Abstract
The characterization and modeling of polarized foregrounds has become a critical issue in the quest for primordial
B
-modes. A typical method to proceed is to factorize and parametrize the ...spectral properties of foregrounds and their scale dependence (i.e. assuming that foreground spectra are well described everywhere by their sky average). Since in reality foreground properties vary across the Galaxy, this assumption leads to inaccuracies in the model that manifest themselves as biases in the final cosmological parameters (in this case the tensor-to-scalar ratio
r
). This is particularly relevant for surveys over large fractions of the sky, such as the Simons Observatory (SO), where the spectra should be modeled over a distribution of parameter values. Here we propose a method based on the existing “moment expansion” approach to address this issue in a power-spectrum-based analysis that is directly applicable in ground-based multi-frequency data. Additionally, the method uses only a small set of parameters with simple physical interpretation, minimizing the impact of foreground uncertainties on the final
B
-mode constraints. We validate the method using SO-like simulated observations, recovering an unbiased estimate of the tensor-to-scalar ratio
r
with standard deviation σ(
r
) ≃ 0.003, compatible with official forecasts. When applying the method to the public BICEP2/
Keck
data, we find an upper bound
r
< 0.06 (95% C.L.), compatible with the result found by BICEP2/
Keck
when parametrizing spectral index variations through a scale-independent frequency decorrelation parameter. We also discuss the formal similarities between the power spectrum-based moment expansion and methods used in the analysis of CMB lensing.
This Voyage 2050 paper highlights the unique science opportunities using spectral distortions of the cosmic microwave background (CMB). CMB spectral distortions probe many processes throughout the ...history of the Universe, delivering novel information that complements past, present and future efforts with CMB anisotropy and large-scale structure studies. Precision spectroscopy, possible with existing technology, would not only provide key tests for processes expected within the cosmological standard model but also open an enormous discovery space to new physics. This offers unique scientific opportunities for furthering our understanding of inflation, recombination, reionization and structure formation as well as dark matter and particle physics. A dedicated experimental approach could open this new window to the early Universe in the decades to come, allowing us to turn the long-standing upper distortion limits obtained with
COBE
/FIRAS some 25 years ago into clear detections of the expected standard distortion signals and also challenge our current understanding of the laws of nature.
Aims. Lumped-element kinetic inductance detectors (LEKIDs) are an attractive technology for millimeter-wave observations that require large arrays of extremely low-noise detectors. We designed, ...fabricated and characterized 64-element (128 LEKID) arrays of horn-coupled, dual-polarization LEKIDs optimized for ground-based CMB polarimetry. Our devices are sensitive to two orthogonal polarizations in a single spectral band centered on 150 GHz with Δν∕ν = 0.2. The 65 × 65 mm square arrays are designed to be tiled into the focal plane of an optical system. We demonstrate the viability of these dual-polarization LEKIDs with laboratory measurements. Methods. The LEKID modules are tested with an FPGA-based readout system in a sub-kelvin cryostat that uses a two-stage adiabatic demagnetization refrigerator. The devices are characterized using a blackbody and a millimeter-wave source. The polarization properties are measured with a cryogenic stepped half-wave plate. We measure the resonator parameters and the detector sensitivity, noise spectrum, dynamic range, and polarization response. Results. The resonators have internal quality factors approaching 1 × 106. The detectors have uniform response between orthogonal polarizations and a large dynamic range. The detectors are photon-noise limited above 1 pW of absorbed power. The noise-equivalent temperatures under a 3.4 K blackbody load are <100 μK √s ${<} 100~\mu\mathrm{K}\sqrt{\mathrm{s}}$ <100μKs . The polarization fractions of detectors sensitive to orthogonal polarizations are >80%. The entire array is multiplexed on a single readout line, demonstrating a multiplexing factor of 128. The array and readout meet the requirements for 4 arrays to be read out simultaneously for a multiplexing factor of 512. Conclusions. This laboratory study demonstrates the first dual-polarization LEKID array optimized specifically for CMB polarimetry and shows the readiness of the detectors for on-sky observations.
