arXiv subjects

J. A. Rubiño-Martín

Publications and source records attributed to J. A. Rubiño-Martín.

At least 19 recordsLinked to original sources

arXiv2026

Validation of harmonic-space likelihood methods for LiteBIRD B-mode polarisation analysis

The LiteBIRD satellite mission aims to measure the tensor-to-scalar ratio $r$ with unprecedented sensitivity through observations of the cosmic microwave background (CMB) $B$-mode polarisation. Robust constraints on $r$ require accurate likelihood modelling across a wide range of angular scales. In this work, we validate harmonic-space likelihood methods against pixel-based benchmarks using 20\,000 end-to-end simulations that include CMB, instrumental noise, and Galactic foreground residuals processed through a realistic component-separation pipeline. We compare a debiased pixel-based likelihood, which serves as our benchmark on large scales ($\ell\leq32$), with an offset Hamimeche \& Lewis (oHL) likelihood applicable across the full multipole range. We systematically explore the space of analysis settings, identifying the number of simulations used for covariance estimation and the choice of beam window function as the most critical factors. Over the full multipole range considered ($\ell\leq128$), where the benchmark combines the pixel-based likelihood at $\ell\leq32$ with a harmonic one at smaller scales, the 68\% upper bound on $r$ from the oHL likelihood is $19$--$29\%$ larger than the benchmark one, depending on the beam window function. This demonstrates its viability as a computationally efficient baseline for LiteBIRD data analysis and cosmological inference from the polarisation $B$-mode field.

astro-ph.CO↗

arXiv2026

QUIJOTE scientific results - XX. Commissioning and First Results from the Thirty and Forty Gigahertz Instrument (TFGI)

We present the commissioning and first results of the Thirty and Forty Gigahertz Instrument (TFGI), which observes the sky at 31 and 41 GHz with angular resolutions of 21' and 18' from the second QUIJOTE telescope at the Teide Observatory. Its primary goal is to conduct a deep cosmological survey in selected regions of the Northern sky with high-sensitivity polarization measurements. The commissioning phase covered Nov2021-Oct2022, during which the instrument operated with a configuration of 7 receivers, 4 at 31 GHz and 3 at 41 GHz. Over this period, approximately 1200 h of data were acquired. Of these, 380 h were dedicated to calibration sources, used to characterize the instrumental properties of TFGI, including the pointing model, beam response, gain stability, polarimetric performance, and instantaneous sensitivity. We provide a detailed characterization of these properties and describe how they are being improved for future observing runs. We use 230 h of observations from bright Galactic regions (Cygnus, W43, W44, and W47) to further validate the instrument performance. As an illustrative example, we present the intensity and polarization spectral energy distributions of W44, finding good agreement with existing measurements. From the noise map of these observations, we measure a polarization sensitivity of ~8.3 $μ$K deg$^{-1}$ after an effective observing depth of 0.57 h deg$^{-2}$. This performance, achieved considering only 2 detectors at 31 GHz, is already comparable to that achieved by WMAP (with almost 3 times the integration time per unit area, 1.61 h deg$^{-2}$). Extrapolating these results to the full TFGI array, with up to 29 detectors, we show that the instrument is expected to reach the target sensitivity of ~ 1 $μ$K deg$^{-1}$ at both 31 and 41 GHz over three cosmological fields covering a total area of 3600 deg$^2$ after an effective integration time of 5.7 years.

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arXiv2026

Galactic Science with the LiteBIRD satellite: Spectral characterization of diffuse Galactic polarized emission at the angular power spectrum level

