chip. Neutral 87Rb atoms propagating freely in a magnetic guide are detected and the noise of their fluorescence emission is analyzed. The variance of the photon distribution allows to determine the number of detected photons / atom and from there the atom detection efficiency. The second order intensity correlation function of the fluorescence shows near-perfect photon anti-bunching and signs of damped Rabi-oscillations. With simple improvements one can boost the detection efficiency to > 95%.Comment: 24 pages, 11 figure

HST/WFPC2 morphologies and color maps of distant luminous infrared galaxies

Using HST/WFPC2 imaging in F606W (or F450W) and F814W filters, we obtained the color maps in observed frame for 36 distant (0.4<z<1.2) luminous infrared galaxies (LIRGs), with average star formation rates of ~100 M_sun/yr. Stars and compact sources are taken as references to align images after correction of geometric distortion. This leads to an alignment accuracy of 0.15 pixel, which is a prerequisite for studying the detailed color properties of galaxies with complex morphologies. A new method is developed to quantify the reliability of each pixel in the color map without any bias against very red or blue color regions.Based on analyses of two-dimensional structure and spatially resolved color distribution, we carried out morphological classification for LIRGs. About 36% of the LIRGs were classified as disk galaxies and 22% as irregulars. Only 6 (17%) systems are obvious ongoing major mergers. An upper limit of 58% was found for the fraction of mergers in LIRGs with all the possible merging/interacting systems included. Strikingly, the fraction of compact sources is as high as 25%, similar to that found in optically selected samples. From their K band luminosities, LIRGs are relatively massive systems, with an average stellar mass of about 1.1x10^11 solar mass. They are related to the formation of massive and large disks, from their morphologies and also from the fact that they represent a significant fraction of distant disks selected by their sizes. The compact LIRGs show blue cores, which could be associated with the formation of the central region of these galaxies. We suggest that there are many massive disks still forming a large fraction of their stellar mass since z=1. For most of them, their central parts (bulge?) were formed prior to the formation of their disks.Comment: 20 pages, 14 figures, accepted for publication in A&

Cypress: A High Yielding, High Quality Long-Grain Rice Variety

Cypress is a high-yielding, early-maturing, semidwarf, long-grain rice variety with excellent grain quality. This bulletin includes information on the history, characteristics, cultural management and pest reaction of Cypress.https://digitalcommons.lsu.edu/agcenter_bulletins/1011/thumbnail.jp

Identification of H2_2CCC as a diffuse interstellar band carrier

We present strong evidence that the broad, diffuse interstellar bands (DIBs) at 4881 and 5450\,\AA are caused by the B\,^1B$_1$\,$\leftarrow$\,X\,^1A$_1$ transition of H$_2$CCC (l-C$_3$H$_2$). The large widths of the bands are due to the short lifetime of the B\,^1B$_1$ electronic state. The bands are predicted from absorption measurements in a neon matrix and observed by cavity ring-down in the gas phase and show exact matches to the profiles and wavelengths of the two broad DIBs. The strength of the 5450\,\AA DIB leads to a l-C$_3$H$_2$ column density of $\sim5\times10^{14}$ cm$^{-2}$ towards HD\,183143 and $\sim2\times10^{14}$\,cm$^{-2}$ to HD\,206267. Despite similar values of $E$($B-V$), the 4881 and 5450\,\AA DIBs in HD\,204827 are less than one third their strength in HD\,183143, while the column density of interstellar C$_3$ is unusually high for HD\,204827 but undetectable for HD\,183143. This can be understood if C$_3$ has been depleted by hydrogenation to species such as l-C$_3$H$_2$ towards HD\,183143. There are also three rotationally resolved sets of triplets of l-C$_3$H$_2$ in the 6150$-$6330\,\AA region. Simulations, based on the derived spectroscopic constants and convolved with the expected instrumental and interstellar line broadening, show credible coincidences with sharp, weak DIBs for the two observable sets of triplets. The region of the third set is too obscured by the $\alpha$-band of telluric O$_2$.Comment: 22 pages, 9 figure