| | Monday | | Tuesday | | Wednesday | | Thursday |
| 08:30 - 09:00 |
Morning Coffee | | Morning Coffee | | Morning Coffee | | Morning Coffee |
| 09:00 - 09:20 |
Welcome [pdf]
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09:00 - 09:35 |
Nicoletta KrachmalnicoffBrief review of polarized Galactic foregrounds
In the last years it has become clear that the contamination coming from Galactic emission represents the main limiting factor to the detection of the imprint of primordial Gravitational Waves in the Cosmic Microwave Backrground (CMB) polarized signal.
Having a thorough understanding of the foreground properties is therefore of fundamental importance in order to achieve a reliable recontruction of the clean CMB maps after the separation of the components and recognition of the cosmological effects in those.
In this talk I willl review the current status of knowledge of the two main Galactic polarized emissions that contaminate CMB observations. Thermal dust radiation is currently constrained by the high frequency observations of the Planck satellite. Synchrotron emission has been recently characterized by low frequency ground based surveys. I will summarize the main results from the latest analysis, and review the schedule of ongoing activities, and expected results. I will also go through the current status and future plans for the inclusion of information in the simulations of the Galactic polarized signal, which represents a fundamental ingredient in preparation of the future ground based and satellite experiments.
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09:00 - 09:35 |
Adrian LeeGround-based review
TBA
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09:00 - 09:35 |
Shaul HananyThe Probe of Inflation and Cosmic Origins
The Probe of Inflation and Cosmic Origins (PICO) is a concept for a next decade space mission that has been developed by many members of the CMB community and with NASA support. PICO is an imaging polarimeter that will scan the sky for 5 years in 21 frequency bands spread between 21 and 799 GHz. It will produce ten independent full-sky surveys of intensity and polarization with a final combined-map noise level equivalent to 3300 Planck missions for the baseline required specifications, and according to our current best-estimate would perform as 6400 Planck missions. I will describe the science goals of the mission and its architecture. More details are given by our 50 page report, astro-ph/1902.10541, or decadal white paper astro-ph/1908.07495
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| 09:20 - 09:55 |
Slava MukhanovPrimordial Gravitational Waves: Theoretical Expectations
TBA
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09:35 - 10:10 |
Michael JonesC-BASS
TBA
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09:35 - 10:10 |
Benjamin RacineMeasurements of Degree-Scale B-mode Polarization with the BICEP/Keck Experiments at South Pole
The BICEP and Keck experiments, located at the South Pole, are currently observing the polarized microwave sky at the degree scale using refractive telescopes. They are searching for a signature of primordial gravitational waves in the so-called B modes of the cosmic microwave background (CMB), parametrized with the tensor-to-scalar ratio r. In this talk I will introduce our latest analysis which includes BICEP2 and Keck Array data up to the end of 2015. These are the deepest CMB polarization maps to date at 95, 150 and for the first time 220GHz. We use these multiple frequency channels in combination with Planck and WMAP data to constrain a model consisting of the lensed-LCDM + r, Galactic dust and synchrotron, which yields r<0.07 at 95% confidence. I will give an update on the subsequent observations from BICEP3 and the Keck Array which took place since 2016, and provided more data at 95, 150, 220 and a new 270GHz channel. Benjamin Schmitt will separately provide an overview of the current status of the design, integration, and deployment of the first BICEP Array receiver, as well as a summary of the CMB-S4 small aperture telescope program.
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09:35 - 10:10 |
Rishi KhatriECHO - A CMB-Bharat proposal
I will present the proposal for next generation CMB space mission: Exploring Cosmic History and Origin (ECHO) by Indian CMB consortium, the CMB-Bharat collaboration.
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| 09:55 - 10:30 |
Rashid SunyaevAll sky surveys in X-Rays and microwave spectral bands: What we expect from eRosita and ART-XC aboard SRG andnew ground-based and space microwave telescopes
I plan to demonstrate some fresh eRosita and ART-XC data to prove that there is a good chance to map few millions of the X-Ray sources during 4 years long sky survey. I will show also that eRosita is an excellent imaging and a good spectroscopy instrument for detailed observations of the extended X-Ray sources. There is a good chance that in 5 years X-Ray and microwave ground-based telescopes will compete in the attempts to discover up to 100 thousand clusters of galaxies and several thousands of strong gravitational lenses inside them. In the final part of my talk I plan to remind the high scientific potential of the search for the myu- and y-type spectral distortions of CMB and detailed study of the CO emission in early Universe and other foregrounds with peculiar spectra.