Detection of primordial $B$-mode polarization in the cosmic microwave background (CMB) from tensor perturbations generated during inflation is a major scientific goal of future CMB missions. Its success will strongly depend on the characterization of polarized foregrounds, a challenge that the LiteBIRD satellite aims to tackle with its 15 frequency bands ranging from 40 to 402 GHz. In this work, we forecast the ability of LiteBIRD to characterize polarized dust and synchrotron emission in the diffuse interstellar medium (ISM), at the angular power spectrum level. From simulated LiteBIRD intensity and polarization maps with different foreground complexities, we compute cross-frequency angular power spectra and fit them to dust and synchrotron spectral energy distributions, which are modeled by a modified black body and a power law, respectively. We find that LiteBIRD will be able to measure the dust temperature, dust and synchrotron spectral indices and spatial correlation with dispersions as low as $σ(T_{\rm d})\sim0.2$ K, $σ(β_{\rm d})\sim0.006$, $σ(β_{\rm s})\sim0.04$ and $σ(ρ)\sim10^{-2}$, as well as to detect and quantify deviations from the proposed parametric model due to variations of the emission properties in the three dimensions of our Galaxy. Additionally, LiteBIRD is likely to rule out the power-law model of polarized foreground angular power spectra suggested by Planck data. It will also be able to detect differences in the values of $β_{\rm d}$, $T_{\rm d}$, and $β_{\rm s}$ between $E$ modes, $B$ modes, and intensity in the diffuse ISM for the first time, highlighting the joint variations of the physical conditions and the magnetic field structure across the Galaxy. We conclude that in addition to detailed studies of CMB polarization, LiteBIRD will open a new window onto the physical conditions governing the ISM of the Milky Way.

astro-ph.GA↗

arXiv2026

Spatial Variations of Polarized Synchrotron Emission in the QUIJOTE MFI Data using Neural Networks

Polarized synchrotron emission from ultra-relativistic electrons spiraling the Galactic magnetic field has become one of the most relevant emissions in the Interstellar medium these last years due to the improvement in the quality of low-frequency observations. One of the recent experiments designed to explore this emission is the QUIJOTE experiment. We aim to study the spatial variations of the synchrotron emission in the QUIJOTE MFI data, by dividing the sky into physically separated regions. For such task, we firstly use a novel component separation method based on artificial neural networks to clean the synchrotron maps. After training the network with simulations, we fit both $EE$ and $BB$ spectra by assuming a power-law model. Then, we give estimations for the index $α_{S}$, the amplitude, and the ratio between $B$ and $E$ amplitudes. When analyzing the real data, we found a clear spatial variation of the synchrotron properties along the sky at 11 GHz, obtaining a steeper index in the Galactic plane of $α_{S}^{EE} = -3.1 \pm 0.3$ and $α_{S}^{BB} = -3.10 \pm 0.28$ and a flatter one at high Galactic latitudes of $α_{S}^{EE} = -3.05 \pm 0.16$ and $α_{S}^{B} = -2.98 \pm 0.23$. We found average values at all sky of $α_{S}^{EE} = -3.04 \pm 0.18$ and $α_{S}^{BB} = -3.00 \pm 0.26$. Furthermore, after obtaining an average value of $A_{S}^{EE} = 3.31 \pm 0.17$ $μK^{2}$ and $A_{S}^{BB} = 0.93 \pm 0.04$ $μK^{2}$, we estimate a ratio between $B$ and $E$ amplitudes of $A_{S}^{BB}/A_{S}^{EE} = 0.28 \pm 0.06$. Based on the results we conclude that, although neural networks seem to be valuable methods to apply on real ISM observations, combined analyses with Planck, WMAP and/or CBASS data are mandatory to reduce the contamination from QUIJOTE maps and then improve the accuracy of the estimations.

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arXiv2026

Probing Anomalous Microwave Emission with the Square Kilometre Array

Anomalous microwave emission (AME) represents an excess of radiation in the 10-60 GHz range, distinct from synchrotron, free-free, or thermal dust emission. Although most commonly attributed to electric dipole radiation from rapidly rotating small dust grains (spinning dust), alternative mechanisms such as magnetic dipole emission (MDE) remain plausible. The detection of AME across diverse environments, from diffuse interstellar clouds to protoplanetary disks and external galaxies, suggests that multiple physical processes or carriers may contribute to its origin. Understanding AME is essential for both Galactic astrophysics and cosmology, as it constitutes a significant foreground for cosmic microwave background (CMB) studies, potentially biasing measurements. This chapter reviews current theoretical frameworks and observational evidence for AME, highlighting the key outstanding questions concerning its emission mechanisms, carriers, and polarization properties. We discuss how the Square Kilometre Array Observatory (SKAO), through its unprecedented sensitivity, angular resolution, and frequency coverage, will transform AME studies. SKA observations will enable detailed mapping of AME morphology, precise characterisation of its spectral energy distribution, and the identification of its carriers in Galactic and extragalactic environments. By combining SKA-mid data with higher-frequency observations from ALMA and other facilities such as SPHEREx, it will be possible to disentangle competing models and exploit AME as a diagnostic probe of interstellar grain physics and the small-scale structure of the interstellar medium.

