Revista Mexicana de Astronomía y Astrofísica
The Revista Mexicana de Astronomía y Astrofísica, founded in 1974, publishes original research papers in all branches of astronomy, astrophysics and closely related fields. It is a digital journal, with open access. The editorial process is free of charge for all authors. Our journal has two main publications, the main journal RMxAA and the Conference Series, RMxAC.
EllipSect: A Surface Brightness Analysis Tool for GALFIT 3
EllipSect is a user-friendly analysis and measurement tool, implemented in Python, that operates on the imaging data together with the output of the widely used 2D surface-brightness fitting code GALFIT 3. It produces publication-quality figures and exportable data products to enable quantitative assessment of GALFIT 3 models and their individual components. In addition, EllipSect computes non-parametric measurements that are not provided by GALFIT 3, including the total effective radius resulting from multi-component fits, cusp radius, and the Petrosian radius. This paper provides examples and a quick guide for EllipSect.
Copyright (c) 2026 Universidad Nacional Autónoma de México https://creativecommons.org/licenses/by-nc/4.0/
Obituary: Sergiy Aleksandrovich Silich (1952 - 2025)
RMxAA author obituary for Sergiy Aleksandrovich Silich (1952 - 2025)
SDSS-V Local Volume Mapper (LVM): Helix Nebula Public data, Data Analysis Pipeline data products
We present a spatially resolved spectroscopic analysis of the Helix Nebula (NGC 7293) using data from the SDSS-V Local Volume Mapper (LVM), by applying the recently developed LVM Data Analysis Pipeline (LVM-DAP). Covering the full optical range (3600-9800 angstroms) over a contiguous ~0.5 degree field, the LVM data provide the first hexagonally sampled, wide-field emission-line maps of all major ionic species in this archetypal planetary nebula. The resulting flux, kinematic, and line-ratio maps reveal the well-known ionization stratification of the nebula, from the compact He++ core to the bright [O III] ring and the extended low-ionization envelope, enabling a detailed comparison with classical aperture spectroscopy. Owing to the sensitivity and uniform spatial sampling of the LVM, numerous faint auroral and diagnostic lines are detected across the nebula, including [O III] 4363, [N II] 5755, and He I lines, allowing precise measurements of weak-line morphology. The derived radial trends confirm the remarkably low dust content and the overall homogeneity of electron temperature and density across the main ring. Ionized-gas kinematics traced by H-alpha further support the scenario of a slowly expanding, limb-brightened shell consistent with previous studies. This work demonstrates the diagnostic power of LVM spectroscopy for extended nebulae and highlights its capability to recover both global and spatially resolved physical conditions across complex ionized structures.
J. G. Fernández Trincado J. G. Fernández Trincado
Analytical Solutions for the dynamics of Planetary Nebulae with and without Common Envelope Evolution
We present new analytical solutions for the dynamics of planetary nebulae. These equations consider the temporal variation of the mechanical luminosity as well as the common envelope evolution scenario. By comparing a database of nebulae with these solutions, a large portion of planetary nebulae can be better explained by the common envelope evolution scenario, especially the fast and slow ones. Single AGB stellar models can only reproduce nebulae with expansion velocities between 20 and 30 km s−1.
Stars: Evolution –Stars: AGB and post-AGB –ISM: planetary nebulae
A COLIBRI Photometric Study of SN 2025bvm: A Normal, Slowly Declining Type Ia Supernova
We present 121 days of multi-band (\Bband, \gband, \rband, \iband) optical photometry of the Type Ia supernova SN 2025bvm, obtained with the COLIBRI telescope. The light curves show a photometric decline of $\Delta m_{15}(B) = 0.777 \pm 0.042$~mag, characteristic of a slow-declining Type Ia supernova. After correcting for host galaxy extinction ($E(B-V)_{host} = 0.308 \pm 0.030$~mag) and adopting a distance of 70~Mpc, we derive a peak absolute magnitude of $M_B = -19.13 \pm 0.40$~mag. This luminosity is fully consistent with its slow decline rate, placing SN 2025bvm within the population of normal Type Ia supernovae. We conclude that SN 2025bvm is a normal Type Ia supernova, whose photometric properties, such as a slow late-time decline and a prominent \iband-band secondary maximum, suggest an explosion that resulted in a particularly massive ejecta.
