Archivi tag: astronomical surveys

Back at the Edge of the Universe

Making full use of the capabilities of the largest and most powerful ground- and space-based observatories, operating throughout the electromagnetic spectrum, large international teams have extensively studied the most distant reaches of the Universe. Many hours of telescope time and computational effort have been employed in what is one the most pressing issues of modern science, and many findings have driven us ever nearer to understanding the formation and evolution of galaxies. Continua a leggere Back at the Edge of the Universe

Science Results from Pan-STARRS1

The Pan-STARRS1 Science Consortium has carried out a multi-color survey of the entire sky north of declination -30 degrees for more than 3 years using the Pan-STARRS1 telescope in Hawaii. The observing mission formally ends in March 2014 and the project is planning to release the data publicly in 2015 through the STScI archive. This meeting will present the breadth of science from Pan-STARRS1, ranging from solar system objects, low-mass stars, galaxy structure, and the transient sky, to the most distant quasars. Presentations from the PS1SC will review the status of the project along with descriptions of the data products and data quality and plans for public release. The meeting will review the results so far and describe future public data access and science exploitation of this immense legacy archive.

27° Texas Symposium on Relativistic Astrophysics

The 27th Texas Symposium on Relativistic Astrophysics will be held in downtown Dallas December 8 – 13, 2013. It is organized by the Department of Physics at The University of Texas at Dallas (UTD) and is chaired by Wolfgang Rindler and Mustapha Ishak. The Symposium will include both invited and contributed talks and posters. This will be a special and historically meaningful Jubilee meeting, marking the 50th anniversary, almost to the day, of the very first of these Texas Symposia, held in Dallas in December 1963. We are excited to welcome hundreds of international astrophysicists back to Dallas fifty years later, both to celebrate the past 50 years of Texas Symposia and relativistic astrophysics and to kick off the next 50 years of remarkable discoveries.

The Symposium will cover the following topics:

Cosmology

  • Cosmic acceleration/dark energy
  • Cosmic microwave background
  • Early universe (Inflation, Cyclic Model, CCC cosmology …)
  • Galaxy formation and reionization
  • Inhomogeneous cosmologies, averaging, and backreaction
  • Large-scale surveys
  • Quantum gravity/cosmology and string cosmology
  • Weak gravitational lensing
  • Experimental/observational cosmology – other topics
  • Theoretical cosmology – other topics
Compact objects and galactic/cluster scales
  • Black holes, mergers, and accretion discs
  • Galaxy evolution and supermassive black holes
  • Imaging black holes
  • Microlensing and exoplanets
  • Neutron stars, pulsars, magnetars, and white dwarfs
  • Nuclear Equation of State for Compact Objects
  • Singularities
  • Strong gravitational lensing
  • Supermassive black hole binaries
  • Tidal disruption of stars by supermassive black holes
  • Compact object observations – other topics
  • Compact object theory – other topics
High-energy astrophysics and astroparticle physics
  • Active galactic nuclei and jets
  • Cosmological implications of the Higgs and the LHC
  • Dark matter astrophysics
  • Dark matter experiments and data
  • Gamma-ray bursts, SNe connection, and sources
  • High-energy cosmic rays (VHE, UHE, mechanisms, etc.)
  • High-energy gamma-rays
  • Nuclear Astrophysics
  • Supernovae and their remnants
  • High-energy astrophysics/astroparticle physics – other topics
Testing general relativity and modified gravity
  • Alternative theories of gravity
  • Strong-field tests of general relativity
  • Testing general relativity at cosmological scales
  • Testing general relativity – other topics
  • Modified gravity – other topics
Gravitational waves
  • Electromagnetic counterparts of gravitational wave sources
  • Ongoing and planned gravitational wave experiments
  • Gravitational wave theory and simulations
  • Results and progress from gravitational wave searches
  • Supernovae and Gravitational Wave Emission
  • Gravitational waves – other topics
Numerical relativity
  • Computer algebra and symbolic programming
  • Locating black hole horizons
  • Numerical simulations
  • Relativistic magnetohydrodynamics
  • Numerical relativity – other topics
Other ongoing and future experiments and surveys
  • ACT, AMS, BOSS, CFHT, Chandra, DES, Euclid, Fermi, HETDEX, HSC, JWST,
  • LHC, LSST, NuSTAR, Pan-STARRS, Planck, SDSS, SKA, SPT, WFIRST, WMAP, …
  • (to be completed after abstract submissions)
And also:
History of relativistic astrophysics
History of the Texas Symposium and interface with other anniversaries
The Kerr solution – 50 years later

