LSST-France Novembre 2020

3 nov. 2020, 12:10 → 6 nov. 2020, 17:00 Europe/Paris

video-conference

Celine Combet (LPSC - Grenoble), Fabio Hernandez (CC-IN2P3), Gaëlle SHIFRIN (Centre de Calcul de l'IN2P3), Mickael Rigault (IPNL)

The next biannual meeting of the LSST-France community will be held from November 3rd to 6th, 2020.

This meeting will be held completely remotely, on zoom, following that link:

https://univ-grenoble-alpes-fr.zoom.us/j/95100341906

It is password-protected and the zoom password will be sent separately to the list of registered participants.

Organisation:

• Talks: Speakers should favour english as much as possible, but French is allowed for speaker having difficulties in english. Slides must be in english
• Discussion/Questions: A dedicated slack channel #meeting-ip2i2020 has been created on the lsst-france workspace (if you don't have access to it, contact Mickael Rigault). Questions and discussions will take place there. 
  Participants can also raise their hand on Zoom to ask a question.
• Participants: Please turn off your microphone when you are not speaking. The camera is up to you, we might change that is the bandwidth does not follow. "Raise your hand" on zoom if you have a question.
• Speakers: have your camera on if possible and upload your slides on the indico prior to your talk.

 

The agendas of the most recent editions of this meeting can be found online:

• February 2020
• November 2019
• November 2018

mardi 3 novembre

13:30 → 13:35 Welcome

13:35 → 15:00 Nouvelles générales / General news

In this session we will cover topics of general interest.

Président de session: Mickael Rigault (IP2I)

13:35 LSST, nouvelles générales

Orateur: Emmanuel Gangler (LPC)

LSST_CSIN2P3_2020.pdf

LSST_France_News_2020_Nov.pdf

Status_of_Rubin_LSST_at_IN2P3__CS_IN2P3_2020.pdf

14:05 LSST Communication

Orateur: Gaëlle SHIFRIN (Centre de Calcul de l'IN2P3)

COM_LSST_Nov2020.pdf

14:25 LSST, Construction & Commisionning

Orateur: Pierre Antilogus (LPNHE)

14:50 LSST-France new members

Orateur: New members

15:00 → 15:15 Break

15:15 → 16:30 Science

Président de session: Fabio Hernandez (CC-IN2P3)

15:15 Review SNe

Orateur: Dr Mickael Rigault (IP2I)

LSST_France__SNeIaReview.pdf

15:40 Review clusters

Orateur: Celine Combet (LPSC - Grenoble)

CL@LSST-france_20201003.pdf

16:05 Review cosmic shear

Orateur: François Lanusse

Cosmic Shear Overview.pdf

mercredi 4 novembre

10:00 → 12:00 Présentations appel à contributions / Accepted contributions: SNela

Président de session: Celine Combet (LPSC - Grenoble)

10:00 The Effect of Host Galaxy Correlations on SNIa Cosmology

Measurements of the standardisable type Ia supernova (SNeIa) out to the earliest epochs in the Universe remain the most robust probe of cosmic acceleration. However, to ensure unbiased precision estimates on the nature of dark energy requires a firm understanding of where the observed 0.15mag dispersion observed in these events originates from, and a detailed description of any evolution in their mean properties with redshift. With correlations between the observed properties of SNeIa and their local environment now routinely used in SNIa standardisation but not physically motivated, characterising this effect is key to ensure that the inferred cosmological parameters are not plagued by systematic uncertainties.
Using just 10% of the Dark Energy Survey Supernova Program (DES-SN) dataset, we have shown that SNeIa in high mass galaxies are intrinsically more luminous (after correction) than their low mass counterparts, but that the magnitude of this difference relies strongly upon assumptions used in determining the distance to each SN. This is a consequence of intrinsic correlations between SN light-curve width and colour, and host galaxy properties, which, if incorrectly modelled, can lead to biases in the estimates distances and hence the cosmological parameters. In this talk I shall extend this analysis, utilising the full DES-SN sample to studying the standardisation of SNeIa with regards to their host galaxy environment. With significant attention focused around how SNIa host properties can be used to improve cosmological constraints from SNe, I will highlight how a subsample of events, solely found in low luminosity environments can maximise our understanding of dark energy from SN, but how incorrectly accounting for contamination and population drift can severely bias the inferred cosmological parameters. With LSST just around the corner, DES-SN presents the ideal test-bed to constrain the correlation between galaxy properties and SNIa luminosity: critical to ensure that our understanding of dark energy is unbiased.

