Astronomy

Simulation and its necessity in astronomical research

Simulation and its necessity in astronomical research


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I was wondering if mainly everything in Astronomical and Astrophysical was dependent on Simulations then what are the educational requirements are necessary to qualify as the Simulation Expert.

What softwares are needed globally? Are all simulations run on a Supercomputer? Do astrophysicist require coding experience? And, is Knowledge of Programming a must?


I agree with @uhoh that you don't have to an expert, but above-average knowledge of coding is definitely useful, bordering on "a must". Not for writing huge programs with 1000s of lines, but for writing smaller pieces of code that help you in everyday tasks.

As uhoh says, you can very well find your place in a group where other people are in charge of numerical modeling, and focus instead on, for instance, interpretation of observational results, physical modeling, or even the technical aspects of telescope operation.

Software

You ask about what software is used: Some of the more popular if you're working with observational data are IRAF for reducing and analyzing the data and SAOImage/ds9 for visualizing. A long list of astronomical software can be found here.

On the other hand, if you're modeling galaxies or the interstellar medium you may want to familiarize yourself with stellar population synthesis codes such as STARBURST99, semi-analytical galaxy formation models such as GALFORM, or radiative transfer codes such as Cloudy.

Coding

For coding, if you are constructing large codes that require many hours of computation - possibly on a supercomputer - you will probably want your code to be fast. Then languages like FORTRAN and C are often used. For programs that don't necessarily need to be fast, comprehensive languages such as Python are very popular. For smaller tasks, shell-scripting can be very useful.

Even if you don't run simulations, you will most likely eventually need to automatize your work. For instance, rather than reducing 100 images one by one, you create a pipeline that does all the biasing, flat-fielding, cosmic-ray-removing, etc. in one go. And rather than going through a catalogue of a million galaxies one by one to look for those that match your preferred criteria, you create filtering software that finds them for you.

Supercomputing

Not all simulations are run a supercomputer. Huge cosmological simulations, galaxy formation simulations, etc. usually are, because you can usually start a simulation and then let it run for three months without interfering. But if your simulations are smaller, and possibly require that you check the process all the time, it's often sufficient/easier to run it on your local computer.


Center for Computational Astrophysics

Numerical simulation in astronomy is regarded as the third methodology of astronomy alongside observational and theoretical astronomy. We need computer simulation because it is practically impossible for us to perform laboratory experiments of astronomical phenomena due to their huge time and spatial scales. We create universes in computers (often very large ones, referred to as supercomputers) reproduce astronomical phenomena there, and observe their behavior. In other words, computers are experimental tools to create virtual universes, and at the same time telescopes to observe them. In these virtual universes, we can watch the very early stage of the cosmos and its evolution, we can reproduce the formation of galaxies, and we can witness the origin, evolution, and final fate of planetary systems including our own. Our project, CfCA, possesses various types of high-performance computers such as a massive parallel computer Cray XC50 “ATERUI Ⅱ,” a bunch of special-purpose computers for gravitational many-body problems “GRAPE” and other facilities, all of which operate twenty-four hours a day, throughout the year. Astronomers all over the world use these resources. In addition, CfCA works on research and development for new software algorithms for the next-generation of simulation astronomy that will enable us to perform the largest numerical experiments ever attempted. By numerical simulations with supercomputers, we will, probably in the very near future, solve the longstanding questions such as the formation of galaxies, the origin of the Solar System, and the real picture of black holes.

A magnetohydrodynamics simulation of interactions between an astrophysical jet (blue) and interstellar clouds (orange). Black lines show magnetic field lines. The jet accelerates the dense interstellar clouds during the propagation of the jet. This simulation revealed that the magnetic field enhances the acceleration of the dense clouds by the magnetic tension force.


Astronomy and astrophysics

Observational and theoretical research in astrophysics at Oxford is conducted across four of our six sub-departments: Astrophysics, Rudolf Peierls Centre for Theoretical Physics, Atmospheric, Oceanic and Planetary Physics and Atomic & Laser Physics. We are involved in a large range of global-scale experiments pushing at the frontiers of knowledge, as well as developing cutting-edge theory, on all scales from the Earth to the earliest signatures of physics imprinted in the cosmic microwave background. We have large groups working on cosmology, galaxies and black holes, through to stars and planets. We address these research areas with a combination of theoretical, simulation and observational work.

