OULE3 - Time DomainImplementation & Validation Phase Isobel Hook Jean-Philippe Beaulieu
Euclid’s time-domain data • Euclid’s deep fields will be observed several times • Of order 40 sqdeg, observed ~ 40 times • Cadence TBD • These may or may not be the same as the fields required for calibration of primary science goals • Euclid’s wide survey will have overlap regions between adjacent fields • 1% overlaps (see Red Book) of 15,000 sqdeg = 150sq deg • Imaged twice or sometimes more, time separation hours to years… • Each exposure is made of 4 dithered frames • Timescale between dithers ~15 minutes • Possibly also dedicated time-domain surveys • If survey time/scheduling permit
Euclid’s time-domain science • Science goals include: • Solar system • Supernovae (Type Ia, II, ultraluminous…) • Exo-planets (detected via microlensing) • Variable QSOs • Other transients (GRBs…?) • These are considered “legacy science”/ “secondary cosmology” • They can drive goals (but not formal requirements on the mission)
Potential dedicated surveys • SNIa cosmology: dedicated survey (6 monthsor longer) • Of order 10-60 sq deg, observed ~ 40 times • Cadence of order 4-8 days • Focus on Y,J,H imaging, possibly with non-standard exposure times • Euclid microlensing : dedicated survey (ideally 6-10 months) • Fields observable twice a year for 1 month • Continuous 1 month observation period of 3 fields in galactic bulge (17 min cadence) • Monitoring in H band, VIS images every 12 hours
Implementation WP Summary - Inputs [From v4.0 of WP descriptions] • Preliminary EUCLID data on time-ordered images from OU‐EUC and OU-VIS • Preliminary versions of the EUCLID catalogues from OU‐PHO, OU-SPE and OU‐MER for object identification [comment: should include external data] • Comment: Should also include simulated data!
Implementation WP Summary -Outputs[From v4.0 of WP descriptions] • Algorithms to produce a catalogue of orbital, time and position parameters for transient solar neighborhood objects • Algorithms to produce a catalogue of light curves, time, redshift, magnitude parameters for transient supernovae‐like objects. A catalogue of any stellar time‐dependent variation. • Algorithms to produce a catalogue of microlensing events
Implementation WP Summary - Deliverables[From v4.0 of WP descriptions] • Documentation describing the algorithms, their implementation and results on the tests. • Prototypes of the algorithms for the computation of the catalogues for solar system, stellar‐like transient and microlensing catalogues. • Example simulated dataset used for the testing of the prototypes. • Comment: What about verifyingthe LE3 data products themselves?
Implementation WP Summary – List of tasks [paraphrased From v4.0 of WP descriptions] • Definition, development and testing of: • [Solar system] • algorithms to detecttransients • algorithmsforcrossmatchingwith existing catalogues • [Supernovae and other stellar-like transients] • algorithmsto detecttransients • algorithmsforcrossmatchingwith existing catalogues • [Exoplanets] • algorithms to generate photometry catalogues (image subtraction) • Algorithms to detect microlensing events • Algorithms to detect transiting planets
Proposed sub-tasks [Example of SN case – based on input from the SN & transients SWG] • Start from simulated ‘raw’ data (see later slide for definition) • Develop algorithms to do the following steps • Create an oversampled stacked image as a reference (will be done by OU-MER?) • Register new images to reference • PSF match of new & reference image (accounting for flux ratio) • Subtract images • Detect objects on the subtracted images • Do photometry on the detections • Select ‘real’ transients based on quality cuts • Match detections with previous catalogues, including other Euclid data and external data • Classify the detections based on various levels of available data • Fit light curves • Enter detection data into a database for further use (including cutouts for visual inspection)
Proposed sub-tasks [Example of exoplanet case – based on input from exoplanet SWGvery close to SN tasks] • Start from simulated ‘raw’ data • Develop algorithms to do the following steps • Create an oversampled stacked image as a reference (will be done by OU-MER?) • Register new images to reference • PSF match of new & reference image (accounting for flux ratio) • Subtract images • Detect objects on the subtracted images • Do photometry on the detections • Select ‘real’ transients based on quality cuts • Classify the detections (microlensing events, variable stars, transiting planets) • Modeling of anomalous microlensing (fitting light curves) Note that there is a need for development of these image subtraction pipelines for both Legacy SN and exoplanets. It is not needed for core science.
Implementation WP members • Total FTE “committed” ~ 0.85FTE. • Others interested : • R. Carlberg + C. Pritchet (Canada – not yet in Euclid)- experience in SNe • JJ Kavelaars (Canada) – experience in solar system • Possibly some members of the SN & transients WG, depending on the boundary of SWG and LE3 work(*) • * Level of available effort depends on whether there is an interesting SN survey in Euclid!
Implementaton WP Summary - List of tasks [paraphrased From v4.0 of WP descriptions] • Definition, development and testing of: • [Solar system] – 0.0 FTE • algorithms to detecttransients • algorithmsforcrossmatchingwith existing catalogues • [Supernovae and other stellar-like transients] ~ 0.35FTE • algorithmsto detecttransients • algorithmsforcrossmatchingwith existing catalogues • [Exoplanets] – 0.4 FTE • algorithms to generatecatalogues • Lowlevelofcommittedeffortis a concern.
Required simulations • Three main scientific areas require simulations: • Solar system (moving objects) • SNe(point-like transients on host galaxies) • Include dithered exposures so that oversampled reference image can be created • Simulated SNeshould have realistic lightcurves, colours, and spatial distribution on host galaxies • Exo-planet microlensing(variable point sources in crowded fields)
Simulated data requirements • Time series of VIS and NISP Y,J,H images (2D) • Possibly with non-standard exposure times and non-standard SAA (if dedicated SN or exoplanet surveys are carried out) • Images should have fake transients added, with realistic properties • Images should be pre-processed (bias corrected, flat fielded and sky subtracted) • Covering an area of ~1 sqdeg (?) • Simulated NISP spectroscopy of the field (IS THIS NEEDED?) • Simulated photo-z catalogue of the field (required for SN case)
Pipeline requirements[Summary of document sent to legacy science coordinators from SN&T SWG] • For transients, the real-time and final reductions have different requirements • Not clear whether they will be the same software • Real-time pipeline: • Mainly for triggering follow-up. Can be less precise, but must be able to filter out junk (requires colour info, z if available, vignettes for human inspection etc) • Software must be rapidly adaptable. Would not be compatible with long code review process • Final reductions • Precision goal of 1% relative PSF photometry • [But not for the entire Euclid dataset– only repeat-imaged areas]
Validation tasks (Beaulieu et al.) Goal : Validation of the algorithms to obtain catalogues for objects in the time domain for Euclid including solar system transients, supernovae, stellar transients and microlensing events. • Science working groups are setting up goals and requirements. • Implementation WP is proposing a road towards these goals & requirements. • Validation will use these two ingredients. Our approach will be to work closely with the implementation WP. Let’s well define the implementation first. Sign in for implementation and/or validation WP.