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10:10 - 10:45 |
Susan ClarkModeling Polarized Dust Emission from the Three-Dimensional Interstellar Medium with Neutral Hydrogen Data
Polarized dust emission is a formidable foreground for the detection of primordial B-modes. Recent insights into the structure of the magnetic interstellar medium (ISM) provide a framework for realistic, data-driven models of the polarized dust foreground. I will discuss advances in modeling this polarized emission using Galactic neutral hydrogen, which probes the three-dimensional structure of the magnetic ISM.
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10:10 - 10:45 |
Jeffrey FilippiniCosmological and Galactic foreground constraints from the first flight of the SPIDER instrument
The SPIDER balloon-borne polarimeter was designed to characterize the polarization of the cosmic microwave background and intervening Galactic foregrounds on degree angular scales. SPIDER completed its first flight in January 2015, observing about 12% of the Southern sky with instruments at 95 and 150 GHz over a period of 16 days. A second flight is planned for December 2020 that will include 280 GHz instruments to improve constraints on Galactic dust. In this talk, we present results from SPIDER's first flight, including constraints on Galactic foreground emission in our observing region, as well as cosmological constraints on primordial gravitational waves contributing to the CMB B-mode spectrum.
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10:10 - 10:45 |
Mathieu RemazeillesElectron temperature spectroscopy through the mapping of relativistic SZ effects
While the "first SZ revolution" has seen the mapping of the thermal Sunyaev-Zeldovich (SZ) Compton-y parameter across the full sky thanks to Planck satellite observations, we envision a "second SZ revolution" for next-generation CMB experiments with the mapping of the relativistic electron gas temperature, Te, across the sky through the extraction of relativistic corrections to the thermal SZ effect. We propose a semi-blind component separation method to mitigate foregrounds and disentangle the y and Te observables of the relativistic SZ effect. Increasing sensitivity and comprehensive spectral coverage with observations at frequencies > 300 GHz are needed to break the y-Te degeneracy in the relativistic SZ spectrum. We will show how our method opens a new spectroscopic window on galaxy clusters not only across frequency but now also across temperature. We will also discuss the promising potential of the "electron temperature power spectrum" as a new map-based cosmological observable to complement the "Compton-y power spectrum" and constrain cosmology with galaxy clusters, and how this new cosmological observable could break parameter degeneracies and possibly alleviate current tensions on some cosmological parameters.
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| 10:30 - 11:00 | Break (30) |
10:45 - 11:15 | Break (30) |
10:45 - 11:15 | Break (30) |
10:45 - 11:15 | Break (30) |
| 11:00 - 11:35 |
Silvia GalliPlanck results, curiosities and tensions in the LCDM model
Planck is an ESA satellite aimed at the observation of the Cosmic Microwave Background. The Planck collaboration has recently published its last legacy release. In this talk I will shortly review the main Planck results and their robustness, highlighting the role of the interplay between large and small scale measurements. I will present some of the curious features found in the data and, time permitting, I will give the Planck point of view on tensions with other astrophysical probes, notably with H0 local distance measurements.
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11:15 - 11:50 |
Gina Panopoulou3D mapping of the dusty, magnetized ISM with starlight polarization
With the increasing sensitivity of ongoing and upcoming CMB experiments comes the need to model dust foregrounds with unprecedented precision. The unknown level of complexity of foreground dust renders this a challenging problem. A growing body of works aims at employing alternative tracers of the ISM in order to inform foreground modeling. One such tracer of the dust and magnetic field in the ISM is the polarization of starlight, induced through absorption by ISM dust. With the advent of ESA’s Gaia mission, the availability of stellar distances enables mapping dust-induced starlight polarization in 3D. I will discuss PASIPHAE, an upcoming optical polarization survey which aims at producing a tomographic map of the magnetic field orientation in the diffuse ISM. I will present results from a path-finding mini-survey and explore the wealth of information we gain by combining tomographic information with HI surveys.