Cosmology

We host world-leading research in both theoretical and observational cosmology at Oxford. Theoretical cosmology, housed in the Beecroft Institute of Particle Astrophysics and Cosmology, focuses on dark energy, dark matter and general relativity as well as high resolution simulations of structure formation. On the observational front, Oxford is at the forefront of survey science with prominent leadership in the next generation of surveys: the Vera Rubin Observatory (dark sector), Euclid (weak lensing), Simons Observatory (CMB). We play a leading role in C-BASS, and played an important part of the Planck team. We also lead the VISTA/VIDEO Survey and play a leading role in the KiDS weak lensing survey.

Galaxy evolution

Our research programme on galaxy formation and evolution spans their structure and history, from the local Milky Way to the highest redshift galaxies. Galactic dynamics underpins much of our work, understanding the dynamical processes that have led to those distributions, particularly in our own galaxy, with emphasis on the distribution of baryonic and dark matter in galaxies, and in determining the masses of nuclear black holes. Our strategy is to exploit a combination of new data with dynamical and stellar population modelling to probe the assembly history of galaxies, using large galaxy surveys (MaNGA, SAMI and WEAVE) for galaxies up to redshift 2, multi-wavelength optical-infrared-radio imaging surveys up to redshift 4, and the James Webb Space Telescope (JWST) for higher redshifts. We have guaranteed access to JWST’s near-infrared multi-object spectrograph NIRSpec (including its IFS capability), which will reveal the nascent stages of galaxies as they first form stars and black holes in their dark haloes.

Pulsars, transients and relativistic astrophysics

Rapidly varying astrophysical sources such as pulsars, accreting black holes, supernovae and — most recently — neutron-star-merger events, are the prime laboratories at our disposal to study physical processes, and to test general relativity in the strong field regime. Deepening our understanding of strong-field gravity and other fundamental physics via pulsars is a key science goal of the Square Kilometre Array (SKA). We are at the forefront of all of the latest advances in transient science, including observations of the electromagnetic counterpart of the first neutron-star-merger event, GW170817, and radio detections of the first gamma-ray bursts detected with ground-based Cherenkov detectors. The Oxford pulsar group co-leads the design and development of the SKA instrumentation needed to deliver pulsar science, and has central involvement in the science exploitation of SKA pathfinder instruments such as LOFAR and MeerKAT. Global Jet Watch is a unique programme run by us to monitor stellar-mass accreting black holes in our Galaxy. The theory of the time evolution of relativistic accretion discs has been developed at Oxford and, in collaboration with the transient group, applied successfully to observations of tidal disruption events. Our outstanding plasma astrophysics programme makes state-of-the-art calculations which elucidate the dynamics of weakly collisional gas flows. This work is critical for understanding black hole accretion as well as the behaviour of the hot intracluster medium in clusters of galaxies.

Exoplanets

Exoplanets is one of the most rapidly developing fields of astrophysics and Oxford is one of the largest exoplanet research hubs in Europe. On the observational front, this work includes advanced statistical and machine-learning methods and precision radial-velocity measurements for exoplanet detection, and detailed atmospheric characterisation via innovative high resolution spectroscopy and high contrast imaging techniques. This in turn complements our instrumentation development of HARMONI and EPICS for the ELT. We are also leaders in advanced retrieval techniques for extracting atmospheric structure and composition from astronomical observations. Simulations have covered the range of planets from uninhabitable terrestrial planets such as lava planets, through habitable-zone terrestrial planets, and up through sub-Neptunes and hot and ultra-hot Jupiters and brown dwarfs. Pioneering work on long-term atmospheric evolution and habitability has been done at the interface of astrophysical, atmospheric and geochemistry disciplines.

Instrumentation

The astrophysics instrumentation group is leading the design and development of key components of two global flagship ground-based astronomy projects: the ELT and the SKA. HARMONI will be the visible and near-infrared integral field spectrograph for the ELT, one of only two instruments that will be deployed at first light. We are now approaching the construction phase for the SKA, and are likely to be leading several work packages in this phase. Oxford also led the development of the innovative C-BASS project. In addition, in 2020 we completed the construction of the WEAVE spectrograph, which will be the main workhorse for the WHT for the next five years. The Astrophysics sub-department has also
developed expertise in the implementation of superconducting receiver technology for the direct detection of THz (sub-mm wavelength) radiation.

Theoretical astrophysics

Working closely with the Astrophysics sub-department, members of our Rudolf Peierls Centre for Theoretical Physics conduct world-leading research into galactic dynamics and kinetic theory of self-gravitating systems, gravitational-wave astrophysics and black-hole physics, planetary dynamics and accretion discs, and astrophysical fluid dynamics.


