.. Time-stamp: <2022-02-21 12:30:40 ycopin> Science ======= Mission spatiale de cosmologie observationnelle EUCLID ------------------------------------------------------ .. image:: http://www.mpia.de/1910892/standard.jpg :alt: Near-Infrared Spectro-Photometer :width: 200 px :align: right **Euclid** est une mission spatiale de l':abbr:`ESA (Agence Spatiale Européenne)` destinée à étudier, via diverses sondes cosmologiques (cisaillement gravitationnel, oscillations acoustiques de baryons, etc.), le contenu sombre – énergie et matière noires – de l'Univers, et dont le décollage est prévu pour mi 2023. Je participe au `Euclid Consortium `_ depuis 2012, essentiellement dans le domaine du traitement et de l'analyse des données en provenance du spectrographie sans fente `NISP `_, et en tant que responsable scientifique à l'IP2I; plus spécifiquement: * *Co-lead* de l'activité de réduction des données de spectrographie sans fente (PF-SIR), * *Deputy calibration scientist*, en charge de la spectroscopie. .. image:: _static/images/EUC_SIM_NISRGS000-25424-1_20210521T082656.195Z_SC8_MAIN_EUCLID_657_1_512px.png :alt: NISP simulated exposure. :width: 400 px :align: center :target: _static/images/EUC_SIM_NISRGS000-25424-1_20210521T082656.195Z_SC8_MAIN_EUCLID_657_1_DET13.SCI.png .. rubric:: Liens * `EUCL-IPN-TN-8-001 <_static/documents/EUCL-IPN-TN-8-001.pdf>`_ *Impact of spectral covariance on line fitting* I look for the impact of the spectral covariance on the line fitting procedure. It appears that the maximum-likelihood estimates — for all line parameters — are equally *un*-biased when using the correct full-covariance χ² definition and the simpler pure-diagonal one (i.e. neglecting spectral correlations). However, best-fit parameter uncertainties — on line flux, position/*redshift* and width — are systematically *under*-estimated by ~40% when using the uncorrelated χ², while properly estimated when minimizing the statistically correct χ². The use of spectral covariance is therefore of crucial importance to derive statistically controlled spectral quantities such as redshift and line fluxes. * `EUCL-IPN-TN-8-002 <_static/documents/EUCL-IPN-TN-8-002.pdf>`_ *Adaptive Emission Line Detection* To derive spectral quantities such as redshift, the first step in the process of precision emission line adjustment in a galaxy spectrum is to detect potential emission lines in a robust and systematic way. I present in this note a collection of algorithms developed for that purpose, including optimal spectrum combination, adaptive fitting and robust M-estimators. * `EUCL-IPN-TN-8-003 <_static/documents/EUCL-IPN-TN-8-003.pdf>`_ *Outlier detection in small samples using pull-clipping* We present and tests different algorithms to compute the mean of very small samples (*n = 4*) in presence of a small fraction of outliers. The favorite choice appears to be the inverse-variance weighted mean of pull-clipped values, both more robust and statistically efficient (from 10% to 40%) than the median. * `Grism-based Spectrograph Modeling `_ This module implements the spectrograph optical model used for the SuperNova Integral Field Spectrograph Lantz04_ data-reduction pipeline, and presented in Copin00_. It provides a flexible chromatic mapping between the input focal plane and the output detector plane, based on an effective simplified ray-tracing model of the key optical elements defining the spectrograph (collimator, prism, grating, camera), described by a restricted number of physically-motivated distortion parameters. .. _Lantz04: http://adsabs.harvard.edu/abs/2004SPIE.5249..146L .. _Copin00: https://tel.archives-ouvertes.fr/tel-00001338/fr/ * `Euclid Spectroscopy Analysis Software `_ This code addresses the different modules in SGS-SPE PE-5300 *Spectral Features Measurement*. Modélisation directe de la spectrographie sans fente ---------------------------------------------------- Je développe dans le cadre de l'expérience Euclid une expertise sur la modélisation directe (*forward modeling*) de la spectrographie sans fente, parfois appelée imagerie dispersée. Cinématique des galaxies '''''''''''''''''''''''' * `Forward modeling of galaxy kinematics in slitless spectroscopy `_ (Outini & Copin, 2020, A&A **633**, 43O) Slitless spectroscopy has long been considered as a complicated and confused technique. Nonetheless, with the advent of Hubble Space Telescope (HST) instruments characterized by a low sky background level and a high spatial resolution (most notably WFC3), slitless spectroscopy has become an adopted survey tool to study galaxy evolution from space. We investigate its application to single object studies to measure not only redshift and integrated spectral features, but also spatially resolved quantities such as galaxy kinematics. We build a complete forward model to be quantitatively compared to actual slitless observations. This model depends on a simplified thin cold disk galaxy description -- including flux distribution, intrinsic spectrum and kinematic parameters -- and on the instrumental signature. It is used to improve redshifts and constrain basic rotation curve parameters, i.e. plateau velocity v0 (in km/s) and central velocity gradient w0 (in km/s/arcsec). The model is tested on selected observations from 3D-HST and GLASS surveys, to estimate redshift and kinematic parameters on several galaxies measured with one or more roll angles. Our forward approach allows to mitigate the self-contamination effect, a primary drawback of slitless spectroscopy, and therefore has the potential to increase precision on redshifts. In a limited sample of well-resolved spiral galaxies from HST surveys, it is possible to significantly constrain galaxy rotation curve parameters. This proof-of-concept work is promising for future large slitless spectroscopic surveys such as EUCLID and WFIRST. * `Presentation `_ at the `The Art of Measuring Galaxy Physical Properties `_ conference |en| * `Mesure de la cinématique interne des galaxies en spectroscopie sans fente `_, thèse de M. Outini |fr| Caractérisation atmosphérique LSST '''''''''''''''''''''''''''''''''' Je travaille, en collaboration avec Jérémy Neveu et al., sur l'utilisation de la spectrographie sans fente pour la caractérisation de la transmission atmosphérique pour LSST. Spectro-photométrie des supernovæ de type Ia -------------------------------------------- .. image:: _static/images/logo_SNfactory.png :alt: Design Dianna LaFerry :width: 200 px :align: right Les supernovæ thermonucléaires (dites de type Ia) sont des chandelles standard à portée cosmologique, et ont permis la découverte de l'expansion accélérée de l'Univers (`prix Nobel de physique 2011 `_) Depuis sa création en 2001, je suis impliqué dans le projet international `Nearby SuperNova Factory `_ de suivi spectro-photométrique de SNe Ia proches, où je suis *data scientist*, responsable du traitement des données du *SuperNova Integral Field Spectrograph*. * `SNfactory presentation <_static/documents/SNf-Berlin15.pdf>`_ (2015/03, Humboldt University, Berlin, |en|) * `LBNL news releases `_ * `Publication list `_ .. raw:: html Spectrographie à champ intégral ------------------------------- Mon expertise instrumentale est la *spectrographie à champ intégral* (`integral-field spectrography `_), parfois appelée *spectrographie 3D*. * A `3D-spectroscopy course <_static/documents/IFSC2015_IFS_YCopin.pdf>`_ I gave at the *Indo-French Astronomy School for Optical Spectroscopy* (2015/11, Pune, |en|). * 3D-specific tools: `Adaptive Voronoi binning `_ (`code IDL/python `_), `kinemetry `_ (`code IDL `_) Galaxies de type précoce ------------------------ J'ai longtemps été impliqué dans le projet `SAURON `_, dont l'objectif principal est l'étude des mécanismes de formation et d'évolution des galaxies de type précoce à partir d'observations 3D sur un spectrographe à champ panoramique dédié. .. |fr| image:: _static/images/france_flag_icon.png :alt: Fr .. |en| image:: _static/images/uk_flag_icon.png :alt: En