119221732
The Impact of Assuming Flatness in the Determination of Neutrino Properties from Cosmological Data
Cosmological data have provided new constraints on the number of neutrino species and the neutrino mass. However these constraints depend on assumptions related to the underlying cosmology. Since a correlation is expected between the number of effective neutrinos N_{eff}, the neutrino mass \sum m_\nu, and the curvature of the universe \Omega_k, it is useful to investigate the current constraints in the framework of a non-flat universe. In this paper we update the constraints on neutrino parameters by making use of the latest cosmic microwave background (CMB) data from the ACT and SPT experiments and consider the possibility of a universe with non-zero curvature. We first place new constraints on N_{eff} and \Omega_k, with N_{eff} = 4.03 +/- 0.45 and 10^3 \Omega_k = -4.46 +/- 5.24. Thus, even when \Omega_k is allowed to vary, N_{eff} = 3 is still disfavored with 95% confidence. We then investigate the correlation between neutrino mass and curvature that shifts the 95% upper limit of \sum m_\nu < 0.45 eV to \sum m_\nu < 0.95 eV. Thus, the impact of assuming flatness in neutrino cosmology is significant and an essential consideration with future experiments.
119451601
A Search for Early Optical Emission at Gamma-Ray Burst Locations by the Solar Mass Ejection Imager (SMEI)
The Solar Mass Ejection Imager (SMEI) views nearly every point on the sky once every 102 minutes and can detect point sources as faint as R ~ 10 mag. Therefore, SMEI can detect or provide upper limits for the optical afterglow from gamma-ray bursts in the tens of minutes after the burst, when different shocked regions may emit optically. Here we provide upper limits for 58 bursts between 2003 February and 2005 April.
18104149
Galaxy Zoo 2: detailed morphological classifications for 304 122 galaxies from the Sloan Digital Sky Survey
We present the data release for Galaxy Zoo 2 (GZ2), a citizen science project with more than 16 million morphological classifications of 304 122 galaxies drawn from the Sloan Digital Sky Survey (SDSS). Morphology is a powerful probe for quantifying a galaxy's dynamical history; however, automatic classifications of morphology (either by computer analysis of images or by using other physical parameters as proxies) still have drawbacks when compared to visual inspection. The large number of images available in current surveys makes visual inspection of each galaxy impractical for individual astronomers. GZ2 uses classifications from volunteer citizen scientists to measure morphologies for all galaxies in the DR7 Legacy survey with mr > 17, in addition to deeper images from SDSS Stripe 82. While the original GZ2 project identified galaxies as early-types, late-types or mergers, GZ2 measures finer morphological features. These include bars, bulges and the shapes of edge-on disks, as well as quantifying the relative strengths of galactic bulges and spiral arms. This paper presents the full public data release for the project, including measures of accuracy and bias. The majority (≳90 per cent) of GZ2 classifications agree with those made by professional astronomers, especially for morphological T-types, strong bars and arm curvature. Both the raw and reduced data products can be obtained in electronic format at http://data.galaxyzoo.org.
31995433
Data Handling and Transfer in the LHCb Experiment
This paper focuses on the management of raw event data files containing the electronic response to particle collisions in the LHCb detector at the LHC storage ring at CERN. The typical file life cycle is presented, starting from writing of raw event streams into files to transfer to the CERN tape storage system and to the offline GRID distributed processing infrastructure. A distributed solution centered on a dedicated database is implemented to address the raw event data management needs. The solution is integrated with the data acquisition system software chain and with the experiment control system. The software architecture and hardware configurations are explained together with the testing methods, current development status and future plans.
118694154
Production of Dimuons by Pions and Protons at Fermilab
In this lecture I shall describe an experiment in progress1 at the Fermi National Accelerator Laboratory (FNAL) to study the production of μ+μ− pairs in hadron-hadron collisions. So far, we have used beams of 225 — GeV π+, π− and protons incident on carbon and tin targets for most of the data. In an earlier run, a 150 GeV positive beam was used with a beryllium target. The results I report of the 150 GeV run are final; those at 225 GeV are preliminary.
27456469
Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System
We report the discovery and confirmation of a transiting circumbinary planet (PH1b) around KIC 4862625, an eclipsing binary in the Kepler field. The planet was discovered by volunteers searching the first six Quarters of publicly available Kepler data as part of the Planet Hunters citizen science project. Transits of the planet across the larger and brighter of the eclipsing stars are detectable by visual inspection every ~137 days, with seven transits identified in Quarters 1-11. The physical and orbital parameters of both the host stars and planet were obtained via a photometric-dynamical model, simultaneously fitting both the measured radial velocities and the Kepler light curve of KIC 4862625. The 6.18 ± 0.17 R_⊕ planet orbits outside the 20 day orbit of an eclipsing binary consisting of an F dwarf (1.734 ± 0.044 R_☉, 1.528 ± 0.087 M_☉) and M dwarf (0.378 ± 0.023 R_☉, 0.408 ± 0.024 M_☉). For the planet, we find an upper mass limit of 169 M_⊕ (0.531 Jupiter masses) at the 99.7% confidence level. With a radius and mass less than that of Jupiter, PH1b is well within the planetary regime. Outside the planet's orbit, at ~1000 AU, a previously unknown visual binary has been identified that is likely bound to the planetary system, making this the first known case of a quadruple star system with a transiting planet.
60746151
LHCb data management on the computing grid
The LHCb detector is one of the four experiments being built to harness the proton-proton collisions provided by the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN). The data rate expected, when the LHC experiments are fully operational, eclipses that of any previous scientific experiments and has motivated the adoption of a grid computing paradigm to store and process the data. Managing PetaBytes of data in a distributed environment provides a rich set of challenges related to scalability, reliability and performance. This thesis will present the data management requirements for executing the workload of the LHCb collaboration. We present the systems designed that support all aspects of the grid data management for LHCb, from data transfer, to data integrity, and efficient data access. The distributed computing environment is inherently unstable and much focus has been made on providing systems that are robust and resilient to observed failures.