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11:15 - 11:50 |
Silvia MasiLSPE: a Large-Scale polarization survey of the CMB
The Large Scale Polarization Explorer is a coordinated experiment to map the polarization of the CMB at large angular scales in the northern hemisphere, using a ground-based instrument (STRIP) devoted to the synchrotron polarized foreground and a balloon-borne instrument (SWIPE) devoted to CMB polarization and the polarized foreground from interstellar dust. We describe the experimental implementation, including several original solutions, and the performance forecast of the experiment.
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11:15 - 11:40 |
Jacques DelabrouilleA space mission for a census of matter and radiation across space and time
In spite of the impressive consistency of the minimal LCDM cosmological model with most cosmological observations to-date, fundamental questions concerning our Universe remain unanswered. We do not know what are dark matter and dark energy, nor the physics at work in the very universe, nor in detail how do spatial inhomogeneities form and evolve. Answers to these questions are encoded in the distribution of matter and energy in the observable universe and their evolution with redshift. In the context of the Voyage 2050 consultation of the scientific community by ESA, we advocate for a large-class space mission to perform a spectro-polarimetric survey of the microwave sky for a comprehensive census of matter and radiation across space and time. I will describe the rationale for the main characteristics and performance goals of the proposed mission.
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| 11:35 - 12:10 |
Masashi HazumiLiteBIRD
In May 2019, LiteBIRD was selected as the JAXA’s strategic L-class satellite #2 targeting a launch in 2027. Its mission is to map the polarization of the cosmic microwave background (CMB) radiation over the full sky at large angular scales with unprecedented precision. LiteBIRD will allow us to make a crucial test of cosmic inflation and quantum gravity theories behind it. It will also provide us with valuable information on particle physics and astrophysics. I will give an overview of the science, instrument design, and project plans of LiteBIRD, where I will emphasize internationality of the project.
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11:50 - 12:15 |
Brandon HensleyDecorrelation from the 3D Interstellar Medium
Modeling and subtracting the polarized dust emission from our Galaxy is one of the most significant challenges facing B-mode experiments. In this talk, I will review the physics of polarized dust emission and discuss the coupling of dust SED variations to the 3D structure of the ISM. I will highlight how ancillary data such as HI emission and starlight polarization as well as MHD simulations can be used for simulating, understanding, and modeling polarized dust foregrounds.
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11:50 - 12:15 |
Jean-Christophe HamiltonQUBIC: the QU Bolometric Interferometer for Cosmology
QUBIC (the Q and U Bolometric Interferometer for Cosmology) is a CMB polarimeter designed to search the B-mode polarization of the CMB, the signature expected from primordial gravitational waves generated during the inflation phase of the early Universe. QUBIC, a collaboration between French, Italian, Argentinean, Irish and British laboratories, is an innovative instrument based on the novel technology of bolometric interferometry that combined the high sensitivity of bolometric detectors (2048 Transition Edge Sensors) along with the observation of interference fringes (400 channels) allowing for an unprecedented control of systematic effects. Furthermore, our synthesized beam being significantly frequency-dependent, QUBIC has spectro-imaging capabilities allowing us to reconstruct multiple sub-frequency CMB polarizations maps within our two wide-band filters (150 and 220 GHz). This opens promising perspectives for the control of foreground B-modes contamination, especially in the likely presence of complex dust emission. End-To-End simulations have shown that QUBIC will reach a sensitivity of σ(r)=0.01 after two years of integration. After integration in 2018 in Paris, QUBIC is now being calibrated and tested showing behavior and performances in excellent agreement with our expectations and simulations. The instrument will be installed in late 2019 in its observation site near San Antonio de los Cobres on the Puna plateau in Salta, Argentina at 5000m a.s.l. offering dry atmosphere and clear sky.
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11:40 - 12:05 |
Jens ChlubaNew Horizons in Cosmology with Spectral Distortions of the Cosmic Microwave Background
It has been widely recognized that spectral distortions of the Cosmic Microwave Background (CMB) provide a unique probe of early-universe and particle physics. In this talk, I will give a broad brush overview of some of the early-universe processes that CMB spectral distortions could shed light on. I will also briefly discuss possible mission concepts and their configuration that could allow extracting these valuable signals in the presence of foregrounds, thereby opening a new window to fundamental physics.
