arXiv subjects

Bruno Moraes

Publications and source records attributed to Bruno Moraes.

At least 19 recordsLinked to original sources

arXiv2026

Smokescreen: A Python package for data vector blinding and encryption in cosmological analyses

Smokescreen is an open-source Python library for data-vector concealment (blinding) in cosmological analyses. Data-vector blinding works by applying cosmology-dependent shifts to the observed data vector, moving it away from the true cosmological signal without affecting its statistical properties, so that analysts cannot infer the true result until the analysis is frozen and the blinding is lifted. The package computes these shifts using Firecrown likelihoods applied to data vectors stored in the SACC format, ensuring that the theoretical model used for blinding is identical to that used for inference whilst remaining agnostic to the specific observable being blinded. To prevent accidental unblinding, the original SACC file, containing the true cosmology, is encrypted. Although developed for the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), Smokescreen is applicable to any experiment using Firecrown likelihoods and the SACC data format.

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arXiv2021

The 6x2pt method: supernova velocities meet multiple tracers

We present a new methodology to analyse in a comprehensive way large-scale and supernovae (or any other distance indicator) surveys. Our approach combines galaxy and supernova position and redshift data with supernova peculiar velocities, obtained through their magnitude scatter, to construct a 6x2pt analysis which includes six power spectra. The 3x3 correlation matrix of these spectra expresses exhaustively the information content of the surveys at the linear level. We proceed then to forecast the performance of future surveys like LSST and 4MOST with a Fisher Matrix analysis, adopting both a model-dependent and a model-independent approach. We compare the performance of the 6x2pt approach to the traditional one using only galaxy clustering and some recently proposed combinations of galaxy and supernovae data and quantify the possible gains by optimally extracting the linear information. We show that the 6x2pt method shrinks the uncertainty area in the $\sigma_8, \gamma$ plane by more than half when compared to the traditional method. The combined clustering and velocity data on the growth of structures has uncertainties at similar levels to those of the CMB but exhibit orthogonal degeneracies, and the combined constraints yield improvements of factors of 5 in each of the five cosmological parameters here considered. Concerning the model-independent results, we find that our method can improve the constraints on $H(z)/H_0$ in all redshift bins by more than 70% with respect to the galaxy clustering alone and by 30% when supernova velocities (but not clustering) are considered, reaching a precision of 3-4% at high redshifts.

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arXiv2021

Constraining AGN feedback model with SZ profile

Relativistic jets from AGN have a wide range of impacts on galaxy groups and clusters and are key for understanding their formation and physical properties. However, this non-gravitational process is not well understood. Galaxy groups with shallow gravitational potentials are ideal laboratories to study and constrain the AGN feedback model. We studied hot gas in ~66,000 SDSS LRG halos with an average halo mass of 3 x 10^13 Msun using the Planck tSZ map. We have detected their average tSZ radial profile at ~17 sigma and compared it with the cosmo-OWLS cosmological hydrodynamical simulations with different AGN feedback models. The best agreement has been obtained for the AGN 8.0 model in the simulations. We have also compared our measured tSZ profile with the prediction from the universal pressure profile assuming the self-similar relation and found them consistent if the model accounts for the clustering of neighboring haloes via a two-halo term.

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arXiv2021

On the weak lensing masses of a new sample of galaxy groups

Galaxy group masses are important to relate these systems with the dark matter halo hosts. However, deriving accurate mass estimates is particularly challenging for low-mass galaxy groups. Moreover, calibration of bservational mass-proxies using weak-lensing estimates have been mainly focused on massive clusters. We present here a study of halo masses for a sample of galaxy groups identified according to a spectroscopic catalogue, spanning a wide mass range. The main motivation of our analysis is to assess mass estimates provided by the galaxy group catalogue derived through an abundance matching luminosity technique. We derive total halo mass estimates according to a stacking weak-lensing analysis. Our study allows to test the accuracy of mass estimates based on this technique as a proxy for the halo masses of large group samples. Lensing profiles are computed combining the groups in different bins of abundance matching mass, richness and redshift. Fitted lensing masses correlate with the masses obtained from abundance matching. However, when considering groups in the low- and intermediate-mass ranges, masses computed according to the characteristic group luminosity tend to predict higher values than the determined by the weak-lensing analysis. The agreement improves for the low-mass range if the groups selected have a central early-type galaxy. Presented results validate the use of mass estimates based on abundance matching techniques which provide good proxies to the halo host mass in a wide mass range.

