15934163
IceRay: An IceCube-centered Radio-Cherenkov GZK Neutrino Detector
We discuss design considerations and simulation results for IceRay, a proposed large-scale ultra-high energy (UHE) neutrino detector at the South Pole. The array is designed to detect the coherent Askaryan radio emission from UHE neutrino interactions in the ice, with the goal of detecting the cosmogenic neutrino flux with reasonable event rates. Operating in coincidence with the IceCube neutrino detector would allow complete calorimetry of a subset of the events. We also report on the status of a testbed IceRay station which incorporates both ANITA and IceCube technology and will provide year-round monitoring of the radio environment at the South Pole.
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.
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
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.
16565234
Evolution of the angular correlation function
For faint photometric surveys, our ability to quantify the clustering of galaxies has depended on interpreting the angular correlation function as a function of the limiting magnitude of the data. Because of the broad redshift distribution of galaxies at faint magnitude limits, the correlation signal has been extremely difficult to detect and interpret. Here we introduce a new technique for measuring the evolution of clustering. We utilize photometric redshifts derived from multicolor surveys to isolate redshift intervals and to calculate the evolution of the amplitude of the angular two-point correlation function. Applying these techniques to the Hubble Deep Field, we find that the shape of the correlation function at z=1 is consistent with a power law with a slope of -0.8. For z > 0.4, the best fit to the data is given by a model of clustering evolution with a comoving r -->0=2.37 h-1 Mpc and =-0.4 -->+ 0.37−0.65, which is consistent with published measures of the clustering evolution. To match the canonical value of r -->0=5.4 h-1 Mpc found for the clustering of local galaxies requires a value of =2.10 -->+ 0.43−0.64 (significantly more than linear evolution). The log likelihood of this latter fit is 4.15 times smaller than that for the r -->0=2.37 h-1 Mpc model. We, therefore, conclude that the parameterization of the clustering evolution of (1+z)-(3+) is not a particularly good fit to the data.
119343207
Slicing through multicolor space: Galaxy redshifts from broadband photometry
As a means of better understanding the evolution of optically selected galaxies we consider the distribution of galaxies within the multicolor space $U$, $B_J$, $R_F$ and $I_N$. We find that they form an almost planar distribution out to $B_J =22.5$ and $z<0.3$. The position of a galaxy within this plane is dependent on its redshift, luminosity and spectral type. While in the original $U$, $B_J$, $R_F$ and $I_N$ space these properties are highly correlated we can define an optimal rotation of the photometric axes that makes much of this information orthogonal. Fitting the observed spectroscopic redshifts with a quadratic function of the four magnitudes we show that redshifts for galaxies can be estimated to an accuracy better than $Δz =0.05$. This dispersion is due to the photometric uncertainties within the photographic data. Assuming no galaxy evolution we derive a set of simulated galaxy fluxes in the U, J, F and N passbands. Using these data we investigate how the redshift is encoded within the broadband magnitudes and the intrinsic dispersion of the photometric-redshift relation. We find that the signal that defines a galaxy's photometric redshift is not related to specific absorption or emission lines but comes from the break in the overall shape of the galaxy continuum at around 4000 A. Using high signal-to-noise photometric data we estimate that it is possible to achieve an intrinsic dispersion of less than $Δz =0.02$.
3132603
Marked correlations in galaxy formation models
The two-point correlation function has been the standard statistic for quantifying how galaxies are clustered. The statistic uses the positions of galaxies, but not their properties. Clustering as a function of galaxy property, be it type, luminosity, color, etc., is usually studied by analysing a subset of the full population, the galaxies in the subset chosen because they have a similar range of properties. We explore an alternative technique—marked correlations—in which one weights galaxies by some property or ‘mark’ when measuring clustering statistics. Marked correlations are particularly well-suited to quantifying how the properties of galaxies correlate with their environment. Therefore, measurements of marked statistics, with luminosity, stellar mass, color, star-formation rate, etc. as the mark, permit sensitive tests of galaxy formation models. We make measurements of such marked statistics in semi-analytic galaxy formation models to illustrate their utility. These measurements show that close pairs of galaxies are expected to be red, to have larger stellar masses, and to have smaller star formation rates. We also show that the simplest unbiased estimator of the particular marked statistic we use extensively is very simple to measure—it does not require construction of a random catalog—and provide an estimate of its variance. Large wide-field surveys of the sky are revolutionizing our view of galaxies and how they evolve. Our results indicate that application of marked statistics to this high quantity of high-quality data will provide a wealth of information about galaxy formation.
2752138
A pilot survey of H I in field galaxies at redshift z ~ 0.2
We present the first results of a targeted survey carried out with the 305 m Arecibo telescope to detect H I line emission from galaxies at redshift z > 0.16. The targets, selected from the Sloan Digital Sky Survey database, are noninteracting disk galaxies in relatively isolated fields. We present here the H I spectra and derived H I parameters for 10 objects detected in this pilot program. All are massive disk galaxies in the redshift interval 0.17-0.25 (i.e., 2-3 Gyr look-back time), with H I masses MH I = (3-8) × 1010 M☉ and high gas mass fractions (H I-to-stellar mass ratios ~ 10%-30%). Our results demonstrate the efficacy of exploiting Arecibo's large collecting area to measure the H I mass and rotational velocity of galaxies above redshift z = 0.2. In particular, this sample includes the highest redshift detections of H I emission from individual galaxies made to date. Extension of this pilot program will allow us to study the H I properties of field galaxies at cosmological distances, thus complementing ongoing radio synthesis observations of cluster samples at z ~ 0.2.
16921302
Toward a resolution of the discrepancy between different estimators of star formation rate
Different wavelength regimes and methods for estimating the space density of the star formation rate (SFR) result in discrepant values. While it is recognized that ultraviolet (UV) and Hα emission-line data must be corrected for the effects of extinction, the magnitude of the required correction is uncertain. Even when these corrections are made there remains a significant discrepancy between SFRs derived from UV and Hα measurements compared with those derived from far-infrared (FIR) and radio luminosities. Since the FIR-radio–derived SFRs are not affected by extinction and simple corrections to reconcile the UV and Hα measurement with these do not fully account for the discrepancies, a more sophisticated correction may be required. Recent results suggest that at least part of the solution may be a form of extinction that increases with increasing SFR (or luminosity, given the common assumption that SFR is proportional to luminosity). We present an analysis of the effects of a dust reddening dependent on star formation rate applied to estimators of SFR. We show (1) that the discrepancies between Hα and FIR-radio SFR estimates may be explained by such an effect and we present an iterative method for applying the correction and (2) that UV-based estimates of SFR are harder to reconcile with FIR-radio estimates using this method, although the extent of the remaining discrepancy is less than for a non-SFR–dependent correction. Particularly at high redshift, our understanding of extinction at UV wavelengths may require a still more complex explanation.