Obituary: Francisco Sánchez Martínez (1936-2025)
Obituary: Francisco Sánchez Martínez (1936-2025) by José Franco.
Copyright (c) 2025 Universidad Nacional Autónoma de México https://creativecommons.org/licenses/by-nc/4.0/
Obituary: Julieta Fierro (1948 - 2025) by Silvia Torres-Peimbert.
Obituary: George F. Smoot (1945-2025) by Omar López-Cruz.
The first 10 years of the HAWC Gamma-Ray Observatory: science results
The High-Altitude Water Cherenkov (HAWC) Observatory, located on the slopes of the Sierra Negra volcano in Mexico, began operations in March 2015. Over the past decade, HAWC has enabled the exploration of a broad range of topics in high-energy astrophysics and particle physics, resulting in more than 90 peer-reviewed publications. These studies have significantly advanced our understanding of several previously unexplored and poorly understood phenomena in the TeV energy regime. The present work provides an overview of the key scientific contributions of HAWC during its first ten years of operation.
Hadronic Clues in Quasars Caught by FERMI-LAT
This work explores whether hadronic processes could be responsible for the high-energy emission seen in quasars identified by the Large Area Telescope (LAT) instrument aboard the Fermi satellite. In contrast to purely leptonic models, the work investigates whether hadronic mechanisms can explain the observed gamma-ray spectra by analyzing the spectral energy distributions (SEDs) of a chosen sample of FSRQs (Flat Spectrum Radio Quasars). By incorporating both hadronic and leptonic components into their multi-wavelength modeling, we evaluate the model's feasibility to simultaneously describe the data collected by Fermi-LAT and neutrinos detected by IceCube. According to the results, a hadronic contribution would be required to explain the SED of quasars detected by Fermi-LAT. However, their contribution to the neutrino flux detected by IceCube remains understated.
Mass profiles of late galaxies using a genetic algorithm II. - Effects of photometry selection and mass-to-light ratio.
The present work continues our testing of the rotation curve fitting procedure first presented in Paper I. We explore the effects of the stellar mass-to-light ratio in the analysis of galaxy kinematical data to estimate its corresponding mass profiles. For this purpose, we analyzed with a parameter-fitting procedure a set of rotation curves obtained with optical longslit spectroscopy observations from a sample of spiral galaxies, with no previously published optical RCs in the literature. This analysis was made assuming two different photometry sets to model the stellar disk: one at the long wavelength end of the optical bands, the SDSS $i$ filter, and another at the NIR, the WISE W1 3.4$\mu$m band. To estimate the corresponding stellar disk $(M/L)^{\star}$, we made use of previously published color-$(M/L)^{\star}$ relations. The fits obtained assuming NIR photometry for the stellar disk produced results closer to the observational data (10-20\% lower $\chi^2_{R}$) than those obtained with its optical counterpart, showing consistency with other studies. The results of these tests, along with those obtained in Paper I, support that the procedure provides a reliable, low time-cost method to obtain first order mass profile estimations from kinematical data, making it suitable for analyzing samples with a great number of galaxies, using photometry data from standardized digital surveys.
Characterization and First Analysis of Three Shallow-Contact Binary Systems
We present a photometric study and characterization of three contact eclipsing binary systems, analyzed using the Wilson-Devinney code in its Python implementation (PyWD2015). Analysis of the CCD-filtered and TESS light curves reveals that two of these systems are totally eclipsing, display starspots and belong to the W-subtype. These systems exhibit good thermal contact with a low degree of overcontact, and their components are consistent with late-type stars. The remaining system is an A-subtype W UMa binary, characterized by a considerable temperature difference between the components (∆T ~2200K) despite a low mass ratio (q = M2/M1). The times of minima derived from our observations, as well as from optical sky surveys, cover sufficient orbital cycles, allowing us to refine their ephemerides and present O-C diagrams fitted with polynomial functions. Additionally, the orbital angular momentum ( J0 ) of each system was calculated, and their positions were plotted on the logM-logL and Temperature-Period diagrams for further comparison.
