In the present work, we propose a neural network based data inversion approach to reduce structured contamination sources, with a particular focus on the mapmaking for Planck High Frequency Instrument (Planck-HFI) data and the removal of large-scale systematic effects within the produced sky maps. The removal of contamination sources is rendered possible by the structured nature of these sources, which is characterized by local spatiotemporal interactions producing couplings between different spatiotemporal scales. We focus on exploring neural networks as a means of exploiting these couplings to learn optimal low-dimensional representations, optimized with respect to the contamination source removal and mapmaking objectives, to achieve robust and effective data inversion. We develop multiple variants of the proposed approach, and consider the inclusion of physics informed constraints and transfer learning techniques. Additionally, we focus on exploiting data augmentation techniques to integrate expert knowledge into an otherwise unsupervised network training approach. We validate the proposed method on Planck-HFI 545 GHz Far Side Lobe simulation data, considering ideal and non-ideal cases involving partial, gap-filled and inconsistent datasets, and demonstrate the potential of the neural network based dimensionality reduction to accurately model and remove large-scale systematic effects. We also present an application to real Planck-HFI 857 GHz data, which illustrates the relevance of the proposed method to accurately model and capture structured contamination sources, with reported gains of up to one order of magnitude in terms of contamination removal performance. Importantly, the methods developed in this work are to be integrated in a new version of the SRoll algorithm (SRoll3), and we describe here SRoll3 857 GHz detector maps that will be released to the community.
The sky is full of variable and transient sources on all time scales, from milliseconds to decades. Planck's regular scanning strategy makes it an ideal instrument to search for variable sky signals in the millimetre and submillimetre regime, on time scales from hours to several years. A precondition is that instrumental noise and systematic effects, caused in particular by non-symmetric beam shapes, are properly removed. We present a method to perform a full sky blind search for variable and transient objects at all Planck frequencies.
Planck focal plane instruments: advanced modelization and combined analysis
本文是我作为IASF-MI研究员的工作成果，Istituto di Astrofisica Spaziale e Fisica Cosmica米兰分部，INAF的一部分，Istituto Nazionale di Astrofisica。这项工作始于2006年1月，在Aniello Mennella的监督下，在米兰大学物理系举行的天体物理学博士课程的背景下。我的工作的主要课题是低频仪器（LFI）辐射计的软件建模。LFI是欧洲航天局普朗克飞行任务上的两个仪器之一，用于高精度测量宇宙微波背景（CMB）的各向异性。我还被选中参加反粒子物理学国际博士学位，IDAPP。IDAPP由意大利大学和研究部（MIUR）资助，由Giovanni Fiorentini（Universita' di Ferrara）协调，旨在支持天体物理学和粒子物理学社区之间日益增长的合作。这是一个与巴黎博士学校合作的国际计划，涉及巴黎第六，第七和第十一大学，导致法国-意大利双博士学位头衔。我的工作是在普朗克号上的热辐射测量仪器高频仪器（HFI）的仪器科学家Jean-Michel Lamarre的共同指导下完成的。由于这次合作，我有机会与HFI团队在巴黎天文台工作了四个月，因此我的活动重点扩大了，包括HFI和LFI数据之间的互相关研究。普朗克是第一个在同一颗卫星上搭载非常不同的探测技术的CMB任务，这是控制系统效应和提高…
Rotational transition lines of CO are one of the major tracers used to study star forming regions and Galactic structures. A large number of observations of CO rotational lines are covering the galactic plane, recently the $Planck$ collaboration release the first full sky coverage of J=1-0, J=2-1, and J=3-2 CO lines at a resolution of 10', 5', and 5' FWHM. However, the measured signal in $Planck$ detectors is integrated over large bandpass $(Δν)/ν\simeq 0.2$. Consequently, the derived CO products are composite maps including several rotational lines. In the 100 GHz $Planck$ channel, the two ma…
We report on the search for optical counterparts of Planck Sunyaev-Zel'dovich (SZ) cluster candidates using a 0.6 meter non-professional telescope. Among the observed sources, an unconfirmed candidate, PSZ2 G156.24+22.32, is found to be associated with a region of more than 100 galaxies within a 3 arcminutes radius around the Sunyaev-Zel'dovich maximum signal coordinates. Using 14 hours of cumulated exposure over the Sloan color filters g', r', i', and, z', we estimate the photometric redshift of these galaxies at zphot=0.29 +- 0.08. Using the red-sequence galaxy method gives a photometric red…
Cryogenic characterization of the Planck sorption cooler system flight model
本文是JINST上发表的发射前状态LFI论文的一部分：http://www.iop.org/EJ/journal/-page=extra.proc5/1748-0221喷气推进实验室（JPL）为欧洲航天局（ESA）普朗克任务制造和组装了两个连续闭合循环氢焦耳-汤姆逊（J-T）吸附冷却器。每个制冷机的设计目的是在两个仪器接口处提供总计约1 W的冷却功率：它们直接冷却普朗克低频仪器（LFI）约20 K，同时为高频仪器（HFI）的4 K J-T机械制冷机提供预冷级。在喷气推进实验室进行子系统级验证后，低温冷却器已于2005年交付欧空局。在本文中，我们介绍了2008年在CSL（Centre Spatial de Liege）设施进行的飞行模型航天器上标称装置的低温鉴定和试验活动的结果。测试结果的输入功率，冷却功率，温度和温度波动的飞行允许范围内，这些接口的报告和分析任务的要求。