We report on the status of an ongoing effort to develop arrays of horn-coupled, polarization-sensitive microwave kinetic inductance detectors (MKIDs) that are each sensitive to two spectral bands ...between 125 and 280 GHz. These multi-chroic MKID arrays are tailored for next-generation, large-detector-count experiments that are being designed to simultaneously characterize the polarization properties of both the cosmic microwave background and Galactic dust emission. We present our device design and describe laboratory-based measurement results from two 23-element prototype arrays. From dark measurements of our first engineering array, we demonstrated a multiplexing factor of 92, showed the resonators respond to bath temperature changes as expected, and found that the fabrication yield was 100%. From our first optically loaded array, we found the MKIDs respond to millimeter-wave pulses; additional optical characterization measurements are ongoing. We end by discussing our plans for scaling up this technology to kilo-pixel arrays over the next 2 years.
The observation of the polarised emission from the Cosmic Microwave Background (CMB) fromfuture ground-based and satellite-borne experiments holds the promise of indirectly detecting theelusive ...signal from primordial tensor fluctuations in the form of large-scale B-modepolarisation. Doing so, however, requires an accurate and robust separation of the signal frompolarised Galactic foregrounds. We present a component separation method for multi-frequency CMBobservations that combines some of the advantages of map-based and power-spectrum-basedtechniques, and which is direcly applicable to data in the presence of realistic foregrounds andinstrumental noise. We demonstrate that the method is able to reduce the contamination fromGalactic foregrounds below an equivalent tensor-to-scalar ratio rFG ≲ 5 × 10-4, as required for next-generation observatories, for a wide range offoreground models with varying degrees of complexity. This bias reduction is associated with amild ∼20–30% increase in the final statistical uncertainties, and holds for largesky areas, and for experiments targeting both the reionisation and recombination bumps in theB-mode power spectrum.
Summary
Background
Long‐term outcome of ustekinumab in Crohn's disease (CD) has not been evaluated.
Aim
To evaluate the long‐term efficacy and safety of ustekinumab and identify the predictive ...factors of ustekinumab failure‐free persistence in a cohort of anti‐TNF refractory CD patients.
Methods
We performed a retrospective multicentre cohort study including all consecutive CD patients who began subcutaneous ustekinumab and presented a clinical response (defined as a significant improvement of CD‐related clinical symptoms assessed by the patient's physician leading to continued ustekinumab) during the first year of treatment. Primary outcome was treatment failure defined as withdrawal of treatment due to loss of response, intolerance or need for surgery.
Results
Eighty‐eight of the 122 (72%) CD patients beginning ustekinumab from March 2011 to December 2014, responded to ustekinumab and were followed up until November 2016. Median time on ustekinumab was 26.6 (13.4‐34.4) months. Forty‐seven patients (54%) continued ustekinumab with a clinical response and 38 (43%) stopped treatment (32 for failure, five for remission and one for pregnancy). Endoscopic response was observed in 82% of patients with endoscopic evaluation and mucosal healing in 39%. Ustekinumab failure‐free persistence rates were 78% at 12 months, 66% at 24 months and 55% at 36 months. No predictive factor of ustekinumab failure‐free persistence was identified. One severe adverse event was observed (anal adenocarcinoma).
Conclusion
In this cohort of refractory CD patients receiving long‐term ustekinumab therapy, more than 50% of patients continued ustekinumab treatment with no loss of response, intolerance or surgery and with a good safety profile.
We report on the status of an ongoing effort to develop arrays of horn-coupled, polarization-sensitive microwave kinetic inductance detectors (MKIDs) that are each sensitive to two spectral bands ...between 125 and 280 GHz. These multi-chroic MKID arrays are tailored for next-generation, large-detector-count experiments that are being designed to simultaneously characterize the polarization properties of both the cosmic microwave background and Galactic dust emission. We present our device design and describe laboratory-based measurement results from two 23-element prototype arrays. From dark measurements of our first engineering array, we demonstrated a multiplexing factor of 92, showed the resonators respond to bath temperature changes as expected, and found that the fabrication yield was 100%. From our first optically loaded array, we found the MKIDs respond to millimeter-wave pulses; additional optical characterization measurements are ongoing. We end by discussing our plans for scaling up this technology to kilo-pixel arrays over the next 2 years.
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