Raphael P. Rolim | Searcharxiv

arXiv2026

VAPOLA -- A multi-year, multi-band polarization survey of AGN and Sgr A* at mm wavelengths with ALMA I. Survey Overview and Science-Ready Archival Products

The Atacama Large Millimeter/submillimeter Array (ALMA) is the most sensitive interferometric array at millimeter and submillimeter wavelengths. Through the ALMA Phasing System (APS), it can participate in global Very Long Baseline Interferometry (VLBI) arrays, enhancing their sensitivity and resolution. However, processing and analzing the ALMA data obtained in APS mode during VLBI observations remains a complex task, requiring specialized expertise and time-consuming calibration and imaging procedures. In this paper, we present VAPOLA-the first online, multi-epoch, multi-band repository of high-level data products from ALMA observations of active galactic nuclei (AGN) and Sgr A* during global VLBI campaigns. Built on an automated pipeline that processes fully calibrated ALMA (QA2) data, generates science-ready products with minimal user intervention. The repository includes fully calibrated interferometric visibilities, full-Stokes images across individual and combined spectral windows, polarimetric and spectral index maps, as well as tabulated polarimetric parameters from visibility-domain polarization fitting. By offering ready-to-use data through a user-friendly web portal, VAPOLA enables non-expert users to perform advanced science analyses without needing in-depth knowledge of ALMA procedures. This resource will facilitate a broad range of scientific investigations, including the characterization of magnetic field properties in accretion flows and relativistic jets, the structure and kinematics of dusty and molecular tori in AGN, and absorption studies of the interstellar medium toward the Galactic Center. In addition, the dataset provides source-integrated parameters and calibration metadata essential for refining VLBI calibration and imaging workflows as well as for placing robust observational constraints on theoretical models of supermassive black holes and their environments.

astro-ph.GA↗

arXiv2025

Constraints on interacting dark energy revisited: implications for the Hubble tension

We revisit a class of coupled dark energy models where dark energy interacts with dark matter via phenomenological energy exchange terms. We include the perturbation of the Hubble rate in the interaction term, which was absent in previous works. We also consider more recent data sets such as cosmic microwave background (CMB) anisotropies from \text{Planck} 2018, type I-a supernovae (SNIa) measurements from Pantheon+ and data from baryon acoustic oscillations (BAO), and redshift space distortions (RSD). One of the models presents a strong incompatibility when different cosmological datasets are used. We analyze the influence of the SH0ES Cepheid host distances on the results and, although for one model the discrepancy of $H_0$ is reduced to $3.2σ$ when compared to the value obtained by the \textit{Planck} collaboration and $3.6σ$ when compared to the SH0ES team, joint analysis is incompatible. Including BAO with RSD shows incompatibility with SH0ES for all models considered here. We perform a model comparison and although there is a preference for interacting dark energy over $Λ$CDM for all the models for joint analysis CMB+BAO+RSD+SNIa, most of the 2D contours do not overlap. We conclude that the models of interactions in the dark sector considered in this paper are not flexible enough to fit all the cosmological data including values of $H_0$ from SH0ES in a statistically acceptable way. Therefore, the addition of one extra degree of freedom (i.e. the coupling between dark matter and dark matter) does not help enough to alleviate the already existing tension in the vanilla $Λ$CDM, suggesting that the models would need to be modified to include further flexibility of predictions to help elucidate this issue.

astro-ph.CO↗