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The Large Synoptic Survey Telescope Project Bob Mann LSST:UK Project Leader Wide-Field Astronomy Unit, Edinburgh LSST basics UK involvement in LSST Operations Plans Computing Issues 2 Large optical survey telescope to be located in Chile Ten year sky survey from 2022 US-led: NSF + DoE (camera) plus foreign partners 6.5m effective primary; 9.6 sq. deg FOV Étendue = mirror area x camera field of view If étendue is large enough, can go wide, deep and fast at same time Different kinds of analysis from the same dataset LSST will have a great impact across almost all of astronomy 3 The LSST Science Book • Contents: – – – – – – – – – – – – – – – Introduction LSST System Design System Performance Education and Public Outreach The Solar System Stellar Populations Milky Way and Local Volume Structure The Transient and Variable Universe Galaxies Active Galactic Nuclei Supernovae Strong Lenses Large-Scale Structure Weak Lensing Cosmological Physics arXiv:0912.0201 LSST@Europe Meeting, Cambridge, UK September 9-12, 2013 4 LSST basics UK involvement in LSST Operations Plans Computing Issues 5 35/36 UK Astronomy Groups 6 LSST:UK Consortium Defines the programme of work for… Works on behalf of… LSST:UK Science Centre (LUSC) Phase B: Commissioning Phase C: Early Ops. Phase D: Standard Operations 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 UK Phase A: Development 1 August 2014: start of construction project October 2019: telescope First Light October 2022: start of main survey operations LUSC-DAC: UK Data Access Centre LUSC-DEV: Software development towards (Level 3) data analysis software Phase A proposal Baseline programme for 2015-2033: ~£32M [not DAC h/w] Initial funding (£17.7M): ▪ £15M contribution to LSST operations (“subscription”) ▪ 6 staff-years of LUSC-DAC staff effort + modest testbed h/w ▪ 16 staff-years of LUSC-DEV staff effort Phase A Project started on 1 July 2015 9 LSST basics UK involvement in LSST Operations Plans Computing Issues 10 Archive Site Difference Imaging Alerts within < 60 sec Solar System orbits < 24h 106 alerts per night: need “event broker” at NCSA to filter these Base Site Summit Site French Site Archive Site Processing Center Data Release Production All extant data included: • per-visit images • per-visit catalogues • co-add images • co-add catalogues • Per-visit forced photom. Data Access Center Data Access and User Services Base Site Data Access Center Data Access and User Services Processing Center Data Release Production UK Site (?) Data Access Center Data Access and User Services Summit Site French Site Archive Site Processing Center Data Release Production Beyond requirements Data Access Center Data Access and User Services of LSST project delivery: • needed for much science • mainly coordinated through Science Collaborations • some resources provided • may be incorporated into L2 Base Site Data Access Center Data Access and User Services Processing Center Data Release Production UK Site (?) Data Access Center Data Access and User Services Summit Site LSST basics UK involvement in LSST Operations Plans Computing Issues 14 Archive Site Archive Sites Nightly difference NCSA imaging: alerts Annual direct image pipeline: data releases CCIN2p3 (Lyon)? Data Access Centre ▪ Offering to take 50% load ▪ Valued at ~$900k/year Data Access Centres Ingest data releases NCSA Run Level 3 data Chile analysis code UK? Others? 15 Image files Databases ~38 billion distinct objects (24B gals, 14B stars) observed ~1000 times ~38 trillion sources 16 Nodes connected by xrootd 17 Compute LSST assume DAC will need ~10% for Level3: i.e. ~20-140 Tflops 18 Two timescales for data ingest Every night – for event streams Once a year – for data releases Different types in different science areas Examples 1. Classification of transients – time critical 2. Galactic archaeology – large, catalogue-based 3. Weak lensing – large, image-based Different DACs may specialise in different types Different computing infrastructures 19 UK computing issues centre on Level 3 Currently no interest in IN2P3-like offer on pipeline Scale of Level 3 not well constrained Nor relationship between different DACs But clear requirements exceed current expertise DAC needs flexibility to support range of users Suggest virtualised or containerised environment 20 LUSC-DEV: Algorithm development Using simulations and data from other surveys LUSC-DAC: Prototyping DAC operations Data ingest and query workload Supporting large-scale analyses of images & DBs(?) Quantitative requirements will become clear over the next year or so Lessons from DES (Joe Zuntz) & Euclid (Keith Noddle) 21 22 1 August 2014 23 US agencies – NSF and DoE Construction: ~$640M Operations: ~$270M out of ~$370M International partners must contribute ~$100M Default model: ~$200k per P.I. inc. students/postdocs Plus extra ~10% for additional load on DAC system or operate own DAC 24 £15M set aside for operations contribution £2.7M for Phase A programme (4 years) LUSC-DAC: six staff-years ▪ DAC testbed, Data Challenges, supporting LUSC-DEV LUSC-DEV: sixteen staff-years ▪ Weak lensing: simulations, PSF, deblending, Euclid synergy ▪ Milky Way: star/galaxy separation, tidal stream detection ▪ Transients: alert handling, classification, cadence optimis. ▪ Solar System: postage stamps, lightcurves ▪ Sensor characterisation: image analysis systematics Stream of ~106 events per night Most boring; need to find the interesting ones Cross-match with other source catalogues Machine learning to attempt classification Time critical: Schedule follow-up observations of interesting ones Need to run all night, every night 26 Catalogue filtering to reveal structures in (colour,position) space Statistical manipulation of multi-PB databases Likely to be repeated with annual data releases Low signal/noise features…iterative?...visualisation? 27 Measuring galaxy shapes very accurately Systematics-limited: simulations to quantify May need to go back to image data If Level 2 pipeline image analysis not good enough Embarrassingly parallel, but large amounts of data and even larger amounts of simulated data More details from Joe Zuntz Commonalities with Euclid weak lensing 28