arXiv subjects

Lucas M. de Sá

Publications and source records attributed to Lucas M. de Sá.

5 recordsLinked to original sources

arXiv2026

Best practices in software citation

Software is both a foundational tool and a primary output of modern computational research, yet citation practices for software remain inconsistent, incomplete, and rarely machine-actionable. Existing infrastructure designed for paper and data citation does not adequately serve the distinct needs of software citation, leaving a gap that impedes reproducibility, misattributes scholarly credit, and obscures the labor embedded in research pipelines. Drawing on a NASA-funded community workshop held in April 2026, we present an analysis of four interconnected themes: (I)~the cultural barriers to consistent citation practice; (II)~the need for clearer community norms and conventions; (III)~gaps in existing technical infrastructure and workflow; and (IV)~the emerging challenges posed by AI-assisted research. For each theme we identify targeted interventions and assign responsibility across stakeholder groups. We conclude that meaningful progress requires simultaneous action on technical and cultural fronts. Journal editors and publishers represent the single highest-leverage point for accelerating this change, and correct citation must become the path of least resistance within researchers' existing workflows.

cs.DL↗

arXiv2026

The Stellar Winds Atlas II: Black Hole Formation at Solar Metallicity

Stellar winds are a primary source of uncertainty in predicting the masses of black holes (BHs) from massive stars. At solar metallicity, theoretical models lead to widely divergent results due to differing wind prescriptions. A key obstacle remains the lack of systematic investigations across a common parameter space. To address this, we construct a ``Wind Atlas'' using detailed 1D MESA stellar evolution models and population synthesis techniques to estimate the Galactic population of solar metallicity BH progenitors. We systematically investigate 14 distinct wind models, ranging from the most traditional and widespread prescriptions to the most recent. By evaluating stellar evolution across this extensive grid, we show that the final BH mass is dictated by a fundamental bifurcation: whether a star collapses as a cool supergiant or is first stripped of its envelope to become a Wolf-Rayet (WR) star. If a star enters the WR stage, its strong thick winds dominate, making the final mass sensitive to the WR wind prescription while largely erasing the memory of its prior mass-loss history. Conversely, stars that face core collapse as supergiants form significantly more massive BHs, producing a mass peak around an initial mass of 40 $M_\odot$. Rather than simply reproducing these divergent outcomes, our comprehensive evaluation demonstrates that this bifurcation is universally controlled by the highly uncertain mass loss during the cool supergiant phase. This framework strongly constrains the problem of BH mass prediction by identifying two key bottlenecks for future studies: envelope stripping efficiency and WR mass-loss rates. Our atlas provides a clear baseline for interpreting current theoretical discrepancies and testing wind models against observational constraints, such as the Galactic WR/OB population ratio.

astro-ph.SR↗

arXiv2026

How Common Are Common Envelopes? Quantifying Their Role in Forming Gravitational-Wave Sources

A central goal of gravitational-wave astronomy is to use merging binary black hole (BBH), black hole-neutron star (BHNS), and binary neutron star (BNS) systems as fossils to reconstruct the formation and evolution of massive stars across cosmic time. In practice, this inference relies on population-synthesis models that map massive stellar binaries to merging compact objects. However, these models disagree on the dominant orbital-hardening mechanisms within isolated binary evolution, particularly on whether common-envelope (CE) evolution is required. To address this, we compile and systematically compare formation-channel predictions from more than 200 isolated-binary population-synthesis simulations, organized within a unified hierarchical taxonomy. We find that BBH and BHNS formation pathways span nearly the full allowed range from CE-dominated to without-CE-dominated evolution (0-100%), while often predicting similar merger rates, revealing a fundamental degeneracy: merger-rate measurements alone do not uniquely constrain the underlying evolutionary pathways. In contrast, BNS formation proceeds almost exclusively through channels involving at least one CE phase (>90-100%), suggesting CE evolution plays a qualitatively different role in BNS than in BBH and BHNS formation. The relative contributions of with-CE and without-CE pathways are governed primarily by assumptions controlling mass-transfer stability, angular-momentum loss, CE efficiency, and supernova physics, which often act non-linearly and in correlated fashion, such that trends from one-at-a-time parameter variations do not generalize across simulation frameworks. Robust interpretation of gravitational-wave populations will therefore require transparent formation-channel definitions, reproducible analysis pipelines, systematic cross-code comparisons, and observational constraints that extend beyond merger rates alone.

astro-ph.HE↗

arXiv2024

Evolution of long-period compact radio sources driven by winds

We address in this work the nature and evolution of the long-period compact star sources, which has recently added several unexpected members. The central hypothesis is that particle winds drive their evolution, being an important factor for these relatively old sources. We show the consistency of this picture and remark some unsolved problems and caveats within it.

astro-ph.HE↗

arXiv2023

Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital Inclination Angle

Matter at ultra-high densities finds a physical realization inside neutron stars. One key property is their maximum mass, which has far-reaching implications for astrophysics and the equation of state of ultra dense matter. In this work, we employ Bayesian analysis to scrutinize the mass distribution and maximum mass threshold of galactic neutron stars. We compare two distinct models to assess the impact of assuming a uniform distribution for the most important quantity, the cosine of orbital inclination angles ($i$), which has been a common practice in previous analyses. This prevailing assumption yields a maximum mass of $2.25$~$M_\odot$ (2.15--3.32~$M_\odot$ within $90\%$ confidence), with a strong peak around the maximum value. However, in the second model, which indirectly includes observational constraints of $i$, the analysis supports a mass limit of $2.56^{+0.87}_{-0.58}~M_\odot$ ($2σ$ uncertainty), a result that points in the same direction as some recent results gathered from gravitational wave observations, although their statistics are still limited. This work stresses the importance of an accurate treatment of orbital inclination angles, and contributes to the ongoing debate about the maximum neutron star mass, further emphasizing the critical role of uncertainties in the individual neutron star mass determinations.

astro-ph.HE↗