eLISA Data Processing Centre Volker Beckmann APC, Francois Arago Centre A. Petiteau, E. Porter, G. Auger, E. Plagnol, P. Binétruy

Data Processing Centre  Thinking about eLISA data analysis  The data stream of eLISA  Ground segment structure of eLISA  Tasks of the Data Processing Centre (DPC)  Structure of the DPC V. Beckmann

Thinking about eLISA data analysis  eLISA is a large and important mission  Data have to be easy to access, understand, analyse, display  Community appreciates real-time information (risk?)  Colleagues want the possibility to verify  Make all data public (raw to high level)  Provide (open source) s/w which allows community to re-do our analysis -- and potentially include own algorithms  Speak their language: astronomers like fits format, catalogs in their formats, easy access through established data bases  Listen to wishes and ideas from the larger community in order to achieve maximum support for our ambitious mission Photo: Ted Carnaham

Data Stream  Omni-directional observations, no ‘pointed observations’, no observers  The accumulated data provide the best sensitivity and include all information  Level 0: raw telemetry  Level 1: fully calibrated and corrected Time Delay Interferometry (TDI) data  Level 2: source identification, parameter extraction, model parameters and probability density function of sources. Transient identification  Level 3: source catalogue, (astro)physical source parameters, strain time series  Use different algorithms in the production of Level 2/3 data  Regular (e.g. weekly) reprocessing of the accumulated data stream V. Beckmann

Data Stream  The data volume is small, the processing demand is large  5 Hz measurements  30 channels ‘mother’ spacecraft, 14 channels on each of the daughter spacecrafts  Housekeeping data (at various frequencies)  11 kbs  << Gbyte per day  Few Gbyte per day (incl. everything L0-L3)

Ground Segment Responsibility for data processing shared between MOC/SOC (ESA), IOTs (member states) and Data Processing Centre (member states)

Tasks of the DPC  Data Processing Centre (DPC) provides two analysis chains:  Quick look analysis (QA) and standard analysis (SA) pipeline.  QA: simplified version of SA. To run on a daily basis on the incoming data stream. Visualize data. Identify potential problems (beyond from what MOC/SOC) can spot.  SA: run full analysis on the accumulated data once a week  Integrate algorithms developed by the eLISA consortium members  Develop, test, maintain, document s/w chains  Distribute and provide user support for the SA pipeline  Report Level 2/Level3 results back to SOC for potential event announcements to the eLISA consortium/community.  Ensure mature level of s/w applied in the DPC  “Listen” to eLISA consortium, stay flexible

Structure of the DPC  Data Processing Centre (DPC) does not define the algorithms, does not (exclusively) provide scientific interpretation.  Changes in algorithms and in definition of products are to be approved by a Change Control Board (CCB) of the eLISA consortium.  Technical changes and quality control (version control, unit testing, etc.) handled locally at the DPC  Though tasks at DPC are not ‘scientific’ deep understanding of eLISA science necessary at DPC management level  Several member states can contribute to DPC (FTE or being in charge of certain tasks).

Structure of the DPC  Project scientist and project manager organise the work of the DPC and ensure contact with eLISA consortium, IOTs, and ESA (MOC/SOC)  Start early (but not too early!): 5 yrs before launch (1 year earlier for management)  Ramp up staff until launch  Important aspects: Quality control (testing!), maturity of s/w chain, be ready for changes after launch, maintain knowledge over the whole mission duration (including post mission activities)  DPC relies strongly on knowledge of the IOTs and the eLISA consortium  Hardware costs: mainly computing (~1,500 CPU during science operations)

FTEs at Data Processing Centre Launch

Data Processing Centre before launch

Data Processing Centre after launch

François Arago Centre  Project at APC, located across the street  Cluster, 640 CPU, 100 kW cooling, 100 TByte disk  10 Gbit/s connection  2 video conference rooms  Concurrent Design Facility (used e.g. for eLISA/NGO)  2 meeting rooms  Offices on demand  Hard- and software support  Projects: LISA-PF, Euclid, CTA, INTEGRAL, HESS…

The DPC as member state contribution  Providing the DPC by ESA member states, reduces the costs for ESA  I.e. the more tasks on data analysis/storage/distribution/support we as consortium can provide, the lower the costs to ESA  This has been done before: e.g. in INTEGRAL, the science data centre is considered as “5th instrument” of the mission (incl. specific consortium for the SDC, I.e. with SDC under control of the member states).  Competing with ESAC  CNES starts a phase-0 study (approved today!) concerning the eLISA data processing centre requirements, risks, options, etc.  Kick-off meeting in December 2012, phase 0 to start January 2013, lasting one year.

Summary  eLISA has to provide excellent service to the whole community, before, during, after the mission  Open to ideas, requests, wishes, concerns  DPC processes L1 to L3 data  Small data volume, large processing needs  Quick look and standard analysis (simulator not included)  Development, integration, testing, maintenance, documentation, user support  Algorithm development by eLISA consortium (not DPC), knowledge about instruments with IOTs  Start 2017 with 2 FTE management, 2018 first s/w integration activities  58 FTE*years until launch  French community is ready to provide the Data Processing Centre services to the eLISA consortium!  See also Beckmann et al. 2012, “The eLISA/NGO Data Processing Centre”, ASP Conf. Series 467 V. Beckmann