Orateur: Mathew Smith (IP2I/IN2P3/CNRS)

Smith_LSST_France_DESSN_2020nov04.pdf

10:20 The dependency of Type Ia supernovae on host galaxy morphology

The galaxy morphology is a way to characterize the Type Ia supernova (SN Ia) environnement. In this talk, first, the correlation between the galaxy morphology and other tracers of SN Ia environnment will be addressed. In a second part, the study of the dependency of SALT2 light curve parameters with respect to the galaxy morphology from the Pantheon compilation will be presented, as well as its potential impact on the Hubble diagram.

Orateur: Philippe Rosnet (Université Blaise Pascal - CNRS/IN2P3)

LSST-France_meeting_2020-10-04.pdf

10:35 Redshift Evolution of the Underlying Type Ia Supernova Stretch Distribution

The true nature of type Ia supernovae (SNe Ia) remains largely unknown, and as survey statistics increase, the question of astrophysical systematic uncertainties rises, notably that of the SN Ia population evolution. In this paper, we study the dependence with redshift of the SN Ia SALT2.4 lightcurve stretch, a purely intrinsic SN property, to probe its potential redshift drift. The SN stretch has been shown to strongly correlate with the SN environment, notably with stellar age tracers. We model the underlying stretch distribution as a function of redshift, using the evolution of the fraction of young and old SNe Ia as predicted by Rigault et al. (2018), and assuming constant underlying stretch distribution for each age population made of Gaussian mixtures. We test our prediction against published samples chosen to have negligible magnitude selection effects, so that any observed change is indeed of astrophysical and not observational origin. We clearly demonstrate that the underlying SN Ia stretch distribution is evolving as a function of redshift and that the young/old drifting model is a much better description of the data than any time-constant model, including the sample-based asymmetric distributions usually used to correct Malmquist bias. The favored underlying stretch model is the bimodal one derived from Rigault et al. (2018): a high-stretch mode shared by both young and old environments, and a low-stretch mode exclusive to old environments. The precise impact of the redshift evolution of the SN Ia population intrinsic properties on cosmology remains to be studied. Yet, the astrophysical drift of the SN stretch distribution does affect current Malmquist bias corrections, and thereby distances derived from SN affected by selection effects. We highlight that such a bias will increase with surveys covering increasingly larger redshift ranges, which is particularly important for LSST.

Orateur: Nora NICOLAS (CNRS IN2P3 IP2I)

Presentation 2020-11-04--LSST_nora.pdf

10:50 Updates on RESSPECT

The RESSPECT project (Recommendation System for Spectroscopic Follow-up) aims to develop a pipeline which can guide the construction of optimal training samples for photometric supernova cosmology. The project has a little more than a year and it is now in its final development stages. I will give a brief overview of the purpose of the project, its current configuration, the remaining steps to complete the development of the pipeline and the expected results.

Orateur: Dr Emille Ishida (LPC-UCA)

RESSPECT_LSST_France_2020_2.pdf

11:10 Organising SNeIa In France

discussion about the organisation of the SNIa activities within the IN2P3

14:00 → 16:00 Présentations appel à contributions / Accepted contributions: Computing et outils (ML, Broker, DC2, etc.)

Président de session: Fabio Hernandez (CC-IN2P3)

14:00 Overview of computing activities (title TBC)

Orateur: Dominique Boutigny (LAPP)

LSST-France-Computing_Overview-Nov2020.pdf

14:30 Updates on the Fink broker, enabling time-domain science with LSST

Orateur: Anais Moller (CNRS / LPC Clermont)

LSST-France_2020.pdf

14:55 Machine learning challenges and opportunities in LSST

In this presentation I will attempt to make an overview of the current state of machine learning in the French LSST community (applications, techniques, available hardware and knowledge, etc.) and start a discussion on the various opportunities that could be adopted forward or actions undertaken.

