286 results on '"Marshall, Phil"'
Search Results
2. Report of the Topical Group on Dark Energy and Cosmic Acceleration: Complementarity of Probes and New Facilities for Snowmass 2021
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Flaugher, Brenna, Miranda, Vivian, Schlegel, David J., Anderson, Adam J., Andrade-Oliveira, Felipe, Baxter, Eric J., Bender, Amy N., Bleem, Lindsey E., Chang, Chihway, Chang, Clarence C., Chen, Thomas Y., Dawson, Kyle S., Digel, Seth W., Drlica-Wagner, Alex, Ferraro, Simone, Garcia, Alyssa, Heitmann, Katrin, Kim, Alex G., Linder, Eric V., Mandal, Sayan, Mandelbaum, Rachel, Marshall, Phil, Meyers, Joel, Newburgh, Laura, Nugent, Peter E., Palmese, Antonella, Pereira, M. E. S., Sehgal, Neelima, White, Martin, and Zhang, Yuanyuan
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,High Energy Physics - Experiment - Abstract
The mechanism(s) driving the early- and late-time accelerated expansion of the Universe represent one of the most compelling mysteries in fundamental physics today. The path to understanding the causes of early- and late-time acceleration depends on fully leveraging ongoing surveys, developing and demonstrating new technologies, and constructing and operating new instruments. This report presents a multi-faceted vision for the cosmic survey program in the 2030s and beyond that derives from these considerations. Cosmic surveys address a wide range of fundamental physics questions, and are thus a unique and powerful component of the HEP experimental portfolio., Comment: Submitted to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021); Topical Group Report for CF06 (Cosmic Frontier Topical Group on Dark Energy and Cosmic Acceleration: Complementarity of Probes and New Facilities
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- 2022
3. Snowmass2021 Cosmic Frontier White Paper: Rubin Observatory after LSST
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Blum, Bob, Digel, Seth W., Drlica-Wagner, Alex, Habib, Salman, Heitmann, Katrin, Ishak, Mustapha, Jha, Saurabh W., Kahn, Steven M., Mandelbaum, Rachel, Marshall, Phil, Newman, Jeffrey A., Roodman, Aaron, and Stubbs, Christopher W.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,High Energy Physics - Phenomenology - Abstract
The Vera C. Rubin Observatory will begin the Legacy Survey of Space and Time (LSST) in 2024, spanning an area of 18,000 square degrees in six bands, with more than 800 observations of each field over ten years. The unprecedented data set will enable great advances in the study of the formation and evolution of structure and exploration of physics of the dark universe. The observations will hold clues about the cause for the accelerated expansion of the universe and possibly the nature of dark matter. During the next decade, LSST will be able to confirm or dispute if tensions seen today in cosmological data are due to new physics. New and unexpected phenomena could confirm or disrupt our current understanding of the universe. Findings from LSST will guide the path forward post-LSST. The Rubin Observatory will still be a uniquely powerful facility even then, capable of revealing further insights into the physics of the dark universe. These could be obtained via innovative observing strategies, e.g., targeting new probes at shorter timescales than with LSST, or via modest instrumental changes, e.g., new filters, or through an entirely new instrument for the focal plane. This White Paper highlights some of the opportunities in each scenario from Rubin observations after LSST., Comment: Contribution to Snowmass 2021
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- 2022
4. Rubin-Euclid Derived Data Products: Initial Recommendations
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Guy, Leanne P., Cuillandre, Jean-Charles, Bachelet, Etienne, Banerji, Manda, Bauer, Franz E., Collett, Thomas, Conselice, Christopher J., Eggl, Siegfried, Ferguson, Annette, Fontana, Adriano, Heymans, Catherine, Hook, Isobel M., Aubourg, Éric, Aussel, Hervé, Bosch, James, Carry, Benoit, Hoekstra, Henk, Kuijken, Konrad, Lanusse, Francois, Melchior, Peter, Mohr, Joseph, Moresco, Michele, Nakajima, Reiko, Paltani, Stéphane, Troxel, Michael, Allevato, Viola, Amara, Adam, Andreon, Stefano, Anguita, Timo, Bardelli, Sandro, Bechtol, Keith, Birrer, Simon, Bisigello, Laura, Bolzonella, Micol, Botticella, Maria Teresa, Bouy, Hervé, Brinchmann, Jarle, Brough, Sarah, Camera, Stefano, Cantiello, Michele, Cappellaro, Enrico, Carlin, Jeffrey L., Castander, Francisco J, Castellano, Marco, Chari, Ranga Ram, Chisari, Nora Elisa, Collins, Christopher, Courbin, Frédéric, Cuby, Jean-Gabriel, Cucciati, Olga, Daylan, Tansu, Diego, Jose M., Duc, Pierre-Alain, Fotopoulou, Sotiria, Fouchez, Dominique, Gavazzi, Raphaël, Gruen, Daniel, Hatfield, Peter, Hildebrandt, Hendrik, Landt, Hermine, Hunt, Leslie K., Ibata, Rodrigo, Ilbert, Olivier, Jasche, Jens, Joachimi, Benjamin, Joseph, Rémy, Kotak, Rubina, Laigle, Clotilde, Lançon, Ariane, Larsen, Søren S., Lavaux, Guilhem, Leclercq, Florent, Leonard, C. Danielle, von der Linden, Anja, Liu, Xin, Longo, Giuseppe, Magliocchetti, Manuela, Maraston, Claudia, Marshall, Phil, Martín, Eduardo L., Mattila, Seppo, Maturi, Matteo, McCracken, Henry Joy, Metcalf, R. Benton, Montes, Mireia, Mortlock, Daniel, Moscardini, Lauro, Narayan, Gautham, Paolillo, Maurizio, Papaderos, Polychronis, Pello, Roser, Pozzetti, Lucia, Radovich, Mario, Rejkuba, Marina, Román, Javier, Sánchez-Janssen, Rubén, Sarpa, Elena, Sartoris, Barbara, Schrabback, Tim, Sluse, Dominique, Smartt, Stephen J., Smith, Graham P., Snodgrass, Colin, Talia, Margherita, Tao, Charling, Toft, Sune, Tortora, Crescenzo, Tutusaus, Isaac, Usher, Christopher, van Velzen, Sjoert, Verma, Aprajita, Vernardos, Georgios, Voggel, Karina, Wandelt, Benjamin, Watkins, Aaron E., Weller, Jochen, Wright, Angus H, Yoachim, Peter, Yoon, Ilsang, and Zucca, Elena
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
This report is the result of a joint discussion between the Rubin and Euclid scientific communities. The work presented in this report was focused on designing and recommending an initial set of Derived Data products (DDPs) that could realize the science goals enabled by joint processing. All interested Rubin and Euclid data rights holders were invited to contribute via an online discussion forum and a series of virtual meetings. Strong interest in enhancing science with joint DDPs emerged from across a wide range of astrophysical domains: Solar System, the Galaxy, the Local Volume, from the nearby to the primaeval Universe, and cosmology., Comment: Report of the Rubin-Euclid Derived Data Products Working Group, 78 pages, 11 figures
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- 2022
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5. The Impact of Observing Strategy on Cosmological Constraints with LSST
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Lochner, Michelle, Scolnic, Dan, Almoubayyed, Husni, Anguita, Timo, Awan, Humna, Gawiser, Eric, Gontcho, Satya Gontcho A, Graham, Melissa L, Gris, Philippe, Huber, Simon, Jha, Saurabh W, Jones, R Lynne, Kim, Alex G, Mandelbaum, Rachel, Marshall, Phil, Petrushevska, Tanja, Regnault, Nicolas, Setzer, Christian N, Suyu, Sherry H, Yoachim, Peter, Biswas, Rahul, Blaineau, Tristan, Hook, Isobel, Moniez, Marc, Neilsen, Eric, Peiris, Hiranya, Rothchild, Daniel, and Stubbs, Christopher
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Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry (incl. Structural) ,Astronomy & Astrophysics - Abstract
The generation-defining Vera C. Rubin Observatory will make state-of-the-art measurements of both the static and transient universe through its Legacy Survey for Space and Time (LSST). With such capabilities, it is immensely challenging to optimize the LSST observing strategy across the survey's wide range of science drivers. Many aspects of the LSST observing strategy relevant to the LSST Dark Energy Science Collaboration, such as survey footprint definition, single-visit exposure time, and the cadence of repeat visits in different filters, are yet to be finalized. Here, we present metrics used to assess the impact of observing strategy on the cosmological probes considered most sensitive to survey design; these are large-scale structure, weak lensing, type Ia supernovae, kilonovae, and strong lens systems (as well as photometric redshifts, which enable many of these probes). We evaluate these metrics for over 100 different simulated potential survey designs. Our results show that multiple observing strategy decisions can profoundly impact cosmological constraints with LSST; these include adjusting the survey footprint, ensuring repeat nightly visits are taken in different filters, and enforcing regular cadence. We provide public code for our metrics, which makes them readily available for evaluating further modifications to the survey design. We conclude with a set of recommendations and highlight observing strategy factors that require further research.