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| 12:10 - 12:35 |
Clara VergèsForecasting the performance of next generation of CMB polarisation experiments in the presence of galactic foregrounds and selected systematic effects
The next generation of CMB polarisation needs to have sufficient sensitivity and frequency coverage to detect and characterise the primordial B-modes signal, and to distinguish it from foregrounds contamination. This requires the deployment of detectors arrays of many thousands of multi-chroic detectors, along with new technologies, such as achromatic half-wave plate (HWP) or sinuous antennas. This increased complexity will introduce new instrumental and systematic effects, which will need to be accounted for in instrument modelling and data analysis. In particular, the use of achromatic HWP and sinuous antennas impacts the polarisation angle of the instrument, and modifies the structure of data, by mixing together Q and U polarisation signals. These effects depend on instrumental bandpasses, frequency and foreground emission laws. Using Mueller matrix formalism for typical stage III CMB polarisation experiments, we study their impact on component separation and forecast limits on tensor-to-scalar ratio detection. This is done within the framework of the formalism introduced in [1], which we generalise to allow for the presence of the systematic effects.
[1] Stompor et al. Forecasting performance of CMB experiments in the presence of complex foreground contaminations. Phys. Rev. D 94, 083526 (2016)
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12:15 - 12:40 |
Debabrata AdakDust polarization modeling at large-scale over the Northern Galactic cap using EBHIS and Planck data
The primary source of systematic uncertainty in the quest for the B-mode polarization of the Cosmic Microwave Background introduced by primordial gravitational waves is polarized thermal emission from Galactic dust. Therefore, accurate characterization and separation of the polarized thermal dust emission is an essential step in detecting such a faint CMB B-mode signal. We provide a modeling framework to simulate polarized thermal dust emission making use of both the Planck dust and Effelsberg-Bonn HI surveys data over the Northern Galactic cap. Our seven-parameter dust model, incorporating three layers of HI gas in different phases as a proxy of variable dust intensity and a phenomenological model of Galactic magnetic field, is able to reproduce both 1- and 2-point statistics of observed dust polarization maps seen by Planck at 353 GHz over a selected 65% low-column density sky region in the northern Galactic cap. This work has important applications in assessing the accuracy of component separation methods and in quantifying the confidence level of separating polarized Galactic emission and the CMB B-mode signal, as is needed for ongoing and future CMB missions.
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12:15 - 12:40 |
Xinmin ZhangAli CMB Project
Ali CMB Polarization Telescope (AliCPT) is a ground based CMB experiment located at Ali, Tibet, China. AliCPT will precisely measure the CMB polarization to detect the primordial gravitational waves, as well as test the CPT symmetry. In this talk, I will give an introduction to the AliCPT project, including site property, project current status and scientific goals.
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12:05 - 12:30 |
Kaustuv BasuSZ effect spectral studies from ground and space
After a golden decade of cluster detection via photometric SZ measurements, the coming decade can see equally impressive advances in SZ spectral science. Detailed modelling of the SZ spectrum can enable, among other things, optimal separation of the thermal and kinematic SZ effects, measurement of cluster temperatures from the relativistic thermal SZ signal, and deriving energy limits for the cosmic rays within clusters from nonthermal SZ. I will describe our efforts at the Bonn University to extract science from some of these SZ spectral signatures, in preparation of the upcoming high-frequency (220-860 GHz) CMB survey data from the CCAT-prime telescope. I will also describe a proposal submitted for the ESA Voyage 2050 call, which focuses on similar SZ spectral studies but goes further and includes all potential science topics that can be addressed when CMB is used as a "backlight".
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| 12:35 - 14:00 | Lunch (85) |
12:40 - 14:00 | Lunch (80) |
12:40 - 14:00 | Lunch (80) |
12:30 - 14:00 | Lunch (90) |
| 14:00 - 14:25 |
Paolo CampetiConstraining the Tensor Power Spectrum with LiteBIRD
We study the constraining power of the LiteBIRD satellite on the standard parametrization of the tensor power spectrum $r$ and $n_{T}$ and by exploiting the Principal Component Analysis (PCA) formalism recently considered in our work Campeti, Poletti & Baccigalupi (2019) arXiv:1905.08200. The motivations for this work are to be found in the numerous examples of non-standard B-mode emission in the literature (e.g. SU(2) axion model, massive inflation, cosmic strings etc.). We aim at establishing the constraining power of LiteBIRD, SO and CMB-S4 on the shape of primordial tensor power spectrum, and to do so we use Principal Component Analysis to go beyond usual power-law parameterization of primordial tensor power spectrum for a model independent approach.