High-Energy Neutron Enhancements Not Classified as GLEs: A Case Study Using Ground-Based Neutron Monitor Data
During their propagation through the interplanetary medium, cosmic rays interact with solar and interplanetary structures, which can cause fluctuations in their intensity observed at ground level. In this work, we apply a statistical method of overlapping epochs to analyze the effect of solar flares and energetic particle events on the intensity of cosmic radiation, considering periods of low geomagnetic activity and a 24-hour interval before and after the onset of the events. Our objective is to identify possible variations of tiny amplitude, observable simultaneously at different monitoring stations. The results indicate that solar flares, whether accompanied by energetic particle events or not, are not associated with noticeable increases in the cosmic ray intensity. This suggests that small increases may go undetected without specific treatment to highlight subtle variations.
Spectral and Dynamical Study of 12p/Pons-Brooks
We present a spectral and dynamical study of the Halley-type comet 12P/Pons-Brooks (~ 71 year period), confirming its intense cometary activity. We performed an N-body simulation, integrating its orbit for 2×105 years, to analyze its chaoticity and close encounters with Venus, Earth, Mars, Jupiter, and Saturn. The orbit becomes highly chaotic for t < 20×103 years, with significant instabilities arising between 15-20×103 years. We calculate a Lyapunov time of ~ 200 yr.
Theory of Functional Connections Applied to the Temporary Gravitational Capture Problem
This paper presents applications of the Theory of Functional Connections (TFC) for solving problems in celestial mechanics, with a focus on temporary gravitational capture. The univariate TFC framework is employed to solve second-order differential equations. The mathematical formulation for the solution of the two-body problem and the circular restricted three-body problem (CR3BP) through TFC is presented and some differences between the circular and elliptic problems are discussed. The application of TFC to solve the temporary gravitational capture based on the CR3BP, considering backward integration, is presented under different formulations, including inertial and rotating frames, as well as initial and boundary value problems. Error comparisons among these cases are provided and the best strategies for solving the capture problem, depending on the need, are discussed.
Collisions in a System of Conical Jet/Counterjet Outflows
Stars predominantly form in compact, non-hierarchical clusters. The gas outflows ejected by protostars can intersect and interact with each other, resulting in complex interactions that affect the dynamics, morphology, and evolution of these outflows. Determining the probability of an encounter between them requires a Bayesian approach that considers the collimation, length (or age), and separation between young stellar objects in clusters. In this study, we employed a Monte Carlo approach to estimate this probability as a function of the jet opening angle and the ratio between the jet length and separation between stars. We propose a function that predicts the number of interactions within a cluster based on the opening angle of the gas outflows ejected by protostars.
Blade Antenna-SDR System Prototype for the CANTAR Global 21-cm Experiment: Simulations, Measurements, and In-Situ Results
We present the design and initial testing of a low-frequency radio telescope prototype developed for the Colombian Antarctic Telescope for 21-cm Absorption during Reionization (CANTAR) experiment. Operating from 100 to 200 MHz, the system integrates a blade dipole antenna inspired by the EDGES high-band design with a software-defined radio (SDR) receiver. We report simulations of antenna impedance and beam chromaticity, along with SDR performance tests (Limenet Mini, Ettus E310, and USRP2920). A dual-stage low-noise amplifier reduces the system temperature, enabling foreground-sensitive observations. Radiometric estimates suggest that sub-mK sensitivity is achievable with 1000 h of integration. This prototype is part of Colombia's emerging infrastructure for 21-cm cosmology, with deployments planned at low-RFI sites in the Colombian Andes and Antarctica.