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- 2022
6. Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: a pioneering process of community-focused experimental design
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Bianco, Federica B., Ivezić, Željko, Jones, R. Lynne, Graham, Melissa L., Marshall, Phil, Saha, Abhijit, Strauss, Michael A., Yoachim, Peter, Ribeiro, Tiago, Anguita, Timo, Bauer, Franz E., Bellm, Eric C., Blum, Robert D., Brandt, William N., Brough, Sarah, Catelan, Màrcio, Clarkson, William I., Connolly, Andrew J., Gawiser, Eric, Gizis, John, Hlozek, Renee, Kaviraj, Sugata, Liu, Charles T., Lochner, Michelle, Mahabal, Ashish A., Mandelbaum, Rachel, McGehee, Peregrine, Neilsen Jr., Eric H., Olsen, Knut A. G., Peiris, Hiranya, Rhodes, Jason, Richards, Gordon T., Ridgway, Stephen, Schwamb, Megan E., Scolnic, Dan, Shemmer, Ohad, Slater, Colin T., Slosar, Anže, Smartt, Stephen J., Strader, Jay, Street, Rachel, Trilling, David E., Verma, Aprajita, Vivas, A. K., Wechsler, Risa H., and Willman, Beth
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Astrophysics - Instrumentation and Methods for Astrophysics - 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 multi-purpose 10-year 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 potential users' community. 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., Comment: Submitted as the opening paper of the Astrophysical Journal Focus Issue on Rubin LSST cadence and survey strategy
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- 2021
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7. The Impact of Observing Strategy on Cosmological Constraints with LSST
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Lochner, Michelle, Scolnic, Dan, Almoubayyed, Husni, Anguita, Timo, Awan, Humna, Gawiser, Eric, Gontcho, Satya Gontcho A, Gris, Philippe, Huber, Simon, Jha, Saurabh W., Jones, R. Lynne, Kim, Alex G., Mandelbaum, Rachel, Marshall, Phil, Petrushevska, Tanja, Regnault, Nicolas, Setzer, Christian N., Suyu, Sherry H., Yoachim, Peter, Biswas, Rahul, Blaineau, Tristan, Hook, Isobel, Moniez, Marc, Neilsen, Eric, Peiris, Hiranya, Rothchild, Daniel, and Stubbs, Christopher
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The generation-defining Vera C. Rubin Observatory will make state-of-the-art measurements of both the static and transient universe through its Legacy Survey for Space and Time (LSST). With such capabilities, it is immensely challenging to optimize the LSST observing strategy across the survey's wide range of science drivers. Many aspects of the LSST observing strategy relevant to the LSST Dark Energy Science Collaboration, such as survey footprint definition, single visit exposure time and the cadence of repeat visits in different filters, are yet to be finalized. Here, we present metrics used to assess the impact of observing strategy on the cosmological probes considered most sensitive to survey design; these are large-scale structure, weak lensing, type Ia supernovae, kilonovae and strong lens systems (as well as photometric redshifts, which enable many of these probes). We evaluate these metrics for over 100 different simulated potential survey designs. Our results show that multiple observing strategy decisions can profoundly impact cosmological constraints with LSST; these include adjusting the survey footprint, ensuring repeat nightly visits are taken in different filters and enforcing regular cadence. We provide public code for our metrics, which makes them readily available for evaluating further modifications to the survey design. We conclude with a set of recommendations and highlight observing strategy factors that require further research., Comment: 49 pages, 17 figures
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- 2021
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8. DESC DC2 Data Release Note
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LSST Dark Energy Science Collaboration, Abolfathi, Bela, Armstrong, Robert, Awan, Humna, Babuji, Yadu N., Bauer, Franz Erik, Beckett, George, Biswas, Rahul, Bogart, Joanne R., Boutigny, Dominique, Chard, Kyle, Chiang, James, Cohen-Tanugi, Johann, Connolly, Andrew J., Daniel, Scott F., Digel, Seth W., Drlica-Wagner, Alex, Dubois, Richard, Gawiser, Eric, Glanzman, Thomas, Habib, Salman, Hearin, Andrew P., Heitmann, Katrin, Hernandez, Fabio, Hložek, Renée, Hollowed, Joseph, Jarvis, Mike, Jha, Saurabh W., Kalmbach, J. Bryce, Kelly, Heather M., Kovacs, Eve, Korytov, Danila, Krughoff, K. Simon, Lage, Craig S., Lanusse, François, Larsen, Patricia, Li, Nan, Longley, Emily Phillips, Lupton, Robert H., Mandelbaum, Rachel, Mao, Yao-Yuan, Marshall, Phil, Meyers, Joshua E., Park, Ji Won, Peloton, Julien, Perrefort, Daniel, Perry, James, Plaszczynski, Stéphane, Pope, Adrian, Rykoff, Eli S., Sánchez, F. Javier, Schmidt, Samuel J., Uram, Thomas D., Villarreal, Antonia, Walter, Christopher W., Wiesner, Matthew P., and Wood-Vasey, W. Michael
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
In preparation for cosmological analyses of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), the LSST Dark Energy Science Collaboration (LSST DESC) has created a 300 deg$^2$ simulated survey as part of an effort called Data Challenge 2 (DC2). The DC2 simulated sky survey, in six optical bands with observations following a reference LSST observing cadence, was processed with the LSST Science Pipelines (19.0.0). In this Note, we describe the public data release of the resulting object catalogs for the coadded images of five years of simulated observations along with associated truth catalogs. We include a brief description of the major features of the available data sets. To enable convenient access to the data products, we have developed a web portal connected to Globus data services. We describe how to access the data and provide example Jupyter Notebooks in Python to aid first interactions with the data. We welcome feedback and questions about the data release via a GitHub repository., Comment: 25 pages, 3 figures; 9 tables. A detailed changelog can be found in Appendix A. To obtain data, visit the DESC Data Portal at https://data.lsstdesc.org/
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- 2021
9. The LSST DESC DC2 Simulated Sky Survey
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LSST Dark Energy Science Collaboration, Abolfathi, Bela, Alonso, David, Armstrong, Robert, Aubourg, Éric, Awan, Humna, Babuji, Yadu N., Bauer, Franz Erik, Bean, Rachel, Beckett, George, Biswas, Rahul, Bogart, Joanne R., Boutigny, Dominique, Chard, Kyle, Chiang, James, Claver, Chuck F., Cohen-Tanugi, Johann, Combet, Céline, Connolly, Andrew J., Daniel, Scott F., Digel, Seth W., Drlica-Wagner, Alex, Dubois, Richard, Gangler, Emmanuel, Gawiser, Eric, Glanzman, Thomas, Gris, Phillipe, Habib, Salman, Hearin, Andrew P., Heitmann, Katrin, Hernandez, Fabio, Hložek, Renée, Hollowed, Joseph, Ishak, Mustapha, Ivezić, Željko, Jarvis, Mike, Jha, Saurabh W., Kahn, Steven M., Kalmbach, J. Bryce, Kelly, Heather M., Kovacs, Eve, Korytov, Danila, Krughoff, K. Simon, Lage, Craig S., Lanusse, François, Larsen, Patricia, Guillou, Laurent Le, Li, Nan, Longley, Emily Phillips, Lupton, Robert H., Mandelbaum, Rachel, Mao, Yao-Yuan, Marshall, Phil, Meyers, Joshua E., Moniez, Marc, Morrison, Christopher B., Nomerotski, Andrei, O'Connor, Paul, Park, HyeYun, Park, Ji Won, Peloton, Julien, Perrefort, Daniel, Perry, James, Plaszczynski, Stéphane, Pope, Adrian, Rasmussen, Andrew, Reil, Kevin, Roodman, Aaron J., Rykoff, Eli S., Sánchez, F. Javier, Schmidt, Samuel J., Scolnic, Daniel, Stubbs, Christopher W., Tyson, J. Anthony, Uram, Thomas D., Villarreal, Antonia, Walter, Christopher W., Wiesner, Matthew P., Wood-Vasey, W. Michael, and Zuntz, Joe
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - 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 (WFD) area of approximately 300 deg^2 as well as a deep drilling field (DDF) of approximately 1 deg^2. We simulate 5 years of the planned 10-year survey. The DC2 sky survey has multiple purposes. First, the LSST DESC working groups can use the dataset to develop a range of DESC analysis pipelines to prepare for the advent of actual data. Second, it serves as a realistic testbed 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., Comment: 39 pages, 19 figures, version accepted for publication in ApJS
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- 2020
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10. The LSST DESC Data Challenge 1: Generation and Analysis of Synthetic Images for Next Generation Surveys
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Sánchez, F. Javier, Walter, Chris W., Awan, Humna, Chiang, James, Daniel, Scott F., Gawiser, Eric, Glanzman, Tom, Kirkby, David P., Mandelbaum, Rachel, Slosar, Anže, Wood-Vasey, W. Michael, AlSayyad, Yusra, Burke, Colin J., Digel, Seth W., Jarvis, Mike, Johnson, Tony, Kelly, Heather, Krughoff, Simon, Lupton, Robert H., Marshall, Phil J., Peterson, John R., Price, Paul A., Sembroski, Glenn, Van Klaveren, Brian, Wiesner, Matthew P., and Xin, Bo
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Data Challenge 1 (DC1) is the first synthetic dataset produced by the Rubin Observatory Legacy Survey of Space and Time (LSST) Dark Energy Science Collaboration (DESC). DC1 is designed to develop and validate data reduction and analysis and to study the impact of systematic effects that will affect the LSST dataset. DC1 is comprised of $r$-band observations of 40 deg$^{2}$ to 10-year LSST depth. We present each stage of the simulation and analysis process: a) generation, by synthesizing sources from cosmological N-body simulations in individual sensor-visit images with different observing conditions; b) reduction using a development version of the LSST Science Pipelines; and c) matching to the input cosmological catalog for validation and testing. We verify that testable LSST requirements pass within the fidelity of DC1. We establish a selection procedure that produces a sufficiently clean extragalactic sample for clustering analyses and we discuss residual sample contamination, including contributions from inefficiency in star-galaxy separation and imperfect deblending. We compute the galaxy power spectrum on the simulated field and conclude that: i) survey properties have an impact of 50\% of the statistical uncertainty for the scales and models used in DC1 ii) a selection to eliminate artifacts in the catalogs is necessary to avoid biases in the measured clustering; iii) the presence of bright objects has a significant impact (2- to 6-$\sigma$) in the estimated power spectra at small scales ($\ell > 1200$), highlighting the impact of blending in studies at small angular scales in LSST, Comment: 21 pages, 21 figures. Accepted at MNRAS
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- 2020
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11. A reversal in dental statistics
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Conference of the New Zealand Dietetic Association, Palmerston North, 4-6 Sep 2002 and Marshall, Phil
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- 2002
12. The LSST DESC DC2 Simulated Sky Survey
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Abolfathi, Bela, Alonso, David, Armstrong, Robert, Aubourg, Éric, Awan, Humna, Babuji, Yadu N, Bauer, Franz Erik, Bean, Rachel, Beckett, George, Biswas, Rahul, Bogart, Joanne R, Boutigny, Dominique, Chard, Kyle, Chiang, James, Claver, Chuck F, Cohen-Tanugi, Johann, Combet, Céline, Connolly, Andrew J, Daniel, Scott F, Digel, Seth W, Drlica-Wagner, Alex, Dubois, Richard, Gangler, Emmanuel, Gawiser, Eric, Glanzman, Thomas, Gris, Phillipe, Habib, Salman, Hearin, Andrew P, Heitmann, Katrin, Hernandez, Fabio, Hložek, Renée, Hollowed, Joseph, Ishak, Mustapha, Ivezić, Željko, Jarvis, Mike, Jha, Saurabh W, Kahn, Steven M, Kalmbach, J Bryce, Kelly, Heather M, Kovacs, Eve, Korytov, Danila, Krughoff, K Simon, Lage, Craig S, Lanusse, François, Larsen, Patricia, Le Guillou, Laurent, Li, Nan, Longley, Emily Phillips, Lupton, Robert H, Mandelbaum, Rachel, Mao, Yao-Yuan, Marshall, Phil, Meyers, Joshua E, Moniez, Marc, Morrison, Christopher B, Nomerotski, Andrei, O’Connor, Paul, Park, HyeYun, Park, Ji Won, Peloton, Julien, Perrefort, Daniel, Perry, James, Plaszczynski, Stéphane, Pope, Adrian, Rasmussen, Andrew, Reil, Kevin, Roodman, Aaron J, Rykoff, Eli S, Sánchez, F Javier, Schmidt, Samuel J, Scolnic, Daniel, Stubbs, Christopher W, Tyson, J Anthony, Uram, Thomas D, Villarreal, Antonio, Walter, Christopher W, Wiesner, Matthew P, Wood-Vasey, W Michael, and Zuntz, Joe
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Astronomical Sciences ,Physical Sciences ,Cosmology ,N-body simulations ,Sky surveys ,astro-ph.IM ,astro-ph.CO ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry (incl. Structural) ,Astronomy & Astrophysics ,Astronomical sciences - 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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- 2021
13. Better support for collaborations preparing for large-scale projects: the case study of the LSST Science Collaborations Astro2020 APC White Paper
