As a theoretical and computational astrophysicist, I study signatures of Einstein's general relativity and its extensions within various astrophysical phenomena. Currently serving as a Richard P. Feynman Distinguished Fellow in Theory and Computing, and a Center for Nonlinear Studies Fellow at Los Alamos National Laboratory, my work is devoted to studying gravity's effects on astrophysical systems. Previously, I was a Postdoctoral Research Associate at Princeton University’s Gravity Initiative.
I was born in Bogotá (Colombia) where I earned a B.Sc. in Mathematics at Fundación Universitaria Konrad Lorenz and concurrently earned a B.Sc. in Physics at Universidad Nacional de Colombia, where I also acquired a M.Sc in Astronomy. Then, I moved to the US, earned a M.Sc in Physics at the eXtreme Gravity Institute, and completed my PhD at the University of Illinois at Urbana-Champaign under the supervision of Nico Yunes.
I am an astrophysicist with diverse interests spanning gravitational physics, high-energy phenomena associated with compact objects, and dynamical systems theory. Specifically, my research i) involves examining observational signatures within both electromagnetic and gravitational spectra to scrutinize the principles of general relativity; and ii) navigates the dynamics of nonlinear waves within the realm of partial differential equations, where a fascinating interplay of mathematics and physics unfolds.
-> In the electromagnetic sector, I conduct numerical investigations into high-energy phenomena surrounding compact objects, employing models for accretion disks, images, and spectra. Currently, I am exploring the ability to confine and identify deviations from general relativity through high-resolution black hole images capable of resolving the photon ring: a narrow, ring-shaped, lensed feature predicted by general relativity, but not yet observed. These photon rings carry information about the underlying spacetime geometry. In collaboration with my collaborators, we recently introduced Adaptive Analytical Ray Tracing (AART), an open-source framework capable of computing high-resolution simulated black hole images and their corresponding radio visibility accessible on very long space-ground baselines.
As a grad student, I led the development of an X-ray reflection model to evaluate the assumption that the metric of astrophysical black holes adheres to the Kerr solution. I also collaborated on a groundbreaking project wherein we deduced, for the first time, the moment of inertia, quadrupole moment, and surface eccentricity of an isolated neutron star. Additionally, we proposed and implemented the first theory-agnostic and equation-of-state-insensitive test of general relativity. This test allowed us to impose the most rigorous constraint on parity violation to date.
I numerically study the high-energy phenomena around compact objects by modeling accretion disks, images, and spectra. In particular, I have led the development of the first X-ray reflection model to test the assumption that the metric of astrophysical black holes is described by the Kerr solution. I have also collaborated on a project where we inferred the moment of inertia, the quadrupole moment, and the surface eccentricity of an isolated neutron star for the first time, and proposed and implemented the first theory-agnostic and equation-of-state-insensitive test of general relativity. We used this test to place the most stringent constraint on parity violation to date. I am currently exploring our ability to constrain and detect deviations from general relativity with high-resolution black hole images.
-> In the gravitational-wave sector, my focus lies in studying the orbital dynamics and gravitational waves emitted by extreme mass-ratio inspirals (EMRIs), which will be observable through the Laser Interferometer Space Antenna (LISA). I have delved into the integrability of quadratic theories of gravity, exploring ways to comprehend observable effects from general perturbations to these systems. On this front, my research explores various perturbations around resonances to discern their impact on constructing inspiral waveforms for testing general relativity.
-> More recently, I have developed a keen interest in numerically exploring nonlinear waves as models for the more intricate hyperbolic equations in physics. Their significance as models extends to elucidating the dynamics of spacetimes, providing insights into solutions for the Einstein equations. Currently, my research involves the numerical evolution of nonlinear waves in different spacetimes to establish connections between linear and nonlinear outcomes within the context of Einstein equations.
In my work, I employ both analytic calculations and computational simulations on large-scale computing systems, that use black holes as laboratories to test our understanding of gravity's fundamental properties.
You can click on any image below to be redirected to one of my papers for further details, or here for animations:
I am currently co-organizing the First Latin American Conference on Astrophysics and Relativity ( LACAR ). The spirit of this conference is to offer a connection between the community that works in General relativity and the astrophysics community of high energies and compact objects, and at the same time to (re)establish connections with the scientific community of Latin American physicists and astrophysicists among them and with the rest of the international community. Join us!