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14:00 - 14:25 |
Jose Alberto Rubino-MartinThe QUIJOTE experiment: latest results
I will review the current status of the QUIJOTE (Q-U-I JOint TEnerife) experiment, a project with the aim of characterising the polarisation of the Cosmic Microwave Background, and other galactic or extragalactic physical processes that emit in microwaves in the frequency range 10-42GHz, and at large angular scales (1 degree resolution). In particular, I will discuss the latest scientific results associated to the wide survey carried out with the first QUIJOTE instrument (MFI), at 11, 13, 17 and 19GHz. These maps are used to characterise the radio foregrounds in the northern sky, with special emphasis on the synchrotron and AME components. The implications of the measured synchrotron properties on the detectability of B-modes with future experiments will be discussed.
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14:00 - 14:25 |
W.L. Kimmy WuDelensing: Updates from the South Pole Telescope and BICEP/Keck Array
Inflation generically predicts a background of primordial gravitational waves, which generate a primordial B-mode component in the polarization of the cosmic microwave background (CMB). The measurement of such a B-mode signature would lend significant support to the paradigm of inflation. Observed B modes also contain a component from the gravitational lensing of primordial E modes, which can obscure the measurement of the primordial B modes. We reduce the sample variance in the BB spectrum contributed from this lensing component by a process called 'delensing.’ In this talk, I will give an update on the current effort to delens BICEP/Keck (BK) data, using data from BK, the South Pole Telescope (SPT) and Planck. This analysis is expected to reduce the uncertainty on the constraint of the primordial gravitational waves, parameterized through the tensor-to-scalar ratio r. In addition, I will provide an outlook for joint-analysis efforts of the BICEP/Keck and the SPT collaborations, under the umbrella of the newly formed South Pole Observatory, to constrain r.
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14:00 - 14:25 |
Jochem BaselmansKinetic Inductance Detector based instruments for the CMB
Future space-based observatories for the CMB require large detector arrays that combine high optical efficiency, polarization purity and space qualified operation in a 50-500 GHz frequency band. We have developed kilo-pixel arrays of kinetic inductance detectors (KIDs), operating at 350 GHz and 850 GHz, together with a space qualifiable readout, to partially fulfil these requirements. This system combines photon-noise limited performance, high optical efficiency and a yield larger than 90%. The expected dead observing time due cosmic ray interactions, when operated in an L2 or a similar far-Earth orbit, is expected to be lower than 0.5% based upon laboratory experiments using cosmic rays and GEANT-4 simulations [1].
Additional benefits in system complexity and integration could be achieved by using on-chip filtering techniques to create a multicoloured, dual polarization pixel. In this context I will present the recent on-sky demonstration of DESHIMA, an on-chip filterbank spectrometer with KID detectors operating in a 80 GHz band around 350 GHz. DESHIMA has successfully detected the redshifted CO 3-2 line from an extra-galactic source and demonstrated imaging capabilities as well [2]. Future developments using this technology will allow the construction of a dual polarized, broad-band spectroscopic pixel with arbitrary frequency resolution, enabling a simper focal plane design and increasing the total instrument throughput.
[1] Baselmans, J. J. A. et al. A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors. Astron. Astrophys. 601, A89 (2017).
[2] Endo, A. et al. First light demonstration of the integrated superconducting spectrometer. Nat. Astron. 418 (2019). doi:10.1038/s41550-019-0850-8
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| 14:25 - 14:50 |
Blake SherwinDelensing: New Methods and New Challenges for Simons Observatory and LiteBIRD
Next-generation CMB experiments will be substantially limited by lensing noise in searches for primordial B-mode polarization. For these searches to realize their full cosmological potential, delensing methods to remove the limiting lensing B-modes must therefore be applied. However, this requires the development of a variety of new methods. I will discuss this subject with illustrations from the Simons Observatory delensing pipeline (which is currently being developed), commenting also on the prospects for delensing LiteBIRD and space-based experiments.
