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The Large Synoptic Survey Telescope Project
Bob MannLSST:UK Project Leader
Wide-Field Astronomy Unit, Edinburgh
Outline
LSST basics
UK involvement in LSST
Operations Plans
Computing Issues
2
LSST Basics
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
astronomy3
LSST@Europe Meeting, Cambridge, UK September 9-12, 2013 4
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
Outline
LSST basics
UK involvement in LSST
Operations Plans
Computing Issues
5
LSST:UK Consortium
6
35/36 UK Astronomy Groups
Two interacting entities
LSST:UK Consortium
LSST:UK Science Centre (LUSC)
Defines theprogramme of work for…
Works onbehalf of…
Timeline for LSST
1 August 2014: start of construction project
October 2019: telescope First Light October 2022: start of main survey
operations September 2032: end of main survey
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
Phase A:Developm
ent
Phase B:Commission
ing
Phase C:Early Ops.
Phase D:Standard
OperationsUK
LUSC Programme
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 20159
Outline
LSST basics
UK involvement in LSST
Operations Plans
Computing Issues
10
Summit Site
Data Products: Level 1 – nightly processing
Archive Site
Difference ImagingAlerts within < 60 secSolar System orbits <
24h
Base Site
106 alerts per night:need “event broker”at NCSA to filter these
Summit Site
Data Products: Level 2 – annual data release
Base SiteData Access CenterData Access and User
Services
All extant data included:• per-visit images• per-visit catalogues• co-add images• co-add catalogues• Per-visit forced photom.
French SiteProcessing
CenterData Release Production
Archive SiteProcessing Center
Data Release Production
Data Access CenterData Access and User
Services
UK Site (?)Data Access
CenterData Access and User
Services
Summit Site
Data Products: Level 3 – user-created products
Base SiteData Access CenterData Access and User
Services
French SiteProcessing
CenterData Release Production
Archive SiteProcessing Center
Data Release Production
Data Access CenterData Access and User
Services
UK Site (?)Data Access
CenterData Access and User
Services
Beyond requirementsof LSST project delivery:• needed for much science• mainly coordinated through
Science Collaborations• some resources provided• may be incorporated into L2
Outline
LSST basics
UK involvement in LSST
Operations Plans
Computing Issues
14
Computing centres
Archive Site Nightly difference
imaging: alerts Annual direct image
pipeline: data releases
Data Access Centre Ingest data releases Run Level 3 data
analysis code
Archive Sites NCSA CCIN2p3 (Lyon)?
▪ Offering to take 50% load
▪ Valued at ~$900k/year
Data Access Centres NCSA Chile UK? Others?
15
DAC Data Volumes
Image files
Databases
~38 billion distinct objects (24B gals, 14B stars) observed ~1000 times ~38 trillion sources
16
Database design
17
Nodesconnectedby xrootd
Computing requirements
18
LSST assume DAC will need ~10% for Level3:i.e. ~20-140 Tflops
Compute
Level 3 analyses run in the DAC 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 critical2. Galactic archaeology – large, catalogue-based3. Weak lensing – large, image-based
Different DACs may specialise in different types Different computing infrastructures
19
Operational computing issues summary
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
Pre-operations computing
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
23
1 August 2014
LSST Budget
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
systemor operate own DAC
24
Phase A proposal outcome £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
1. Classification of transients 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
2. Galactic archaeology
Catalogue filteringto 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
3. Weak gravitational lensing 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