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arXiv2019

Probing hot gas around luminous red galaxies through the Sunyaev-Zel'dovich effect

We construct the mean thermal Sunyaev-Zel'dovich (tSZ) Comptonization y profile around Luminous Red Galaxies (LRGs) in the redshift range 0.16 < z < 0.47 from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) using the Planck y map. The mean central tSZ signal for the full sample is y ~ 1.8 * 10^(-7) and we detect tSZ emission out to ~30 arcmin, which is well beyond the 10 arcmin angular resolution of the y map and well beyond the virial radii of the LRGs. We compare the measured profile with predictions from the cosmo-OWLS suite of cosmological hydrodynamical simulations. This comparison agrees well for models that include feedback from active galactic nuclei (AGN), but not with hydrodynamic models without this energetic feedback mechanism. This suggests that an additional heating mechanism is required over SNe feedback and star formation to explain the y data profile. We also compare our results with predictions based on the halo model with a universal pressure profile (UPP) giving the y signal. The predicted profile is consistent with the data, but only if we account for the clustering of haloes via a two-halo term and if halo masses are estimated using the mean stellar-to-halo mass (SHM) relation of Coupon et al. (2015) or Wang et al.(2016) estimated from gravitational lensing measurements. We also discuss the importance of scatter in the SHM relation on the model predictions.

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arXiv2019

Cosmological Measurements from Angular Power Spectra Analysis of BOSS DR12 Tomography

We constrain cosmological parameters by analysing the angular power spectra of the Baryon Oscillation Spectroscopic Survey DR12 galaxies, a spectroscopic follow-up of around 1.3 million SDSS galaxies over 9,376 deg$^2$ with an effective volume of $\sim 6.5$ (Gpc $h^{-1}$)$^3$ in the redshift range $0.15 \leq z < 0.80$. We split this sample into 13 tomographic bins ($Δz = 0.05$); angular power spectra were calculated using a Pseudo-$C_{\ell}$ estimator, and covariance matrices were estimated using log-normal simulated maps. Cosmological constraints obtained from these data were combined with constraints from Planck CMB experiment as well as the JLA supernovae compilation. Considering a $w$CDM cosmological model measured on scales up to $k_{max} = 0.07h$ Mpc$^{-1}$, we constrain a constant dark energy equation-of-state with a $\sim 4\%$ error at the 1-$σ$ level: $w_0 = -0.993^{+0.046}_{-0.043}$, together with $Ω_m = 0.330\pm 0.012$, $Ω_b = 0.0505 \pm 0.002$, $S_8 \equiv σ_8 \sqrt{Ω_m/0.3} = 0.863 \pm 0.016$, and $h = 0.661 \pm 0.012$. For the same combination of datasets, but now considering a $Λ$CDM model with massive neutrinos and the same scale cut, we find: $Ω_m = 0.328 \pm 0.009$, $Ω_b = 0.05017^{+0.0009}_{-0.0008}$, $S_8 = 0.862 \pm 0.017$, and $h = 0.663^{+0.006}_{-0.007}$ and a 95\% credible interval (CI) upper limit of $\sum m_ν < 0.14$ eV for a normal hierarchy. These results are competitive if not better than standard analyses with the same dataset, and demonstrate this should be a method of choice for future surveys, opening the door for their full exploitation in cross-correlations probes.