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14:25 - 14:50 |
Ricardo T. Genova-SantosThe GroundBIRD experiment: current status and future prospects
GroundBIRD is a new KID-based CMB polarimeter at 150 and 220 GHZ, recently deployed at the Teide Observatory in Tenerife. It will observe 40% of the sky at both frequencies during ~3 years with the aim to constrain the recombination bump down to r=0.01. In this talk I will describe in detail this project and will show the first commissioning results.
[pdf]
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14:25 - 14:50 |
Marius MilleaBayesian optimal lensing with the South Pole Telescope and lessons for the future
The quadratic estimator for the gravitational lensing potential, the estimator used by all generic lensing reconstructions from CMB data to-date, becomes statistically suboptimal as noise levels dip below ~5 μK-arcmin in polarization. Improving this estimate is a necessity for CMB-S4 to meet its stated goals; improvements will also help any space-based experiments such as LiteBIRD that aim to perform any kind of delensing with high resolution ground-based data. I will review existing methods for such improved "optimal lensing" analyses, and focus on a particular Bayesian technique which I find most promising. We have recently applied this technique to a small but very deep observation from the South Pole Telescope, whose noise levels are such that optimal lensing yields noticeable improvements over the quadratic estimate. I will present results from this analysis, and highlight lessons that can be taken away for future optimal analyses at scale.
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14:25 - 14:50 |
Sophie Henrot-VersilleThe challenges of calibration
Calibration of CMB B-modes experiments is a key ingredient toward the inference of constraints on primordial cosmology. The determination of the instrumental parameters that enter data analysis pipelines is a real challenge for two reasons: we need to measure those parameters with an outstanding accuracy given the foreseen instrumental systematics error budget, and this requires to develop specific calibration strategies making use of dedicated devices that have to be elaborated for this particular purpose. We will discuss those challenges in the light of what is currently planned for LiteBIRD.
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| 14:50 - 15:20 |
Poster Talks |
14:50 - 15:20 |
Poster Talks |
14:50 - 15:15 |
Suvodip MukherjeeIs patchy reionization an obstacle in detecting the primordial gravitational wave signal?
The large-scale B-mode polarization of cosmic microwave background (CMB) is a direct probe to the low frequency primordial gravitational wave signal. However, the unambiguous measurement of this signal requires a precise understanding of all the possible contaminations. One such potential contamination arises from the patchiness in the spatial distribution of free electrons during the epoch of reionization. I will discuss the origin of this effect and the contribution of this signal in the B-mode polarization. Our estimate from the semi-numerical simulations of cosmic reionization indicates that the contamination can bias the measurement of tensor to scalar ratio and it is important to remove this contamination to make a robust measurement of the primordial B-mode signal. The contamination from patchy reionization carries the same frequency dependence as the primordial B-mode signal and hence is not possible to be distinguished in the frequency domain. However, the shape of the spatial power spectrum is different from the primordial B-modes and hence can be separated in this domain by efficient cleaning algorithm. With the successful implementation of such statistical tools, upcoming space-based CMB mission LiteBIRD can reduce the contamination from patchy-reionization in the primordial B-mode polarization and can also study the reionization history using the B-mode polarization from patchy reionization.
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14:50 - 15:15 |
Samantha SteverCosmic ray systematic effects in cosmology space telescopes - problems and solutions
The flight of Planck HFI ushered a new area of telescope sensitivity in the field of cosmology in space. However, a higher-than-anticipated rate of cosmic ray 'glitches' threatened the mission. As instrument sensitivity increases with new scientific requirements, so does the need for precise and complete understanding of systematic effects such as cosmic rays. Especially for polarisation-sensitive sky-scanning missions, we must understand the sources of cosmic ray vulnerability and protect against them. In this work, we will discuss sources of CR vulnerability, including detector hits, thermal excursions on the detector wafers, and others. We will review the studies towards this in current missions. and discuss how to face this issue with future missions.