Exploring the dark sector of the Universe with supercomputers

L’Universo è composto dal 95% di energia scura e materia scura. Comprendere la fisica del cosiddetto “settore scuro” rappresenta la principale sfida della cosmologia moderna. Oggi, grazie a sofisticate simulazioni numeriche, possiamo iniziare a comprendere l’evoluzione dell’Universo primordiale e la formazione delle strutture cosmiche.

The primary lens through which scientists look at the night sky is no longer only a telescope, it’s also a supercomputer. The new and coming generations of supercomputers will finally be capable of modeling the Universe in the detail and volume required by astronomical surveys of the sky that are now underway, or soon will be. Scientists use large cosmological simulations to test theories about the structure of the Universe and the evolution of the distribution of galaxies and clusters of galaxies. State of the art supercomputers let cosmologists make predictions and test them against data from powerful telescopes and space probes. Two decades of surveying the sky have culminated in the celebrated Cosmological Standard Model. Yet two of the model’s key pillars, dark matter and dark energy, together accounting for 95% of the Universe, remain mysterious. A research team led by Argonne is tackling this mystery, aided by some of the world’s fastest supercomputers. To model the distribution of matter in the Universe, the researchers are running some of the largest, most complex simulations of the large-scale structure of the universe ever undertaken.The Argonne team has run a 1.1-trillion-particle simulation on half a million processor cores of Mira, Argonne’s new Blue Gene/Q supercomputer. The team was among a few science teams from across the country to gain early access to the system, which is now online.

“In a very real sense, we only understand 4% of the Universe. To basic scientists like us, that’s a crime—that’s not allowed”, says Argonne physicist Steve Kuhlmann.

The power and speed of supercomputers and simulation codes  have significantly advanced over the past decade. Mira enables cosmology runs with greater resolution and accuracy on much larger simulation volumes, giving researchers the ability to confront theory with observational data from wide-area cosmological surveys. Exploring the cosmic structure of the dark Universe is an enormously complex problem. As the Universe expands, gravitational attraction causes matter to coalesce and form structures, first sheets, then filaments where the sheets intersect, and then clumps where the filaments meet. As time progresses, one can begin to see more clearly the basic structure of an enormous web of voids, filaments, and clumps. Simulations at Argonne have calculated this web-like structure, the so-called cosmic web, in a cube of simulated space more than 13 trillion light-years across. “Because these trillions of particles are meant to trace matter in the entire universe, they are extremely massive, something in the range of a billion suns”, said Argonne computational physicist Salman Habib, the project’s director. “We know the gravitational dynamics of how these tracer particles interact, and so we evolve them forward to see what kind of densities and structure they produce, as a result of both gravity and the expansion of the Universe. That’s essentially what the simulation does: it takes an initial condition and moves it forward to the present to see if our ideas about structure formation in the Universe are correct”.

Dark energy may be the most profound mystery in all of science”, says University of Chicago cosmologist Michael Turner.

Next-generation sky surveys will map billions of galaxies to explore the physics of the “dark universe”. Science requirements for these surveys demand simulations at extreme scales in order to resolve galaxy-scale mass concentrations over the observational volumes of sky surveys. A key aspect of the Argonne project involves developing a major simulation suite covering approximately 100 different cosmological scenarios and combining them in a framework that can generate predictions for any scenario within the range covered by the original runs.

ANL: Exploring the dark universe at the speed of petaflops

ANL: Dark energy: Q&A with Steve Kuhlmann

CosmicConference – Domenica 1° Dicembre ore 18

Il 96% dell’Universo

www.astroperinaldo.it