Larissa Santos

University of Science and Technology of China | USTC · Department of Astronomy

One of the main goals of most future CMB experiments is the precise measurement of CMB B-mode polarization, whose major obstacle is the Galactic foregrounds. In this paper, we evaluate the foreground cleaning performance of the variants of the ILC method on partial sky B-modes and analyze the main sources of biases on the BB power spectrum. Special...

The future 21 cm intensity mapping observations constitute a promising way to trace the matter distribution of the Universe and probe cosmology. Here, we assess its capability for cosmological constraints using as a case study the BINGO radio telescope, that will survey the Universe at low redshifts (0.13 < z < 0.45). We use neural networks (NNs) t...

AliCPT is the first Chinese cosmic microwave background (CMB) experiment which will make the most precise measurements of the CMB polarization in the northern hemisphere. The key science goal for AliCPT is the detection of primordial gravitational waves (PGWs). It is well known that an epoch of cosmic inflation, in the very early universe, can prod...

BINGO will observe hydrogen distribution by means of the 21 cm line signal by drift-scan mapping through a tomographic analysis called \emph{Intensity Mapping} (IM) between 980 and 1260 MHz which aims at analyzing Dark Energy using \emph{Baryon Acoustic Oscillations}. In the same frequency range, there are several other unwanted signals as well as...

AliCPT is the first Chinese cosmic microwave background (CMB) experiment which will make the most precise measurements of the CMB polarization in the northern hemisphere. The key science goal for AliCPT is the detection of primordial gravitational waves (PGWs). It is well known that an epoch of cosmic inflation, in the very early universe, can prod...

Constructing a fast and efficient estimator for the B -mode power spectrum of the cosmic microwave background (CMB) is of critical importance for CMB science. For a general CMB survey, the Quadratic Maximum Likelihood (QML) estimator for CMB polarization has been proved to be the optimal estimator with minimal uncertainties, but it is computational...

Constructing a fast and optimal estimator for the $B$-mode power spectrum of cosmic microwave background (CMB) is of critical importance for CMB science. For a general CMB survey, the Quadratic Maximum Likelihood (QML) estimator for CMB polarization has been proved to be the optimal estimator with minimal uncertainties, but it is computationally ve...

A crucial problem for partial sky analysis of CMB polarization is the E-B leakage problem. Such leakage arises from the presence of `ambiguous' modes that satisfy properties of both E and B modes. Solving this problem is critical for primordial polarization B mode detection in partial sky CMB polarization experiments. In this work we introduce a ne...

A crucial problem for part-sky analysis of CMB polarization is the $E$-$B$ leakage problem. Such leakage arises from the presence of 'ambiguous' modes that satisfy properties of both $E$ and $B$ modes. Solving this problem is critical for primordial polarization $B$ mode detection in part-sky CMB polarization experiments. In this work we introduce...

The similarity of the absolute luminosity profiles of Type Ia supernovae (SNIa) has led their use in extragalactic astronomy as secondary standard candles. In general, the empirical relation of SNIa on the absolute peak magnitude $M_{\rm B}$ is calibrated by Cepheid variables in the near distance scale and directly extrapolated to much farther dist...

The Analytical Blind Separation (ABS) method is dedicated to extract the CMB signal from its contaminants without any prior information about foregrounds. In this study, we apply the ABS method to simulated polarization sky maps in order to test its ability in the recovery of the CMB $E$- and $B$-mode power spectra. We simulate multi-frequency $Q$...

In this study, we apply the Analytical method of Blind Separation (ABS) of the cosmic microwave background (CMB) from foregrounds to estimate the CMB temperature power spectrum from multi-frequency microwave maps. We test the robustness of the ABS estimator and assess the accuracy of the power spectrum recovery using realistic simulations based on...

In this study, we apply the Analytical method of Blind Separation (ABS) of the cosmic microwave background (CMB) from foregrounds to estimate the CMB temperature power spectrum from multi-frequency microwave maps. We test the robustness of the ABS estimator and assess the accuracy of the power spectrum recovery by using realistic simulations based...