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Bianco, Federica B., Banerji, Manda, Bochanski, John, Brandt, William N., Burchat, Patricia, Gizis, John, Ivezić, Zeljko, Keaton, Charles, Kaviraj, Sugata, Loredo, Tom, Mandelbaum, Rachel, Marshall, Phil, McGehee, Peregrine, Schafer, Chad, Schwamb, Megan E., Sokoloski, Jennifer L, Strauss, Michael A., Street, Rachel, Trilling, David, and Verma, Aprajita
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Through the lens of the LSST Science Collaborations' experience, this paper advocates for new and improved ways to fund large, complex collaborations at the interface of data science and astrophysics as they work in preparation for and on peta-scale, complex surveys, of which LSST is a prime example. We advocate for the establishment of programs to support both research and infrastructure development that enables innovative collaborative research on such scales., Comment: White Paper submitted to the Astro2020 (The "2020 Decadal Survey") APC call for "State of the Profession Considerations"
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- 2019
14. Dark Energy and Modified Gravity
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Slosar, Anže, Davis, Tamara, Eisenstein, Daniel, Hložek, Renée, Ishak-Boushaki, Mustapha, Mandelbaum, Rachel, Marshall, Phil, Sakstein, Jeremy, and White, Martin
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Despite two decades of tremendous experimental and theoretical progress, the riddle of the accelerated expansion of the Universe remains to be solved. On the experimental side, our understanding of the possibilities and limitations of the major dark energy probes has evolved; here we summarize the major probes and their crucial challenges. On the theoretical side, the taxonomy of explanations for the accelerated expansion rate is better understood, providing clear guidance to the relevant observables. We argue that: i) improving statistical precision and systematic control by taking more data, supporting research efforts to address crucial challenges for each probe, using complementary methods, and relying on cross-correlations is well motivated; ii) blinding of analyses is difficult but ever more important; iii) studies of dark energy and modified gravity are related; and iv) it is crucial that R&D for a vibrant dark energy program in the 2030s be started now by supporting studies and technical R&D that will allow embryonic proposals to mature. Understanding dark energy, arguably the biggest unsolved mystery in both fundamental particle physics and cosmology, will remain one of the focal points of cosmology in the forthcoming decade., Comment: 5 pages + references; science white paper submitted to the Astro2020 decadal survey
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- 2019
15. Data-Driven Reconstruction of Gravitationally Lensed Galaxies using Recurrent Inference Machines
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Morningstar, Warren R., Levasseur, Laurence Perreault, Hezaveh, Yashar D., Blandford, Roger, Marshall, Phil, Putzky, Patrick, Rueter, Thomas D., Wechsler, Risa, and Welling, Max
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
We present a machine learning method for the reconstruction of the undistorted images of background sources in strongly lensed systems. This method treats the source as a pixelated image and utilizes the Recurrent Inference Machine (RIM) to iteratively reconstruct the background source given a lens model. Our architecture learns to minimize the likelihood of the model parameters (source pixels) given the data using the physical forward model (ray tracing simulations) while implicitly learning the prior of the source structure from the training data. This results in better performance compared to linear inversion methods, where the prior information is limited to the 2-point covariance of the source pixels approximated with a Gaussian form, and often specified in a relatively arbitrary manner. We combine our source reconstruction network with a convolutional neural network that predicts the parameters of the mass distribution in the lensing galaxies directly from telescope images, allowing a fully automated reconstruction of the background source images and the foreground mass distribution., Comment: Submitted to ApJ
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- 2019
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16. A Big Sky Approach to Cadence Diplomacy
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Olsen, Knut, Di Criscienzo, Marcella, Jones, R. Lynne, Schwamb, Megan E., Lin, Hsing Wen "Edward", Awan, Humna, Marshall, Phil, Gawiser, Eric, Bolton, Adam, and Eisenstein, Daniel
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The LSST survey was designed to deliver transformative results for four primary objectives: constraining dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. While the LSST Wide-Fast-Deep survey and accompanying Deep Drilling and mini-surveys will be ground-breaking for each of these areas, there remain competing demands on the survey area, depth, and temporal coverage amid a desire to maximize all three. In this white paper, we seek to address a principal source of tension between the different LSST science collaborations, that of the survey area and depth that they each need in the parts of the sky that they care about. We present simple tools which can be used to explore trades between the area surveyed by LSST and the number of visits available per field and then use these tools to propose a change to the baseline survey strategy. Specifically, we propose to reconfigure the WFD footprint to consist of low-extinction regions (limited by galactic latitude), with the number of visits per field in WFD limited by the LSST Science Requirements Document (SRD) design goal, and suggest assignment of the remaining LSST visits to the full visible LSST sky. This proposal addresses concerns with the WFD footprint raised by the DESC (as 25 percent of the current baseline WFD region is not usable for dark energy science due to MW dust extinction), eases the time required for the NES and SCP mini-surveys (since in our proposal they would partially fall into the modified WFD footprint), raises the number of visits previously assigned to the GP region, and increases the overlap with DESI and other Northern hemisphere follow-up facilities. This proposal alleviates many of the current concerns of Science Collaborations that represent the four scientific pillars of LSST and provides a Big Sky approach to cadence diplomacy., Comment: 12 page, 5 figures, submitted to Call for White Papers on LSST Cadence Optimization
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- 2018
17. Optimizing the LSST Observing Strategy for Dark Energy Science: DESC Recommendations for the Deep Drilling Fields and other Special Programs
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Scolnic, Daniel M., Lochner, Michelle, Gris, Phillipe, Regnault, Nicolas, Hložek, Renée, Aldering, Greg, Allam Jr, Tarek, Awan, Humna, Biswas, Rahul, Blazek, Jonathan, Chang, Chihway, Gawiser, Eric, Goobar, Ariel, Hook, Isobel M., Jha, Saurabh W., McEwen, Jason D., Mandelbaum, Rachel, Marshall, Phil, Neilsen, Eric, Rhodes, Jason, Rothchild, Daniel, Noarbe, Ignacio Sevilla, Slosar, Anže, and Yoachim, Peter
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We review the measurements of dark energy enabled by observations of the Deep Drilling Fields and the optimization of survey design for cosmological measurements. This white paper is the result of efforts by the LSST DESC Observing Strategy Task Force (OSTF), which represents the entire collaboration, and aims to make recommendations on observing strategy for the DDFs that will benefit all cosmological analyses with LSST. It is accompanied by the DESC-WFD white paper (Lochner et al.). We argue for altering the nominal deep drilling plan to have $>6$ month seasons, interweaving $gri$ and $zy$ observations every 3 days with 2, 4, 8, 25, 4 visits in $grizy$, respectively. These recommendations are guided by metrics optimizing constraints on dark energy and mitigation of systematic uncertainties, including specific requirements on total number of visits after Y1 and Y10 for photometric redshifts (photo-$z$) and weak lensing systematics. We specify the precise locations for the previously-chosen LSST deep fields (ELAIS-S1, XMM-LSS, CDF-S, and COSMOS) and recommend Akari Deep Field South as the planned fifth deep field in order to synergize with Euclid and WFIRST. Our recommended DDF strategy uses $6.2\%$ of the LSST survey time. We briefly discuss synergy with white papers from other collaborations, as well as additional mini-surveys and Target-of-Opportunity programs that lead to better measurements of dark energy., Comment: The LSST DESC response (DDF) to the Call for White Papers on LSST Cadence Optimization. Comments welcome
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- 2018
18. Optimizing the LSST Observing Strategy for Dark Energy Science: DESC Recommendations for the Wide-Fast-Deep Survey
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Lochner, Michelle, Scolnic, Daniel M., Awan, Humna, Regnault, Nicolas, Gris, Philippe, Mandelbaum, Rachel, Gawiser, Eric, Almoubayyed, Husni, Setzer, Christian N., Huber, Simon, Graham, Melissa L., Hložek, Renée, Biswas, Rahul, Eifler, Tim, Rothchild, Daniel, Allam Jr, Tarek, Blazek, Jonathan, Chang, Chihway, Collett, Thomas, Goobar, Ariel, Hook, Isobel M., Jarvis, Mike, Jha, Saurabh W., Kim, Alex G., Marshall, Phil, McEwen, Jason D., Moniez, Marc, Newman, Jeffrey A., Peiris, Hiranya V., Petrushevska, Tanja, Rhodes, Jason, Sevilla-Noarbe, Ignacio, Slosar, Anže, Suyu, Sherry H., Tyson, J. Anthony, and Yoachim, Peter
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Cosmology is one of the four science pillars of LSST, which promises to be transformative for our understanding of dark energy and dark matter. The LSST Dark Energy Science Collaboration (DESC) has been tasked with deriving constraints on cosmological parameters from LSST data. Each of the cosmological probes for LSST is heavily impacted by the choice of observing strategy. This white paper is written by the LSST DESC Observing Strategy Task Force (OSTF), which represents the entire collaboration, and aims to make recommendations on observing strategy that will benefit all cosmological analyses with LSST. It is accompanied by the DESC DDF (Deep Drilling Fields) white paper (Scolnic et al.). We use a variety of metrics to understand the effects of the observing strategy on measurements of weak lensing, large-scale structure, clusters, photometric redshifts, supernovae, strong lensing and kilonovae. In order to reduce systematic uncertainties, we conclude that the current baseline observing strategy needs to be significantly modified to result in the best possible cosmological constraints. We provide some key recommendations: moving the WFD (Wide-Fast-Deep) footprint to avoid regions of high extinction, taking visit pairs in different filters, changing the 2x15s snaps to a single exposure to improve efficiency, focusing on strategies that reduce long gaps (>15 days) between observations, and prioritizing spatial uniformity at several intervals during the 10-year survey., Comment: The LSST DESC response (WFD) to the Call for White Papers on LSST Cadence Optimization. Comments welcome
- Published
- 2018
19. Fundamental Physics with the Hubble Space Telescope
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Dalal, Neal, Dvorkin, Cora, Heyl, Jeremy, Jain, Bhuvnesh, Kamionkowski, Marc, Marshall, Phil, and Weinberg, David
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Cosmology is intrinsically intertwined with questions in fundamental physics. The existence of non-baryonic dark matter requires new physics beyond the Standard Model of elemenatary-particle interactions and Einstein's general relativity, as does the accelerating expansion of the universe. Current tensions between various cosmological measurements may be harbingers of yet more new physics. Progress on understanding dark matter and cosmic acceleration requires long term, high-precision measurements and excellent control of systematics, demanding observational programs that are often outside the discovery/characterization mode that drives many areas of astronomy. We outline potential programs through which the Hubble Space Telescope (HST) could have a major impact on issues in fundamental physics in the coming years. To realize this impact, we suggest the introduction of a "HST Fundamental Physics" observational program that would be subject to a modified proposal and review process., Comment: Report of the HST and Fundamental Physics Working Group, constituted by STScI Director Ken Sembach to identify ways that HST could enable advances in fundamental physics
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- 2017
20. Models of gravitational lens candidates from Space Warps CFHTLS
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Küng, Rafael, Saha, Prasenjit, Ferreras, Ignacio, Baeten, Elisabeth, Coles, Jonathan, Cornen, Claude, Macmillan, Christine, Marshall, Phil, More, Anupreeta, Oswald, Lucy, Verma, Aprajita, and Wilcox, Julianne K.
