Presentation on theme: "VOYAGE Virtual Observatory, Yet Another Great Extension ?! should simulation data be included in a Virtual Observatory ? Alexander Knebe, Swinburne University."— Presentation transcript:
VOYAGE Virtual Observatory, Yet Another Great Extension ?! should simulation data be included in a Virtual Observatory ? Alexander Knebe, Swinburne University what ? why ? how ? …this is all biased towards cosmological n-body simulations
VOYAGE what are (cosmological) simulations anyway ? what ?
rotation curves of galaxies existence of Dark Matter DM hierarchical structure formation nature of Dark Matter CDM high redshift observations cosmology CDM testing model using N-body simulations reveals… (Bahcall et al. 2001) VOYAGE what determines the model ? what ? model fixed ? observations observations
high resolution N-body simulations: observations: steep, cuspy density profiles hundreds of satellite galaxies small disk sizes mostly shallow density cores only a few satellites observed larger disk sizes what ? VOYAGE what’s the problem ? breakdown of CDM paradigm on scales < 1 Mpc ?
VOYAGE time for a VOYAGE ? i.e., observed number of satellite galaxies orbiting in dark matter halo more data needed: from observers from simulators why ? correctly measured? correct models ? (Klypin et al. 1999)
VOYAGE why should VO be extended ? simulations are time intensive simulations contain 6D information: x(t), v(t) cross-comparison of models possible let’s pull the strings together: problems get solved only by exchange of ideas simulators need observers to gauge and improve models observers need simulators to calibrate observations why ?
VOYAGE simulations lead to observations ?! one ring encompasses it all ? simulated tidal stream of disrupted satellite galaxy milky way type dark matter halo observed stellar stream in own milky way halo why ? (Odenkirchen et al. 2003) (Gill et al. 2002)
VOYAGE a little survey based on questionaire returned by 53 out of 106, Astrophysical Supercomputing Using Particle Simulations, IAU Symposium 208, Tokyo, July 2001 (P. Teuben, astro-ph/ ) how ?
VOYAGE has the VOYAGE already begun ? all in non-compatible data formats, but the data is being used ! VIRGOSCDM, CDM, OCDM, CDM model particles Mpc/h box “Hubble Volume” CDM, CDM model particles 3000 Mpc/h box “COBE grid”68 (COBE-normalized) models (more than you can poke a stick at…) 64 3 particles 128 Mpc/h box NEMO data archivecollection of links to data releases plus some more by individual groups… how ?
VOYAGE can one feed on data alone ? how ? MLAPMadaptive multi-grid code (Knebe et al. 2001) GADGETtree-SPH code (Springel et al. 2000) HYDRAAP 3 M code (Couchman et al. 1995) hierarchical TreeCodeultra-fast (!?) tree code (Dehnen 2000) PM codesimple PM code (Klypin 1995) (incl. analysis tools !) available codes: (mostly no analysis tools distributed !) most codes are proprietary products !
VOYAGE is there any consistency ? how ? The Santa Barbara Cluster Comparison Project (Frenk et al. 1999) the oponents the oponents 6 Lagrangian codes(particle based) vs. 5 Eulerian codes (grid based) the outcome the outcome reassuring but also confusing the winner the winner ?
VOYAGE what’s the bottomline ? how ? add data add basic analysis (“simulated observations”) + add software: codes analysis tools
VOYAGE is it feasible ? hmm ? requires great coordination requires input from simulators simulations outdate quickly...
VOYAGE Swinburne’s contribution !!! MLAPM is already publically available next MLAPM version will contain on-the-fly analysis we do have sophisticated visualisation tools for MLAPM data we do have high-resolution data (cf. Daisuke Kawata’s talk) we are more than happy to be part of this VOYAGE !