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 (M/L)* in the analysis of galaxy kinematical data to estimate the corresponding mass profiles. For this purpose, we analyzed 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 using a parameter-fitting procedure. This analysis was performed 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 near-infrared (NIR), the WISE W1 3.4 mu m band. To estimate the corresponding stellar disk (M/L)*, we used previously published color-(M/L)* 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 large number of galaxies, using photometry data from standardized digital surveys.
The use of orbiting space mirrors to reflect sunlight onto the Earth's surface has been contemplated in numerous applications, including 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 for mega-projects. In this study, an Earth-space mirror two-body analysis is performed, considering the Solar Radiation Pressure and.. 2 Earth oblateness perturbation, such that when sunlight strikes the perfectly reflecting space mirror surface, the ray reflects off the mirror in the direction of the Earth's center. In this study, two candidate orbits for solar reflectors were considered: 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 the Earth coincide. Using Gauss' perturbing equations, a set of orbital parameters is provided to achieve a Sun-synchronous Solar Reflector Orbit that distributes the solar energy intercepted by the mirror azimuthally. The characteristic acceleration of the mirror was also selected appropriately from the sun-synchronous condition. Additionally, it was shown that in this scenario, a Low Sun-Synchronous Earth Orbit can be accomplished only for polar orbits, but not for in-plane motion. In this scenario, only Medium Sun-Synchronous Earth Orbits can be achieved.
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 extends the two-point estimator to three-point correlations. Thanks to GPU optimization, Lya2pcf reduces the computational time compared to the widely used PICCA code. We applied Lya2pcf to data from SDSS DR16 and DESI Year-5 mocks, demonstrating overall performance gains. We present 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 resulting signal-to-noise ratio demonstrate the viability of incorporating three-point statistics into future cosmological analyses.
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 angstrom) over a contiguous similar to 0.5 degrees 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 the 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 for precise measurements of the weak-line morphology. The derived radial trends confirm the remarkably low dust content and overall homogeneity of the 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 study 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.
We present 121 days of multi-band (B, g', r', i') optical photometry of the Type Ia supernova SN 2025bvm, obtained with the COLIBRI telescope at the OAN-SPM. The light curves show a photometric decline of Delta m(15)(B) = 0.867 +/- 0.051 mag, which is characteristic of a slow-declining Type Ia supernova. After correcting for host galaxy extinction (E(B - V)(host) = 0.308 +/- 0.030 mag) and adopting a distance of 70 Mpc, we derived a peak absolute magnitude of M-B = -19.13 +/- 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 i'-band secondary maximum, suggest an explosion that resulted in particularly massive ejecta.
This study explores whether hadronic processes could be responsible for the high-energy emission observed in quasars identified by the Large Area Telescope (LAT) instrument aboard the Fermi satellite. In contrast to purely leptonic models, this study investigates whether hadronic mechanisms can explain the observed gamma-ray spectra by analyzing the spectral energy distributions (SEDs) of a chosen sample of Flat-Spectrum Radio Quasars (FSRQs). By incorporating both hadronic and leptonic components into their multiwavelength modeling, we evaluated 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 is required to explain the SED of quasars detected by Fermi-LAT. However, their contribution to the neutrino flux detected by the IceCube remains underestimated.
We present new analytical solutions for planetary nebulae dynamics. These equations consider the temporal variation of the mechanical luminosity and 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.
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.
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 Bogot & aacute;, 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.
The Wedge Double Wollaston (WeDoWo) or “double Wollaston” module is a device capable of displaying four images of a single field of view (FOV); each image corresponds to a different polarization angle (0°, 45°, 90°, and 135°), providing enough information for the Stokes I, Q, and U parameters calculation and the linear polarization angle and fraction values retrieved from the source observed, in this case, an astronomical source, in a single exposure (single-shot). In this paper, we present the design of a SiO2 (Crystalline Silica) WeDoWo module, describe the characterization process carried out in the laboratory and the subsequent calibration. Likewise, we show the application of this module for imaging astronomical polarimetry using the 1.0-meter telescope of the National Astronomical Observatory from Tonantzintla, Puebla (OAN-TNT), and illustrate the advantages and limitations of this technique and the optimal performance of this module.
New radial velocity (RV) and light curve (LC) data for the eclipsing binary V878 Her have been simultaneously modeled with the Wilson-Devinney code (WD2003). Two distinct LC datasets were investigated: one was from the Transiting Exoplanet Survey Satellite (TESS) while the others were acquired from a ground-based observatory in Canada. Supporting spectroscopic data were acquired using the 1.83-m Plaskett Telescope at the Dominion Astrophysical Observatory (DAO) between 2009-2020. Potential progenitors of this near contact binary (NCB) were evaluated using an evolutionary model derived from cool close binaries. It is argued that V878 Her is not in the thermal relaxation oscillation (TRO) phase but, instead, it is a first timer, i.e. in a state of contact binary formation. Its most probable ZAMS progenitor had masses equal to about 1.7 and 0.6 M☉ with an orbital period of nearly 1.6 days.
The filtered B, V, R and I light curves of four short period (P < 0.25d) eclipsing binary systems are presented and analysed; two having P ≈ 0.22d, close to the short period limit for contact binaries (CBs). New ephemerides are provided. No third light was found necessary in any case, and one or more spots were introduced to account for asymmetries in the light curves. Two systems belong to the W sub-type of the W-UMa CBs and a third one to the A sub-type of the W-UMa type CBs. The last one is a semi-detached binary with a large temperature difference between the components and a low mass ratio q = 0.191. All components of the binaries are of the K spectral type, and the secondary of the semi-detached binary is of the M spectral type. Absolute parameters of the components were calculated using different evolutionary diagrams. Interestingly, two target have estimated total masses that are smaller than the lower mass limit known for Cbs.