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arXiv2019

Upper Bound of Neutrino Masses from Combined Cosmological Observations and Particle Physics Experiments

We investigate the impact of prior models on the upper bound of the sum of neutrino masses, $\sum m_ν$. We use data from Large Scale Structure of galaxies, Cosmic Microwave Background, Type Ia SuperNovae, and Big Bang Nucleosynthesis. We probe physically motivated neutrino mass models (respecting oscillation experiment constraints) and compare them to constraints using standard cosmological approximations. The former give a consistent upper bound of $\sum m_ν \lesssim 0.26$ eV ($95\%$ CI) and yields a strong competitive upper bound for the lightest neutrino mass species, $m_0^ν < 0.086$ eV ($95\%$ CI). By contrast one of the approximations, which is somewhat inconsistent with oscillation experiments, yields an upper bound of $\sum m_ν \lesssim 0.15$ eV ($95\%$ CI), which differs substantially from the former upper bound. We, therefore, argue that cosmological neutrino mass and hierarchy determination should be pursued using physically motivated models since approximations might lead to incorrect and nonphysical upper bounds.

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arXiv2019

Representation learning for automated spectroscopic redshift estimation

Determining the radial positions of galaxies up to a high accuracy depends on the correct identification of salient features in their spectra. Classical techniques for spectroscopic redshift estimation make use of template matching with cross-correlation. These templates are usually constructed from empirical spectra or simulations based on the modeling of local galaxies. We propose two new spectroscopic redshift estimation schemes based on new learning techniques for galaxy spectra representation, using either a dictionary learning technique for sparse representation or denoising autoencoders. We investigate how these representations impact redshift estimation. These methods have been tested on realistic simulated galaxy spectra, with photometry modelled after the Large Synoptic Survey Telescope (LSST) and spectroscopy reproducing properties of the Sloan Digital Sky Survey (SDSS). They were compared to Darth Fader, a robust technique extracting line features and estimating redshift through eigentemplates cross-correlations. We show that both dictionary learning and denoising autoencoders provide improved accuracy and reliability across all signal-to-noise regimes and galaxy types. The representation learning framework for spectroscopic redshift analysis introduced in this work offers high performance in feature extraction and redshift estimation, improving on a classical eigentemplates approach. This is a necessity for next-generation galaxy surveys, and we demonstrate a successful application in realistic simulated survey data.

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arXiv2018

Convolutional Neural Networks for Spectroscopic Redshift Estimation on Euclid Data

In this paper, we address the problem of spectroscopic redshift estimation in Astronomy. Due to the expansion of the Universe, galaxies recede from each other on average. This movement causes the emitted electromagnetic waves to shift from the blue part of the spectrum to the red part, due to the Doppler effect. Redshift is one of the most important observables in Astronomy, allowing the measurement of galaxy distances. Several sources of noise render the estimation process far from trivial, especially in the low signal-to-noise regime of many astrophysical observations. In recent years, new approaches for a reliable and automated estimation methodology have been sought out, in order to minimize our reliance on currently popular techniques that heavily involve human intervention. The fulfilment of this task has evolved into a grave necessity, in conjunction with the insatiable generation of immense amounts of astronomical data. In our work, we introduce a novel approach based on Deep Convolutional Neural Networks. The proposed methodology is extensively evaluated on a spectroscopic dataset of full spectral energy galaxy distributions, modelled after the upcoming Euclid satellite galaxy survey. Experimental analysis on observations of idealistic and realistic conditions demonstrate the potent capabilities of the proposed scheme.

