Resumen:

In this work we analyze Type Ia supernovae (SNe Ia) data from the Pantheon+ compilation (Scolnic et al. 2022) to investigate late-time physics effects that impact the expansion history, $H(z)$, at low redshifts $(z ~< 2)$. Dynamic Dark Energy models allow for increased acceleration of the expansion at late times while preserving the physics of the early universe, consistent with the well-established Cosmic Microwave Background (CMB) results. We focus on a Late Dark Energy (LDE) model that introduces a deviation in the DE Equation of State, $w_{late}$, at a specific redshift, $z_a$, via a sigmoid function. The constraints found for our LDE parameters are of general applicability to any dynamic DE model. Our analysis reveals that the LDE model provides a slightly better fit to the SNe Pantheon+ data than the standard $\Lambda$ CDM alone. The fit results (assuming flat geometry and holding $\Omega_m$ constant and equal to the \emph{2018-Planck} value of $0.3153$) are: $(H_{0} = 73.3^{+0.2}_{-0.6} \hspace{0.1cm} km \hspace{0.1cm} s^{-1} Mpc^{-1} )$, $(w_{late} = -0.95^{+0.15}_{-0.02} )$, $(z_a = 0.81 \pm 0.46)$, and $(\chi ^{2}/DOF = 1110.5/1236)$. To further constrain dynamic DE models based on CMB results, we utilize the sound horizon and the angular scale of CMB anisotropies (from the \emph{Planck} CMB angular power spectrum) to define the distance to the last scattering surface and compare it with that derived from our LDE model. The current work presents posterior distributions of model parameters and confidence regions in parameter space that are applicable to any dynamic DE model. Although LDE models do not solve the $H_0$ tension entirely, these constraints are valuable when investigating models that include late time physics effects in addition to other potential solutions.

Resumen:

This talk presents the findings of a study on galaxies in cosmic voids and their relationship with the universe's evolution. We investigate the impact of large-scale structure on void galaxies' properties and whether these properties are solely influenced by the low local density in these regions. Using SDSS-DR16 data, we identify cosmic voids and galaxy groups to characterize the large-scale and local environment. Analyzing galaxy properties (color, SFR, concentration) in voids compared to the general sample, we observe that void galaxies exhibit bluer colors, higher star formation rates, and lower concentration than galaxies in other regions. Additionally, we examine the influence of void type on galaxy properties, contrasting voids embedded in overdense regions (S-type) with those approaching average universe density (R-type). Our analysis reveals that galaxies in R-type voids are bluer, have higher star formation rates, and are less concentrated than those in S-type voids. These results suggest a potential correlation between galaxy properties and the large-scale environment provided by voids.

Resumen:

The QU Bolometric Interferometer for Cosmology (QUBIC) is a cutting-edge CMB polarimeter installed on the Puna plateau in Argentina. Its optimized design enables the measurement of B-mode polarization, one of the major challenges of observational cosmology. However, this signal is subject to systematic effects and astrophysical foregrounds, which QUBIC aims to control through multichroic observations and a novel approach called Bolometric Interferometry. This technique combines the advantages of interferometry and bolometric detectors to produce wide-band, background-limited sensitivity. Additionally, the QUBIC synthesized beam's frequency-dependent shape produces maps of the CMB polarization in multiple sub-bands within the instrument's two physical bands. QUBIC is thus complementary to other instruments and particularly suited to characterizing and removing Galactic foreground contamination. In this talk, I will present the status of QUBIC, including calibration results, the first real sky observations, and forecasts for B-modes detection. I will also highlight QUBIC's unique spectral-imaging feature, which allows it to identify foreground contamination, even in the pessimistic case of Galactic dust exhibiting frequency domain decorrelation.

Resumen:

The detailed understanding of the Galactic emission processes in the frequency range from 1 to 3000 GHz is crucial for a state-of-the-art characterization of the Cosmic Microwave Background (CMB) anisotropies both in intensity and polarization. The Q-U-I JOint TEnerife (QUIJOTE) experiment is one of the current observational efforts devoted to understanding the CMB anisotropies and the microwave sky, which at these wavelengths is dominated by four Galactic mechanisms: synchrotron, free-free, thermal dust and Anomalous Microwave Emission (AME). In this context, the new QUIJOTE-MFI wide survey, covering the northern sky at 10-20 GHz range, is useful for pinning down the AME spectrum at low frequencies, allowing a more reliable separation between the AME and other components than in previous analysis. In this talk I will present a brief overview of these aspects, with emphasis on the new results about the study of the AME in different environments coming from the recently released QUIJOTE data. Finally, I will also present the QUIJOTE-MFI2 instrument, the upcoming upgraded version of the former MFI instrument, which could be used in the future for the characterization of the southern microwave sky from the Atacama desert (Chile) through the European Low Frequency Survey (ELFS) collaboration.

Resumen:

Identifying and characterizing the processes that transform galaxies from star-forming to quiescent is a fundamental goal of extragalactic astronomy. One critical transformation mechanism is galactic-scale feedback due to active nuclei (AGN). AGN winds are hardly resolved by observations of distant galaxies, where the bulk of galaxy/supermassive black hole growth occurs, but they can be resolved in nearby active galaxies. Our group has been studying the AGN feeding and feedback processes over 15 years, using optical and near-infrared integral field spectroscopy of inner kiloparsec of nearby active galaxies obtained with large telescopes. These observations are used to spatially resolve the molecular and ionized gas emission structure and kinematics. We find that while outflows in ionized gas are seen in most objects studied, in molecular gas they are are less common, which usually is dominated by rotation in the disk of galaxies and shows inflows in some cases. The observed ionized outflows are not powerful enough to effectively quench star formation in the AGN host galaxies in most cases.