Stunning Simulation Of Stars Being Born is Most Realistic Ever (Astronomy)

A team including Northwestern University astrophysicists has developed the most realistic, highest-resolution 3D simulation of star formation to date. The result is a visually stunning, mathematically-driven marvel that allows viewers to float around a colorful gas cloud in 3D space while watching twinkling stars emerge.

Called STARFORGE (Star Formation in Gaseous Environments), the computational framework is the first to simulate an entire gas cloud — 100 times more massive than previously possible and full of vibrant colors — where stars are born.

It also is the first simulation to simultaneously model star formation, evolution and dynamics while accounting for stellar feedback, including jets, radiation, wind and nearby supernovae activity. While other simulations have incorporated individual types of stellar feedback, STARFORGE puts them altogether to simulate how these various processes interact to affect star formation.

Using this beautiful virtual laboratory, the researchers aim to explore longstanding questions, including why star formation is slow and inefficient, what determines a star’s mass and why stars tend to form in clusters.

The researchers have already used STARFORGE to discover that protostellar jets — high-speed streams of gas that accompany star formation — play a vital role in determining a star’s mass. By calculating a star’s exact mass, researchers can then determine its brightness and internal mechanisms as well as make better predictions about its death.

Newly accepted by the Monthly Notices of the Royal Astronomical Society, an advanced copy of the manuscript, detailing the research behind the new model, appeared online today. An accompanying paper, describing how jets influence star formation, was published in the same journal in February 2021.

“People have been simulating star formation for a couple decades now, but STARFORGE is a quantum leap in technology,” said Northwestern’s Michael Grudić, who co-led the work. “Other models have only been able to simulate a tiny patch of the cloud where stars form — not the entire cloud in high resolution. Without seeing the big picture, we miss a lot of factors that might influence the star’s outcome.”

“How stars form is very much a central question in astrophysics,” said Northwestern’s Claude-André Faucher-Giguère, a senior author on the study. “It’s been a very challenging question to explore because of the range of physical processes involved. This new simulation will help us directly address fundamental questions we could not definitively answer before.”

Snapshot from a STARFORGE simulation. A rotating gas core collapses, forming a central star that launches bipolar jets along its poles as it feeds on gas from the surrounding disk. The jets entrain gas away from the core, limiting the amount that the star can ultimately accrete.

Grudić is a postdoctoral fellow at Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). Faucher-Giguère is an associate professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences and member of CIERA. Grudić co-led the work with Dávid Guszejnov, a postdoctoral fellow at the University of Texas at Austin.

From start to finish, star formation takes tens of millions of years. So even as astronomers observe the night sky to catch a glimpse of the process, they can only view a brief snapshot.

“When we observe stars forming in any given region, all we see are star formation sites frozen in time,” Grudić said. “Stars also form in clouds of dust, so they are mostly hidden.”

For astrophysicists to view the full, dynamic process of star formation, they must rely on simulations. To develop STARFORGE, the team incorporated computational code for multiple phenomena in physics, including gas dynamics, magnetic fields, gravity, heating and cooling and stellar feedback processes. Sometimes taking a full three months to run one simulation, the model requires one of the largest supercomputers in the world, a facility supported by the National Science Foundation and operated by the Texas Advanced Computing Center.

The resulting simulation shows a mass of gas — tens to millions of times the mass of the sun — floating in the galaxy. As the gas cloud evolves, it forms structures that collapse and break into pieces, which eventually form individual stars. Once the stars form, they launch jets of gas outward from both poles, piercing through the surrounding cloud. The process ends when there is no gas left to form anymore stars.

Pouring jet fuel onto modeling

Already, STARFORGE has helped the team discover a crucial new insight into star formation. When the researchers ran the simulation without accounting for jets, the stars ended up much too large — 10 times the mass of the sun. After adding jets to the simulation, the stars’ masses became much more realistic — less than half the mass of the sun.

“Jets disrupt the inflow of gas toward the star,” Grudić said. “They essentially blow away gas that would have ended up in the star and increased its mass. People have suspected this might be happening, but, by simulating the entire system, we have a robust understanding of how it works.”

Beyond understanding more about stars, Grudić and Faucher-Giguère believe STARFORGE can help us learn more about the universe and even ourselves.

