126012638
Studies of hadron-electron separators for the ZEUS barrel calorimeter
Abstract Two possible upgrades, a shower maximum detector and a presampler, designed to improve the low energy electron/hadron separation capabilities of the ZEUS barrel calorimeter are described and test-beam results are reported. The presampler can also be used to correct for energy loss of particles traversing the dead material in front of the calorimeter.
119123041
Observational constraints on the ultrahigh energy cosmic neutrino flux from the second flight of the ANITA experiment
The Antarctic Impulsive Transient Antenna (ANITA) completed its second Long Duration Balloon flight in January 2009, with 31 days aloft (28.5 live days) over Antarctica. ANITA searches for impulsive coherent radio Cherenkov emission from 200 to 1200 MHz, arising from the Askaryan charge excess in ultrahigh energy neutrino-induced cascades within Antarctic ice. This flight included significant improvements over the first flight in payload sensitivity, efficiency, and flight trajectory. Analysis of in-flight calibration pulses from surface and subsurface locations verifies the expected sensitivity. In a blind analysis, we find 2 surviving events on a background, mostly anthropogenic, of 0.97{+-}0.42 events. We set the strongest limit to date for 10{sup 18}-10{sup 21} eV cosmic neutrinos, excluding several current cosmogenic neutrino models.
119205836
Status of SalSA
We report on the status of the Salt Sensor Array (SalSA), a proposed experiment for detecting ultra-high energy neutrinos through the radio \v{C}erenkov technique with an array of radio-microwave antennas embedded in a large, naturally occurring salt formation. We review the measurements to date aimed at assessing SalSA's feasibility, including a return visit of the Hockley Salt Mine in Hockley, Texas, and discuss the current status of the project.
19032720
Search for MSSM Higgses at the Tevatron
We present an overview of searches for MSSM Higgs at the Tevatron, concentrating on searches probing the high tan {beta} region. We discuss the search for A/H {yields} {tau}{tau} which is soon to be completed in the Run I data and review the new tau triggers implemented by CDF and D0 in Run II, which will greatly impact this analysis. We also present the results of a Run I search for A/Hbb {yields} bbbb performed by CDF and highlight expected improvements in this channel by both experiments in Run II.
122312631
Design and initial performance of the Askaryan Radio Array prototype EeV neutrino detector at the South Pole
Abstract We report on studies of the viability and sensitivity of the Askaryan Radio Array (ARA), a new initiative to develop a Teraton-scale ultra-high energy neutrino detector in deep, radio-transparent ice near Amundsen-Scott station at the South Pole. An initial prototype ARA detector system was installed in January 2011, and has been operating continuously since then. We describe measurements of the background radio noise levels, the radio clarity of the ice, and the estimated sensitivity of the planned ARA array given these results, based on the first five months of operation. Anthropogenic radio interference in the vicinity of the South Pole currently leads to a few-percent loss of data, but no overall effect on the background noise levels, which are dominated by the thermal noise floor of the cold polar ice, and galactic noise at lower frequencies. We have also successfully detected signals originating from a 2.5 km deep impulse generator at a distance of over 3 km from our prototype detector, confirming prior estimates of kilometer-scale attenuation lengths for cold polar ice. These are also the first such measurements for propagation over such large slant distances in ice. Based on these data, ARA-37, the ∼200 km 2 array now in its initial construction phase, will achieve the highest sensitivity of any planned or existing neutrino detector in the 10 16 –10 19  eV energy range.
