| 1. |
- Abolfathi, Bela, et al.
(författare)
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The LSST DESC DC2 Simulated Sky Survey
- 2021
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 253:31
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Tidskriftsartikel (refereegranskat)abstract
- We describe the simulated sky survey underlying the second data challenge (DC2) carried out in preparation for analysis of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) by the LSST Dark Energy Science Collaboration (LSST DESC). Significant connections across multiple science domains will be a hallmark of LSST; the DC2 program represents a unique modeling effort that stresses this interconnectivity in a way that has not been attempted before. This effort encompasses a full end-to-end approach: starting from a large N-body simulation, through setting up LSST-like observations including realistic cadences, through image simulations, and finally processing with Rubin's LSST Science Pipelines. This last step ensures that we generate data products resembling those to be delivered by the Rubin Observatory as closely as is currently possible. The simulated DC2 sky survey covers six optical bands in a wide-fast-deep area of approximately 300 deg2, as well as a deep drilling field of approximately 1 deg2. We simulate 5 yr of the planned 10 yr survey. The DC2 sky survey has multiple purposes. First, the LSST DESC working groups can use the data set to develop a range of DESC analysis pipelines to prepare for the advent of actual data. Second, it serves as a realistic test bed for the image processing software under development for LSST by the Rubin Observatory. In particular, simulated data provide a controlled way to investigate certain image-level systematic effects. Finally, the DC2 sky survey enables the exploration of new scientific ideas in both static and time domain cosmology.
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| 2. |
- Bellm, Eric C., et al.
(författare)
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The Zwicky Transient Facility : System Overview, Performance, and First Results
- 2019
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Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 131:995
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Tidskriftsartikel (refereegranskat)abstract
- The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg(2) field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF's public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope.
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| 3. |
- Bianco, Federica B., et al.
(författare)
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Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time : A Pioneering Process of Community-focused Experimental Design
- 2022
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 258:1
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Tidskriftsartikel (refereegranskat)abstract
- Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to conduct a multipurpose 10 yr optical survey of the Southern Hemisphere sky: the Legacy Survey of Space and Time. Significant flexibility in survey strategy remains within the constraints imposed by the core science goals of probing dark energy and dark matter, cataloging the solar system, exploring the transient optical sky, and mapping the Milky Way. The survey's massive data throughput will be transformational for many other astrophysics domains and Rubin's data access policy sets the stage for a huge community of potential users. To ensure that the survey science potential is maximized while serving as broad a community as possible, Rubin Observatory has involved the scientific community at large in the process of setting and refining the details of the observing strategy. The motivation, history, and decision-making process of this strategy optimization are detailed in this paper, giving context to the science-driven proposals and recommendations for the survey strategy included in this Focus Issue.
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| 4. |
- Filipcic, Igor, et al.
(författare)
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Efficacy of repetitive transcranial magnetic stimulation using a figure-8-coil or an H1-Coil in treatment of major depressive disorder; A randomized clinical trial
- 2019
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Ingår i: Journal of Psychiatric Research. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0022-3956 .- 1879-1379. ; 114, s. 113-119
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Tidskriftsartikel (refereegranskat)abstract
- Repetitive transcranial magnetic stimulation (rTMS) is an evidence-based treatment option for major depressive disorder (MDD). However, comparisons of efficacy between the two FDA-approved protocols of rTMS modalities are lacking. The aim of this industry-independent, randomized-controlled, single-blind trial was to evaluate clinical outcome of the two FDA-approved rTMS protocols delivered by H1-coil and the figure-8-coil, in MDD patients. A total of 228 MDD patients were randomized to 20 sessions of H1-coil or 8-coil as an adjunct to standard-of-care pharmacotherapy, or standard-of-care pharmacotherapy alone. Baseline MDD symptom severity was almost the same in the three groups. Hamilton depression rating scale (HAM-D17) mean score was 17 (5.3) in H1-coil, 17 (5.4) in 8-coil, and 19 (6.1) in control group. The primary outcome was the proportion of patients achieving remission defined as HAM-D17 score amp;lt;= 7 at end-of-treatment at week-4. In the intention-to-treat analysis odds ratio for remission was 1.74 (CI95% 0.79-3.83) in H1-coil compared to the 8-coil group. The difference between two rTMS protocols was not significant. Remission rate was significantly greater in both HF-rTMS groups compared to the control: 60% (CI95% 48-71%), 43% (C195% 31-55%) and 11% (CI95% 5-20%) respectively. The response was significantly better in H1-coil, than in 8-coil group OR = 2.33; CI95% 1.04-5.21 (P = 0.040). The HAM-D17 was lowered by 59% in the H1-coil, 41% in the 8-coil (P = 0.048), and 17% in the control group (P amp;lt; 0.001 vs H1-coil; P = 0.003 vs 8-coil). Safety, tolerability, and the changes in quality of life were comparable. We confirmed the safety and efficacy of both FDA-approved protocols as adjunctive treatments of MDD. Better response rate and greater reduction of depression severity were observed in the H1-coil group, but without a significant difference in the remission rate between the two rTMS modalities.
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| 5. |
- Ivezić, Željko, et al.
(författare)
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LSST : From Science Drivers to Reference Design and Anticipated Data Products
- 2019
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 873:2
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Tidskriftsartikel (refereegranskat)abstract
- We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the solar system, exploring the transient optical sky, and mapping the Milky Way. LSST will be a large, wide-field ground-based system designed to obtain repeated images covering the sky visible from Cerro Pachon in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg(2) field of view, a 3.2-gigapixel camera, and six filters (ugrizy) covering the wavelength range 320-1050 nm. The project is in the construction phase and will begin regular survey operations by 2022. About 90% of the observing time will be devoted to a deep-wide-fast survey mode that will uniformly observe a 18,000 deg(2) region about 800 times (summed over all six bands) during the anticipated 10 yr of operations and will yield a co-added map to r similar to 27.5. These data will result in databases including about 32 trillion observations of 20 billion galaxies and a similar number of stars, and they will serve the majority of the primary science programs. The remaining 10% of the observing time will be allocated to special projects such as Very Deep and Very Fast time domain surveys, whose details are currently under discussion. We illustrate how the LSST science drivers led to these choices of system parameters, and we describe the expected data products and their characteristics.
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