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Astrophysics - Astrophysics of Galaxies - Abstract
We report modelling follow-up of recently-discovered gravitational-lens candidates in the Canada France Hawaii Telescope Legacy Survey. Lens modelling was done by a small group of specially-interested volunteers from the SpaceWarps citizen-science community who originally found the candidate lenses. Models are categorised according to seven diagnostics indicating (a) the image morphology and how clear or indistinct it is, (b) whether the mass map and synthetic lensed image appear to be plausible, and (c) how the lens-model mass compares with the stellar mass and the abundance-matched halo mass. The lensing masses range from ~10^11 Msun to >10^13 Msun. Preliminary estimates of the stellar masses show a smaller spread in stellar mass (except for two lenses): a factor of a few below or above ~10^11 Msun. Therefore, we expect the stellar-to-total mass fraction to decline sharply as lensing mass increases. The most massive system with a convincing model is J1434+522 (SW05). The two low-mass outliers are J0206-095 (SW19) and J2217+015 (SW42); if these two are indeed lenses, they probe an interesting regime of very low star-formation efficiency. Some improvements to the modelling software (SpaghettiLens), and discussion of strategies regarding scaling to future surveys with more and frequent discoveries, are included., Comment: 16 pages, 10 figures, 1 table, online supplement table_1.csv contains additional detailed numbers shown in table 1 and figure 7
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- 2017
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21. Scientific Synergy Between LSST and Euclid
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Rhodes, Jason, Nichol, Robert C., Aubourg, Éric, Bean, Rachel, Boutigny, Dominique, Bremer, Malcolm N., Capak, Peter, Cardone, Vincenzo, Carry, Benoît, Conselice, Christopher J., Connolly, Andrew J., Cuillandre, Jean-Charles, Hatch, N. A., Helou, George, Hemmati, Shoubaneh, Hildebrandt, Hendrik, Hložek, Renée, Jones, Lynne, Kahn, Steven, Kiessling, Alina, Kitching, Thomas, Lupton, Robert, Mandelbaum, Rachel, Markovic, Katarina, Marshall, Phil, Massey, Richard, Maughan, Ben J., Melchior, Peter, Mellier, Yannick, Newman, Jeffrey A., Robertson, Brant, Sauvage, Marc, Schrabback, Tim, Smith, Graham P., Strauss, Michael A., Taylor, Andy, and Von Der Linden, Anja
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Euclid and the Large Synoptic Survey Telescope (LSST) are poised to dramatically change the astronomy landscape early in the next decade. The combination of high cadence, deep, wide-field optical photometry from LSST with high resolution, wide-field optical photometry and near-infrared photometry and spectroscopy from Euclid will be powerful for addressing a wide range of astrophysical questions. We explore Euclid/LSST synergy, ignoring the political issues associated with data access to focus on the scientific, technical, and financial benefits of coordination. We focus primarily on dark energy cosmology, but also discuss galaxy evolution, transient objects, solar system science, and galaxy cluster studies. We concentrate on synergies that require coordination in cadence or survey overlap, or would benefit from pixel-level co-processing that is beyond the scope of what is currently planned, rather than scientific programs that could be accomplished only at the catalog level without coordination in data processing or survey strategies. We provide two quantitative examples of scientific synergies: the decrease in photo-z errors (benefitting many science cases) when high resolution Euclid data are used for LSST photo-z determination, and the resulting increase in weak lensing signal-to-noise ratio from smaller photo-z errors. We briefly discuss other areas of coordination, including high performance computing resources and calibration data. Finally, we address concerns about the loss of independence and potential cross-checks between the two missions and potential consequences of not collaborating., Comment: 33 pages, 7 figures, to appear in ApJS, revised with additional references and minor corrections
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- 2017
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22. Science-Driven Optimization of the LSST Observing Strategy
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LSST Science Collaboration, Marshall, Phil, Anguita, Timo, Bianco, Federica B., Bellm, Eric C., Brandt, Niel, Clarkson, Will, Connolly, Andy, Gawiser, Eric, Ivezic, Zeljko, Jones, Lynne, Lochner, Michelle, Lund, Michael B., Mahabal, Ashish, Nidever, David, Olsen, Knut, Ridgway, Stephen, Rhodes, Jason, Shemmer, Ohad, Trilling, David, Vivas, Kathy, Walkowicz, Lucianne, Willman, Beth, Yoachim, Peter, Anderson, Scott, Antilogus, Pierre, Angus, Ruth, Arcavi, Iair, Awan, Humna, Biswas, Rahul, Bell, Keaton J., Bennett, David, Britt, Chris, Buzasi, Derek, Casetti-Dinescu, Dana I., Chomiuk, Laura, Claver, Chuck, Cook, Kem, Davenport, James, Debattista, Victor, Digel, Seth, Doctor, Zoheyr, Firth, R. E., Foley, Ryan, Fong, Wen-fai, Galbany, Lluis, Giampapa, Mark, Gizis, John E., Graham, Melissa L., Grillmair, Carl, Gris, Phillipe, Haiman, Zoltan, Hartigan, Patrick, Hawley, Suzanne, Hlozek, Renee, Jha, Saurabh W., Johns-Krull, C., Kanbur, Shashi, Kalogera, Vassiliki, Kashyap, Vinay, Kasliwal, Vishal, Kessler, Richard, Kim, Alex, Kurczynski, Peter, Lahav, Ofer, Liu, Michael C., Malz, Alex, Margutti, Raffaella, Matheson, Tom, McEwen, Jason D., McGehee, Peregrine, Meibom, Soren, Meyers, Josh, Monet, Dave, Neilsen, Eric, Newman, Jeffrey, O'Dowd, Matt, Peiris, Hiranya V., Penny, Matthew T., Peters, Christina, Poleski, Radoslaw, Ponder, Kara, Richards, Gordon, Rho, Jeonghee, Rubin, David, Schmidt, Samuel, Schuhmann, Robert L., Shporer, Avi, Slater, Colin, Smith, Nathan, Soares-Santos, Marcelles, Stassun, Keivan, Strader, Jay, Strauss, Michael, Street, Rachel, Stubbs, Christopher, Sullivan, Mark, Szkody, Paula, Trimble, Virginia, Tyson, Tony, de Val-Borro, Miguel, Valenti, Stefano, Wagoner, Robert, Wood-Vasey, W. Michael, and Zauderer, Bevin Ashley
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky and over ten years of repeated observation. However, exactly how the LSST observations will be taken (the observing strategy or "cadence") is not yet finalized. In this dynamically-evolving community white paper, we explore how the detailed performance of the anticipated science investigations is expected to depend on small changes to the LSST observing strategy. Using realistic simulations of the LSST schedule and observation properties, we design and compute diagnostic metrics and Figures of Merit that provide quantitative evaluations of different observing strategies, analyzing their impact on a wide range of proposed science projects. This is work in progress: we are using this white paper to communicate to each other the relative merits of the observing strategy choices that could be made, in an effort to maximize the scientific value of the survey. The investigation of some science cases leads to suggestions for new strategies that could be simulated and potentially adopted. Notably, we find motivation for exploring departures from a spatially uniform annual tiling of the sky: focusing instead on different parts of the survey area in different years in a "rolling cadence" is likely to have significant benefits for a number of time domain and moving object astronomy projects. The communal assembly of a suite of quantified and homogeneously coded metrics is the vital first step towards an automated, systematic, science-based assessment of any given cadence simulation, that will enable the scheduling of the LSST to be as well-informed as possible., Comment: 312 pages, 90 figures. Browse the current version at https://github.com/LSSTScienceCollaborations/ObservingStrategy, new contributions welcome!
- Published
- 2017
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23. Large Synoptic Survey Telescope Galaxies Science Roadmap
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Robertson, Brant E., Banerji, Manda, Cooper, Michael C., Davies, Roger, Driver, Simon P., Ferguson, Annette M. N., Ferguson, Henry C., Gawiser, Eric, Kaviraj, Sugata, Knapen, Johan H., Lintott, Chris, Lotz, Jennifer, Newman, Jeffrey A., Norman, Dara J., Padilla, Nelson, Schmidt, Samuel J., Smith, Graham P., Tyson, J. Anthony, Verma, Aprajita, Zehavi, Idit, Armus, Lee, Avestruz, Camille, Barrientos, L. Felipe, Bowler, Rebecca A. A., Bremer, Malcom N., Conselice, Christopher J., Davies, Jonathan, Demarco, Ricardo, Dickinson, Mark E., Galaz, Gaspar, Grazian, Andrea, Holwerda, Benne W., Jarvis, Matt J., Kasliwal, Vishal, Lacerna, Ivan, Loveday, Jon, Marshall, Phil, Merlin, Emiliano, Napolitano, Nicola R., Puzia, Thomas H., Robotham, Aaron, Salim, Samir, Sereno, Mauro, Snyder, Gregory F., Stott, John P., Tissera, Patricia B., Werner, Norbert, Yoachim, Peter, Borne, Kirk D., and Collaboration, Members of the LSST Galaxies Science
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The Large Synoptic Survey Telescope (LSST) will enable revolutionary studies of galaxies, dark matter, and black holes over cosmic time. The LSST Galaxies Science Collaboration has identified a host of preparatory research tasks required to leverage fully the LSST dataset for extragalactic science beyond the study of dark energy. This Galaxies Science Roadmap provides a brief introduction to critical extragalactic science to be conducted ahead of LSST operations, and a detailed list of preparatory science tasks including the motivation, activities, and deliverables associated with each. The Galaxies Science Roadmap will serve as a guiding document for researchers interested in conducting extragalactic science in anticipation of the forthcoming LSST era., Comment: For more information, see https://galaxies.science.lsst.org
- Published
- 2017
24. The SAGA Survey: I. Satellite Galaxy Populations Around Eight Milky Way Analogs
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Geha, Marla, Wechsler, Risa H., Mao, Yao-Yuan, Tollerud, Erik J., Weiner, Benjamin, Bernstein, Rebecca, Hoyle, Ben, Marchi, Sebastian, Marshall, Phil J., Munoz, Ricardo, and Lu, Yu
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present the survey strategy and early results of the "Satellites Around Galactic Analogs" (SAGA) Survey. The SAGA Survey's goal is to measure the distribution of satellite galaxies around 100 systems analogous to the Milky Way down to the luminosity of the Leo I dwarf galaxy ($ M_r < -12.3 $). We define a Milky Way analog based on $K$-band luminosity and local environment. Here, we present satellite luminosity functions for 8 Milky Way analog galaxies between 20 to 40 Mpc. These systems have nearly complete spectroscopic coverage of candidate satellites within the projected host virial radius down to $ r_o < 20.75 $ using low redshift $gri$ color criteria. We have discovered a total of 25 new satellite galaxies: 14 new satellite galaxies meet our formal criteria around our complete host systems, plus 11 additional satellites in either incompletely surveyed hosts or below our formal magnitude limit. Combined with 13 previously known satellites, there are a total of 27 satellites around 8 complete Milky Way analog hosts. We find a wide distribution in the number of satellites per host, from 1 to 9, in the luminosity range for which there are five Milky Way satellites. Standard abundance matching extrapolated from higher luminosities predicts less scatter between hosts and a steeper luminosity function slope than observed. We find that the majority of satellites (26 of 27) are star-forming. These early results indicate that the Milky Way has a different satellite population than typical in our sample, potentially changing the physical interpretation of measurements based only on the Milky Way's satellite galaxies., Comment: 22 pages, 19 figures, 2 tables. Updated to published version. Survey website: http://sagasurvey.org/
- Published
- 2017
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25. Validation of field-based running tests to determine maximal aerobic speed in professional rugby league.
