1. Virtual Observatory for cosmological simulations
Hervé Wozniak
Journées LSST France mars 2017

2. Cosmo sims for LSST preparation and analysis
Need of suite of cosmological simulations (w/ or wo/ baryonic matter) to prepare for LSST observations and data analysis:
Mock catalogs
Weak/strong lensing mock maps
Detection statistics (e.g. dwarfs)
Etc.
Feedback loop of LSST observations on cosmo sims (model parameters, baryonic physics etc.)
(2015)
H. Wozniak / Journées LSST France mars 2017
20/03/2017

3. Produits simulation Millenium… (mini-Millenium)
Snapshots
(DM part.)
2005, Blaizot & Lemson
(MPA and GAVO)
via recherches de structures
Haloes
Props. & Trees
via modèle semi-analytique DB DB
(L-)Galaxies
Spectra
MoMAF
online
Mock cat.
DM part.
Mock cat.
haloes
Mock cat.
galaxies
Mock cat.
spectra
Lensing maps
SZ/Xray …
Mock image
galaxies
Mock image
spectra
Lensing maps

4. What is the Virtual Observatory?
« an enabling and coordinating entity to foster the development of tools, protocols, and collaborations necessary to realize the full scientific potential of astronomical databases in the coming decade »
NVO White Paper, juin 2000
Science driven initiative
Immediate keyword: interoperability
 communication  interfaces  standardization  international organization (i.e. W3C for the Web)
International coordination: IVOA (International Virtual Observatory Alliance)
French partner: OV-France funded by INSU and CNES
H. Wozniak / Journées LSST France mars 2017
20/03/2017

5. Simplified access to products
interoperability
Lemson & Colberg 2004
H. Wozniak / Journées LSST France mars 2017
20/03/2017

6. ‘Theoretical’ Virtual Observatory
Taking care of the specificity of simulated data
no sky coordinates, need to keep track of algorithms, physical recipes, input parameters, etc.
Job of the IVOA Theory Interest Group since 2004
Position of the problem (main steps):
Discovering published simulation projects
Through VO-registries, googlization, word of mouth, etc.
For selected projects, discovering simulation datasets
Through browsing…
Retrieving data
full datasets or cutout in nD in case of Pb
Asynchronous download…
H. Wozniak / Journées LSST France mars 2017
20/03/2017

7. SimDAL: Simulation Data Access Layer
Define SimDAL API in 3 parts:
Repository (discovery)
Search (for a relevant dataset in a project)
Data Access
Core use cases:
R1: Discover sets of simulations published in the Virtual Observatory and find the associated services. Examples: Discover services publishing simulations of large structures in a cosmological context or services publishing synthetic stellar spectra.
R2: Find particular simulations and their associated datasets according to specific input parameters or characteristics of the outputs (for e.g. statistics on the results). Example: In a service publishing synthetic stellar spectra, find models of stars with an effective temperature between 2000 and 3000 K.
R3: Download simulation raw datasets or subsets extracted with a cut-out. Example: Download a data cube of a simulation of dark matter or download a theoretical spectrum in a specific wavelength range.
H. Wozniak / Journées LSST France mars 2017
20/03/2017

8. SimDM: Simulation Data Model
Kind of ‘Provenance’ model for theoretical products
H. Wozniak / Journées LSST France mars 2017
20/03/2017

9. H. Wozniak / Journées LSST France 20-22 mars 2017
20/03/2017

10. Controlled vocabulary
Understanding the metadata
Semantic web, SKOS, etc.
Job of the IVOA semantic Working Group
H. Wozniak / Journées LSST France mars 2017
20/03/2017

11. The main (future) efforts for LSST
Perform raw cosmological simulations
Produce mock products according to LSST or Science consortia requirements
Setup VO-compatible access services (how much fte?)
(optional) Register in VO registries to enable discovery
Only if a world-wide exposure is necessary/wanted
Enjoy!
H. Wozniak / Journées LSST France mars 2017
20/03/2017

12. Examples of “theory” VO services
H. Wozniak / Journées LSST France mars 2017
20/03/2017

13. Additional reading
“An online theoretical virtual observatory for hydrodynamical, cosmological simulations”
Languignon D., Le Petit F. (eds), 2016, Simulation Data Access Layer 1.0, IVOA Proposed Recommendation (
Lemson G., Wozniak H. (eds), 2012, Simulation Data Model 1.0 , IVOA Recommendation (
Lemson G., Wozniak H., Zuther J. (eds.), 2008, « Framework for the inclusion of theory data and services in the VObs », Euro-VO DCA Theory Expert Group report (
Lemson G., Colberg J., 2004, « Theory in the VO » (
Wozniak H., Chapter 14 : « Simulation et modélisation astrophysique dans le cadre de l’Observatoire virtuel », in « Modéliser & Simuler. Epistémologies & Pratiques de la modélisation et de la simulation », M. Silberstein & F. Varenne (Eds), Editions Matériologiques,  (2013, April 18th)
H. Wozniak / Journées LSST France mars 2017
20/03/2017