The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5• wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for the discovery of new objects. Supernova imaging observations are being acquired between September 1 and November 30 of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe II, plus a large number of photometrically identified SNe Ia, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.
We present ugriz light curves for 146 spectroscopically confirmed or spectroscopically probable Type Ia supernovae from the 2005 season of the SDSS-II Supernova survey. The light curves have been constructed using a photometric technique that we call scene modelling, which is described in detail here; the major feature is that supernova brightnesses are extracted from a stack of images without spatial resampling or convolution of the image data. This procedure produces accurate photometry along with accurate estimates of the statistical uncertainty, and can be used to derive photometry taken with multiple telescopes. We discuss various tests of this technique that demonstrate its capabilities. We also describe the methodology used for the calibration of the photometry, and present calibrated magnitudes and fluxes for all of the spectroscopic SNe Ia from the 2005 season.
Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few µs with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 σ significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 σ if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.
The ESS Design: Accelerator 6The ESS Design: Target 66The ESS Design: Controls 93The ESS Design: Conventional Facilities 109Physica ScriptaPhys. Scr. 93 (2018) 014001 (121pp) https://doi.org/10. 1088/1402-4896/aa9bff This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercialNoDerivs 3.0 licence. Content from this work may be used under the terms of the Creative Commons Attribution-NonCommercialNoDerivs 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Neutron scattering is a well-developed and extensively used means to get access to fundamental properties of biological matter as well as of physical materials. Until the end of the twentieth century that was mainly practiced with-and limited in performance by-the continuous flux of neutrons from ageing nuclear reactors (e.g. the Institut Laue-Langevin (ILL), the flagship of neutron research in Europe and in the world) [1]). Looking forward to the following two decades, an OECD report published in 1998 diagnosed the foreseeable decrease of the number of operational facilities [2] and the need to progress in performance. Considering the high scientific interest and the increasing importance of the subject for society at large, the report concluded by strongly recommending the construction of next generation neutron sources in America, Europe and Asia. Pulsed spallation neutron sources (SNS) using a proton beam power exceeding 1 MW were specifically mentioned as the most interesting high performance facilities in the future landscape of neutron laboratories.The USA was the first country to follow this advice by building the SNS in the Oak Ridge National Laboratory (ORNL) which started in 2006 [3, 4]. Japan followed in 2009 with the Japan Proton Accelerator Research Centre (J-PARC) in Tokai [5,6]. In Europe, the subject was part of a concerted effort to further develop the European world-leading largescale research infrastructures suite. In 2003, the European Strategy Forum for Research Infrastructures (ESFRI), set up by the Research Ministries of the Member States and associated countries, concluded that a 5 MW long-pulse, single target station layout with nominally 22 'public' instruments was the optimum technical reference design for an European Spallation Source (ESS) that would meet the needs of the European science community in the second quarter of the century [7].Six years later, in 2009, it materialised in a real project with the adoption of the site of Lund (Sweden). A preconstruction phase followed until the end of 2013 during which the design was finalised [8]. Construction then started with the first neutron beams planned to be available in 2019, and the ESS facility to be operational at full performance in 2025.2 Description 2.1 Principle and specifics. The high level parameters of ESS are shown in table 1. As at SNS and J-PARC, neutrons at ESS are produced by spallation, when the 2 GeV protons hit the meta...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.