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Bennett, Thomas, Marshall, Phil, Barrett, Steve, Malone, James J., Simpson, Andrew, Bray, James, Christopherson, Calum, Nickolay, Tom, Metcalfe, James, and Towlson, Chris
- Subjects
- *
RUGBY League football , *SPRINTING , *RUGBY League football players , *RATE of perceived exertion , *PRESEASON (Sports) , *RUNNING - Abstract
Practitioners place importance on high-speed running (HSR) to monitor training practice and match-play demands, whilst attempting to maximise fitness and minimize the risk of injury occurrence. Practitioners apply various methods to quantify HSR, such as absolute thresholds, percentage of maximum sprint speed and maximal aerobic speed (MAS). A recent survey demonstrates the 5-minute run and 1200m shuttle test (ST) to be implemented among rugby league practitioners to quantify HSR by incorporating MAS. However, it is unclear as to how valid these methods are to accurately quantify MAS. Therefore, the aim of this study was to assess the validity of the 5-minute run and 1200m ST when compared to a gold standard measure for MAS. Twenty 1st team professional rugby league players competing in the European Super League participated in this study. Players were required to complete an incremental treadmill test, 5-minute run and 1200m ST over a two-week period in pre-season. MAS, peak heart rate (HRmax), peak lactate (Lapeak) and rating of perceived exertion (RPE) where collected upon completion of each test. Results demonstrated the 1200m ST to have a higher correlation for MAS than the 5-minute run (1200m ST: r = 0.73, 5-minute run: r = 0.64). However, when assessing validity using the level of agreement between data, the 5-minute run underreported MAS by 0.45 m·s-1 whereas the 1200m ST underreported MAS by 0.77 m·s-1. Ultimately, both field-based tests used in this study underreport MAS when compared to an incremental treadmill test, although the 5-minute run provides a closer agreement and therefore a more valid measurement for MAS than the 1200m ST. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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26. Maximizing Science in the Era of LSST: A Community-Based Study of Needed US Capabilities
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Najita, Joan, Willman, Beth, Finkbeiner, Douglas P., Foley, Ryan J., Hawley, Suzanne, Newman, Jeffrey A., Rudnick, Gregory, Simon, Joshua D., Trilling, David, Street, Rachel, Bolton, Adam, Angus, Ruth, Bell, Eric F., Buzasi, Derek, Ciardi, David, Davenport, James R. A., Dawson, Will, Dickinson, Mark, Drlica-Wagner, Alex, Elias, Jay, Erb, Dawn, Feaga, Lori, Fong, Wen-fai, Gawiser, Eric, Giampapa, Mark, Guhathakurta, Puragra, Hoffman, Jennifer L., Hsieh, Henry, Jennings, Elise, Johnston, Kathryn V., Kashyap, Vinay, Li, Ting S., Linder, Eric, Mandelbaum, Rachel, Marshall, Phil, Matheson, Thomas, Meibom, Soren, Miller, Bryan W., O'Meara, John, Reddy, Vishnu, Ridgway, Steve, Rockosi, Constance M., Sand, David J., Schafer, Chad, Schmidt, Sam, Sesar, Branimir, Sheppard, Scott S., Thomas, Cristina A., Tollerud, Erik J., Trump, Jon, and von der Linden, Anja
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The Large Synoptic Survey Telescope (LSST) will be a discovery machine for the astronomy and physics communities, revealing astrophysical phenomena from the Solar System to the outer reaches of the observable Universe. While many discoveries will be made using LSST data alone, taking full scientific advantage of LSST will require ground-based optical-infrared (OIR) supporting capabilities, e.g., observing time on telescopes, instrumentation, computing resources, and other infrastructure. This community-based study identifies, from a science-driven perspective, capabilities that are needed to maximize LSST science. Expanding on the initial steps taken in the 2015 OIR System Report, the study takes a detailed, quantitative look at the capabilities needed to accomplish six representative LSST-enabled science programs that connect closely with scientific priorities from the 2010 decadal surveys. The study prioritizes the resources needed to accomplish the science programs and highlights ways that existing, planned, and future resources could be positioned to accomplish the science goals., Comment: 174 pages; one chapter of this report was previously published as arXiv:1607.04302
- Published
- 2016
27. Large Synoptic Survey Telescope Galaxies Science Roadmap
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Robertson, Brant E, Banerji, Manda, Cooper, Michael C, Davies, Roger, Driver, Simon P, Ferguson, Annette MN, Ferguson, Henry C, Gawiser, Eric, Kaviraj, Sugata, Knapen, Johan H, Lintott, Chris, Lotz, Jennifer, Newman, Jeffrey A, Norman, Dara J, Padilla, Nelson, Schmidt, Samuel J, Smith, Graham P, Tyson, J Anthony, Verma, Aprajita, Zehavi, Idit, Armus, Lee, Avestruz, Camille, Barrientos, L Felipe, Bowler, Rebecca AA, Bremer, Malcom N, Conselice, Christopher J, Davies, Jonathan, Demarco, Ricardo, Dickinson, Mark E, Galaz, Gaspar, Grazian, Andrea, Holwerda, Benne W, Jarvis, Matt J, Kasliwal, Vishal, Lacerna, Ivan, Loveday, Jon, Marshall, Phil, Merlin, Emiliano, Napolitano, Nicola R, Puzia, Thomas H, Robotham, Aaron, Salim, Samir, Sereno, Mauro, Snyder, Gregory F, Stott, John P, Tissera, Patricia B, Werner, Norbert, Yoachim, Peter, Borne, Kirk D, and Collaboration, Members of the LSST Galaxies Science
- Subjects
astro-ph.GA ,astro-ph.CO ,astro-ph.IM - Abstract
The Large Synoptic Survey Telescope (LSST) will enable revolutionary studiesof galaxies, dark matter, and black holes over cosmic time. The LSST GalaxiesScience Collaboration has identified a host of preparatory research tasksrequired to leverage fully the LSST dataset for extragalactic science beyondthe study of dark energy. This Galaxies Science Roadmap provides a briefintroduction to critical extragalactic science to be conducted ahead of LSSToperations, and a detailed list of preparatory science tasks including themotivation, activities, and deliverables associated with each. The GalaxiesScience Roadmap will serve as a guiding document for researchers interested inconducting extragalactic science in anticipation of the forthcoming LSST era.
- Published
- 2017
28. Gravitational lens modelling in a citizen science context
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Küng, Rafael, Saha, Prasenjit, More, Anupreeta, Baeten, Elisabeth, Coles, Jonathan, Cornen, Claude, Macmillan, Christine, Marshall, Phil, More, Surhud, Odermatt, Jonas, Verma, Aprajita, and Wilcox, Julianne K.
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We develop a method to enable collaborative modelling of gravitational lenses and lens candidates, that could be used by non-professional lens enthusiasts. It uses an existing free-form modelling program (glass), but enables the input to this code to be provided in a novel way, via a user-generated diagram that is essentially a sketch of an arrival-time surface. We report on an implementation of this method, SpaghettiLens, which has been tested in a modelling challenge using 29 simulated lenses drawn from a larger set created for the Space Warps citizen science strong lens search. We find that volunteers from this online community asserted the image parities and time ordering consistently in some lenses, but made errors in other lenses depending on the image morphology. While errors in image parity and time ordering lead to large errors in the mass distribution, the enclosed mass was found to be more robust: the model-derived Einstein radii found by the volunteers were consistent with those produced by one of the professional team, suggesting that given the appropriate tools, gravitational lens modelling is a data analysis activity that can be crowd-sourced to good effect. Ideas for improvement are discussed, these include (a) overcoming the tendency of the models to be shallower than the correct answer in test cases, leading to systematic overestimation of the Einstein radius by 10 per cent at present, and (b) detailed modelling of arcs., Comment: 10 pages, 12 figures
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- 2015
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29. The Effect of Complex Training on Muscle Architecture in Rugby League Players.
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Scott, David J., Marshall, Phil, Orange, Samuel T., and Ditroilo, Massimiliano
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RESISTANCE training ,SKELETAL muscle ,CONFIDENCE intervals ,PHYSICAL training & conditioning ,EXERCISE physiology ,RUGBY football ,RANDOMIZED controlled trials ,PHYSIOLOGICAL adaptation ,DESCRIPTIVE statistics ,QUADRICEPS muscle ,CALF muscles ,STATISTICAL sampling ,PLYOMETRICS - Abstract
Purpose: To compare the effects of variable-resistance complex training (VRCT) versus traditional complex training (TCT) on muscle architecture in rugby league players during a 6-week mesocycle. Methods: Twenty-four rugby league players competing in the British University & Colleges Sport (BUCS) Premier North Division were randomized to VRCT (n = 8), TCT (n = 8), or control (n = 8). Experimental groups completed a 6-week lower-body complex training intervention (2×/wk), which involved alternating high-load resistance exercise with plyometric exercise in the same session. The VRCT group performed resistance exercises at 70% of 1-repetition maximum (1RM) + 0% to 23% of 1RM from band resistance with a 90-second intracontrast rest interval, whereas the TCT group performed resistance exercise at 93% of 1RM with a 4-minute intracontrast rest interval. Muscle thickness (MT), pennation angle, and fascicle length (L
f ) were assessed for the vastus lateralis (VL) and gastrocnemius medialis using ultrasound imaging. Results: Both TCT and VRCT groups significantly improved VL MT and VL Lf compared with control (all P <.05). Standardized within-group changes in MT and Lf (Cohen dav ± 95% CI) were moderate for TCT (dav = 0.91 ± 1.0; dav = 1.1 ± 1.1) and unclear for VRCT (dav = 0.44 ± 0.99; dav = 0.47 ± 0.99), respectively. Differences in change scores between TCT and VRCT were unclear. Conclusions: VRCT and TCT can be utilized during the competitive season to induce favorable MT and Lf muscle architecture adaptations for the VL. TCT may induce greater muscle architecture adaptations of the VL, whereas VRCT may be of more practical value given the shorter intracontrast rest interval between resistance and plyometric exercises. [ABSTRACT FROM AUTHOR]- Published
- 2023
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30. The Effect of Complex Training on Physical Performance in Rugby League Players.
