Unités de recherche 1. Scientific report: auto-evaluation of the ADAMIS team a. Activities and results ADAMIS is an interdisciplinary research group aiming at more effective, advanced, and robust scientific exploitation and interpretation of existing and anticipated astrophysical and cosmological data sets in particular in the view of their rapidly growing sizes and complexity. ADAMIS approach to reaching such goals is to perform research at the interface of physics, statistics, computer science, signal processing, and applied mathematics with an aim of not only capitalizing on the most recent developments in those areas but of engaging directly in interdisciplinary research to find novel, more comprehensive and robust solutions. This often requires simultaneous advances in multiple science areas and consequently interdisciplinary collaborations involving researchers from diverse fields and which the group members strive to instigate and coordinate. Two main themes of the group research are a development of novel data analysis techniques as driven by needs of actual experiments and their application to some of the most exciting current and forthcoming data, and advanced numerical simulations of complex astrophysical phenomena, e.g. compact sources. These two themes are closely intertwined, as simulated, high-quality mock data sets are necessary to validate and tests data analysis algorithms. They also share a similar technical background. The group’s focus is on 3 science areas: CMB data analysis, GW data analysis, and simulations. CMB data analysis PLANCK ADAMIS has played and continues on playing an important role within the Planck HFI collaboration. Permanent members of ADAMIS (Cardoso, Delabrouille, LeJeune, Stompor) together with students and postdocs have worked over the years on a number of aspects of the mission often in leading and coordinating roles as outlined below. They are HFI Core Team members and have Planck Scientists status within the collaboration. ADAMIS has been a major player on French and international arena in the foreground component separation effort. Two of the ADAMIS conceived and developed numerical codes, SMICA and NILC (Cardoso, Delabrouille, LeJeune), have been retained in a final selection of 4 codes (out of more than dozen in the running) to be used for final Planck analysis. Cardoso and LeJeune lead the effort of applying these codes to the actual Planck data. The group researchers (Stompor) have also contributed in a major way to the development of the Planck HFI map- making codes, developing, together with the group at LAL, a polarized destriper code, polkaPIX, (Tristram et al, 2011, [in2p3-00604975]), which is principal map-making work horse software of the HFI Data Processing Center used to produce official Planck products as well as internal releases. Complementary, Stompor has been one of the co-authors of the maximum likelihood map-making code, MADmap, (Cantalupo et al, 2011, [in2p3-00517907]), which is the leading code of this type used for Planck at the US Data Center. (Incidentally, and notably, the code has also become the backbone of the on-board map-maker of the Hershel SPIRES instrument.) Fig. 1. An example demonstrating the performance of the component separation code, SMICA, on a simulated PLANCK data set. Left panel shows the recovered total intensity CMB map. Right panel depicts the corresponding power spectrum (in yellow) as compared to the input one (black line) as well as residual noise and foreground contamination levels. The low level of contamination of the SMICA CMB map is one of the criteria that have led to the selection of SMICA for the final analysis of the Planck data. Delabrouille has led the Planck-wide effort of modeling the sky in the microwave band, so-called Planck Sky Model, initially for the purpose of the Planck data analysis and later to become one of the Planck products. The preprint detailing the work has been just made public (Delabrouille et al, 2012, preprint) and the software has been released. Delabrouille also coordinated the work of the Planck Working Group 2 devoted to the component separation problem. Cardoso co-led the effort of a challenge-like comparison of Planck component separation codes (Leach et al, 2008, [in2p3-00294140], including Delabrouille and Stompor) - a work, which has become since a reference in the field. Cardoso and Stompor have contributed to a development of the power spectrum estimators for Planck HFI, such as the Maximum Likelihood techniques, CLICK (with IAP), and pseudo-spectral ones, XPOL/XPURE (with LAL). SMALL-SCALE CMB POLARIZATION EXPERIMENTS Stompor is a senior investigator on two cutting-edge, US-led small-scale experiments: balloon-borne EBEX and ground-based POLARBEAR. The experiments aim at the detection and later characterization of the elusive CMB B- mode polarization signal and thus providing a tantalizing hint in favor of inflation. They also promise to provide an exquisite constraint on the total mass scale of neutrinos potentially deciding the nature of their mass hierarchy. Stompor has instigated and coordinated a French involvement in those, securing funding from INSU and IN2P3 PICS Vague D : campagne d’évaluation 2012-2013 1 Février 2012