“Understanding galaxy formation hinges on assumptions about star formation,” Grudić said. “If we can understand star formation, then we can understand galaxy formation. And by understanding galaxy formation, we can understand more about what the universe is made of. Understanding where we come from and how we’re situated in the universe ultimately hinges on understanding the origins of stars.”

“Knowing the mass of a star tells us its brightness as well as what kinds of nuclear reactions are happening inside it,” Faucher-Giguère said. “With that, we can learn more about the elements that are synthesized in stars, like carbon and oxygen — elements that we are also made of.”

Multimedia Downloads

Featured image:Snapshot from the first full STARFORGE simulation. Nicknamed the “Anvil of Creation,” a giant molecular cloud with individual star formation and comprehensive feedback, including protostellar jets, radiation, stellar winds and core-collapse supernovae. © Northwestern University/UT Austin


Simulation of the binary black hole merger GW150914.

Einstein Toolkit

We are developing and supporting open community software for relativistic astrophysics that takes advantage of emerging petascale computers and advanced cyberinfrastructure. The toolkit combines a core set of components needed to simulate astrophysical objects such as black holes, compact objects, and collapsing stars, as well as a full suite of analysis tools.

Deep Learning

Examples of glitches classified by our deep learning method. This allows better characterization of gravitational wave detectors algorithms. (From George, Shen, & Huerta 2017)

Deep Learning, i.e, machine learning, based on deep artificial neural networks, is one of the fastest growing fields of artificial intelligence (AI) research today. We are applying deep learning with artificial neural networks, in combination with HPC numerical relativity simulations, in a variety of multimessenger astrophysics applications. Our current focus is on signal processing for gravitational wave detectors (LIGO, VIRGO, NANOGrav), analyzing data from telescopes (DES, LSST), and modeling waveforms from gravitational wave sources using algorithms that learn from numerical relativity simulations. This allows for real-time detection and parameter estimation of gravitational wave signals in LIGO, for denoising LIGO data contaminated with non-Gaussian noise, and for classification and unsupervised clustering of glitches (anomalies) in the LIGO detectors. We are now also developing fast automated transient search algorithms based on deep learning using raw image data from telescopes (e.g., DES and LSST) to rapidly classify electromagnetic counterparts to gravitational wave events.

Adaptive mesh refinement

Example of AMR simulation of a common envelope binary system from Ricker and Taam 2012, ApJ, 746, 74

We participate in the development and use of adaptive mesh refinement (AMR) techniques for astrophysical hydrodynamics simulations in the FLASH and Nyx codes. FLASH is a widely used, freely available package employed for simulations ranging from core-collapse supernovae and high-energy laser experiments to galaxy cluster evolution and large-scale structure. Nyx is a publicly available cosmological simulation code originally developed for simulations of the Lyman alpha forest. Our current development efforts focus on new physics solvers for these codes and new sub-resolution modeling techniques to better incorporate physical effects due to unresolved scales.


Research Notes

Research Notes of the AAS is non-peer reviewed, indexed and secure record of works in progress, comments and clarifications, null results, or timely reports of observations in astronomy and astrophysics. Research Notes are moderated but not edited, which allows them to be rapidly published online within days of acceptance. The brief articles published in RNAAS are searchable in ADS and fully citable, and they are archived for perpetuity.


The ARC

The Astronomy Research Centre (ARC) at the University of Victoria brings together world-renowned researchers in astrophysics, engineering, computation, and instrumentation working in or near Victoria, BC.

UVic scientists and engineers work closely with colleagues at the nearby NRC Herzberg Institute in Saanich, the NRC DRAO in Penticton, and at TRIUMF in Vancouver, to form one of the largest concentrations of astronomy-related talent in Canada.

Our mission is to communicate the exciting astronomical research being done at/with UVic, to facilitate new collaborations and synergy, to support high quality undergraduate, graduate and post-doctoral training, and to foster public engagement in science.

We encourage you to explore and learn from UVic's Office of Indigenous Academic & Community Engagement pages and ARC's Indigenous Acumen page.

ARC Director's Corner

Welcome to the UVic Astronomy Research Centre!   We were established in 2015 as a communication platform to increase awareness and opportunities in astronomical research at UVic.   Our members from UVic’s faculties of Science and Engineering work with researchers at the nearby NRC’s Herzberg Astronomy & Astrophysics Research Centre in Saanich, BC, the NRC’s Dominion Radio Astronomy Observatory in Penticton, BC, the TRIUMF lab in Vancouver, BC, and with industrial partners across Canada.