In both WMAP and Planck observations on the temperature anisotropy of cosmic microwave background (CMB) radiation a number of large-scale anomalies were discovered in the past years, including the CMB parity asymmetry in the low multipoles. By defining a directional statistics, we find that the CMB parity asymmetry is directional dependent, and the...

Measuring the imprint of primordial gravitational waves in the cosmic microwave background (CMB) polarisation field is one of the main goals in modern cosmology. However, the so called $B$-mode polarisation can be generated by different sources besides the primary one predicted by inflationary theories, known as secondary $B$-mode signal. Among the...

In this paper, we perform a forecast analysis to test the capacity of future baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) experiments to constrain phenomenological interacting dark energy models using the Fisher matrix formalism. We consider a Euclid-like experiment, in which BAO measurements is one of the main goals, to...

We investigate the primordial gravitational waves (PGWs) in the general scenario where the inflation is preceded by a pre-inflationary stage with the effective equation of state $w$. Comparing with the results in the usual inflationary models, the power spectrum of PGWs is modified in two aspects: One is the mixture of the perturbation modes caused...

One of the main goals of modern cosmology is to search for primordial gravitational waves by looking on their imprints in the B-type polarization in the cosmic microwave background radiation. However, this signal is contaminated by various sources, including cosmic weak lensing, foreground radiations, instrumental noises, as well as the E-to-B leak...

The detection of the magnetic type $B$-mode polarization is the main goal of future cosmic microwave background (CMB) experiments. In the standard model, the $B$-mode map is a strongly non-gaussian field due to the lensed component. Besides the two-point correlation function, the other statistics are also very important to dig the information of th...

The foundation of modern cosmology relies on the so-called cosmological principle which states an homogeneous and isotropic distribution of matter in the universe on large scales. However, recent observations, such as the temperature anisotropy of the cosmic microwave background (CMB) radiation, the motion of galaxies in the universe, the polarizat...

The measured CMB angular distribution shows a great consistency with the LCDM model. However, isotropy violations were reported in CMB temperature maps of both WMAP and Planck data. We investigate the influence of different masks employed in the analysis of CMB angular distribution, in particular in the excess of power in the Southeastern quadrant...

Some peculiar features found in the angular distribution of the Cosmic Microwave Background (CMB) measured by the Wilkinson Microwave Anisotropy Probe (WMAP) deserve further investigation. Among them, the quadrant asymmetry, likely related to the north-south asymmetry. In this paper, we aim to extend the analysis of the quadrant asymmetry in the $\...

We explore the possibility of obtaining better constraints from future astronomical data by means of the Fisher information matrix formalism. In particular, we consider how cosmic microwave background (CMB) lensing information can improve our parameter error estimation. We consider a massive neutrino scenario and a time-evolving dark energy equatio...

Some inflationary models predict the existence of isocurvature primordial fluctuations, in addition to the well known adiabatic perturbations. Such mixed models are not yet ruled out by available data sets. The talk presented at the Young Research Meeting covered the possibility of obtaining better constraints on the isocurvature contribution from...

Context. Intriguing features in the angular distribution of the cosmic microwave background (CMB), such as the north-south asymmetry, were reported in the one- and three-year Wilkinson Microwave Anisotropy Probe (WMAP) data and should be studied in detail. We investigate some of these asymmetries in the CMB temperature angular distribution consider...

We investigate some of the asymmetries reported in the CMB temperature angular distribution considering the {\Lambda}CDM model in the 3, 5 and 7 year WMAP data. We aim to analyze the 4 quadrants of the ILC CMB maps using 3 Galactic cuts: the WMAP KQ85 mask, a |b|<10 degrees and the WMAP KQ85 mask +|b|<10 degrees Galactic cuts. We used the two-point...

Some inflationary models predict the existence of isocurvature primordial fluctuations, in addition to the well known adiabatic perturbation. Such mixed models are not yet ruled out by available data sets. In this paper we explore the possibility of obtaining better constraints on the isocurva- ture contribution from future astronomical data. We co...