Analysis of Spatio-Temporal Changes in Future Artificial Light Pollution and Projections Until 2029 and 2041: A Case Study in the Brazilian States of Roraima, Amazonas, Acre, and Rondônia
This study presents an integrated spatial and temporal analysis of night sky brightness transitions, classified into Bortle classes using the MOLUSCE plugin. Future projections for 2029 and 2041 were generated based on remote sensing data from 2017 and 2020. The results indicate that the “Excellent Sky” and “Typical Dark Sky” classes may decrease by 100% and 56%, respectively, while the “Rural Sky” class could lose approximately 284,679 km2. In contrast, the “Rural-suburban Transition” class is projected to grow by 73%, with smaller increases in the “Suburban”, “Bright Suburban”, “Suburban/urban Transition”, and “Urban Center” classes. The “Urban Center” class shows a steady growth rate of 0.004%. These trends suggest a continued spread of light pollution into rural areas. The results provide valuable input for national and local authorities to anticipate future light-pollution patterns and develop effective mitigation strategies.
Astronomical Site Selection Scenarios for Asia
This study aimed to identify and evaluate suitable areas for astronomical observations in Asia using Geographic Information System (GIS) and Multi-Criteria Decision Analysis (MCDA) methods. Our study provides spatial coverage with satellite-based datasets to determine the ideal astronomical areas in Asia for future telescope construction. These datasets were created by adding a digital elevation model (DEM) and artificial light (AL), along with atmospheric data such as cloud cover (CC), precipitation water vapor content (PWV), aerosol optical density (AOD), and wind speed (WS). The dataset was analyzed using a combination of MCDA and GIS techniques. On the continent, the Tibetan Plateau and its surroundings (except the area around 90° E - 35° N) in northern China were identified as the most suitable areas for astronomical studies with radio telescopes. Suitable areas for infrared and optical telescopes are mainly found in the southeast of the Tibetan Plateau (around 83° E - 31° N). According to the analysis, an area of 369,096 km2, which corresponds to approximately 0.83% of the continent, is best suited for infrared observations. Approximately 3.87% of the continent, that is, about 1,725,246 km2, is best suited for radio telescopes, while 0.8%, that is, 355,842 km2, is best suited for observations with optical telescopes. The Corona-Borealis Observatory (Ngari) is located in the most ideal location for all three scenarios. The findings of this study are of great importance for future plans for astronomical sites on the continent.
Gaseous Disks in White Dwarfs: Properties of the Current Sample
In recent years, the number of white dwarfs (WDs) known to feature infrared (IR) excesses attributed to circumstellar dust disks has grown significantly. Gaseous disks have also been detected in some WDs with dust. We obtained optical spectra with Gemini/GMOS for 13 WDs exhibiting IR excesses to search for gaseous components. No Ca II emission was detected, suggesting that the gas phase may be short-lived compared to the dusty stage. By combining our data with those from the literature, we compiled the largest sample (to date) of WDs with and without gaseous disks. We found no significant differences in stellar properties between the two groups, although disks with gas may be, on average, brighter. The detection rate of Ca II emission supports the idea that the gas phase persists for only a fraction of the total disk lifetime. A more definitive assessment will likely require dedicated searches for both gas and dust across large WD samples.
Analysis of Telescope-Detector Coupling for a Mid-Infrared Solar Flare Observations Telescope
This study analyzes various optical couplings between an RC telescope and an MIR detector to develop a portable instrument for solar observation. The coupling systems included lenses or mirrors –custom-made and catalog types–, as well as direct coupling analysis. Simulations of the couplings were performed using the Zemax package to estimate the ray dispersion, Airy disk diameter, and PSF. Coupling with catalog lenses shows better performance, and their FOV allows the observation of a region as wide as the solar diameter. Direct coupling provides a higher spatial resolution for resolving smaller solar active regions, although it has a smaller FOV than indirect coupling. Therefore, depending on the observation goal on the Sun, the telescope can operate with either optical coupling configuration to cover a larger or smaller area on the solar disk.
