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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 galaxiesrotation curves of galaxies
existence of Dark Matter DM
• hierarchical structure formationhierarchical structure formation
nature of Dark Matter CDM
• high redshift observationshigh redshift observations
cosmology CDM
testing model using N-body simulations reveals…
(Bahcall et al. 2001)
VOYAGE what determines the model ?
what ?
model fixed ?
ob
serv
atio
ns
ob
serv
atio
ns
• high resolution N-body simulations:high resolution N-body simulations: • observations: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 ofsatellite 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
what code do you use ?
0 20 40 60 80 100
public
own
what analysis tools do you use ?
0 20 40 60 80 100
IDL
own
what sort of data do you store ?
0 20 40 60 80 100
grid
particles
what do you compare your data to ?
0 20 40 60 80 100
observations
others other models
own other models
would you make your data available ?
0 20 40 60 80 100
no
already available
yes
based on questionaire returned by 53 out of 106, Astrophysical Supercomputing Using Particle Simulations,IAU Symposium 208, Tokyo, July 2001 (P. Teuben, astro-ph/0204470)
how ?
VOYAGE has the VOYAGE already begun ?
all in non-compatible data formats,but the data is being used !
VIRGO SCDM, CDM, OCDM, CDM model2563 particles
239.5 Mpc/h box
“Hubble Volume” CDM, CDM model10243 particles3000 Mpc/h box
“COBE grid” 68 (COBE-normalized) models (more than you can poke a stick at…)
643 particles128 Mpc/h box
NEMO data archive collection of links to data releases
plus some more by individual groups…
how ?
VOYAGE can one feed on data alone ?
how ?
MLAPM adaptive multi-grid code (Knebe et al. 2001)
GADGET tree-SPH code (Springel et al. 2000)
HYDRA AP3M code (Couchman et al. 1995)
hierarchical TreeCode ultra-fast (!?) tree code (Dehnen 2000)
PM code simple PM code (Klypin 1995)(incl. analysis tools !)
available codes: (mostly no analysis tools distributed !)
http://astronomy.swin.edu.au/cosmology
most codes are proprietary products !
VOYAGE is there any consistency ?
how ?
The Santa Barbara Cluster Comparison Project (Frenk et al. 1999)
• the oponents
6 Lagrangian codes (particle based)vs.
5 Eulerian codes (grid based)
• the outcome
reassuring but also confusing
• 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 http://astronomy.swin.edu.au/MLAPM
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 !
VOYAGE Swinburne’s contribution
!!!
filament fragmentation
C
DM
W
DM
z=5 z=3 z=1 z=0
(Knebe et al. 2003)
VOYAGE Swinburne’s contribution
!!!
streams from disrupted satellite galaxies
(Gill et al. 2002)
VOYAGE Virtual Observatory, Yet Another Great Extension ?!
thank you for your attentionand
bon voyage...
Alexander Knebe, Swinburne University
VOYAGE is there any consistency ?
how ?
The Santa Barbara Cluster Comparison Project
grid based codes
particle based codes
particle based codes
grid based codes
temperature profile entropy profile
(Frenk et al. 1999)
VOYAGE a little survey
what analysis tools do you use ?
0 20 40 60 80 100
IDL
own
what sort of data do you store ?
0 20 40 60 80 100
grid
particles
what do you compare your data to ?
0 20 40 60 80 100
observations
others other models
own other models
would you make your data available ?
0 20 40 60 80 100
no
already available
yes
based on questionaire returned by 53 out of 106, Astrophysical Supercomputing Using Particle Simulations,IAU Symposium 208, Tokyo, July 2001 (P. Teuben, astro-ph/0204470)
how ?
what code do you use ?
0 20 40 60 80 100
public
own
VOYAGE a little survey
what code do you use ?
0 20 40 60 80 100
public
own
what sort of data do you store ?
0 20 40 60 80 100
grid
particles
what do you compare your data to ?
0 20 40 60 80 100
observations
others other models
own other models
would you make your data available ?
0 20 40 60 80 100
no
already available
yes
based on questionaire returned by 53 out of 106, Astrophysical Supercomputing Using Particle Simulations,IAU Symposium 208, Tokyo, July 2001 (P. Teuben, astro-ph/0204470)
how ?
what analysis tools do you use ?
0 20 40 60 80 100
IDL
own
VOYAGE a little survey
what code do you use ?
0 20 40 60 80 100
public
own
what analysis tools do you use ?
0 20 40 60 80 100
IDL
own
what do you compare your data to ?
0 20 40 60 80 100
observations
others other models
own other models
would you make your data available ?
0 20 40 60 80 100
no
already available
yes
based on questionaire returned by 53 out of 106, Astrophysical Supercomputing Using Particle Simulations,IAU Symposium 208, Tokyo, July 2001 (P. Teuben, astro-ph/0204470)
how ?
what sort of data do you store ?
0 20 40 60 80 100
grid
particles
VOYAGE a little survey
what code do you use ?
0 20 40 60 80 100
public
own
what analysis tools do you use ?
0 20 40 60 80 100
IDL
own
what sort of data do you store ?
0 20 40 60 80 100
grid
particles
would you make your data available ?
0 20 40 60 80 100
no
already available
yes
based on questionaire returned by 53 out of 106, Astrophysical Supercomputing Using Particle Simulations,IAU Symposium 208, Tokyo, July 2001 (P. Teuben, astro-ph/0204470)
how ?
what do you compare your data to ?
0 20 40 60 80 100
observations
others other models
own other models
VOYAGE a little survey
what code do you use ?
0 20 40 60 80 100
public
own
what analysis tools do you use ?
0 20 40 60 80 100
IDL
own
what sort of data do you store ?
0 20 40 60 80 100
grid
particles
what do you compare your data to ?
0 20 40 60 80 100
observations
others other models
own other models
would you make your data available ?
0 20 40 60 80 100
no
already available
yes
based on questionaire returned by 53 out of 106, Astrophysical Supercomputing Using Particle Simulations,IAU Symposium 208, Tokyo, July 2001 (P. Teuben, astro-ph/0204470)
how ?