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arXiv2018

Weak-lensing calibration of a stellar mass-based mass proxy for redMaPPer and Voronoi Tessellation clusters in SDSS Stripe 82

We present the first weak lensing calibration of $μ_{\star}$, a new galaxy cluster mass proxy corresponding to the total stellar mass of red and blue members, in two cluster samples selected from the SDSS Stripe 82 data: 230 redMaPPer clusters at redshift $0.1\leq z<0.33$ and 136 Voronoi Tessellation (VT) clusters at $0.1 \leq z < 0.6$. We use the CS82 shear catalog and stack the clusters in $μ_{\star}$ bins to measure a mass-observable power law relation. For redMaPPer clusters we obtain $M_0 = (1.77 \pm 0.36) \times 10^{14}h^{-1} M_{\odot}$, $α= 1.74 \pm 0.62$. For VT clusters, we find $M_0 = (4.31 \pm 0.89) \times 10^{14}h^{-1} M_{\odot}$, $α= 0.59 \pm 0.54$ and $M_0 = (3.67 \pm 0.56) \times 10^{14}h^{-1} M_{\odot}$, $α= 0.68 \pm 0.49$ for a low and a high redshift bin, respectively. Our results are consistent, internally and with the literature, indicating that our method can be applied to any cluster finding algorithm. In particular, we recommend that $μ_{\star}$ be used as the mass proxy for VT clusters. Catalogs including $μ_{\star}$ measurements will enable its use in studies of galaxy evolution in clusters and cluster cosmology.

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arXiv2018

Morpho-z: improving photometric redshifts with galaxy morphology

We conduct a comprehensive study of the effects of incorporating galaxy morphology information in photometric redshift estimation. Using machine learning methods, we assess the changes in the scatter and catastrophic outlier fraction of photometric redshifts when galaxy size, ellipticity, Sérsic index and surface brightness are included in training on galaxy samples from the SDSS and the CFHT Stripe-82 Survey (CS82). We show that by adding galaxy morphological parameters to full $ugriz$ photometry, only mild improvements are obtained, while the gains are substantial in cases where fewer passbands are available. For instance, the combination of $grz$ photometry and morphological parameters almost fully recovers the metrics of $5$-band photometric redshifts. We demonstrate that with morphology it is possible to determine useful redshift distribution $N(z)$ of galaxy samples without any colour information. We also find that the inclusion of quasar redshifts and associated object sizes in training improves the quality of photometric redshift catalogues, compensating for the lack of a good star-galaxy separator. We further show that morphological information can mitigate biases and scatter due to bad photometry. As an application, we derive both point estimates and posterior distributions of redshifts for the official CS82 catalogue, training on morphology and SDSS Stripe-82 $ugriz$ bands when available. Our redshifts yield a 68th percentile error of $0.058(1+z)$, and a catastrophic outlier fraction of $5.2$ per cent. We further include a deep extension trained on morphology and single $i$-band CS82 photometry.

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arXiv2017

The Mass-Concentration Relation and the Stellar-to-Halo Mass Ratio in the CFHT Stripe 82 Survey

We present a new measurement of the mass-concentration relation and the stellar-to-halo mass ratio over the halo mass range $5\times 10^{12}$ to $2\times 10^{14}M_{\odot}$. To achieve this, we use weak lensing measurements from the CFHT Stripe 82 Survey (CS82), combined with the central galaxies from the redMaPPer cluster catalogue and the LOWZ/CMASS galaxy sample of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey Tenth Data Release. The stacked lensing signals around these samples are modelled as a sum of contributions from the central galaxy, its dark matter halo, and the neighboring halos, as well as a term for possible centering errors. We measure the mass-concentration relation: $c_{200c}(M)=A(\frac{M_{200c}}{M_0})^{B}$ with $A=5.24\pm1.24, B=-0.13\pm0.10$ for $0.2<z<0.4$ and $A=6.61\pm0.75, B=-0.15\pm0.05$ for $0.4<z<0.6$. These amplitudes and slopes are completely consistent with predictions from recent simulations. We also measure the stellar-to-halo mass ratio for our samples, and find results consistent with previous measurements from lensing and other techniques.