34851507
Constraints on Cosmic Neutrino Fluxes from the ANITA Experiment
P. F. Dowkontt, 4 M. A. DuVernois,5 P. A. Evenson, 6 D. Goldstein, 1 P. W. Gorham, 9 C. L. Hebert, 9 M. H. Israel,4 J. G. Learned, 9 K. M. Liewer,10 J. T. Link,9 S. Matsuno, 9 P. Miočinović,9 J. Nam, 1 C. J. Naudet, 10 R. Nichol,2 K. Palladino, 2 M. Rosen, 9 D. Saltzberg, 7 D. Seckel, 6 A. Silvestri,1 B. T. Stokes, 9 G. S. Varner, 9 and F. Wu1 1Department of Physics and Astronomy, University of California at Irvine, Irvine, California 2Department of Physics, Ohio State University, Columbus, Ohio 3Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 4Department of Physics, Washington University in St. Louis, St. Louis, Missouri 5School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 6Bartol Research Institute, University of Delaware, Newark, Delaware 7Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 8Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, Pennsylvania 9Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 10Jet Propulsion Laboratory, Pasadena, California
118985428
Three-Point Correlation Functions of SDSS Galaxies in Redshift Space: Morphology, Color, and Luminosity Dependence
We present measurements of the redshift-space three-point correlation function of galaxies in the Sloan Digital Sky Survey (SDSS). For the first time, we analyze the dependence of this statistic on galaxy morphology, color, and luminosity. In order to control systematics due to selection effects, we used r-band, volume-limited samples of galaxies, constructed from magnitude-limited SDSS data (14.5 <r< 17.5), and further divided the samples into two morphological types (early and late) or two color populations (red and blue). The three-point correlation function of SDSS galaxies follows the hierarchical relation well, and the reduced three-point amplitudes in redshift-space are almost scale-independent (Qz =0 .5 ∼ 1.0). In addition, their dependence on the morphology, color, and luminosity is not statistically significant. Given the robust morphological, color, and luminosity dependences of the two-point correlation function, this implies that galaxy biasing is complex on weakly non-linear to non-linear scales. We show that a simple deterministic linear relation with the underlying mass could not explain our measurements on these scales.
14811276
Computational AstroStatistics: Fast and Efficient Tools for Analysing Huge Astronomical Data Sources
I present here a review of past and present multi-disciplinary research of the Pittsburgh Computational AstroStatistics2 (PiCA) group. This group is dedicated to developing fast and efficient statistical algorithms for analysing huge astronomical data sources. I begin with a short review of multi-resolutional kd-trees which are the building blocks for many of our algorithms. For example, quick range queries and fast N-point correlation functions. I will present new results from the use of Mixture Models (Connolly et al. 2000) in density estimation of multi-color data from the Sloan Digital Sky Survey (SDSS). Specifically, the selection of quasars and the automated identification of X-ray sources. I will also present a brief overview of the False Discovery Rate (FDR) procedure (Miller et al. 2001a) and show how it has been used in the detection of “Baryon Wiggles” in the local galaxy power spectrum and source identification in radio data. Finally, I will look forward to new research on an automated Bayes Network anomaly detector and the possible use of the Locally Linear Embedding algorithm (LLE; Roweis & Saul 2000) for spectral classification of SDSS spectra.
117845595
Eigenspectra of the SDSS DR1 quasars
We construct eigenspectra from the DR1 quasars in the SDSS using the Karhunen-Lo\`eve (KL) transform (or Principal Component Analysis, PCA) in different redshift and luminosity bins. We find that the quasar spectra can be classified, by the first two eigenspectra, into a continuous sequence in the variation of the spectral slope. We also find a dependence on redshift and luminosity in the eigencoefficients. The dominant redshift effect is the evolution of the blended Fe~II emission (optical) and the Balmer continuum (the ``small-bump'', $\lambda_{rest} \approx 2000-4000$\AA), while the luminosity effect is related to the Baldwin effect. Correlations among several major broad emission lines are found, including the well-known ``Eigenvector-1''.
11979776
High redshift detection of the integrated Sachs-Wolfe effect
We present evidence of a large angle correlation between the cosmic microwave background measured by WMAP and a catalog of photometrically detected quasars from the SDSS. The observed cross correlation is 0.30{+-}0.14 {mu}K at zero lag, with a shape consistent with that expected for correlations arising from the integrated Sachs-Wolfe effect. The photometric redshifts of the quasars are centered at z{approx}1.5, making this the deepest survey in which such a correlation has been observed. Assuming this correlation is due to the ISW effect, this constitutes the earliest evidence yet for dark energy and it can be used to constrain exotic dark energy models.
119051388
Luminosity Functions From Photometric Redshifts. I. Techniques
The determination of the galaxy luminosity function is an active and fundamental field in observational cosmology. In this paper we propose a cost effective way of measuring galaxy luminosity functions at faint magnitudes. Our technique employs the use of galaxy redshifts estimated from their multicolor photometry (Connolly et al. 1995). Associated with the redshift estimate is a well defined error distribution. We have derived a variant of Lynden-Bell's (1971) C--method that considers, for each galaxy, the probability distribution in absolute magnitude resultant from the redshift error. This technique is tested through simulations and potential biases are quantified. We then apply the technique to a sample of galaxies with multicolor photometric data at moderately faint (B=23) limits, and compare the results to a subset of these data with spectroscopic redshifts. We find that the luminosity function derived from the photometric redshifts is consistent with that determined from spectroscopic redshifts.