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Scott, David J., Ditroilo, Massimiliano, Orange, Samuel T., and Marshall, Phil
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LEG physiology ,TIME ,PHYSICAL training & conditioning ,EXERCISE physiology ,STRENGTH training ,RUGBY football ,RANDOMIZED controlled trials ,COMPARATIVE studies ,MUSCLE strength ,BODY movement ,DESCRIPTIVE statistics ,ATHLETIC ability ,PLYOMETRICS ,JUMPING ,SPRINTING - Abstract
Purpose: To compare the effects of variable-resistance complex training (VRCT) versus traditional complex training (TCT) on strength, power, speed, and leg stiffness (K
leg ) in rugby league players during a 6-week mesocycle. Methods: Twenty-four rugby league players competing in the British University and Colleges Sport Premier North Division were randomized to VRCT (n = 8), TCT (n = 8), or control (CON; n = 8). Experimental groups completed a 6-week lower-body complex training intervention (2×/wk) that involved alternating high-load resistance exercise with plyometric exercise within the same session. The VRCT group performed resistance exercises at 70% of 1-repetition maximum (1RM) + 0% to 23% of 1RM from band resistance with a 90-second intracontrast rest interval, whereas the TCT group performed resistance exercise at 93% of 1RM with a 4-minute intracontrast rest interval. Back-squat 1RM, countermovement jump peak power, reactive strength index, sprint times, and Kleg were assessed pretraining and posttraining. Results: VRCT and TCT significantly improved 1RM back squat, countermovement jump peak power, and 5-m sprint time (all P <.05). VRCT also improved Kleg , whereas TCT improved 10- and 20-m sprint times (all P <.05). Between groups, both VRCT and TCT improved 1RM back squat compared with CON (both P <.001). Additionally, VRCT improved Kleg compared with CON (right leg: P =.016) and TCT improved 20-m sprint time compared with CON (P =.042). Conclusions: VRCT and TCT can be implemented during the competitive season to improve strength, power, and 5-m sprint time. VRCT may lead to greater improvements in reactive strength index and Kleg , whereas TCT may enhance 10- and 20-m sprint times. [ABSTRACT FROM AUTHOR]- Published
- 2023
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31. Brief Review of Methods to Quantify High-Speed Running in Rugby League: Are Current Methods Appropriate?
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Bennett, Thomas, Marshall, Phil, Barrett, Steve, Malone, James J., and Towlson, Chris
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- 2022
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32. Strong Lens Time Delay Challenge: II. Results of TDC1
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Liao, Kai, Treu, Tommaso, Marshall, Phil, Fassnacht, Christopher D., Rumbaugh, Nick, Dobler, Gregory, Aghamousa, Amir, Bonvin, Vivien, Courbin, Frederic, Hojjati, Alireza, Jackson, Neal, Kashyap, Vinay, Kumar, S. Rathna, Linder, Eric, Mandel, Kaisey, Meng, Xiao-Li, Meylan, Georges, Moustakas, Leonidas A., Prabhu, Tushar P., Romero-Wolf, Andrew, Shafieloo, Arman, Siemiginowska, Aneta, Stalin, Chelliah S., Tak, Hyungsuk, Tewes, Malte, and van Dyk, David
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present the results of the first strong lens time delay challenge. The motivation, experimental design, and entry level challenge are described in a companion paper. This paper presents the main challenge, TDC1, which consisted of analyzing thousands of simulated light curves blindly. The observational properties of the light curves cover the range in quality obtained for current targeted efforts (e.g.,~COSMOGRAIL) and expected from future synoptic surveys (e.g.,~LSST), and include simulated systematic errors. \nteamsA\ teams participated in TDC1, submitting results from \nmethods\ different method variants. After a describing each method, we compute and analyze basic statistics measuring accuracy (or bias) $A$, goodness of fit $\chi^2$, precision $P$, and success rate $f$. For some methods we identify outliers as an important issue. Other methods show that outliers can be controlled via visual inspection or conservative quality control. Several methods are competitive, i.e., give $|A|<0.03$, $P<0.03$, and $\chi^2<1.5$, with some of the methods already reaching sub-percent accuracy. The fraction of light curves yielding a time delay measurement is typically in the range $f = $20--40\%. It depends strongly on the quality of the data: COSMOGRAIL-quality cadence and light curve lengths yield significantly higher $f$ than does sparser sampling. Taking the results of TDC1 at face value, we estimate that LSST should provide around 400 robust time-delay measurements, each with $P<0.03$ and $|A|<0.01$, comparable to current lens modeling uncertainties. In terms of observing strategies, we find that $A$ and $f$ depend mostly on season length, while P depends mostly on cadence and campaign duration., Comment: referee's comments incorporated; to appear in ApJ
- Published
- 2014
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33. LSST Science Book, Version 2.0
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LSST Science Collaboration, Abell, Paul A., Allison, Julius, Anderson, Scott F., Andrew, John R., Angel, J. Roger P., Armus, Lee, Arnett, David, Asztalos, S. J., Axelrod, Tim S., Bailey, Stephen, Ballantyne, D. R., Bankert, Justin R., Barkhouse, Wayne A., Barr, Jeffrey D., Barrientos, L. Felipe, Barth, Aaron J., Bartlett, James G., Becker, Andrew C., Becla, Jacek, Beers, Timothy C., Bernstein, Joseph P., Biswas, Rahul, Blanton, Michael R., Bloom, Joshua S., Bochanski, John J., Boeshaar, Pat, Borne, Kirk D., Bradac, Marusa, Brandt, W. N., Bridge, Carrie R., Brown, Michael E., Brunner, Robert J., Bullock, James S., Burgasser, Adam J., Burge, James H., Burke, David L., Cargile, Phillip A., Chandrasekharan, Srinivasan, Chartas, George, Chesley, Steven R., Chu, You-Hua, Cinabro, David, Claire, Mark W., Claver, Charles F., Clowe, Douglas, Connolly, A. J., Cook, Kem H., Cooke, Jeff, Cooray, Asantha, Covey, Kevin R., Culliton, Christopher S., de Jong, Roelof, de Vries, Willem H., Debattista, Victor P., Delgado, Francisco, Dell'Antonio, Ian P., Dhital, Saurav, Di Stefano, Rosanne, Dickinson, Mark, Dilday, Benjamin, Djorgovski, S. G., Dobler, Gregory, Donalek, Ciro, Dubois-Felsmann, Gregory, Durech, Josef, Eliasdottir, Ardis, Eracleous, Michael, Eyer, Laurent, Falco, Emilio E., Fan, Xiaohui, Fassnacht, Christopher D., Ferguson, Harry C., Fernandez, Yanga R., Fields, Brian D., Finkbeiner, Douglas, Figueroa, Eduardo E., Fox, Derek B., Francke, Harold, Frank, James S., Frieman, Josh, Fromenteau, Sebastien, Furqan, Muhammad, Galaz, Gaspar, Gal-Yam, A., Garnavich, Peter, Gawiser, Eric, Geary, John, Gee, Perry, Gibson, Robert R., Gilmore, Kirk, Grace, Emily A., Green, Richard F., Gressler, William J., Grillmair, Carl J., Habib, Salman, Haggerty, J. S., Hamuy, Mario, Harris, Alan W., Hawley, Suzanne L., Heavens, Alan F., Hebb, Leslie, Henry, Todd J., Hileman, Edward, Hilton, Eric J., Hoadley, Keri, Holberg, J. B., Holman, Matt J., Howell, Steve B., Infante, Leopoldo, Ivezic, Zeljko, Jacoby, Suzanne H., Jain, Bhuvnesh, Jedicke, Jee, M. James, Jernigan, J. Garrett, Jha, Saurabh W., Johnston, Kathryn V., Jones, R. Lynne, Juric, Mario, Kaasalainen, Mikko, Styliani, Kafka, Kahn, Steven M., Kaib, Nathan A., Kalirai, Jason, Kantor, Jeff, Kasliwal, Mansi M., Keeton, Charles R., Kessler, Richard, Knezevic, Zoran, Kowalski, Adam, Krabbendam, Victor L., Krughoff, K. Simon, Kulkarni, Shrinivas, Kuhlman, Stephen, Lacy, Mark, Lepine, Sebastien, Liang, Ming, Lien, Amy, Lira, Paulina, Long, Knox S., Lorenz, Suzanne, Lotz, Jennifer M., Lupton, R. H., Lutz, Julie, Macri, Lucas M., Mahabal, Ashish A., Mandelbaum, Rachel, Marshall, Phil, May, Morgan, McGehee, Peregrine M., Meadows, Brian T., Meert, Alan, Milani, Andrea, Miller, Christopher J., Miller, Michelle, Mills, David, Minniti, Dante, Monet, David, Mukadam, Anjum S., Nakar, Ehud, Neill, Douglas R., Newman, Jeffrey A., Nikolaev, Sergei, Nordby, Martin, O'Connor, Paul, Oguri, Masamune, Oliver, John, Olivier, Scot S., Olsen, Julia K., Olsen, Knut, Olszewski, Edward W., Oluseyi, Hakeem, Padilla, Nelson D., Parker, Alex, Pepper, Joshua, Peterson, John R., Petry, Catherine, Pinto, Philip A., Pizagno, James L., Popescu, Bogdan, Prsa, Andrej, Radcka, Veljko, Raddick, M. Jordan, Rasmussen, Andrew, Rau, Arne, Rho, Jeonghee, Rhoads, James E., Richards, Gordon T., Ridgway, Stephen T., Robertson, Brant E., Roskar, Rok, Saha, Abhijit, Sarajedini, Ata, Scannapieco, Evan, Schalk, Terry, Schindler, Rafe, Schmidt, Samuel, Schmidt, Sarah, Schneider, Donald P., Schumacher, German, Scranton, Ryan, Sebag, Jacques, Seppala, Lynn G., Shemmer, Ohad, Simon, Joshua D., Sivertz, M., Smith, Howard A., Smith, J. Allyn, Smith, Nathan, Spitz, Anna H., Stanford, Adam, Stassun, Keivan G., Strader, Jay, Strauss, Michael A., Stubbs, Christopher W., Sweeney, Donald W., Szalay, Alex, Szkody, Paula, Takada, Masahiro, Thorman, Paul, Trilling, David E., Trimble, Virginia, Tyson, Anthony, Van Berg, Richard, Berk, Daniel Vanden, VanderPlas, Jake, Verde, Licia, Vrsnak, Bojan, Walkowicz, Lucianne M., Wandelt, Benjamin D., Wang, Sheng, Wang, Yun, Warner, Michael, Wechsler, Risa H., West, Andrew A., Wiecha, Oliver, Williams, Benjamin F., Willman, Beth, Wittman, David, Wolff, Sidney C., Wood-Vasey, W. Michael, Wozniak, Przemek, Young, Patrick, Zentner, Andrew, and Zhan, Hu
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Extragalactic Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Galaxy Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy., Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/scibook
- Published
- 2009
34. Evidence for the accelerated expansion of the Universe from weak lensing tomography with COSMOS
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Schrabback, Tim, Hartlap, Jan, Joachimi, Benjamin, Kilbinger, Martin, Simon, Patrick, Benabed, Karim, Bradač, Maruša, Eifler, Tim, Erben, Thomas, Fassnacht, Christopher D., High, F. William, Hilbert, Stefan, Hildebrandt, Hendrik, Hoekstra, Henk, Kuijken, Konrad, Marshall, Phil, Mellier, Yannick, Morganson, Eric, Schneider, Peter, Semboloni, Elisabetta, Van Waerbeke, Ludovic, and Velander, Malin
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present a tomographic cosmological weak lensing analysis of the HST COSMOS Survey. Applying our lensing-optimized data reduction, principal component interpolation for the ACS PSF, and improved modelling of charge-transfer inefficiency, we measure a lensing signal which is consistent with pure gravitational modes and no significant shape systematics. We carefully estimate the statistical uncertainty from simulated COSMOS-like fields obtained from ray-tracing through the Millennium Simulation. We test our pipeline on simulated space-based data, recalibrate non-linear power spectrum corrections using the ray-tracing, employ photometric redshifts to reduce potential contamination by intrinsic galaxy alignments, and marginalize over systematic uncertainties. We find that the lensing signal scales with redshift as expected from General Relativity for a concordance LCDM cosmology, including the full cross-correlations between different redshift bins. For a flat LCDM cosmology, we measure sigma_8(Omega_m/0.3)^0.51=0.75+-0.08 from lensing, in perfect agreement with WMAP-5, yielding joint constraints Omega_m=0.266+0.025-0.023, sigma_8=0.802+0.028-0.029 (all 68% conf.). Dropping the assumption of flatness and using HST Key Project and BBN priors only, we find a negative deceleration parameter q_0 at 94.3% conf. from the tomographic lensing analysis, providing independent evidence for the accelerated expansion of the Universe. For a flat wCDM cosmology and prior w in [-2,0], we obtain w<-0.41 (90% conf.). Our dark energy constraints are still relatively weak solely due to the limited area of COSMOS. However, they provide an important demonstration for the usefulness of tomographic weak lensing measurements from space. (abridged), Comment: 26 pages, 25 figures, matches version accepted for publication by Astronomy and Astrophysics
- Published
- 2009
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35. Direct Observation of Cosmic Strings via their Strong Gravitational Lensing Effect: II. Results from the HST/ACS Image Archive
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Morganson, Eric, Marshall, Phil, Treu, Tommaso, Schrabback, Tim, and Blandford, Roger D.