Members of the ARC include students, postdocs, staff, faculty, adjuncts, and associates involved in a wide range of astronomical research, including ground and space-based instrumentation.   All of our work requires research supp ort, through local and national computer servers, rapid access to cloud computing, and high performance computing for intensive simulations.   These are top priorities for the ARC, both to serve our members, and to share the research outcomes from this cluster of excellence across Canada and with the broader community.

ARC hosts or supports local astronomy-related workshops, and helps to coordinate major funding requests and other research initiatives.   Currently, ARC hosts an NSERC-CREATE training program on New Technologies for Canadian Observatories, and is involved in the CFI-funded GIRMOS instrument being built at NRC-Herzberg for the Gemini-South Observatory.   In addition, several members of ARC are involved in a large CFI proposal for the final design phase of a new 11-meter spectroscopic survey telescope, the Maunakea Spectroscopic Explorer.    

Finally, ARC s upports UVic activities, such as the observatory open houses and group tours, and student-led initiatives, such the astrophotography group.   More recently, ARC has initiated efforts to be more inclusive of Indigenous students, Indigenous knowledge, and diverse perspectives in astronomy.   This is a pillar in the UVic Strategic Plan, and we hope to provide a more welcoming space for all those who are curious about the sky.

We encourage you to browse these webpages, and explore the exciting research outcomes, research opportunities, and other activities supported by the ARC.

Program Management Team

The Program Management Team helps to identify and prioritize the goals of the ARC, and oversees the strategic planning to reach those goals.   This team is comprised of members from all significant partners in the ARC.  


Astronomy & Astrophysics

Few things in the Universe hold a unique fascination like space, stars, and the creation of the elements. Humans have long gazed towards the sky, searching for meaning and order to the Universe around them. Astronomy is one of the oldest sciences. It is the study and observation of celestial objects and phenomena, like stars, planets and the Milky Way Galaxy, that lie beyond our Earth’s atmosphere.

Astrophysics is concerned not only with the observation of our Galaxy but also how the Universe originated and how it has evolved (cosmology). Astrophysicists apply the physical laws of microphysical processes to explain astronomical events. These laws determine the lifecycle of stars, planets and galaxies in the Universe as well as how the Universe has changed with time.

Associated Schools, Institutes & Centres

Impact

Our astronomical research focuses on the numerical simulation of binary star mergers, supernova explosions, and nucleosynthesis. Stars are the building blocks of the galaxy. These luminous balls of light helped explorers navigate the seas and now help modern-day scientists understand the Universe. When a dying star explodes, it ejects its mass and heavy elements into the surrounding space. Everything on Earth, including life, is composed of the chemical elements produced in stars and supernova explosions, which is what makes astrophysics research important.

We perform theoretical and observational research using Big Data methodologies to understand:


Policies

AAS Journals have adopted a policy that reflects the importance of software to the astronomical community, and the need for clear communication about such software which ensures that credit is appropriately given to its authors. The policy provides clear guidelines for citing software in all articles, and supports the publication of descriptive articles about software relevant to research in astronomy and astrophysics.

Professional and Ethical Standards for the AAS Journals

As implicit conditions for publishing in The Astrophysical Journal and The Astronomical Journal, authors are expected to adhere to basic standards of professional ethics and conduct that are common across all areas of scholarly publishing.

The Planetary Science Journal Policies and Guidelines

Manuscripts submitted for publication in The Planetary Science Journal must generally be prepared in the same way and must meet the same criteria as for all articles published in the AAS journals. The following specific policies and guidelines govern the submission and review of PSJ manuscripts.

The Astrophysical Journal Letters Requirements

Manuscripts submitted for publication in The Astrophysical Journal Letters must generally be prepared in the same way and must meet the same criteria as for all articles published in the AAS journals. However, a Letter should report results of significantly greater importance and potential impact than typically published in other AAS journals. The results should have a significant immediate impact on a number of other investigators, and they should be of broad current interest in astronomy.

Research Note Preparation Guidelines

Submissions to RNAAS should be brief communications — 1,500 words or fewer, with no more than a single figure or table (but not both) — and should be written in a style similar to that of a traditional journal article, including references, where appropriate.

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PSJ Science Editors

Brian Jackson, Edgard G. Rivera-Valentin, and Maria Womack join Faith Vilas as PSJ Science Editors. Read more here.

Research Notes of the AAS

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