Orateur: Alexandre Boucaud (APC / IN2P3)

ML challenges and opportunities

15:20 On using CC-IN2P3's notebooks platform (title TBC)

Orateur: Benjamin Racine

Example Notebook for CC

Jupyterlab at CC

jeudi 5 novembre

10:00 → 12:00 Présentations appel à contributions / Accepted contributions: Calibration, des pixels aux catalogues (PSF, deblending, etc.)

Président de session: Mickael Rigault (IP2I)

10:00 Modeling Atmospheric turbulence for optical wide field surveys in astronomy

Atmospheric turbulence is one of the significant problems to get unbiased flux and shape measurement on a ground-based experiment as the Vera Rubin Observatory. Indeed, atmospheric turbulences is one of the main arguments to get an unbiased flux and shape from space as Euclid will do. In this talk, I’ll present one solution to take into account Atmospheric turbulences for the current ground-based experiment. I’ll present the solution developed in parallel for the Point Spread Function modelling of the Dark Energy Survey and the astrometric solution of the Hyper Suprime Cam which is using Gaussian processes to modelled the spatial variation due to the atmospheric turbulence.

Orateur: Pierre-Francois Leget (LPNHE)

pf_leget_astmosphere.pdf

10:20 ZTF photometric calibration

The Zwicky Transient Facility (ZTF) has started observing transient objects since 2018 for six years. The goal of the survey is to reach a sample of 6000 Type Ia Supernovas to probe the nearby Universe. With the actual calibration pipeline, ZTF is reaching 15 mmag of precision. Efforts have being deployed within the collaboration to imporve the precision and reach the mmag level. One of the tracks is a biased estimation of the zero point (ZP). My work stands in this frame of improving the photometric calibration through the study of the ZP estimation.

Orateur: Melissa Amenouche (Laboratoire de Physique de Clermont)

LSST France ZTF calibration.pdf

ZTF_calibration_amenouche.pdf

10:35 Transient detection in the HSC data

We process HSC data using LSST software with the aim on detecting SN in the HSC transient survey. Currently, we are studying the efficiency of SN detection. To do so, we add fakes around the galaxies of a bunch of visits, and others with arbitrary positions. I will present the progress done in this work with the perspectives.

Orateur: Manal YASSINE ({CNRS}UMR7346)

HSC5-11-2020LSSTFrance_meetingOnline.pdf

10:50 Forward model extraction of slitless spectra

Update on the recent developments of Spectractor to get accurate atmospheric transmission curves with AuxTel.

Orateur: Jérémy Neveu (LAL)

jneveu_spectractor_lsst-france-2020.pdf

11:10 StarDICE, Status report

tbd

Orateur: Marc Betoule (LPNHE)

11:30 Organising the Calibration effort

14:00 → 15:10 Présentations appel à contributions / Accepted contributions: Clusters

Président de session: Celine Combet (LPSC - Grenoble)

14:00 The WaZP cluster finder

We present a new (2+1)D galaxy cluster finder based on photometric redshifts called Wavelet Z Photometric (WaZP), that searches for clusters in wavelet-based density maps of galaxies selected in photometric redshift space without any assumption on the cluster galaxy populations. This cluster finder was applied to DES first year (Y1A1) data, where the results were compared to clusters detected by the South Pole Telescope (SPT) survey and the redMaPPer cluster finder, the latter based on the same photometric data. We intend to run WaZP on DC2 and evaluate its performance on LSST like data and explore its physical and cosmological applications.