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We have searched 4.5 square degrees of archival HST/ACS images for cosmic strings, identifying close pairs of similar, faint galaxies and selecting groups whose alignment is consistent with gravitational lensing by a long, straight string. We find no evidence for cosmic strings in five large-area HST treasury surveys (covering a total of 2.22 square degrees), or in any of 346 multi-filter guest observer images (1.18 square degrees). Assuming that simulations ccurately predict the number of cosmic strings in the universe, this non-detection allows us to place upper limits on the unitless Universal cosmic string tension of G mu/c^2 < 2.3 x 10^-6, and cosmic string density of Omega_s < 2.1 x 10^-5 at the 95% confidence level (marginalising over the other parameter in each case). We find four dubious cosmic string candidates in 318 single filter guest observer images (1.08 square degrees), which we are unable to conclusively eliminate with existing data. The confirmation of any one of these candidates as cosmic strings would imply G mu/c^2 ~ 10^-6 and Omega_s ~ 10^-5. However, we estimate that there is at least a 92% chance that these string candidates are random alignments of galaxies. If we assume that these candidates are indeed false detections, our final limits on G mu/c^2 and Omega_s fall to 6.5 x 10^-7 and 7.3 x 10^-6. Due to the extensive sky coverage of the HST/ACS image archive, the above limits are universal. They are quite sensitive to the number of fields being searched, and could be further reduced by more than a factor of two using forthcoming HST data., Comment: 21 pages, 18 figures
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- 2009
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36. An Atlas of Predicted Exotic Gravitational Lenses
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de Xivry, Gilles Orban and Marshall, Phil
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Wide-field optical imaging surveys will contain tens of thousands of new strong gravitational lenses. Some of these will have new and unusual image configurations, and so will enable new applications: for example, systems with high image multiplicity will allow more detailed study of galaxy and group mass distributions, while high magnification is needed to super-resolve the faintest objects in the high redshift universe. Inspired by a set of six unusual lens systems [including five selected from the Sloan Lens ACS (SLACS) and Strong Lensing Legacy (SL2S) surveys, plus the cluster Abell 1703], we consider several types of multi-component, physically-motivated lens potentials, and use the ray-tracing code "glamroc" to predict exotic image configurations. We also investigate the effects of galaxy source profile and size, and use realistic sources to predict observable magnifications and estimate very approximate relative cross-sections. We find that lens galaxies with misaligned disks and bulges produce swallowtail and butterfly catastrophes, observable as "broken" Einstein rings. Binary or merging galaxies show elliptic umbilic catastrophes, leading to an unusual Y-shaped configuration of 4 merging images. While not the maximum magnification configuration possible, it offers the possibility of mapping the local small-scale mass distribution. We estimate the approximate abundance of each of these exotic galaxy-scale lenses to be ~1 per all-sky survey. In higher mass systems, a wide range of caustic structures are expected, as already seen in many cluster lens systems. We interpret the central ring and its counter-image in Abell 1703 as a "hyperbolic umbilic" configuration, with total magnification ~100 (depending on source size). The abundance of such configurations is also estimated to be ~1 per all-sky survey., Comment: 21 pages, 30 figures, accepted by MNRAS, copyright material cleared for re-printing. High-resolution version available from http://www.slac.stanford.edu/~pjm/atlas
- Published
- 2009
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37. Strong gravitational lensing probes of the particle nature of dark matter
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Moustakas, Leonidas A., Abazajian, Kevork, Benson, Andrew, Bolton, Adam S., Bullock, James S., Chen, Jacqueline, Cheng, Edward, Coe, Dan, Congdon, Arthur B., Dalal, Neal, Diemand, Juerg, Dobke, Benjamin M., Dobler, Greg, Dore, Olivier, Dutton, Aaron, Ellis, Richard, Fassnacht, Chris D., Ferguson, Henry, Finkbeiner, Douglas, Gavazzi, Raphael, High, Fredrick William, Jeltema, Tesla, Jullo, Eric, Kaplinghat, Manoj, Keeton, Charles R., Kneib, Jean-Paul, Koopmans, Leon V. E., Koushiappas, Savvas M., Kuhlen, Michael, Kusenko, Alexander, Lawrence, Charles R., Loeb, Abraham, Madau, Piero, Marshall, Phil, Metcalf, R. Ben, Natarajan, Priya, Primack, Joel R., Profumo, Stefano, Seiffert, Michael D., Simon, Josh, Stern, Daniel, Strigari, Louis, Taylor, James E., Wayth, Randall, Wambsganss, Joachim, Wechsler, Risa, and Zentner, Andrew
- Subjects
Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
There is a vast menagerie of plausible candidates for the constituents of dark matter, both within and beyond extensions of the Standard Model of particle physics. Each of these candidates may have scattering (and other) cross section properties that are consistent with the dark matter abundance, BBN, and the most scales in the matter power spectrum; but which may have vastly different behavior at sub-galactic "cutoff" scales, below which dark matter density fluctuations are smoothed out. The only way to quantitatively measure the power spectrum behavior at sub-galactic scales at distances beyond the local universe, and indeed over cosmic time, is through probes available in multiply imaged strong gravitational lenses. Gravitational potential perturbations by dark matter substructure encode information in the observed relative magnifications, positions, and time delays in a strong lens. Each of these is sensitive to a different moment of the substructure mass function and to different effective mass ranges of the substructure. The time delay perturbations, in particular, are proving to be largely immune to the degeneracies and systematic uncertainties that have impacted exploitation of strong lenses for such studies. There is great potential for a coordinated theoretical and observational effort to enable a sophisticated exploitation of strong gravitational lenses as direct probes of dark matter properties. This opportunity motivates this white paper, and drives the need for: a) strong support of the theoretical work necessary to understand all astrophysical consequences for different dark matter candidates; and b) tailored observational campaigns, and even a fully dedicated mission, to obtain the requisite data., Comment: Science white paper submitted to the Astro2010 Decadal Cosmology & Fundamental Physics Science Frontier Panel
- Published
- 2009
38. Telerehabilitation for patients who have been hospitalised with covid-19: a qualitative study.
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Killingback, Clare, Thompson, Mark, Nettleton, Marion, Hyde, Lucy, Marshall, Phil, Shepherdson, Joanne, Crooks, Michael G., Green, Angela, and Simpson, Andrew J.
- Subjects
TELEREHABILITATION ,PILOT projects ,AFFINITY groups ,OCCUPATIONAL roles ,LIFESTYLES ,WELL-being ,COVID-19 ,EVALUATION of human services programs ,RESEARCH methodology ,INTERVIEWING ,PATIENTS' attitudes ,QUALITATIVE research ,EXPERIENCE ,SOCIAL isolation ,HOSPITAL care ,TELECONFERENCING ,SUPERVISION of employees ,THEMATIC analysis ,DATA analysis software ,PATIENT education ,DISCHARGE planning ,GROUP process - Abstract
The aim of this qualitative study was to explore the views of participants of a group-based, supervised, telerehabilitation programme, following discharge from hospital with Covid-19. This study was part of a single-centre, fast-track (wait-list), randomised, mixed-methods, feasibility trial of telerehabilitation (Registration: Clinicaltrials.gov reference:285205). Semi-structured interviews were conducted over a virtual teleconference platform with 10 participants who took part in a telerehabilitation programme following Covid-19 after discharge from an acute hospital. Data were transcribed verbatim and analysed using thematic analysis. Five themes were important from the participant perspective: telerehabilitation programme as part of the Covid-19 journey; the telerehabilitation programme design and delivery; peer aspects; the role of the instructor; and the role of technology and online delivery. Overall, the telerehabilitation programme was a positive experience for participants. The instructors were central to this positive view as was the group nature of the programme. The group aspect was particularly important in supporting the broader perceived wellbeing gains, such as the sense of enjoyment and reduced social isolation. Several participants would have liked to have continued with the exercises beyond the six-week intervention indicating that the programme could be a way to help people sustain a physically active lifestyle. Participants who were recovering from Covid-19 following hospital admission perceived the telerehabilitation to be a positive experience overall. The group aspect of the telerehabilitation programme was important in supporting the broader perceived wellbeing gains such as the sense of enjoyment and reduced social isolation. Telerehabilitation programmes for Covid-19 may need to include pathways for participants to continue to engage in exercise beyond the time-limited six-week intervention to support ongoing self-management. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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39. “I'm a failure again I can't do it”: Attitudes towards, and experiences of, exercise participation in adults with class III obesity
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Orange, Samuel, primary, Roebuck, Jessica, additional, Marshall, Phil, additional, Madden, Leigh, additional, Vince, Rebecca, additional, and Bell, Beth, additional
- Published
- 2023
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40. Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX J1347.5-1145
- Author
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Bradač, Maruša, Schrabback, Tim, Erben, Thomas, McCourt, Michael, Million, Evan, Mantz, Adam, Allen, Steve, Blandford, Roger, Halkola, Aleksi, Hildebrandt, Hendrik, Lombardi, Marco, Marshall, Phil, Schneider, Peter, Treu, Tommaso, and Kneib, Jean-Paul
- Subjects
Astrophysics - Abstract
The galaxy cluster RX J1347-1145 is one of the most X-ray luminous and most massive clusters known. Its extreme mass makes it a prime target for studying issues addressing cluster formation and cosmology. In this paper we present new high-resolution HST/ACS and Chandra X-ray data. The high resolution and sensitivity of ACS enabled us to detect and quantify several new multiply imaged sources, we now use a total of eight for the strong lensing analysis. Combining this information with shape measurements of weak lensing sources in the central regions of the cluster, we derive a high-resolution, absolutely-calibrated mass map. This map provides the best available quantification of the total mass of the central part of the cluster to date. We compare the reconstructed mass with that inferred from the new Chandra X-ray data, and conclude that both mass estimates agree extremely well in the observed region, namely within 400 / h_70 kpc of the cluster center. In addition we study the major baryonic components (gas and stars) and hence derive the dark matter distribution in the center of the cluster. We find that the dark matter and baryons are both centered on the BCG within the uncertainties (alignment is better than <10 kpc). We measure the corresponding 1-D profiles and find that dark matter distribution is consistent with both NFW and cored profiles, indicating that a more extended radial analysis is needed to pinpoint the concentration parameter, and hence the inner slope of the dark matter profile., Comment: 12 pages, Accepted for publication in ApJ, full-res version http://www.physics.ucsb.edu/~marusa/RXJ1347.pdf
- Published
- 2007
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41. AMUSE-Virgo I. Super-massive black holes in low-mass spheroids
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Gallo, Elena, Treu, Tommaso, Jacob, Jeremy, Woo, Jong-Hak, Marshall, Phil, and Antonucci, Robert
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Astrophysics - Abstract
