16975620
The radio Cherenkov technique for ultra-high energy neutrino detection
I review the status of the radio Cherenkov detection technique in searches for ultra-high energy (UHE) neutrinos of cosmic origin. After outlining the physics motivations for UHE neutrino searches, I give an overview of the status of current and proposed experiments in the field.
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.
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.
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.
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.
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
17940543
Five High-Redshift Quasars Discovered in Commissioning Imaging Data of the Sloan Digital Sky Survey*
We report the discovery of five quasars with redshifts of 4.67–5.27 and z'-band magnitudes of 19.5–20.7 (MB ~ -27). All were originally selected as distant quasar candidates in optical/near-infrared photometry from the Sloan Digital Sky Survey (SDSS), and most were confirmed as probable high-redshift quasars by supplementing the SDSS data with J and K measurements. The quasars possess strong, broad Lyα emission lines, with the characteristic sharp cutoff on the blue side produced by Lyα forest absorption. Three quasars contain strong, broad absorption features, and one of them exhibits very strong N V emission. The amount of absorption produced by the Lyα forest increases toward higher redshift, and that in the z = 5.27 object (DA ≈ 0.7) is consistent with a smooth extrapolation of the absorption seen in lower redshift quasars. The high luminosity of these objects relative to most other known objects at z 5 makes them potentially valuable as probes of early quasar properties and of the intervening intergalactic medium.
15573911
The shape of the SDSS DR5 galaxy power spectrum
We present a Fourier analysis of the clustering of galaxies in the combined Main galaxy and Luminous Red Galaxy (LRG) Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) sample. The aim of our analysis is to consider how well we can measure the cosmological matter density using the signature of the horizon at matter-radiation equality embedded in the large-scale power spectrum. The new data constrains the power spectrum on scales 100--600h^-1Mpc with significantly higher precision than previous analyses of just the SDSS Main galaxies, due to our larger sample and the inclusion of the LRGs. This improvement means that we can now reveal a discrepancy between the shape of the measured power and linear CDM models on scales 0.01<k<0.15hMpc^-1, with linear model fits favouring a lower matter density (Omega_m=0.22+/-0.04) on scales 0.01<k<0.06hMpc^-1 and a higher matter density (Omega_m=0.32+/-0.01) when smaller scales are included, assuming a flat LCDM model with h=0.73 and n_s=0.96. This discrepancy could be explained by scale-dependent bias and, by analysing subsamples of galaxies, we find that the ratio of small-scale to large-scale power increases with galaxy luminosity, so all of the SDSS galaxies cannot trace the same power spectrum shape over 0.01<k<0.2hMpc^-1. However, the data are insufficient to clearly show a luminosity-dependent change in the largest scale at which a significant increase in clustering is observed, although they do not rule out such an effect. Significant scale-dependent galaxy bias on large-scales, which changes with the r-band luminosity of the galaxies, could potentially explain differences in our Omega_m estimates and differences previously observed between 2dFGRS and SDSS power spectra and the resulting parameter constraints.
119393423
SDSS-RASS: Next Generation of Cluster-Finding Algorithms.
We outline here the next generation of cluster-finding algorithms. We show how advances in Computer Science and Statistics have helped develop robust, fast algorithms for finding clusters of galaxies in large multi-dimensional astronomical databases like the Sloan Digital Sky Survey (SDSS). Specifically, this paper presents four new advances: (1) A new semi-parametric algorithm - nicknamed "C4" - for jointly finding clusters of galaxies in the SDSS and ROSAT All-Sky Survey databases; (2) The introduction of the False Discovery Rate into Astronomy; (3) The role of kernel shape in optimizing cluster detection; (4) A new determination of the X-ray Cluster Luminosity Function which has bearing on the existence of a "deficit" of high redshift, high luminosity clusters. This research is part of our "Computational AstroStatistics" collaboration (see Nichol et al. 2000) and the algorithms and techniques discussed herein will form part of the "Virtual Observatory" analysis toolkit.
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.
119506600
Physical evidence for dark energy
The authors present measurements of the angular cross-correlation between luminous red galaxies from the Sloan Digital Sky Survey and the cosmic microwave background temperature maps from the Wilkinson Microwave Anisotropy Probe. They find a statistically significant achromatic positive correlation between these two data sets, which is consistent with the expected signal from the late Integrated Sachs-Wolfe (ISW) effect. they do not detect any anti-correlation on small angular scales as would be produced from a large Sunyaev-Zel'dovich (SZ) effect, although they do see evidence for some SZ effect for their highest redshift samples. Assuming a flat universe, their preliminary detection of the ISW effect provides independent physical evidence for the existence of dark energy.