Orateur: Michel Aguena (LAPP)

The WaZP cluster finder

14:20 Weak-lensing mass determination of DC2 clusters

I will present my work on the analysis of DC2 catalogs for weak-lensing mass determination of galaxy clusters, for cluster count cosmology application. Among others, the objectives were to test the cosmoDC2_v1.1.4_image catalog for W.L. mass reconstruction (as an ideal galaxy catalog), and after to study the effect of image deterioration of a sky survey on the cluster mass, due to the presence of the atmosphere and the telescope. Indeed, it affects the measure of the true galaxy ellipticities, and then introduces a biais in the W.L. cluster mass, where galaxy shape measurement is crucial. For my work, I used a DC2 object catalog (dc2_object_run2.1i_dr1) by comparing with the results obtained with the ideal galaxy catalog.

Orateur: Constantin Payerne (LPSC)

WL cluster masses in DC2.pdf

14:40 Using the magnification effect to measure the mass of LSST galaxy clusters

I this presentation I will introduce the use of the gravitational magnification effect as a complementary probe to constrain the weak lensing mass of galaxy clusters in the LSST. I will explain the methodology, its advantages and show preliminary results on the DESC DC2 simulation.

Orateur: Marina Ricci (LAPP)

LSSTFr_ Gravitational_magnification_by_galaxy_clusters.pdf

15:00 Simulating multi-wavelength counterparts of LSST with a baryon pasting approach

In this talk I will introduce the "Baryon Pasting" project that aims at developing simple and physically motivated methods to model the properties of galaxies, groups, clusters and the cosmic web. The goal is to maximize the scientific returns of multi-wavelength surveys and concerns cluster cosmology but also weak lensing and galaxy clustering analyses. I will focus on the current efforts to obtain SZ and X-ray counterparts of the DC2 simulation and the scientific applications in the frame of the scientific preparation of LSST cosmological analyses.

Orateur: Marina Ricci (LAPP)

LSSTFr_Ricci_Baryon_Pasting_Project.pdf

15:10 → 15:20 Break

15:20 → 16:00 Présentations appel à contributions / Accepted contributions: LSS, cosmic shear

Président de session: Gaëlle SHIFRIN (Centre de Calcul de l'IN2P3)

15:20 Testing General Relativity using current cosmic shear data, and perspective with the Vera Rubin Observatory.

In this talk, I’ll present in the first part some current work of testing General relativity using current cosmic shear data. Moreover, I’ll present some perspective of doing the same job using VRO data.

Orateur: Pierre-Francois Leget (LPNHE)

pf_leget_shear_subaru.pdf

15:40 comptage de paires pour TXPIPE

je presenterai un nouvel algorthme pour le pipeline TXPIPE (3x2pts) qui permet de traiter la combinatoire du comptage de paires pour les donnees LSST

Orateur: stephane plaszczynski (CNRS)

SparkCorr_LSSTFR.pdf

vendredi 6 novembre

10:00 → 10:15 Equity, diversity and inclusion

Orateur: Cécile Roucelle (APC)

Mediation_EDI.pdf

10:15 → 11:00 Restitution par thème, plan pour les 6 prochains mois | Summaries and plans for next 6 months

Président de session: Gaëlle SHIFRIN (Centre de Calcul de l'IN2P3)

10:15 Restitution : Computing

Orateur: Bastien Gounon

Computing_Session_Recap.pdf

10:25 Restitution : SNe

Orateur: Mathew Smith (IP2I/IN2P3/CNRS)

LSST-France-SN: A summary

10:35 Restitution : Calibration, PSF, blending

Orateur: Dr Julian Bautista (CPPM)

10:45 Restitution : Clusters

Orateur: Calum Murray

10:55 Restitution : LSS, WL

Orateur: Pierre-Francois Leget (LPNHE)

11:00 → 11:15 Break

11:15 → 12:30 Discussion générale | General discussion

Président de session: Gaëlle SHIFRIN (Centre de Calcul de l'IN2P3)

11:15 Organisation de la science dans LSST-France

• Rappel du cadrage
• Retour sondage
• Nouvelles thématiques ?
• LSST/Euclid

Orateur: Celine Combet (LPSC - Grenoble)

Science@LSST-france_20201106.pdf

12:10 Quel nom pour la collaboration ?

Orateur: Gaëlle SHIFRIN (Centre de Calcul de l'IN2P3)

Naming_Nov2020.pdf