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arXiv2026

Systematic errors in spectral measurements with the Tenerife Microwave Spectrometer

We present an analytical instrument model of the TMS radiometer, a pseudo-correlation system designed for absolute sky-temperature measurements through a continuous comparison between sky and reference-load signals. The goal of this work is to quantify and understand the impact of instrumental non-idealities that are intrinsic to absolute radiometric measurements. We used a combination of the Jones-matrix formalism, to describe non-ideal signal mixing effects in the different instrument components, and the Friis formalism, to account for noise-temperature contributions which introduce specific offset terms. The model includes all components from the cryostat entrance window onwards and allows us to propagate realistic losses, return losses, and noise figures through the system. We find that non-ideal mixing effects, such as intensity-to-polarization and sky-to-load leakage, are expected to appear at the percent level, but they could be in principle calibrated out. The total TMS intensity response exhibits a frequency-dependent offset with a band-averaged level of 6.9 K, dominated by the cryostat window, and with smaller contributions from the infrared filter and orthomode transducers. Under the required TMS thermal stability of 1 mK over one hour, the resulting variation in the output signal can reach up to 91.3 mK, which sets the fundamental limit on the absolute sky-temperature accuracy. In contrast, relative spectral measurements across the 10-20 GHz band are stable at the few-microkelvin level, consistent with the instrument target sensitivity of ~ 10 Jy/sr. This work provides a detailed and quantitative assessment of the systematic effects affecting absolute radiometric measurements and establishes a robust framework for the calibration and performance optimization of the TMS instrument.

astro-ph.IM↗

arXiv2026

Spectral Properties of Anomalous Microwave Emission in 144 Galactic Clouds

Anomalous Microwave Emission (AME) is a diffuse microwave component thought to arise from spinning dust grains, yet remains poorly understood. We analyze AME in 144 Galactic clouds by combining low-frequency maps from S-PASS (2.3 GHz), C-BASS (4.76 GHz), and QUIJOTE (10-20 GHz) with 21 ancillary maps. Using aperture photometry and parametric SED fitting via MCMC methods without informative priors, we measure AME emissivity, peak frequency, and spectral width. We achieve peak frequency constraints nearly three times tighter than previous work and identify 83 new AME sources. AME spectra are generally broader than predicted by spinning dust models for a single phase of the interstellar medium, suggesting either multiple spinning dust components along the line of sight or incomplete representation of the grain size distribution in current models. However, the narrowest observed widths match theoretical predictions, supporting the spinning dust hypothesis. The AME amplitude correlates most strongly with the thermal dust peak flux and radiance, showing $\sim30$% scatter and sublinear scaling, which suggests reduced AME efficiency in regions with brighter thermal dust emission. AME peak frequency increases with thermal dust temperature in a trend current theoretical models do not reproduce, indicating that spinning dust models must incorporate dust evolution and radiative transfer in a self-consistent framework where environmental parameters and grain properties are interdependent. PAH tracers correlate with AME emissivity, supporting a physical link to small dust grains. Finally, a log-Gaussian function provides a good empirical description of the AME spectrum across the sample, given current data quality and frequency coverage.

astro-ph.GA↗

arXiv2026

QUIJOTE scientific results XIX. New constraints on the synchrotron spectral index using a semi-blind component separation method