We present the first results from the AGN Multiwavelength Survey of Early-type galaxies in the Virgo cluster (AMUSE-Virgo). This large program targets 100 early-type galaxies with the Advanced CCD Imaging Spectrometer on board the Chandra X-ray Observatory and the Multi-band Imaging Photometer on board the Spitzer Space Telescope, with the aim of providing an unbiased census of low-level super-massive black hole (SMBH) activity in the local universe. Here we report on the Chandra observations of the first 16 targets, and combine them with results from archival data of another, typically more massive, 16 targets. Point-like X-ray emission from a position coincident with the optical nucleus is detected in 50% of the galaxies (down to our completeness limit of ~4E+38 erg/sec). Two of the X-ray nuclei are hosted by galaxies (VCC1178=N4464 and VCC1297=N4486B) with absolute B magnitudes fainter than -18, where nuclear star clusters are known to become increasingly common. After carefully accounting for possible contamination from low mass X-ray binaries, we argue that the detected nuclear X-ray sources are most likely powered by low-level accretion on to a SMBH, with a <11% chance contamination in VCC1178, where a star cluster is barely resolvable in archival Hubble Space Telescope images. Based on black hole mass estimates from the global properties of the host galaxies, all the detected nuclei are highly sub-Eddington, with luminosities in the range -8.4
- Published
- 2007
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42. Direct Observation of Cosmic Strings via their Strong Gravitational Lensing Effect: I. Predictions for High Resolution Imaging Surveys
- Author
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Gasparini, Maria Alice, Marshall, Phil, Treu, Tommaso, Morganson, Eric, and Dubath, Florian
- Subjects
Astrophysics - Abstract
We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular resolution and survey area. We show that angular resolution is the most important factor, and that interesting limits on the dimensionless string tension Gmu/c^2 can be obtained by existing and planned surveys. At the resolution of the Hubble Space Telescope (0.14"), it is sufficient to survey of order a few square degrees -- well within reach of the current HST archive -- to probe the regime Gmu/c^2 ~ 10^{-7}. If lensing by cosmic strings is not detected, such a survey would improve the limit on the string tension by a factor of two over that available from the cosmic microwave background. Future high resolution imaging surveys, covering a few hundred square degrees or more, either from space in the optical or from large-format radio telescopes on the ground, would be able to further lower this limit to Gmu/c^2 < 10^{-8}., Comment: 7 pages, 3 figures, accepted for publication in MNRAS following in-press correction
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- 2007
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43. A Bayesian approach to strong lensing modelling of galaxy clusters
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Jullo, Eric, Kneib, Jean-Paul, Limousin, Marceau, Elíasdóttir, Árdis, Marshall, Phil, and Verdugo, Tomas
- Subjects
Astrophysics - Abstract
In this paper, we describe a procedure for modelling strong lensing galaxy clusters with parametric methods, and to rank models quantitatively using the Bayesian evidence. We use a publicly available Markov chain Monte-Carlo (MCMC) sampler ('Bayesys'), allowing us to avoid local minima in the likelihood functions. To illustrate the power of the MCMC technique, we simulate three clusters of galaxies, each composed of a cluster-scale halo and a set of perturbing galaxy-scale subhalos. We ray-trace three light beams through each model to produce a catalogue of multiple images, and then use the MCMC sampler to recover the model parameters in the three different lensing configurations. We find that, for typical Hubble Space Telescope (HST)-quality imaging data, the total mass in the Einstein radius is recovered with ~1-5% error according to the considered lensing configuration. However, we find that the mass of the galaxies is strongly degenerated with the cluster mass when no multiple images appear in the cluster centre. The mass of the galaxies is generally recovered with a 20% error, largely due to the poorly constrained cut-off radius. Finally, we describe how to rank models quantitatively using the Bayesian evidence. We confirm the ability of strong lensing to constrain the mass profile in the central region of galaxy clusters in this way. Ultimately, such a method applied to strong lensing clusters with a very large number of multiple images may provide unique geometrical constraints on cosmology. The implementation of the MCMC sampler used in this paper has been done within the framework of the Lenstool software package, which is publicly available., Comment: Accepted to "Gravitational Lensing" Focus Issue of the New Journal of Physics (invited), 35 pages, 11 figures at reduced resolution
- Published
- 2007
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44. Analytic models of plausible gravitational lens potentials
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Baltz, Edward A., Marshall, Phil, and Oguri, Masamune
- Subjects
Astrophysics - Abstract
Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses., Comment: 24 pages, 10 figures, matches published version
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- 2007
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45. Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56
- Author
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Bradac, Marusa, Clowe, Douglas, Gonzalez, Anthony H., Marshall, Phil, Forman, William, Jones, Christine, Markevitch, Maxim, Randall, Scott, Schrabback, Tim, and Zaritsky, Dennis
- Subjects
Astrophysics ,General Relativity and Quantum Cosmology ,High Energy Physics - Phenomenology - Abstract
The galaxy cluster 1E0657-56 (z = 0.296) is remarkably well-suited for addressing outstanding issues in both galaxy evolution and fundamental physics. We present a reconstruction of the mass distribution from both strong and weak gravitational lensing data. Multi-color, high-resolution HST ACS images allow detection of many more arc candidates than were previously known, especially around the subcluster. Using the known redshift of one of the multiply imaged systems, we determine the remaining source redshifts using the predictive power of the strong lens model. Combining this information with shape measurements of "weakly" lensed sources, we derive a high-resolution, absolutely-calibrated mass map, using no assumptions regarding the physical properties of the underlying cluster potential. This map provides the best available quantification of the total mass of the central part of the cluster. We also confirm the result from Clowe et al. (2004,2006a)., Comment: Accepted for publication in ApJ; Version with full-resolution figures available at http://www.slac.stanford.edu/~marusa/Work/bradac_strong_weak_III.pdf
- Published
- 2006
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46. Physical component analysis of galaxy cluster weak gravitational lensing data
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Marshall, Phil
- Subjects
Astrophysics - Abstract
We present a novel approach for reconstructing the projected mass distribution of clusters of galaxies from sparse and noisy weak gravitational lensing shear data. The reconstructions are regularised using knowledge gained from numerical simulations of clusters: trial mass distributions are constructed from N physically-motivated components, each of which has the universal density profile and characteristic geometry observed in simulated clusters. The parameters of these components are assumed to be distributed \emph{a priori} in the same way as they are in the simulated clusters. Sampling mass distributions from the components' parameters' posterior probability density function allows estimates of the mass distribution to be generated, with error bars. The appropriate number of components is inferred from the data itself via the Bayesian evidence, and is typically found to be small, reflecting the quality of the simulated data used in this work. Ensemble average mass maps are found to be robust to the details of the noise realisation, and succeed in recovering the input mass distribution (from a realistic simulated cluster) over a wide range of scales. We comment on the residuals of the reconstruction and their implications, and discuss the extension of the method to include strong lensing information., Comment: 12 pages, 7 figures
- Published
- 2005
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47. The SNAP Strong Lens Survey
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Marshall, Phil, Blandford, Roger, and Sako, Masao
- Subjects
Astrophysics - Abstract
Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ``piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe., Comment: 6 pages, 4 figures. To appear in the conference proceedings of "Wide Field Imaging from Space" (published in New Astronomy Reviews), eds. T. McKay, A. Fruchter, and E. Linder
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- 2005
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48. Exercise prehabilitation in elective intra-cavity surgery: A role within the ERAS pathway? A narrative review
- Author
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Orange, Samuel T., Northgraves, Matthew J., Marshall, Phil, Madden, Leigh A., and Vince, Rebecca V.
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- 2018
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49. Bayesian evidence as a tool for comparing datasets
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Marshall, Phil, Rajguru, Nutan, and Slosar, Anze
- Subjects
Astrophysics - Abstract
We introduce a new conservative test for quantifying the consistency of two or more datasets. The test is based on the Bayesian answer to the question, ``How much more probable is it that all my data were generated from the same model system than if each dataset were generated from an independent set of model parameters?''. We make explicit the connection between evidence ratios and the differences in peak chi-squared values, the latter of which are more widely used and more cheaply calculated. Calculating evidence ratios for three cosmological datasets (recent CMB data (WMAP, ACBAR, CBI, VSA), SDSS and the most recent SNe Type 1A data) we find that concordance is favoured and the tightening of constraints on cosmological parameters is indeed justified., Comment: 4 pages, accepted by Phys. Rev. D
- Published
- 2004
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50. Very Small Array observations of the Sunyaev-Zel'dovich effect in nearby galaxy clusters
- Author
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Lancaster, Katy, Genova-Santos, Ricardo, Falcon, Nelson, Grainge, Keith, Gutierrez, Carlos, Kneissl, Ruediger, Marshall, Phil, Pooley, Guy, Rebolo, Rafael, Rubino-Martin, Jose-Alberto, Saunders, Richard D. E., Waldram, Elizabeth, and Watson, Robert A.
- Subjects
Astrophysics - Abstract
We present VSA observations (~34GHz) on scales ~20 arcmin towards a complete, X-ray-flux-limited sample of seven clusters at redshift z<0.1. Four have significant SZ detections in the presence of CMB primordial anisotropy. We use a bayesian MCMC method for inference from the VSA data, with X-ray priors on cluster positions and temperatures, and radio priors on sources. We make assumptions of beta-model gas distributions and of hydrostatic equilibrium, to evaluate probability densities for the gas mass and total mass out to r_200. Our combined estimate of the gas fraction is 0.08^{+0.06}_{-0.04}h^{-1} The random errors are poor (note that the errors are higher than would have been obtained with the usual chi-squared method) but the control of bias is good. We have described the MCMC analysis method specifically in terms of SZ but hope the description will be of more general use. We find that the effects of primordial CMB contamination tend to be similar in the estimates of both the gas mass and total mass over our narrow range of angular scales, so that there is little effect of primordials on the gas fraction determination. Using our total mass estimates we find a normalisation of the mass-temperature relation based on the profiles from the VSA cluster pressure maps that is in good agreement with recent M-T determinations from X-ray cluster measurements., Comment: Replaces earlier version. 16 pages, 5 figures, LaTeX. Minor revisions to content, accepted by MNRAS for publication
- Published
- 2004
- Full Text
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