121 research outputs found

    Cosmoglobe DR1. III. First full-sky model of polarized synchrotron emission from all WMAP and Planck LFI data

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    We present the first model of full-sky polarized synchrotron emission that is derived from all WMAP and Planck LFI frequency maps. The basis of this analysis is the set of end-to-end reprocessed Cosmoglobe Data Release 1 sky maps presented in a companion paper, which have significantly lower instrumental systematics than the legacy products from each experiment. We find that the resulting polarized synchrotron amplitude map has an average noise rms of 3.2 μK3.2\,\mathrm{\mu K} at 30 GHz and 2∘2^{\circ} FWHM, which is 30% lower than the recently released BeyondPlanck model that included only LFI+WMAP Ka-V data, and 29% lower than the WMAP K-band map alone. The mean BB-to-EE power spectrum ratio is 0.40Β±0.020.40\pm0.02, with amplitudes consistent with those measured previously by Planck and QUIJOTE. Assuming a power law model for the synchrotron spectral energy distribution, and using the TT--TT plot method, we find a full-sky inverse noise-variance weighted mean of Ξ²s=βˆ’3.07Β±0.07\beta_{\mathrm{s}}=-3.07\pm0.07 between Cosmoglobe DR1 K-band and 30 GHz, in good agreement with previous estimates. In summary, the novel Cosmoglobe DR1 synchrotron model is both more sensitive and systematically cleaner than similar previous models, and it has a more complete error description that is defined by a set of Monte Carlo posterior samples. We believe that these products are preferable over previous Planck and WMAP products for all synchrotron-related scientific applications, including simulation, forecasting and component separation.Comment: 15 pages, 15 figures, submitted to A&

    Cosmoglobe: Towards end-to-end CMB cosmological parameter estimation without likelihood approximations

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    We implement support for a cosmological parameter estimation algorithm as proposed by Racine et al. (2016) in Commander, and quantify its computational efficiency and cost. For a semi-realistic simulation similar to Planck LFI 70 GHz, we find that the computational cost of producing one single sample is about 60 CPU-hours and that the typical Markov chain correlation length is ∼\sim100 samples. The net effective cost per independent sample is ∼\sim6 000 CPU-hours, in comparison with all low-level processing costs of 812 CPU-hours for Planck LFI and WMAP in Cosmoglobe Data Release 1. Thus, although technically possible to run already in its current state, future work should aim to reduce the effective cost per independent sample by at least one order of magnitude to avoid excessive runtimes, for instance through multi-grid preconditioners and/or derivative-based Markov chain sampling schemes. This work demonstrates the computational feasibility of true Bayesian cosmological parameter estimation with end-to-end error propagation for high-precision CMB experiments without likelihood approximations, but it also highlights the need for additional optimizations before it is ready for full production-level analysis.Comment: 10 pages, 8 figures. Submitted to A&

    Cosmoglobe DR1 results. II. Constraints on isotropic cosmic birefringence from reprocessed WMAP and Planck LFI data

