Adding Theory to the Virtual Observatory Sarah Maddison Centre for Astrophysics & Supercomputing Swinburne University Outline Two possible ways to add theory to the AVO/eAA Case study from Swinburne Astronomy Online ANITA Workshop, January 2003

Addition of theoretical astrophysics to AVO could be done in many ways, two of which include: Two Ways to Add Theory to AVO (1) database of codes; and (2) database of theoretical models & synthetic obs ANITA Workshop, January 2003

(1) Database of codes: There are currently a variety of freely available codes online and ready to download, including: ZEUS: grid based code for astrophysical radiation MHD available through the NCSA. – Codes available include: ZEUS2D,ZEUS3D,ZEUSMP (explicit Eulerian grid codes) TITAN (1D implicit adaptive mesh code) KRONOS (3D PPM + PM hydro grid code) 4D2 (SGI visualisation tool for 3D data) – Code freely available & bugs reported to NCSA. Comes with method paper describing algorithm, a users guide, plus test suite. Asked to register to track software use. – Written by Jim Stone (after Mike Norman) ANITA Workshop, January 2003

(1) Database of codes: There are currently a variety of freely available codes online and ready to download, including: HYDRA: Consortium which provides public-domain software for N-body hydro. Interested in galaxy & cluster formation. – Software available: hydra (adaptive PP-PM + SPH code) ap3m (adaptive PP-PM code, older but faster than hydra) – Code freely available & bugs reported. Contains installation file, algorithm papers, cosmological IC & BC generator. Also asked to register. – Written by Hugh Couchman, Frazer Pearce & Peter Thomas. ANITA Workshop, January 2003

(1) Database of codes: There are currently a variety of freely available codes online and ready to download, including: GADGET: galaxies with dark matter and gas interact – N-body + SPH code for cosmological simulations, includes star formation & feedback. Serial & MPI parallel versions. – Code is free software distributed under the GNU General Public License. Comes with code paper, users guide and ReadMe files. Asked to register to track software use. – Written by Volker Springel & extended by Naoki Yoshida ANITA Workshop, January 2003

(1) Database of codes: There are currently a variety of freely available codes online and ready to download, including: MLAPM: adaptive grid code for cosmological sims; Knebe NMSU Particle Code: PM code; Klypin & Hotzman N-Body Shop: variety of N-body tools; U.Wash HPCC SWIFT: solar system integration software for calculating planetary orbits, written by Hal Levison & Martin Duncan CLOUDY: plasma simulation code for interpreting spectroscopic data, written by Gary Ferland ANITA Workshop, January 2003

(1) Database of codes: – All these downloadable codes available at individual sites could easily be incorporated in the VO (with VO acting as a library). – One step further: run codes over the web or via the VO advantage: could compare different types of codes on the same problem (e.g. grid versus particle codes) problem: whose computer parallel codes run on and who stores the data problem: not all codes publicly available… would be limited by number of codes made available problem: who would maintain them?…authors like now or could be use at own risk (just like observational data!!) limited more by participation... ANITA Workshop, January 2003

(2) Database of models & synthetic obs: – run your codes with a range of parameters and make the results publicly available (e.g. stellar evolution codes, N-body codes, hydro codes, radiative transfer codes etc...) Virgo Consortium: formation of galaxies, clusters, large scale structure, and evolution of IGM. Projects include: –The Hubble Volume: study cluster, filament & void formation; snapshot data, lightcones, cluster catalogue –The VIRGO project: cosmological N-body simulation data archive; snapshots at various z for various cosmologies ANITA Workshop, January 2003 GRETA - European radiative transfer group, some models online

(2) Database of models & synthetic obs: – run your codes with a range of parameters and make the results publicly available (e.g. stellar evolution codes, N-body codes, hydro codes, radiative transfer codes etc...) – advantage: can make synthetic data to compare with your observations, including resolution & seeing etc. – problem: huge job of working out what parameters to search and how to tabulate/store the data, but the same problems exist with observational data… – limited only by time (=money) and imagination! ANITA Workshop, January 2003

Swinburne Astronomy Online includes a major project subject on Computational Astrophysics, allowing students with minimal computing experience to run numerical experiments in computational astrophysics & gain a deeper understanding of complex astronomical concepts. A Case Study Contains 6 modules: – stellar orbits – pulsar population synthesis – galactic dynamics – galaxy interactions – solar system dynamics – stellar evolution For details, see ANITA Workshop, January 2003

– Stellar Orbits: Simple N=2 or 3 codes to experiment with orbits; written inhouse by SAO Group How it works: ANITA Workshop, January 2003 – Pulsar Population Synthesis: Creates synthetic pulsar population & observes with a virtual telescope (,beamwidth, bandwidth, channels, integration..); written inhouse by Pulsar Group

How it works: – Galactic Dynamics: 3D N-body code with a 3 component galaxy model; written inhouse by Cosmology Group ANITA Workshop, January 2003 – Galaxy Interactions: 3D N-body code with two 3 component galaxy models; inhouse N-body code plus GalactICs for initial conditions

How it works: – Solar System Dynamics: 3D N-body code SWIFT to model N p planets & N TP test particles ANITA Workshop, January Setup the N p planets (given e, a, i, M) 2. Setup the N TP test particles (given range of e, a, i) 3. Run integrator and evolve system – Stellar Evolution: access to pre-computed stellar evolution data for various M star and z; code & data by Lattaznio

The mechanics: – Students log on to specific module in web server – PHP scripting allows various input parameters & runs job – Job submitted to Swinburne supercomputer (SAO nodes) – Pseudo queuing system setup – Results/data/plots returned to student data directory; currently just 3 models stored; students ed at completion of long job  But students did some really great real science projects! ANITA Workshop, January 2003 The results: – Tons of beta testing required! – Loads of documentation required – Loads of helpdesk support

There is no reason why the VO could not include a theory component (may need to change name…) Exactly how this would be done depends on what user want (access to codes or access to data - what codes & what data) An educational test case indicates that good science can be done using either model (database of results, or interface to a code) Next step: decide what users want! Summary ANITA Workshop, January 2003