We introduce a novel approach to estimate the spectral index, $β_s$, of polarised synchrotron emission, combining the moment expansion of CMB and the constrained-ILC. We reconstructed the maps of the first two synchrotron moments, combining multi-frequency data, and applied the `T-T plot' technique between two moment maps to estimate the synchrotron spectral index. This approach offers a new technique for mapping the foreground spectral parameters, complementing the model-based parametric component separation methods. Applying this technique, we derived a new constraint on the spectral index of polarised synchrotron emission using QUIJOTE MFI wide-survey 11 and 13 GHz data, Wilkinson Microwave Anisotropy Probe data at K and Ka bands, and Planck LFI 30 GHz data. In the Galactic plane and North Polar Spur regions, we obtained an inverse-variance-weighted mean synchrotron index of $β_s = -3.11$ with a standard deviation of $0.21$ due to intrinsic scatter, consistent with previous results based on parametric methods using the same dataset. We find that the inverse-variance-weighted mean spectral index, including both statistical and systematic uncertainties, is $β_s^{\rm plane} = -3.05 \pm 0.01$ in the Galactic plane and $β_s^{\rm high\text{-}lat} = -3.13 \pm 0.02$ at high latitudes, indicating a moderate steepening of the spectral index from low to high Galactic latitudes. Our analysis indicates that, within the current upper limit on the Anomalous Microwave Emission polarisation fraction, our results are not subject to any appreciable bias. Furthermore, we infer the spectral index over the entire QUIJOTE survey region, partitioning the sky into 21 patches. This technique can be further extended to constrain the synchrotron spectral curvature by reconstructing higher-order moments when better-quality data become available.

astro-ph.CO↗

arXiv2025

LiteBIRD science goals and forecasts: improved full-sky reconstruction of the gravitational lensing potential through the combination of Planck and LiteBIRD data

Cosmic microwave background (CMB) photons are deflected by large-scale structure through gravitational lensing. This secondary effect introduces higher-order correlations in CMB anisotropies, which are used to reconstruct lensing deflections. This allows mapping of the integrated matter distribution along the line of sight, probing the growth of structure, and recovering an undistorted view of the last-scattering surface. Gravitational lensing has been measured by previous CMB experiments, with $\textit{Planck}$'s $42\,σ$ detection being the current best full-sky lensing map. We present an enhanced $\textit{LiteBIRD}$ lensing map by extending the CMB multipole range and including the minimum-variance estimation, leading to a $49$ to $58\,σ$ detection over $80\,\%$ of the sky, depending on the final complexity of polarized Galactic emission. The combination of $\textit{Planck}$ and $\textit{LiteBIRD}$ will be the best full-sky lensing map in the 2030s, providing a $72$ to $78\,σ$ detection over $80\,\%$ of the sky, almost doubling $\textit{Planck}$'s sensitivity. Finally, we explore different applications of the lensing map, including cosmological parameter estimation using a lensing-only likelihood and internal delensing, showing that the combination of both experiments leads to improved constraints. The combination of $\textit{Planck}$ + $\textit{LiteBIRD}$ will improve the $S_8$ constraint by a factor of 2 compared to $\textit{Planck}$, and $\textit{Planck}$ + $\textit{LiteBIRD}$ internal delensing will improve $\textit{LiteBIRD}$'s tensor-to-scalar ratio constraint by $6\,\%$. We have tested the robustness of our results against foreground models of different complexity, showing that improvements remains even for the most complex foregrounds.

astro-ph.CO↗

arXiv2025

First release of LiteBIRD simulations from an end-to-end pipeline

The LiteBIRD satellite mission aims at detecting Cosmic Microwave Background $B$ modes with unprecedented precision, targeting a total error on the tensor-to-scalar ratio $r$ of $δr \sim 0.001$. Operating from the L2 Lagrangian point of the Sun-Earth system, LiteBIRD will survey the full sky across 15 frequency bands (34 to 448 GHz) for 3 years.The current LiteBIRD baseline configuration employs 4508 detectors sampling at 19.1 Hz to achieve an effective polarization sensitivity of $ 2 μ\mathrm{K-arcmin}$ and an angular resolution of 31 arcmin (at 140 GHz).We describe the first release of the official LiteBIRD simulations, realized with a new simulation pipeline developed using the LiteBIRD Simulation Framework, see https://github.com/litebird/litebird_sim . This pipeline generates 500 full-sky simulated maps at a Healpix resolution of nside=512. The simulations include also one year of Time Ordered Data for approximately one-third of LiteBIRD's total detectors.