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    Cosmic birefringence is a parity-violating effect that might have rotated the plane of linearly polarized light of the cosmic microwave background (CMB) by an angle Ξ²\beta since its emission. This has recently been measured to be non-zero at a statistical significance of 3.6Οƒ3.6\sigma in the official Planck PR4 and 9-year WMAP data. In this work, we constrain Ξ²\beta using the reprocessed BeyondPlanck LFI and Cosmoglobe DR1 WMAP polarization maps. These novel maps have both lower systematic residuals and a more complete error description than the corresponding official products. Foreground EBEB correlations could bias measurements of Ξ²\beta, and while thermal dust EBEB emission has been argued to be statistically non-zero, no evidence for synchrotron EBEB power has been reported. Unlike the dust-dominated Planck HFI maps, the majority of the LFI and WMAP polarization maps are instead dominated by synchrotron emission. Simultaneously constraining Ξ²\beta and the polarization miscalibration angle, Ξ±\alpha, of each channel, we find a best-fit value of Ξ²=0.35∘±0.70∘\beta=0.35^{\circ}\pm0.70^{\circ} with LFI and WMAP data only. When including the Planck HFI PR4 maps, but fitting Ξ²\beta separately for dust-dominated, Ξ²>70 GHz\beta_{>70\,\mathrm{GHz}}, and synchrotron-dominated channels, β≀70 GHz\beta_{\leq 70\,\mathrm{GHz}}, we find β≀70 GHz=0.53∘±0.28∘\beta_{\leq 70\,\mathrm{GHz}}=0.53^{\circ}\pm0.28^\circ. This differs from zero with a statistical significance of 1.9Οƒ1.9\sigma, and the main contribution to this value comes from the LFI 70 GHz channel. While the statistical significances of these results are low on their own, the measurement derived from the LFI and WMAP synchrotron-dominated maps agrees with the previously reported HFI-dominated constraints, despite the very different astrophysical and instrumental systematics involved in all these experiments.Comment: 10 pages, 7 figures, 2 tables. Submitted to A&

    Cosmoglobe DR1 results. I. Improved Wilkinson Microwave Anisotropy Probe maps through Bayesian end-to-end analysis

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    We present Cosmoglobe Data Release 1, which implements the first joint analysis of WMAP and Planck LFI time-ordered data, processed within a single Bayesian end-to-end framework. This framework builds directly on a similar analysis of the LFI measurements by the BeyondPlanck collaboration, and approaches the CMB analysis challenge through Gibbs sampling of a global posterior distribution, simultaneously accounting for calibration, mapmaking, and component separation. The computational cost of producing one complete WMAP+LFI Gibbs sample is 812 CPU-hr, of which 603 CPU-hrs are spent on WMAP low-level processing; this demonstrates that end-to-end Bayesian analysis of the WMAP data is computationally feasible. We find that our WMAP posterior mean temperature sky maps and CMB temperature power spectrum are largely consistent with the official WMAP9 results. Perhaps the most notable difference is that our CMB dipole amplitude is 3366.2Β±1.4Β ΞΌK3366.2 \pm 1.4\ \mathrm{\mu K}, which is $11\ \mathrm{\mu K}higherthantheWMAP9estimateand higher than the WMAP9 estimate and 2.5\ {\sigma}$ higher than BeyondPlanck; however, it is in perfect agreement with the HFI-dominated Planck PR4 result. In contrast, our WMAP polarization maps differ more notably from the WMAP9 results, and in general exhibit significantly lower large-scale residuals. We attribute this to a better constrained gain and transmission imbalance model. It is particularly noteworthy that the W-band polarization sky map, which was excluded from the official WMAP cosmological analysis, for the first time appears visually consistent with the V-band sky map. Similarly, the long standing discrepancy between the WMAP K-band and LFI 30 GHz maps is finally resolved, and the difference between the two maps appears consistent with instrumental noise at high Galactic latitudes. All maps and the associated code are made publicly available through the Cosmoglobe web page.Comment: 65 pages, 61 figures. Data available at cosmoglobe.uio.no. Submitted to A&

    From BeyondPlanck to Cosmoglobe: Preliminary WMAP\mathit{WMAP} Q\mathit Q-band analysis