A New Set of Classical-Like Mass Assignment Schemes for Power Spectrum Estimation
In this study, we present the impact of the mass-assignment scheme (MAS) on the estimation of the power spectrum and bispectrum in simulations of structure formation. We used numerical simulations to study the aliasing effect for both power spectrum and bispectrum estimation using the classical MAS, such as Nearest Grid Point, Cloud In Cell, and Triangular Shaped Cloud, to estimate, which of them suffers from a smaller aliasing effect for both small and large scales. We propose a new set of MAS, the NJ1, NJ2, and NJ3 functions, and study its aliasing effect, obtaining an improvement with respect to the classical schemes without the need for additional computational resources. We show that with the newly proposed MAS, we achieve comparable or even better performance in the aliasing of the power spectrum and bispectrum at the expense of a lower computational cost compared to high-order interpolation schemes such as PCS, resulting in an effective improvement in the estimation of the power spectrum and bispectrum.
We present the 2025 release of the spectral synthesis code CLOUDY, highlighting the significant enhancements in the scope and accuracy of the physics that have been made since the previous release. This key development resolves the Lyman-alpha line into j-resolved fine-structure doublets, thereby making CLOUDY useful to the X-ray community. We also updated the inner-shell ionization line energies and incorporated the 1 keV feature that is commonly observed in X-ray binaries. In addition, we updated the Stout database for the carbon isoelectronic sequence, improving the CLOUDY microphysical calculations for all wavelengths. The molecular network has also been extended with new silicon-bearing species, titanium-related reactions, and phosphorus-containing molecules, enhancing CLOUDY’s ability to model the complex chemistry relevant to exoplanet atmospheres. Finally, we outline future developments aimed at maximizing scientific returns from current and upcoming generations of observatories.
Sun-synchronous Solar Reflector Orbits designed for Illumination from Space
The use of orbiting space mirrors to reflect sunlight onto the Earth's surface has been contemplated in a large number of applications, which include illumination from space, large terrestrial solar power farms, space-based solar power (collecting solar power directly from space), geoengineering, and Terraforming schemes. Previous studies have demonstrated the feasibility of using space-based solar reflectors to achieve such mega projects. In this work, an Earth-space mirror two-body analysis is performed, taking into account the Solar Radiation Pressure and $J_2$ Earth oblateness perturbation, such that, when the sunlight strikes the perfectly reflecting space mirror surface, the ray reflects off the mirror in the direction of Earth's center. In this study, two candidate orbits for solar reflectors were conducted: a polar orbit perpendicular to the ecliptic plane of Earth, and an in-plane orbit in the ecliptic plane of Earth. We assumed that the ecliptic and equatorial planes of Earth coincide. Using Gauss' perturbing equations, it is provided a set of orbital parameters to achieve a Sun-synchronous Solar Reflector Orbit, that distributes azimuthally the solar energy intercepted by the mirror. The characteristic acceleration of the mirror is also chosen properly from the Sun-Synchronous condition. Additionally, it is shown that, in this scenario, a Low Sun-Synchronous Earth Orbit can be accomplished only for polar orbits, but not for the in-plane motion. In this last scenario, Medium Sun-Synchronous Earth Orbits can only be achieved.
Lya2pcf: An Efficient Pipeline to Estimate Two- and Three-Point Correlation Functions of the Lyman-$\alpha$ forest
We present Lya2pcf, a pipeline designed to compute three-dimensional two-point and three-point correlation functions using Lyman-$\alpha$ forest data. The code implements standard algorithms for computing the two-point correlation function with its distortion and covariance matrices; and it extends the two-point estimator to three-point correlations. Thanks to GPU optimization, Lya2pcf reduces computational time when compared to the widely used PICCA code. We apply Lya2pcf to data from SDSS DR16 and DESI Year-5 mocks, demonstrating overall performance gains. We show the first measurement of the anisotropic three-point correlation function on a large spectroscopic sample for all possible triangles with scales up to 80 Mpc/h. The fast computation and the resulting signal-to-noise ratio demonstrate the viability of incorporating three-point statistics into future cosmological analyses.