astro-ph.IM↗

arXiv2025

A Simulation Framework for the LiteBIRD Instruments

LiteBIRD, the Lite (Light) satellite for the study of $B$-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission focused on primordial cosmology and fundamental physics. In this paper, we present the LiteBIRD Simulation Framework (LBS), a Python package designed for the implementation of pipelines that model the outputs of the data acquisition process from the three instruments on the LiteBIRD spacecraft: LFT (Low-Frequency Telescope), MFT (Mid-Frequency Telescope), and HFT (High-Frequency Telescope). LBS provides several modules to simulate the scanning strategy of the telescopes, the measurement of realistic polarized radiation coming from the sky (including the Cosmic Microwave Background itself, the Solar and Kinematic dipole, and the diffuse foregrounds emitted by the Galaxy), the generation of instrumental noise and the effect of systematic errors, like pointing wobbling, non-idealities in the Half-Wave Plate, et cetera. Additionally, we present the implementation of a simple but complete pipeline that showcases the main features of LBS. We also discuss how we ensured that LBS lets people develop pipelines whose results are accurate and reproducible. A full end-to-end pipeline has been developed using LBS to characterize the scientific performance of the LiteBIRD experiment. This pipeline and the results of the first simulation run are presented in Puglisi et al. (2025).

astro-ph.IM↗

arXiv2025

LiteBIRD Science Goals and Forecasts. $E$-mode Anomalies

Various so-called anomalies have been found in both the WMAP and Planck cosmic microwave background (CMB) temperature data that exert a mild tension against the highly successful best-fit 6 parameter cosmological model, potentially providing hints of new physics to be explored. That these are real features on the sky is uncontested. However, given their modest significance, whether they are indicative of true departures from the standard cosmology or simply statistical excursions, due to a mildly unusual configuration of temperature anisotropies on the sky which we refer to as the "fluke hypothesis", cannot be addressed further without new information. No theoretical model of primordial perturbations has to date been constructed that can explain all of the temperature anomalies. Therefore, we focus in this paper on testing the fluke hypothesis, based on the partial correlation between the temperature and $E$-mode CMB polarisation signal. In particular, we compare the properties of specific statistics in polarisation, built from unconstrained realisations of the $Λ$CDM cosmological model as might be observed by the LiteBIRD satellite, with those determined from constrained simulations, where the part of the $E$-mode anisotropy correlated with temperature is constrained by observations of the latter. Specifically, we use inpainted Planck 2018 SMICA temperature data to constrain the $E$-mode realisations. Subsequent analysis makes use of masks defined to minimise the impact of the inpainting procedure on the $E$-mode map statistics. We find that statistical assessments of the $E$-mode data alone do not provide any evidence for or against the fluke hypothesis. However, tests based on cross-statistical measures determined from temperature and $E$ modes can allow this hypothesis to be rejected with a moderate level of probability.

astro-ph.CO↗

arXiv2025

LiteBIRD Science Goals and Forecasts: constraining isotropic cosmic birefringence

Cosmic birefringence (CB) is the rotation of the photons' linear polarisation plane during propagation. Such an effect is a tracer of parity-violating extensions of standard electromagnetism and would probe the existence of a new cosmological field acting as dark matter or dark energy. It has become customary to employ cosmic microwave background (CMB) polarised data to probe such a phenomenon. Recent analyses on Planck and WMAP data provide a hint of detection of the isotropic CB angle with an amplitude of around $0.3^\circ$ at the level of $2.4$ to $3.6σ$. In this work, we explore the LiteBIRD capabilities in constraining such an effect, accounting for the impact of the more relevant systematic effects, namely foreground emission and instrumental polarisation angles. We build five semi-independent pipelines and test these against four different simulation sets with increasing complexity in terms of non-idealities. All the pipelines are shown to be robust and capable of returning the expected values of the CB angle within statistical fluctuations for all the cases considered. We find that the uncertainties in the CB estimates increase with more complex simulations. However, the trend is less pronounced for pipelines that account for the instrumental polarisation angles. For the most complex case analysed, we find that LiteBIRD will be able to detect a CB angle of $0.3^\circ$ with a statistical significance ranging from $5$ to $13 \, σ$, depending on the pipeline employed, where the latter uncertainty corresponds to a total error budget of the order of $0.02^\circ$.