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    We present the first application of the Cosmoglobe analysis framework by analyzing 9-year WMAP\mathit{WMAP} time-ordered observations using similar machinery as BeyondPlanck utilizes for Planck\mathit{Planck} LFI. We analyze only the Q\mathit Q-band (41 GHz) data and report on the low-level analysis process from uncalibrated time-ordered data to calibrated maps. Most of the existing BeyondPlanck pipeline may be reused for WMAP\mathit{WMAP} analysis with minimal changes to the existing codebase. The main modification is the implementation of the same preconditioned biconjugate gradient mapmaker used by the WMAP\mathit{WMAP} team. Producing a single WMAP\mathit{WMAP} Q\mathit Q1-band sample requires 22 CPU-hrs, which is slightly more than the cost of a Planck\mathit{Planck} 44 GHz sample of 17 CPU-hrs; this demonstrates that full end-to-end Bayesian processing of the WMAP\mathit{WMAP} data is computationally feasible. In general, our recovered maps are very similar to the maps released by the WMAP\mathit{WMAP} team, although with two notable differences. In temperature we find a ∼2 μK\sim2\,\mathrm{\mu K} quadrupole difference that most likely is caused by different gain modeling, while in polarization we find a distinct 2.5 μK2.5\,\mathrm{\mu K} signal that has been previously called poorly-measured modes by the WMAP\mathit{WMAP} team. In the Cosmoglobe processing, this pattern arises from temperature-to-polarization leakage from the coupling between the CMB Solar dipole, transmission imbalance, and sidelobes. No traces of this pattern are found in either the frequency map or TOD residual map, suggesting that the current processing has succeeded in modelling these poorly measured modes within the assumed parametric model by using Planck\mathit{Planck} information to break the sky-synchronous degeneracies inherent in the WMAP\mathit{WMAP} scanning strategy.Comment: 11 figures, submitted to A&A. Includes updated instrument model and changes addressing referee comment

    BeyondPlanck IV. On end-to-end simulations in CMB analysis -- Bayesian versus frequentist statistics

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    End-to-end simulations play a key role in the analysis of any high-sensitivity CMB experiment, providing high-fidelity systematic error propagation capabilities unmatched by any other means. In this paper, we address an important issue regarding such simulations, namely how to define the inputs in terms of sky model and instrument parameters. These may either be taken as a constrained realization derived from the data, or as a random realization independent from the data. We refer to these as Bayesian and frequentist simulations, respectively. We show that the two options lead to significantly different correlation structures, as frequentist simulations, contrary to Bayesian simulations, effectively include cosmic variance, but exclude realization-specific correlations from non-linear degeneracies. Consequently, they quantify fundamentally different types of uncertainties, and we argue that they therefore also have different and complementary scientific uses, even if this dichotomy is not absolute. Before BeyondPlanck, most pipelines have used a mix of constrained and random inputs, and used the same hybrid simulations for all applications, even though the statistical justification for this is not always evident. BeyondPlanck represents the first end-to-end CMB simulation framework that is able to generate both types of simulations, and these new capabilities have brought this topic to the forefront. The Bayesian BeyondPlanck simulations and their uses are described extensively in a suite of companion papers. In this paper we consider one important applications of the corresponding frequentist simulations, namely code validation. That is, we generate a set of 1-year LFI 30 GHz frequentist simulations with known inputs, and use these to validate the core low-level BeyondPlanck algorithms; gain estimation, correlated noise estimation, and mapmaking

    A Deep Insight into the Sialotranscriptome of the Gulf Coast Tick, Amblyomma maculatum

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    Background: Saliva of blood sucking arthropods contains compounds that antagonize their hosts ’ hemostasis, which include platelet aggregation, vasoconstriction and blood clotting; saliva of these organisms also has anti-inflammatory and immunomodullatory properties. Perhaps because hosts mount an active immune response against these compounds, the diversity of these compounds is large even among related blood sucking species. Because of these properties, saliva helps blood feeding as well as help the establishment of pathogens that can be transmitted during blood feeding. Methodology/Principal Findings: We have obtained 1,626,969 reads by pyrosequencing a salivary gland cDNA library from adult females Amblyomma maculatum ticks at different times of feeding. Assembly of this data produced 72,441 sequences larger than 149 nucleotides from which 15,914 coding sequences were extracted. Of these, 5,353 had.75 % coverage to their best match in the non-redundant database from the National Center for Biotechnology information, allowing for the deposition of 4,850 sequences to GenBank. The annotated data sets are available as hyperlinked spreadsheets. Putative secreted proteins were classified in 133 families, most of which have no known function. Conclusions/Significance: This data set of proteins constitutes a mining platform for novel pharmacologically activ
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