arXiv subjects

Gustavo Magallanes-Guijón

Publications and source records attributed to Gustavo Magallanes-Guijón.

4 recordsLinked to original sources

arXiv2026

Exploring blazars through sonification. Visual and auditory insights into multifrequency variability

Using open astronomical multifrequency databases, we constructed light curves and developed a comprehensive visualisation and sonification analysis for the blazars Mrk~501, Mrk~1501, Mrk~421, BL~Lacerta, AO~0235+164, 3C~66A, OJ~049, OJ~287, and PKS~J2134-0153. This study employed Musical Instrument Digital Interface (MIDI) and Parameter Mapping Sonification (PMSon) techniques to generate waveforms, spectrograms, and sonifications. These representations demonstrate that data visualisation and sonification are powerful tools for analysing astronomical objects like blazars, providing insights into their multifrequency variability. This work highlights how sonification and visualisation can aid in identifying potential patterns, power variations, regularities, and gaps in the data. This multimodal approach also underscores the importance of inclusivity in scientific communication, offering accessible methods for exploring the complex behaviour of blazars.

astro-ph.HE↗

arXiv2025

Modeling the shadow of Sgr A* through an eclipsing black hole

The Event Horizon Telescope (EHT) observations of Sgr\,A* resolved the shadow image and emission ring-like structure, which is associated to the photon ring of the supermassive black hole, at the galactic centre, revealing a diameter of $51.8~μ\text{as}$. The ring-like structure is consistent with that of a Kerr black hole. However, the source of the high bright regions in the image and the time variability remain an open question. Besides the plasma properties and emission models, the spacetime geometry also holds an important role. We present an image depicting the bright hot spots consistent with Sgr\,A* observations at a wavelength $ λ= 1.3\, {\rm mm}$. The image is the result of an eclipsing Schwarzschild black hole situated along the line of sight between the galactic centre and Earth. The separation from both, primary (Sgr\,A*) and secondary (eclipsing) black holes is $10233\, {\rm AU}$. The central supermassive black hole located at the centre of the galaxy has an observational mass of $4.14\times10^6\,M_{\odot}$ and the secondary eclipsing black hole has an inferred mass of $1035\,M_{\odot}$.

astro-ph.HE↗

arXiv2025

A 78- and 96- minute quasi-periodic gamma-ray oscillations in Sagittarius A*

Using publicly available gamma-rays data from the Fermi satellite and the Fermitools package, we constructed 867-day light curves of Sagittarius A* to search for potential periodicities from 2008 to 2024. By applying statistical and computational inference methods, we used periodograms, a window function, unsupervised machine learning (K-Means), the Markov Chain Monte Carlo method, noise colour analysis, and phase-folding techniques. Additionally, the datasets were fitted with a Jacobi elliptical function using a likelihood approach. In total, 1,463,040 minutes were analysed. This analysis revealed a significant period of enhanced activity lasting ~78 minutes, followed by a quiescent phase of about ~18 minutes, resulting in a total quasi-periodic oscillation (QPO) of around 96 minutes.

astro-ph.HE↗

arXiv2024

A Supermassive Binary Black Hole Candidate in Mrk 501

Using multifrequency observations, from radio to gamma-rays of the blazar Mrk~501, we constructed their corresponding light curves and built periodograms using RobPer and Lomb-Scargle algorithms. Long-term variability was also studied using the power density spectrum and the detrended function analysis. Using the software VARTOOLS, we also computed the analysis of variance, box-least squares and discrete fourier transform. The result of these techniques showed an achromatic periodicity <~ 229 d. This, combined with the result of pink-color noise in the spectra, led us to propose that the periodicity was produced via a secondary eclipsing supermassive binary black hole orbiting the primary one locked inside the central engine of Mrk~501. We built a relativistic eclipsing model of this phenomenon using Jacobi elliptical functions, finding a periodic relativistic eclipse occurring every ~ 224 d in all the studied wavebands. This implies that the frequency of the emitted gravitational waves falls slightly above 0.1 mHz, well within the operational range of the upcoming LISA space-based interferometer, and as such, these gravitational waves must be considered as a prime science target for future LISA observations.

astro-ph.HE↗