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| 15:20 - 16:20 | Poster Session (60) |
15:20 - 16:20 | Poster Session (60) |
15:15 - 16:00 | Break (45) |
15:15 - 16:00 | Break (45) |
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16:00 - 16:25 |
Aditya RottiForeground challenges for measurements of spectral distortions
The tiny spectral distortion signals are hidden under foreground contaminations which are several orders of magnitude higher. It will be critical to model and remove these foregrounds if we are to measure the signals of interest. The moment expansion machinery offers a systematic way of extending the parametrization for describing different foreground components. We show first demonstrations of measurement of the spectral distortion signals in the presence of realistic foregrounds. Finally I will discuss the critical challenges that still need to be overcome to make the measurements of spectral distortion feasible. I will also discuss the applicability of these methods for B-mode studies.
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16:00 - 16:25 |
Yuki SakuraiLiteBIRD LFT Polarization Modulator Unit
We present our design and development of a polarization modulator unit (PMU) for the low-frequency telescope (LFT) of LiteBIRD space mission. LiteBIRD is a next generation cosmic microwave background (CMB) polarization satellite to measure the primordial B-mode. The baseline design of LiteBIRD is composed of reflective low-frequency and refractive medium- and high-frequency telescopes with more than 4000 TESs in focal planes. Each telescope employs the PMU based on a continuous rotating half-wave plate (HWP) at the aperture. The LFT PMU consists of a multi-layered sapphire as a broadband achromatic HWP and a mechanism to continuously rotate it at around 60 rpm. The HWP temperature is kept below 20 K to minimize thermal emission from the HWP itself. In this presentation, we will discuss the necessity of the PMU for the space mission and its advantage in the particular LiteBIRD LFT optical configuration. Also we will summarize the current development status and plan especially about the broadband HWP and the space-compatible cryogenic rotation mechanism.
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| 16:20 - 16:45 |
Yuto MinamiSimultaneous determination of the cosmic birefringence and miscalibrated polarization angles from CMB experiments
We show that the cosmic birefringence and miscalibrated polarization angles can be deter-mined simultaneously by cosmic microwave background (CMB) experiments using the cross-correlation between E- and B-mode polarization data. This is possible because the polarization angles of the CMB are rotated by both the cosmic birefringence and miscalibration effects, whereas those of the Galactic foreground emission are rotated only by the latter. Our method does not require prior knowledge of the E- and B-mode power spectra of the foreground emission, but uses only the knowledge of the CMB polarization spectra. Specifically, we relate the observed EB correlation to the difference between the observed E- and B-mode spectra in the sky, and use different multipole dependences of the CMB (given by theory) and foreground spectra (given by data) to derive the likelihood for the miscalibration angle α and the birefringence angle β. We show that a future satellite mission similar to LiteBIRD can determine β with a precision of 10 arcmin.
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16:20 - 16:45 |
Jonathan AumontDust moments: towards a new modelling of the galactic dustemission for the CMB B-modes analysis
Measuring the CMB primordial B-modes to probe the inflationary epoch has become one of the main goals of cosmology and, more generally, of fundamental physics. Nevertheless, this measurement is extremely challenging as the instrumental systematic effects and the foreground emissions must be handled with exquisite accuracy. In particular, the polarized dust emission must be characterized very precisely to avoid bias in the constraint of the tensor-to-scalar ratio parameter, r, related to the amplitude to the B-mode signal and thus to the energy scale of inflation. So far, in the data analysis of current CMB polarization experiments, the spectral frequency dependence of dust polarization and its angular structure on the sky are assumed to be separable. However, as pointed out by recent Planck and BICEP results, this picture is too simplistic, as variations of the dust Spectral Energy Distribution along the line of sight across the sky induce frequency de-correlation, which may bias the estimation of r. The astrophysical modeling of this effect has thus become a main challenge in the quest of primordial B-modes. The Planck total intensity data offer the sensitivity and frequency coverage needed to build such a model on astrophysical grounds. We model the frequency dependence of dust emission in harmonic space, relating it to the moments of the dust spectral index and temperature. In this talk, we will describe the formalism and we will present the results when applying the method to Planck data. We will also discuss the implications for future CMB experiments.
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16:25 - 17:30 |
Panel Discussion |
16:25 - 17:00 |
Renée HložekConcluding Remarks
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| 16:45 - 17:45 |
Panel Discussion |
16:45 - 17:45 |
Panel Discussion |
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17:00 |
Adjourn |
| 18:00- |
Reception at ESO Supernova Visitor Center |