astro-ph.CO↗

arXiv2024

Requirements on the gain calibration for LiteBIRD polarisation data with blind component separation

Future cosmic microwave background (CMB) experiments are primarily targeting a detection of the primordial $B$-mode polarisation. The faintness of this signal requires exquisite control of systematic effects which may bias the measurements. In this work, we derive requirements on the relative calibration accuracy of the overall polarisation gain ($Δg_ν$) for LiteBIRD experiment, through the application of the blind Needlet Internal Linear Combination (NILC) foreground-cleaning method. We find that minimum variance techniques, as NILC, are less affected by gain calibration uncertainties than a parametric approach, which requires a proper modelling of these instrumental effects. The tightest constraints are obtained for frequency channels where the CMB signal is relatively brighter (166 GHz channel, $Δ{g}_ν\approx 0.16 \%$), while, with a parametric approach, the strictest requirements were on foreground-dominated channels. We then propagate gain calibration uncertainties, corresponding to the derived requirements, into all frequency channels simultaneously. We find that the overall impact on the estimated $r$ is lower than the required budget for LiteBIRD by almost a factor $5$. The adopted procedure to derive requirements assumes a simple Galactic model. We therefore assess the robustness of obtained results against more realistic scenarios by injecting the gain calibration uncertainties, according to the requirements, into LiteBIRD simulated maps and assuming intermediate- and high-complexity sky models. In this case, we employ the so-called Multi-Clustering NILC (MC-NILC) foreground-cleaning pipeline and obtain that the impact of gain calibration uncertainties on $r$ is lower than the LiteBIRD gain systematics budget for the intermediate-complexity sky model. For the high-complexity case, instead, it would be necessary to tighten the requirements by a factor $1.8$.

astro-ph.CO↗

arXiv2024

LiteBIRD Science Goals and Forecasts. Mapping the Hot Gas in the Universe

We assess the capabilities of the LiteBIRD mission to map the hot gas distribution in the Universe through the thermal Sunyaev-Zeldovich (SZ) effect. Our analysis relies on comprehensive simulations incorporating various sources of Galactic and extragalactic foreground emission, while accounting for specific instrumental characteristics of LiteBIRD, such as detector sensitivities, frequency-dependent beam convolution, inhomogeneous sky scanning, and $1/f$ noise. We implement a tailored component-separation pipeline to map the thermal SZ Compton $y$-parameter over 98% of the sky. Despite lower angular resolution for galaxy cluster science, LiteBIRD provides full-sky coverage and, compared to the Planck satellite, enhanced sensitivity, as well as more frequency bands to enable the construction of an all-sky $y$-map, with reduced foreground contamination at large and intermediate angular scales. By combining LiteBIRD and Planck channels in the component-separation pipeline, we obtain an optimal $y$-map that leverages the advantages of both experiments, with the higher angular resolution of the Planck channels enabling the recovery of compact clusters beyond the LiteBIRD beam limitations, and the numerous sensitive LiteBIRD channels further mitigating foregrounds. The added value of LiteBIRD is highlighted through the examination of maps, power spectra, and one-point statistics of the various sky components. After component separation, the $1/f$ noise from LiteBIRD is effectively mitigated below the thermal SZ signal at all multipoles. Cosmological constraints on $S_8=σ_8\left(Ω_{\rm m}/0.3\right)^{0.5}$ obtained from the LiteBIRD-Planck combined $y$-map power spectrum exhibits a 15% reduction in uncertainty compared to constraints from Planck alone. This improvement can be attributed to the increased portion of uncontaminated sky available in the LiteBIRD-Planck combined $y$-map.