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arXiv2017

Stellar-to-halo mass relation of cluster galaxies

In the hierarchical formation model, galaxy clusters grow by accretion of smaller groups or isolated galaxies. During the infall into the centre of a cluster, the properties of accreted galaxies change. In particular, both observations and numerical simulations suggest that its dark matter halo is stripped by the tidal forces of the host. We use galaxy-galaxy weak lensing to measure the average mass of dark matter haloes of satellite galaxies as a function of projected distance to the centre of the host, for different stellar mass bins. Assuming that the stellar component of the galaxy is less disrupted by tidal stripping, stellar mass can be used as a proxy of the infall mass. We study the stellar to halo mass relation of satellites as a function of the cluster-centric distance to measure tidal stripping. We use the shear catalogues of the DES science verification archive, the CFHTLenS and the CFHT Stripe 82 (CS82) surveys, and we select satellites from the redMaPPer catalogue of clusters. For galaxies located in the outskirts of clusters, we find a stellar to halo mass relation in good agreement with the theoretical expectations from \citet{moster2013} for central galaxies. In the centre of the cluster, we find that this relation is shifted to smaller halo mass for a given stellar mass. We interpret this finding as further evidence for tidal stripping of dark matter haloes in high density environments.

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arXiv2017

On Mass Concentrations & Magnitude Gaps of Galaxy Systems in the CS82 Survey

Galaxy systems with large magnitude gaps - defined as the difference in magnitude between the central galaxy and the brightest satellite in the central region - have been claimed to have earlier formation histories. In this study we measure the mass concentration, as an indicator of early formation, of ensembles of galaxy systems divided by redshift and magnitude gaps in the $r$ band. We use cross-correlation weak lensing measurements with NFW parametric mass profiles to measure masses and concentrations of these ensembles from a catalogue of systems built from the SDSS Coadd by the redMaPPer algorithm. The lensing shear data come from the CFHT Stripe 82 (CS82) survey, and consists of $i$-band images of the SDSS Stripe 82 region. We find that the stack made up of systems with larger magnitude gaps has a high probability of being more concentrated on average, in the lowest redshift slice ($0.2<z<0.4$), both when dividing in quartiles ($P=0.98$) and terciles ($P=0.85$). These results lend credibility to the claim that the magnitude gap is an indicator of earlier formed systems.

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arXiv2017

The abundance of compact quiescent galaxies since z ~ 0.6

We set out to quantify the number density of quiescent massive compact galaxies at intermediate redshifts. We determine structural parameters based on i-band imaging using the CFHT equatorial SDSS Stripe 82 (CS82) survey (~170 sq. degrees) taking advantage of an exquisite median seeing of ~0.6''. We select compact massive (M > 5x10^10 M_sun) galaxies within the redshift range of 0.2 10. We systematically measure a factor of ~5 more compacts at the same redshift than what was previously reported on smaller fields with HST imaging, which are more affected by cosmic variance. This means that the decrease in number density from z ~ 1.5 to z ~ 0.2 might be only of a factor of ~2-5, significantly smaller than what previously reported. This supports progenitor bias as the main contributor to the size evolution. This milder decrease is roughly compatible with the predictions from recent numerical simulations. Only the most extreme compact galaxies, with Reff < 1.5x( M/10^11 M_sun)^0.75 and M > 10^10.7 M_sun, appear to drop in number by a factor of ~20 and hence likely experience a noticeable size evolution.

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arXiv2016

Lensing is Low: Cosmology, Galaxy Formation, or New Physics?

