The Gaia Simulator. Carine Babusiaux & Xavier Luri CU2

Transcription

1 The Gaia Simulator Carine Babusiaux & Xavier Luri

2 The need for simulations Mission design (SWG, 99-04) Mission concept and goals Instrument design data reduction feasability demonstration Data reduction preparation (DPAC, ) Data treatment architecture Algorithms development Test the algorithms and models Performances analysis During operation? ( ) Validation of the scientific models on real data. Support the scientific exploitation of the Gaia data

3 Organisation within DPAC Requests for simulated data are sent in each cycle (every 6 months) by the different CUs in DPAC The development of the different modules of the simulator is jointly agreed, taking into account : each CU's needs their global priorities within the overall consortium the availability of the simulation models (which can depend on industrial tests or other CU accuracy models) the available manpower. Today : About 80 active members more than lines of code several terabytes of simulated data have been produced

4 The Universe observable by Gaia

5 scanning law 45 o

6 payload

7 optical path

8 focal plane SM1-2 AF1-9 BP RP RVS

9 photons collection AF RP RVS on-board detection, selection and windowing raw data sent to ground

10 DPAC!

11 Example... crowding 2 FoV gates cosmic-rays windows overlap RP observation of the open cluster ngc6231

12 The Gaia Simulator structure GaiaSimu Universe Instrument Utils GASS Telemetry GIBIS Pixel-level data GOG Gaia catalogue

13 GAia System-level Simulator - GASS The GASS data generator provides simulations of the telemetry stream of the mission based on some simplications of the instrument and Universe models allowing a large amount of data to be simulated over a significant period of time. GASS provides realistic data for: Predictions to be used for mission design. Filling of test databases Testing of core reduction algorithms Evaluation of mission performances, in particular for peculiar objects (binary stars, NEO s, extrasolar planets,...) GASS is developed in UB. The GASS manager is E. Masana.

14 GASS is run in large computer clusters and specially at the Mare Nostrum supercomputer. GASS 4 sec scan G < 25 SM ASTRO patches

15 Gaia Instrument and Basic Image Simulator The GIBIS data generator provides simulations of the data at the pixel level. The resulting simulations are as realistic as possible and restricted, due to computing time limitations, to a region of a sky over a short period of time. GIBIS provides realistic pixel level data for: Mission and Instrument design Detection & selection algorithm development Instrument calibration studies Analysis of the reduction algorithms in peculiar conditions, coming from the instrument (not-nominal behaviour) and from the sky (crowding, background, extended objects, ) GIBIS is developed at the Observatoire de Paris-Meudon. The GIBIS manager is C. Babusiaux.

16 GIBIS GIBIS is available as a web service and is also run in batch mode in computer clusters.

17 Gaia Object Generator - GOG The GOG data generator provides simulations of number counts and lists of observable objects from the Universe model and, for a given source or a collection of sources, simulations of intermediate and endof-mission Gaia data. GOG aims to simulating the contents of the MDB at any stage of the data processing. GOG is developed at UB. The GOG manager is Y. Isasi.

18 GOG GOG is available as a web service and is also run in batch mode in computer clusters.

19 The Future : Science with the Gaia Simulator should mostly complete its work by end of 2010 : what next? The Gaia Simulator is a very powerfull tool that will be available to the community. Tool with three levels: Detail analysis - GIBIS Mission simulation GASS Catalogue simulation GOG Will allow comparisons of models against real data

20 Some examples of science with the simulator Details studies of the characteristics of the Gaia catalogue completeness precision & accuracy Details studies of peculiar sources disentangling instrumental effects to astrophysical properties photocenter displacement (e.g. stellar spots) shape and background variations new analysis of any newly discovered astrophysical effect Comparisons with the Universe model

21 Thanks!