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

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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?

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DAC Data Volumes

Image files

Databases

~38 billion distinct objects (24B gals, 14B stars) observed ~1000 times ~38 trillion sources

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Database design

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Nodesconnectedby xrootd

Computing requirements

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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

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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

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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

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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

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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

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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

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