We examine the consistency of WMAP9 and Planck data. We compare sky maps, power spectra, and inferred LCDM cosmological parameters. Residual dipoles are seen in the WMAP and Planck sky map differences, but are consistent within the uncertainties and are not large enough to explain the widely-noted differences in angular power spectra at higher l. After removing residual dipoles and galactic foregrounds, the residual difference maps exhibit a quadrupole and other large-scale systematic structure. We identify this structure as possibly originating from Planck's beam sidelobe pick-up, but note th…
The Planck collaboration has extensively used the six Planck HFI frequency maps to detect the Sunyaev-Zel'dovich (SZ) effect with dedicated methods, e.g., by applying (i) component separation to construct a full sky map of the y parameter or (ii) matched multi-filters to detect galaxy clusters via their hot gas. Although powerful, these methods may still introduce biases in the detection of the sources or in the reconstruction of the SZ signal due to prior knowledge (e.g., the use of the GNFW profile model as a proxy for the shape of galaxy clusters, which is accurate on average but not on ind…
Separation of polarized dust emission in Planck observations with Scattering Transforms
Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité（巴黎高等师范学院物理实验室，ENS，PSL大学，CNRS，索邦大学，巴黎西岱大学）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Department of Astronomy and Astrophysics, University of Chicago（芝加哥大学天文学与天体物理学系）；CNRS-UCB International Research Laboratory, Centre Pierre Binétruy, IRL 2007, CPB-IN2P3（CNRS-UCB国际研究实验室，皮埃尔·比内屈中心，IRL 2007，CPB-IN2P3）
The clustering of local extrema will be exploited to examine Gaussianity, asymmetry, and the footprint of the cosmic-string network on the CMB observed by Planck. The number density of local extrema ($n_{\rm pk}$ for peak and $n_{\rm tr}$ for trough) and sharp clipping ($n_{\rm pix}$) statistics support the Gaussianity hypothesis for all component separations. However, the pixel at the threshold reveals a more consistent treatment with respect to end-to-end simulations. A very tiny deviation from associated simulations in the context of trough density, in the threshold range $θ\in [-2-0]$ for …
Herschel has revolutionized our ability to measure column densities (N$_{\rm H}$) and temperatures (T) of molecular clouds thanks to its far infrared multiwavelength coverage. However, the lack of a well defined background intensity level in the Herschel data limits the accuracy of the N$_{\rm H}$ and T maps. We provide a method that corrects the missing Herschel background intensity levels using the Planck model for foreground Galactic thermal dust emission. We present a Fourier method that combines the publicly available Planck model on large angular scales with the Herschel images on smalle…
The Planck satellite detectors are calibrated in the 2015 release using the "orbital dipole", which is the time-dependent dipole generated by the Doppler effect due to the motion of the satellite around the Sun. Such an effect has also relativistic time-dependent corrections of relative magnitude 10^(-3), due to coupling with the "solar dipole" (the motion of the Sun compared to the CMB rest frame), which are included in the data calibration by the Planck collaboration. We point out that such corrections are subject to a frequency-dependent multiplicative factor. This factor differs from unity…
We provide a fast algorithm to diagnose any directional dependence in the cosmological parameters by calculating maps of local cosmological parameter estimates and their joint errors. The technique implements a fast quadratic estimator technique based on Wiener filtering and convolution of the sky with a patch shape. It uses only three map-resolution spherical harmonic transforms per parameter and applies to any data set with full sky or a partial sky coverage. We apply this method to Planck SMICA-2015 and obtain fluctuation map for six cosmological parameters. Our estimate shows that the Plan…
We compare the absolute gain photometric calibration of the Planck/HFI and Herschel/SPIRE instruments on diffuse emission. The absolute calibration of HFI and SPIRE each relies on planet flux measurements and comparison with theoretical far-infrared emission models of planetary atmospheres. We measure the photometric cross calibration between the instruments at two overlapping bands, 545 GHz / 500 $μ$m and 857 GHz / 350 $μ$m. The SPIRE maps used have been processed in the Herschel Interactive Processing Environment (Version 12) and the HFI data are from the 2015 Public Data Release 2. For our …
