arXiv subjects

Tony Tyson

Publications and source records attributed to Tony Tyson.

7 recordsLinked to original sources

arXiv2026

The Cross-Survey Decade: A Call to Action

By 2027, three flagship wide-field surveys will be operating simultaneously from ground and space, observing overlapping sky and representing more than $6 billion in US and European public investment. Together they will produce overlapping petabyte-scale datasets across thousands of square degrees. This is a different class of challenge: the observations are no longer the bottleneck; realizing their joint scientific return now depends on shared computational infrastructure and coordination. Decades of community studies show that combining these datasets does more than improve precision. For science ranging from weak lensing to transient discovery and Galactic-plane astronomy, joint processing and analysis can unlock capabilities no single survey provides alone. Yet the required infrastructure -- joint pixel-level processing, cross-calibration and validation, interoperable data access, and the people to build and sustain it -- falls outside any single mission or institution's mandate. We issue a call to action for cross-survey science infrastructure, built around four pillars: (1) joint pixel-level processing and validation; (2) an AI-ready data substrate for scientific foundation models; (3) standardized, interoperable data access across surveys, democratizing participation in astrophysical discovery; and (4) dedicated personnel and career pathways. We outline concrete steps for policymakers, agencies, observatories, universities, the research community, and philanthropy, and argue that the moment to act is now, while foundational technical choices can still be aligned at a fraction of the cost of reconciling them later.

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arXiv2024

Maximizing the scientific return of Roman and Rubin with a joint wide-sky observing strategy

This work presents the case for a single-band LSST-matched depth Roman Community Survey over the footprint of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) Wide-Fast-Deep to enhance the key science programs of both missions. We propose to observe the ~18K sq deg LSST Wide-Fast-Deep footprint in the F146 filter to mAB~25; this will take approximately 5 months of Roman observing time. The combination of the multiwavelength nature of LSST and angular resolution of Roman would lead to enhanced scientific returns for both the Roman and LSST surveys. Galaxy deblending and crowded field photometry will be significantly improved. The extension of Rubin LSST six-band optical photometry to IR wavelengths would improve photometric redshift (photo-z) estimation, leading to improved cosmological parameter estimation, penetrate interstellar dust in the Galactic plane, improve differential chromatic refraction derived Spectral Energy Distributions, maximize galaxy-star separation and minimize crowding confusion through improved angular resolution. Conversely, the LSST survey will provide a time-domain extension of the Roman survey on the shared footprint and 6-band optical photometry with sensitivity extending all the way to ultraviolet wavelengths.

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arXiv2017

Science-Driven Optimization of the LSST Observing Strategy

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.

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arXiv2009

Educating the Next Generation of Leading Scientists: Turning Ideas into Action

The core of scientific research is turning new ideas into reality. From the school science fair to the search for the secrets of dark energy, high-quality research consists of scientific investigation constrained within the scope of a well-defined project. Large or small, generously funded or just scraping by,scientific projects use time, money, and information to turn ideas into plans, plans into action, and action into results. While we, as a community, do much to educate students in the techniques of research, we do not systematically train students in the nature and organization of scientific projects or in the techniques of project management. We propose a two-pronged attack to address this issue in the next decade. First, to generate a broad base of future scientists who have a basic familiarity with the ideas of projects, we propose that the community develop standards for the content of a project design and management course in astronomy and astrophysics. Second, to train future scientists to assume leadership roles in new investigations in astronomy and astrophysics, we propose that the community develop standards for graduate programs in the area of research project leadership.

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arXiv2009

The Case for Deep, Wide-Field Cosmology

Much of the science case for the next generation of deep, wide-field optical/infrared surveys has been driven by the further study of dark energy. This is a laudable goal (and the subject of a companion white paper by Zhan et al.). However, one of the most important lessons of the current generation of surveys is that the interesting science questions at the end of the survey are quite different than they were when the surveys were being planned. The current surveys succeeded in this evolving terrain by being very general tools that could be applied to a number of very fundamental measurements. Likewise, the accessibility of the data enabled the broader cosmological and astronomical community to generate more science than the survey collaborations could alone. With that in mind, we should consider some of the basic physical and cosmological questions that surveys like LSST and JDEM-Wide will be able to address.

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arXiv2009

Exploring Dark Energy with Next-Generation Photometric Redshift Surveys

The coming decade will be an exciting period for dark energy research, during which astronomers will address the question of what drives the accelerated cosmic expansion as first revealed by type Ia supernova (SN) distances, and confirmed by later observations. The mystery of dark energy poses a challenge of such magnitude that, as stated by the Dark Energy Task Force (DETF), "nothing short of a revolution in our understanding of fundamental physics will be required to achieve a full understanding of the cosmic acceleration." The lack of multiple complementary precision observations is a major obstacle in developing lines of attack for dark energy theory. This lack is precisely what next-generation surveys will address via the powerful techniques of weak lensing (WL) and baryon acoustic oscillations (BAO) -- galaxy correlations more generally -- in addition to SNe, cluster counts, and other probes of geometry and growth of structure. Because of their unprecedented statistical power, these surveys demand an accurate understanding of the observables and tight control of systematics. This white paper highlights the opportunities, approaches, prospects, and challenges relevant to dark energy studies with wide-deep multiwavelength photometric redshift surveys. Quantitative predictions are presented for a 20000 sq. deg. ground-based 6-band (ugrizy) survey with 5-sigma depth of r~27.5, i.e., a Stage 4 survey as defined by the DETF.

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arXiv2000

The Normal Cluster Weak Lensing Survey: Mass Profiles and M/L Ratios of Eight Clusters at z=0.2

We present a survey of mass profiles and mass-to-light ratios of eight typical galaxy clusters at a common redshift (z ~ 0.2). We use weak gravitational lensing as a probe because it is unique in avoiding any assumptions about the dynamical state of the clusters. To avoid bias toward the rare and spectacular clusters that are easy targets for lensing work, we selected an ensemble of much more common clusters with moderate X-ray luminosity. Although the survey is still in progress, two conclusions are emerging: (1) within a cluster, mass follows light very closely on the angular scales that we can measure, $0.2-2h^{-1}$ Mpc, and (2) there is a significant cluster-to-cluster scatter in mass-to-light (M/L) ratios despite uniformity of observing, reduction, and analysis procedures. We also derive an estimate of $Ω_{matter}$ based on extrapolation from the mass properties of these typical clusters. Finally, we discuss the discovery of other clusters in our fields through their lensing signal.

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