BeyondPlanck XIII. Intensity foreground sampling, degeneracies, and priors
| Autor: | Andersen, K. J., Herman, D., Aurlien, R., Banerji, R., Basyrov, A., Bersanelli, M., Bertocco, S., Brilenkov, M., Carbone, M., Colombo, L. P. L., Eriksen, H. K., Eskilt, J. R., Foss, M. K., Franceschet, C., Fuskeland, U., Galeotta, S., Galloway, M., Gerakakis, S., Gjerløw, E., Hensley, B., Iacobellis, M., Ieronymaki, M., Ihle, H. T., Jewell, J. B., Karakci, A., Keihänen, E., Keskitalo, R., Lunde, J. G. S., Maggio, G., Maino, D., Maris, M., Mennella, A., Paradiso, S., Partridge, B., Reinecke, M., San, M., Stutzer, N. -O., Suur-Uski, A. -S., Svalheim, T. L., Tavagnacco, D., Thommesen, H., Watts, D. J., Wehus, I. K., Zacchei, A. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | A&A 675, A13 (2023) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202243186 |
| Popis: | We present the intensity foreground algorithms and model employed within the BeyondPlanck analysis framework. The BeyondPlanck analysis is aimed at integrating component separation and instrumental parameter sampling within a global framework, leading to complete end-to-end error propagation in the $Planck$ Low Frequency Instrument (LFI) data analysis. Given the scope of the BeyondPlanck analysis, a limited set of data is included in the component separation process, leading to foreground parameter degeneracies. In order to properly constrain the Galactic foreground parameters, we improve upon the previous $\texttt{Commander}$ component separation implementation by adding a suite of algorithmic techniques. These algorithms are designed to improve the stability and computational efficiency for weakly constrained posterior distributions. These are: 1) joint foreground spectral parameter and amplitude sampling, building on ideas from Miramare; 2) component-based monopole determination; 3) joint spectral parameter and monopole sampling; and 4) application of informative spatial priors for component amplitude maps. We find that the only spectral parameter with a significant signal-to-noise ratio using the current BeyondPlanck data set is the peak frequency of the anomalous microwave emission component, for which we find $\nu_{\mathrm{p}}=25.3\pm0.5$ GHz; all others must be constrained through external priors. Future works will be aimed at integrating many more data sets into this analysis, both map and time-ordered based, thereby gradually eliminating the currently observed degeneracies in a controlled manner with respect to both instrumental systematic effects and astrophysical degeneracies. When this happens, the simple LFI-oriented data model employed in the current work will need to be generalized to account for both a richer astrophysical model and additional instrumental effects. Comment: 27 pages, 23 figures, 3 tables, part 13 of the BeyondPlanck release. All BeyondPlanck products and software will be released publicly at http://beyondplanck.science. Paper version as accepted by A&A |
| Databáze: | arXiv |
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