Physical Properties of Hii Regions at Sub-kpc Scales Using Integral Field Spectroscopy on IC 342
In this study, we use Integral Field Spectroscopic (IFS) observations for one of the closest galaxies to us, the grand design spiral IC342, to derive the physical properties of Hii regions at sub-kpc scales. To our knowledge, the IFS data represent the most comprehensive observational effort in the optical range for this galaxy. The final IFS datacube consists of 349 individual pointings using IFS instrumentation from the SDSS-IV MaNGA survey. Using a prototype of the data analysis pipeline that will be devoted to the SDSS-V Local Volume Mapper (LVM) survey, we measured different observables from the optical emission line. In particular, using the flux map of the H$\alpha$ emission line, we derived the location and size of Hii region candidates for IC342. Using the integrated flux for different emission lines within each region, we derived the radial distribution of different physical properties from the ionized gas (e.g., optical extinction, H$\alpha$ luminosity, oxygen abundance, etc.). Compared with larger samples of galaxies with IFS data, our results suggest that the physical properties of the ionized gas of IC342 are similar to those of galaxies with similar stellar masses in the nearby universe.
Copyright (c) 2025 https://creativecommons.org/licenses/by-nc/4.0/
We determined the surface lithium abundance of the eclipsing binary components in V 505 Per (HIP 10961) to be $A(Li)$ = 2.65$\pm$0.07 and 2.35$\pm$0.1, which supports the rather unexpected conclusion that their surface Li abundances differ. We find effective temperatures of 6600 K + 6550 K ($\sim$150 K higher than previously reported), which places the stars at the hot limit of the Lithium Dip, thus alleviating the previously suggested discrepancy with cluster stars of similar ages and temperatures. These temperatures are also more consistent with the system's Gaia spectral energy distribution. Our iron abundances, $[Fe/H] = -0.15\pm 0.07$ and $-0.25\pm 0.1$, agree with the predictions of the higher temperatures deduced from our spectra and from the evolutionary tracks. The rotation rate implied by our line profiles, 12.5$\pm$1 km\s$^{-1}$, is smaller than the synchronous rotation rate, which is a curious result given the circular orbit and the age of the system.
Spectroscopic Study of Blue Straggler Stars in the Globular Cluster NGC 3201
We conducted a spectroscopic study of 39 blue straggler stars in the globular cluster NGC 3201. The spectra of these stars have been previously reported. We determined the radial velocity, atmospheric parameters (T$_{eff}$, log $g$), Mg abundance, and metallicity ([Fe/H]) for all sources in the sample. The mean radial velocity and [Fe/H] were determined to be 498.0$\pm$5.3 km/s and -1.42$\pm$0.27, respectively. The derived [Fe/H] is consistent, within uncertainties, with the cluster's [Fe/H] of -1.59 dex. The mean [Mg/Fe] for the sample was estimated to be 0.36$\pm$0.73. Importantly, this study is the first to estimate [Mg/Fe] for blue straggler stars in the cluster NGC 3201.
Espartaco 2, a New Stellar Spectrograph at Universidad de los Andes
We present the construction and early results of ESPARTACO 2, a new stellar spectrograph built for research and education at the Astronomical Observatory of the Universidad de los Andes in Bogotá, Colombia. This instrument offers several resolution modes, from 20,000 in the first order using a 50 $\mu$m fiber, to 100,000 in the second order in the near-infrared. Precise radial-velocity measurements were made possible by simultaneous wavelength calibration. Combined with the 40-cm Meade telescope located at our facilities, a limiting magnitude of 6 was achieved. This instrument represents a significant improvement over its predecessor in terms of throughput, reliability, and ease of use.
Confirmation and Characterization of Galactic Planetary Nebulae: Insights from a Spectroscopic Study
We present a spectroscopic investigation of 25 objects previously reported as possible Planetary Nebulae (PNe) in recent catalogs to obtain their physical properties and establish their true nature. We found 11 objects showing intense emission lines, 11 objects where it was not possible to measure $\mathrm{H{\beta}}$, and 3 objects where no lines were present. We used diagnostic diagrams to confirm the true PN nature of the eight objects. We obtained elemental abundances for the three objects, the values of which are in agreement with the mean PNe values for our Galaxy. Four objects show [NII] $\lambda$6583 being more intense than $\mathrm{H{\alpha}}$, and for two of them, this can be explained by the presence of shocks in the gas. Finally, we report angular sizes based on $\mathrm{H{\alpha}}$ and [OIII] $\lambda$5007 emission.