Unités de recherche programs, France-Berkeley Fonds and Marie Curie Re-Integration program (FP6), to permit for exchanges of young researchers. ADAMIS (co)organized multiple internal data analysis workshops and collaboration meetings. The ADAMIS EBEX (Stompor) and POLARBEAR collaborators (Stompor and PhD students Errard and Fabbian) contributed essential Fig. 2. Examples of preliminary data from the POLARBEAR experiment: left panel - a total intensity map with superimposed polarization field of the supernova remnant TauA. Located at the heart of the Crab Nebula and polarized due to synchrotron emission, it is observed regularly by the POLARBEAR experiment and used as a calibrator for the polarization angles of its focal plane ; right panel - a map of the emission of a H II region of our Galaxy, where young stars are forming, as observed by the POLARBEAR Telescope during its commissioning phase in March 2012 and corresponding to roughly 30 mins of observation time. parts of the data analysis pipeline for these experiments including component separation techniques (Stompor et al, 2009, [in2p3-00517908]) and power spectrum estimators (Grain et al, 2009, 2012, [in2p3-00434062]). They have also performed first realistic estimation of performance of such experiments as far as detecting the primordial, inflationary signal is concerned, in the presence of the foregrounds and the E-to-B leakage effect (Stivoli et al 2010 [in2p3-00535987], Fantaye et al 2011 [in2p3-00618398]). ANALYSIS OF PUBLICLY AVAILABE DATA SETS Delabrouille, Cardoso, and collaborators produced a superior, high resolution, low foreground contamination, full- sky CMB map from the WMAP 3-year data and studied its properties (Delabrouille et al 2009, [in2p3-00709909]). The map has become a basis for many WMAP re-analysis and follow-up investigations. More recently, Delabrouille and a postdoc (Basak), benefiting from the tools developed as part of the ADAMIS work, have preformed a unique re-analysis of the WMAP 7-year data improving in multiple ways over that performed by the original team and resulting in an improved, high quality data product in a form of a cleaner more reliable CMB map of the sky (Basak & Delabrouille 2012, [in2p3-00709880], in2p3-00709880]). Delabrouille and Cardoso studied the foregrounds in the WMAP data (Ghosh etal 2011, [in2p3-00709898]). Fig. 3. This figure illustrates component separation performed on the WMAP data (the K-band map, at 22GHz, is displayed in the top left panel). A method developed in the ADAMIS group is used to first estimate in a near-optimal way the Cosmic Microwave Background signal present in the map. This method makes use of constrained linear combinations of all WMAP observations (5 frequency channels), using a decomposition of the data on a frame of spherical needlets (wavelets on the sphere). The CMB map (top right) shows no sign of contamination by foreground emission. It is subtracted from the K-band map to yield a CMB-free map of residuals (bottom-left) which is then filtered to reduce the contamination by noise, yielding a low-noise map of foreground emission in which both compact sources and diffuse emission from galactic synchrotron are clearly seen (bottom right). NOVEL TECHNIQUES AND ALGORITHMS Faÿ et al (2008), [in2p3-00709912] have proposed a novel needlet based pseudo power spectrum estimator for total intensity data. This technique is particularly suitable for experiments with partial sky coverage. Stompor et al (2009) [in2p3-00517908] rephrased the standard parametric Maximum Likelihood component separation approach to allow it to be performed into two separate and computationally feasible steps. The approach, permitting statistically sound error propagation, has become a stepping stone for a number of performance studies evaluating the impact of the foregrounds on the output of the CMB polarization experiments. Vague D : campagne d’évaluation 2012-2013 2 Février 2012
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