astro-ph.CO↗

arXiv2024

KISS: instrument description and performance

Kinetic inductance detectors (KIDs) have been proven as reliable systems for astrophysical observations, especially in the millimetre range. Their compact size enables to optimally fill the focal plane, thus boosting sensitivity. The KISS (KIDs Interferometric Spectral Surveyor) instrument is a millimetre camera that consists of two KID arrays of 316 pixels each coupled to a Martin-Puplett interferometer (MPI). The addition of the MPI grants the KIDs camera the ability to provide spectral information in the 100 and 300 GHz range. In this paper we report the main properties of the KISS instrument and its observations. We also describe the calibration and data analysis procedures used. We present a complete model of the observed data including the sky signal and several identified systematics. We have developed a full photometric and spectroscopic data analysis pipeline that translates our observations into science-ready products. We show examples of the results of this pipeline on selected sources: Moon, Jupiter and Venus. We note the presence of a deficit of response with respect to expectations and laboratory measurements. The detectors noise level is consistent with values obtained during laboratory measurements, pointing to a sub-optimal coupling between the instrument and the telescope as the most probable origin for the problem. This deficit is large enough as to prevent the detection of galaxy clusters, which were KISS main scientific objective. Nevertheless, we have demonstrated the feasibility of this kind of instrument, in the prospect for other KID interferometers (such as the CONCERTO instrument). As this regard, we have developed key instrumental technologies such as optical conception, readout electronics and raw calibration procedures, as well as, adapted data analysis procedures.

astro-ph.IM↗

arXiv2024

QUIJOTE scientific results -- XVIII. New constraints on the polarization of the Anomalous Microwave Emission in bright Galactic regions: $ρ$\,Ophiuchi, Perseus and W43

This work focuses on the study of the AME, an important emission mechanism between 10 and 60 GHz whose polarization properties are not yet fully understood, and is therefore a potential contaminant for future CMB polarization observations. We use new QUIJOTE-MFI maps 11, 13, 17 and 19 GHz, together with other public ancillary data including WMAP and Planck, to study the polarization properties of the AME in three Galactic regions: rho-Ophiuchi, Perseus and W43. We have obtained the SEDs for those three regions over the frequency range 0.4-3000 GHz, both in intensity and polarization. The intensity SEDs are well described by a combination of free-free emission, thermal dust, AME and CMB anisotropies. In polarization, we extracted the flux densities using all available data between 11 and 353 GHz. We implemented an improved intensity-to-polarization leakage correction that has allowed for the first time to derive reliable polarization constraints well below the 1% level from Planck-LFI data. A frequency stacking of maps in the range 10-60 GHz has allowed us to reduce the statistical noise and to push the upper limits on the AME polarization level. We have obtained upper limits on the AME polarization fraction of order <1% (95% confidence level) for the three regions. In particular we get Pi_AME < 1.1% (at 28.4 GHz), Pi_AME < 1.1% (at 22.8 GHz) and Pi_AME < 0.28% (at 33 GHz) in rho-Ophiuchi, Perseus and W43 respectively. At the QUIJOTE 17 GHz frequency band, we get Pi_AME< 5.1% for rho-Ophiuchi, Pi_AME< 3.5% for Perseus and Pi_AME< 0.85% for W43. Our final upper limits derived using the stacking procedure are Pi_AME < 0.58% for rho-Ophiuchi, Pi_AME < 1.64% for Perseus and Pi_AME < 0.31% for W43. Altogether, these are the most stringent constraints to date on the AME polarization fraction of these three star-forming regions.

astro-ph.CO↗

arXiv2024

LSPE-STRIP on-sky calibration strategy using bright celestial sources

In this paper we describe the global on-sky calibration strategy of the LSPE-Strip instrument. Strip is a microwave telescope operating in the Q- and W-bands (central frequencies of 43 and 95 GHz respectively) from the Observatorio del Teide in Tenerife, with the goal to observe and characterise the polarised Galactic foreground emission, and complement the observations of the polarisation of the cosmic microwave background to be performed by the LSPE-SWIPE instrument and other similar experiments operating at higher frequencies to target the detection of the B-mode signal from the inflationary epoch of the Universe. Starting from basic assumptions on some of the instrument parameters (NET, 1/f noise knee frequency, beam properties, observing efficiency) we perform realistic simulations to study the level of accuracy that can be achieved through observations of bright celestial calibrators in the Strip footprint (sky fraction of 30 %) on the determination and characterisation of the main instrument parameters: global and relative gain factors (in intensity and in polarisation), polarisation direction, polarisation efficiency, leakage from intensity to polarisation, beams, window functions and pointing model.

astro-ph.CO↗