Teaching is an integral part of my identity as an academic. My teaching philosophy is based on the conviction that students learn more efficiently if encouraged to be the leaders of their learning process. I believe that learning is a process in which students must be actively engaged.
Upon finishing my first master's degree, I was invited to be a lecturer at Fundacion Universitaria Konrad Lorenz in Colombia. So I have had the opportunity to design and teach several online courses on computational methods (Modeling and Simulation, High-Performance Computing) and mentored several senior math students in their Bachelor's thesis.
As a graduate teaching assistant at Montana State University, I helped conduct problem and lab sessions, recitations and graded homework assignments and exams for introductory physics classes (PHYS 205 and PHYS 220). At the University of Illinois at Urbana Champaign, I was the teaching assistant for the General Relativity (PHYS 515) graduate course, working first for Prof. Yunes and then for Prof. Witek during my last year. During my graduate studies, I served as co-advisor, together with Prof. Yunes, for several physics major undergraduates for their Senior undergraduate project.
Together with my friend Carlos Albertho Benavides-Gallego
we translated to Spanish Prof. Bambi's textbook: Introduction to General Relativity. The English version of the book was published by Springer Nature Singapore in 2018 and since then downloaded millions (>3M) of times. The book was then translated to Chinese and published by Fudan University Press in 2020 after fixing some typos of the English version. With this version in Spanish, published by the prestigious Editorial Reverté, we are thus at the third edition of the book! The e-book can be found on Amazon. El libro comienza revisando la mecánica newtoniana, para luego pasar a la relatividad especial y general. La mayoría de los cálculos se presentan con bastante detalle y paso a paso, como se haría en una pizarra durante una clase magistral.
Below you can find the links to the material of some courses materials (in Spanish only):
Este curso introductorio a la programación científica con Python está diseñado para permitirle a sus participantes conocer y desarrollar las herramientas necesarias para comenzar a abordar problemas científicos y de ingeniería a través de metodologías problema-solución y herramientas robustas para su solución. La primera versión del curso la base en el material compartido durante el SciCoder 4, que ocurrió en NYC en el 2013. Sin duda alguna ha sido mi workshop favorito.
Todo el material de la clase está en este repositorio de Bitbucket.
Este curso lo preparé para la Society for Industrial and Applied Mathematics - Colombian Section CoSIAM, con el objetivo presentar una introducción a la modelación y simulación matemática. A través de varios tipos de modelos matemáticos, presento herramientas de código abierto y libre que se adaptan a la implementación de modelos y simulaciones simples. Es un curso auto contenido y creado en tiempos de pandemia. Los videos están en el canal de YouTube de CoSIAM:
- La primera parte consiste en las consideraciones generales y teóricas de la modelación determinística, además de un breve tour por estimación de parámetros de manera Bayesiana con cadenas de Markov al estilo Monte Carlo (MCMC).
- La segunda parte está dedicada a introducir algunos conceptos de modelos estocásticos y algunas aplicaciones, como campos aleatorios Gaussianos.
Mi idea es que los participantes cuenten con más herramientas para abordar el Math Challenge de CoSIAM. ¡Buena suerte!
On this page, I have written some general advice on applications to grad school and material on writing, research, and giving talks.
In addition to research, I am interested in outreach and astronomy education. In 2009 I started with Nelson Vargas an astronomy outreach group (Astro-K) at the Konrad Lorenz University, to spread interest and enthusiasm for astronomy to the general public. We have prepared festivals, public talks, radio programs and courses. During the summer of 2012 I did an internship with the European Union Universe Awareness (EU-UNAWE) educational programme at the Department of Astronomy of Leiden University in the Netherlands, where I did research on Open Educational Repositories, public outreach initiatives and astronomy development evaluations under the supervision of Pedro Russo .
A cycle of webinars to connect physicists working on particle and high-energy physics, astroparticles, and astrophysics.
You can read here. what Symmetry Magazine wrote about this initiative.
In this podcast we interview some of the postdoctoral researchers at the physics department at Princeton University. Each episode features a postdoc as a scientist, coworker, member of our community, and of course, as a person that we want to get to know a little bit more.
Astrobitos is a periodical astrophysical literature journal written in Spanish by graduate students. Our goal is to present interesting papers in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.