We present the results of a low resolution optical spectroscopic observation of Near-Earth Asteroid (NEA) 2018 CB during its close approach to Earth, conducted with the 2.1 m telescope of the Guillermo Haro Astrophysical Observatory (OAGH), located in Cananea, Sonora, Mexico, using a Boller & Chivens Spectrograph, with a grating of 50 l/mm that covers the interval between 4000Å and 9500Å. The taxonomic classification was performed using the values of the “spectral distance” (Dx), calculated with respect to the mean spectra of the 24 taxonomic classes of DeMeo et al. (2009), and also with respect to individual asteroid spectra from the Phase II of the Small Main-Belt Asteroid Spectroscopy Survey (SMASSII). We determined that 2018 CB is an Xk-class NEA.
The evolution of the H2O maser emission at the S128 source during 19812024 is analyzed, based on long-term regular observations. The emission from -73 to -70 km/s corresponds mainly to source B, while that of velocities < -76 km/s to source A. It was identified that in the time interval 2004-2006, the maser activity gradually shifted from source B to source A. The active phases of masers B and A lasted approximately 23 and 16 years, respectively. It is assumed that the common cause of the variability of the maser emission at both sources (A and B) can be shock waves that occur near the ionization front. When clouds collide, a disturbance propagates along the resulting ionization front, which leads to the appearance of shock waves. It is shown that the disturbance is spreading in the south-north direction. The star formation process occurs in the same direction.
In this work we searched for open clusters in the fields of star-forming regions in the Galaxy using the HDBSCAN applied to the astrometric data from the Gaia DR3 catalog. We identified 28 new open clusters, of which the real existence is supported by the membership probability determined from astrometric data and by the presence of cluster sequences in their color-magnitude diagrams, which allows for a reliable isochrone fit. Of the open clusters identified, 3 are younger than 50 Myr, 19 are of intermediate age, and 6 are old clusters. The clusters have apparent radii ranging from 3 to 20 arcmin. For all clusters, we estimate mean proper motion, mean parallax, and fundamental parameters considering the member stars for each cluster. One of the discovered clusters has a distance of 10 kpc and a log(age) ≈ 10.1, making it one of the most distant and oldest cataloged open clusters.
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 H(3, 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 [N II] )6583 being more intense than Ha, and for two of them, this can be explained by the presence of shocks in the gas. Finally, we report angular sizes based on Ha and [O III] )5007 emission.
This study presents photometric analysis of the intermediate-age open cluster King 6, utilizing photometric data in UBV(RI)$_c$ passband and data from the 2MASS mission. The Gaia DR3 kinematic data were used to estimate the membership probabilities and TESS data is employed to search for variable stars within the cluster. The cluster's radius is estimated to be 9$^\prime$.0 based on the stellar density profile, while optical and near-infrared color-color diagrams} revealed color excesses of E(B-V) = 0.58$ \pm$ 0.03, E(J-K) = 0.24 $\pm$ 0.03, and E(V-K) = 1.53 $\pm$ 0.01 mag. Interstellar extinction law is normal in the direction of the cluster. The cluster$^\prime$s estimated age is $\sim$251 Myr and distance is 724 $\pm$ 5 pc. The mass function slope was found to be x = 0.57 $\pm$ 0.28 by considering stars $\geq$ 1 M$_\odot$. Our analysis indicates that the cluster is dynamically relaxed. Furthermore, we identified three new variable stars for the first time in the cluster region using TESS data. These variables belong to the category of slow pulsating B-type variables, with periods of 46.70, 47.92, and 37.56 hours.
Light pollution, a rapidly escalating anthropogenic phenomenon driven by the excessive and often ineffcient use of artificial lighting, has profound implications for astronomy, ecology, and human health. This study presents the first comprehensive characterization of night sky quality in Colombia, focusing on sites of astronomical and ecological significance. The selected locations include the Astronomical Observatory of UTP, the Tatacoa Desert, the Bogotá Botanical Garden, and Cerro Guadalupe. Utilizing the Sky Quality Camera, we collected all-sky data to measure surface brightness and correlated color temperature of the night sky. Our findings reveal a significant loss of natural sky visibility in urban areas and demonstrate the detrimental effects of artificial lighting on critical astronomical sites such as La Tatacoa. This study provides a crucial foundation for future research and informs on the development of public policies aimed at preserving the night sky.
This study numerically investigates the dynamics of barred spiral galaxies using 3D Ferrers bar response models. A total of 708 models were analyzed, incorporating variations in the axisymmetric potential (nucleus, bulge, disk, halo), bar length, mass, angular velocity, and disk stellar velocity dispersion. Model evaluation employed the Spearman correlation (to assess input-output relationships) and permutation feature importance in a Random Forest Regressor (to measure input variable impacts). Orbital configurations of test particles reveal the critical role of bar dynamics in shaping galaxies' morphological and kinematic properties. Key findings emphasize how the bar potential influences major orbital families, affecting barred galaxies' long-term structure. These results provide deeper insights into galactic component interactions and a robust framework for understanding bar properties.
A cyclic flat universe with Quintom behavior and a future Big Rip as presented in the framework of Rastall gravity, which is an extension of the standard ACDM model. The Hubble parameter oscillates periodically between positive and negative values in each cycle. Cosmic transit has been simulated through an oscillating time-dependent deceleration parameter and is expected to occur at approximately 8.7 Gyr. Causality is satisfied at all times, except near the initial singularity and the future Big Rip singularity. The apparent horizon, entropy, and other thermodynamic quantities associated with the current model were analyzed. The energy conditions were investigated.