We present high signal-to-noise galaxy-galaxy lensing measurements of the BOSS CMASS sample using 250 square degrees of weak lensing data from CFHTLenS and CS82. We compare this signal with predictions from mock catalogs trained to match observables including the stellar mass function and the projected and two dimensional clustering of CMASS. We show that the clustering of CMASS, together with standard models of the galaxy-halo connection, robustly predicts a lensing signal that is 20-40% larger than observed. Detailed tests show that our results are robust to a variety of systematic effects. Lowering the value of $S_{\rm 8}=σ_{\rm 8} \sqrt{Ω_{\rm m}/0.3}$ compared to Planck2015 reconciles the lensing with clustering. However, given the scale of our measurement ($r<10$ $h^{-1}$ Mpc), other effects may also be at play and need to be taken into consideration. We explore the impact of baryon physics, assembly bias, massive neutrinos, and modifications to general relativity on $ΔΣ$ and show that several of these effects may be non-negligible given the precision of our measurement. Disentangling cosmological effects from the details of the galaxy-halo connection, the effects of baryons, and massive neutrinos, is the next challenge facing joint lensing and clustering analyses. This is especially true in the context of large galaxy samples from Baryon Acoustic Oscillation surveys with precise measurements but complex selection functions.

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arXiv2016

Measuring subhalo mass in redMaPPer clusters with CFHT Stripe 82 Survey

We use the shear catalog from the CFHT Stripe-82 Survey to measure the subhalo masses of satellite galaxies in redMaPPer clusters. Assuming a Chabrier Initial Mass Function (IMF) and a truncated NFW model for the subhalo mass distribution, we find that the sub-halo mass to galaxy stellar mass ratio increases as a function of projected halo-centric radius $r_p$, from $M_{\rm sub}/M_{\rm star}=4.43^{+ 6.63}_{- 2.23}$ at $r_p \in [0.1,0.3]$ $h^{-1}Mpc$ to $M_{\rm sub}/M_{\rm star}=75.40^{+ 19.73}_{- 19.09}$ at $r_p \in [0.6,0.9]$ $h^{-1}Mpc$. We also investigate the dependence of subhalo masses on stellar mass by splitting satellite galaxies into two stellar mass bins: $10<\log(M_{\rm star}/M_{\rm sun})<10.5$ and $11<\log(M_{\rm star}/M_{\rm sun})<12$. The best-fit subhalo mass of the more massive satellite galaxy bin is larger than that of the less massive satellites: $\log(M_{\rm sub}/M_{\rm sun})=11.14 ^{+ 0.66 }_{- 0.73}$ ($M_{\rm sub}/M_{\rm star}=19.5^{+19.8}_{-17.9}$) versus $\log(M_{\rm sub}/M_{\rm sun})=12.38 ^{+ 0.16 }_{- 0.16}$ ($M_{\rm sub}/M_{\rm star}=21.1^{+7.4}_{-7.7}$).

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arXiv2015

Cosmological Constraints From Weak Lensing Peak Statistics With CFHT Stripe 82 Survey

We derived constraints on cosmological parameters using weak lensing peak statistics measured on the $\sim130~{\rm deg}^2$ of the Canada-France-Hawaii Telescope Stripe 82 Survey (CS82). This analysis demonstrates the feasibility of using peak statistics in cosmological studies. For our measurements, we considered peaks with signal-to-noise ratio in the range of $ν=[3,6]$. For a flat $Λ$CDM model with only $(Ω_{\rm m}, σ_8)$ as free parameters, we constrained the parameters of the following relation $Σ_8=σ_8(Ω_{\rm m}/0.27)^α$ to be: $Σ_8=0.82 \pm 0.03 $ and $α=0.43\pm 0.02$. The $α$ value found is considerably smaller than the one measured in two-point and three-point cosmic shear correlation analyses, showing a significant complement of peak statistics to standard weak lensing cosmological studies. The derived constraints on $(Ω_{\rm m}, σ_8)$ are fully consistent with the ones from either WMAP9 or Planck. From the weak lensing peak abundances alone, we obtained marginalised mean values of $Ω_{\rm m}=0.38^{+0.27}_{-0.24}$ and $σ_8=0.81\pm 0.26$. Finally, we also explored the potential of using weak lensing peak statistics to constrain the mass-concentration relation of dark matter halos simultaneously with cosmological parameters.

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