Coloquio en el IFIS: “60 años del Fondo Cósmico de Microondas”

El próximo miércoles 11 de junio, Cristóbal Sifón, académico del IFIS de nuestra universidad, dictará el coloquio “60 años del Fondo Cósmico de Microondas” a las 11:00 horas en la Sala 208 del Instituto de Física, Campus Curauma, PUCV.

Compartimos el resumen de la presentación:

El 13 de mayo de 1965 los ingenieros Arno Penzias y Robert Wilson publicaron en la revista The Astrophysical Journal un artículo humildemente titulado “Un exceso de temperatura de antena a 4080 Mc/s”.

En otro artículo publicado conjuntamente, un grupo de astrofísicos teóricos liderados por Robert Dicke describió ese “exceso de temperatura de antena” como nada menos que la radiación de fondo — la temperatura — del Universo, entregando evidencia directa en favor del modelo de Big Bang caliente en que el Universo comenzó en un estado mucho más denso y caliente que el que observamos hoy.

Experimentos modernos, algunos desde suelo chileno, han observado esta radiación con altísimo detalle y nos entregan información muy detallada sobre el contenido y la evolución del Universo.

En este coloquio revisaremos la historia de este descubrimiento, el pasado, presente y futuro del estudio del Universo a través de la radiación cósmica de fondo, y el rol de Chile en este camino.

Sobre el orador:

Cristóbal Sifón es profesor del IFIS de la PUCV. Obtuvo su doctorado en astrofísica en la Universidad de Leiden en 2016 y también ha sido investigador asociado postdoctoral en la Universidad de Princeton. Sus intereses de investigación incluyen el estudio de los cúmulos de galaxias y sus implicaciones para la cosmología.

Extendemos la invitación a la comunidad del Instituto de Física y público interesado a participar de este coloquio.

Créditos imagen: NASA.

Coloquio en el IFIS: “Geodésicas en la variedad de los estados cuánticos y metrología cuántica”

Este miércoles 4 de junio, Dominique Spehner, académico del Departamento de Ingeniería Matemática de la Universidad de Concepción, dictará el coloquio “Geodésicas en la variedad de los estados cuánticos y metrología cuántica” a las 11:00 horas en la Sala 208 del Instituto de Física, Campus Curauma, PUCV.

Compartimos el resumen de la presentación:

En esta charla, mostraremos que las geodésicas en la variedad de los estados cuánticos mixtos (matrices densidad) para la distancia de Bures corresponden a evoluciones temporales no markovianas del sistema. Estas evoluciones están generadas por ciertos hamiltonianos que acoplan el sistema con su entorno (ancilla).

También se hará hincapié en el papel de las geodésicas en metrología cuántica. La metrología cuántica tiene como propósito usar las propiedades cuánticas para estimar con una mejor precisión parámetros físicos, a partir de un análisis estadístico sobre resultados de mediciones. Si el parámetro es proporcional al tiempo de parametrización de la geodésica, veremos que el error en la estimación usando solamente mediciones sobre el sistema alcanza el mínimo error que se puede lograr usando cualesquiera mediciones sobre el sistema y el ancilla y cualquier estado inicial. En otros términos, no hay pérdida de información en el ancilla sobre el parámetro, a pesar del entrelazamiento del sistema con la ancilla.

Extendemos la invitación a la comunidad del Instituto de Física y público interesado a participar de este coloquio.

Seminario de Astrofísica: “The Multi-Scale Interplay Between Dark and Luminous Matter”

Este martes 3 de junio, el Dr. Antonio D. Montero-Dorta, profesor de la Universidad Técnica Federico Santa María, presentará el seminario “The Multi-Scale Interplay Between Dark and Luminous Matter” a las 14:30 horas en la Sala 208 del Instituto de Física, Campus Curauma, PUCV.

Compartimos el abstract de la presentación:

The prevailing paradigm of galaxy formation posits that galaxies form within dark matter halos, which provide the potential wells needed for baryonic matter to accumulate, cool, and condense. Halos, in turn, are collapsed structures that originate from the high-density peaks of the underlying matter field. These objects are connected, albeit in a complex way, by their internal properties, clustering, and responses to the environment.

Characterizing the mapping between galaxies, halos, and the matter density field is essential not only for extracting cosmological information from galaxy surveys, but also for uncovering the physical mechanisms that shape galaxy evolution.

In this talk, I will present recent analytical and data-driven advances that enable a more detailed statistical dissection of halo and galaxy clustering in cosmological simulations, paying special attention to key physical phenomena such as assembly bias and the connection between clustering and the cosmic web. I will also discuss the observational detectability of these effects, along with the application of innovative techniques to data from upcoming large-scale galaxy surveys.

Extendemos la invitación a la comunidad del Instituto de Física y público interesado a participar de este seminario que busca aportar a la comprensión de la estructura del universo.

Seminario de Astrofísica: “The Effect of Massive Stellar Feedback Across the Carina Nebula Complex”

Seminario de Astrofísica en el IFIS. Este martes 20 de mayo, Constanza Norambuena, estudiante de Astronomía UC, presenta “The Effect of Massive Stellar Feedback Across the Carina Nebula Complex” desde las 14:30 horas en la Sala 208 del Instituto de Física PUCV, Campus Curauma. 

Compartimos el abstract de la presentación: 

Massive stars play a crucial role in affecting their surrounding environment, influencing star formation through radiative feedback. The Carina Nebula, located approximately 2.3 kpc away, serves as an excellent laboratory for studying these processes due to its large spatial extent and diverse star-forming environments.

In this project, we analyze ten selected regions within the nebula using ALMA Band 3 observations with the Atacama Compact Array and Total Power. Our focus is on molecular line emission (HCO⁺, HCN, CS) to investigate the physical and chemical conditions of the gas affected by massive stellar feedback.

This talk will focus on providing a brief overview of interferometry, the data processing steps, including imaging the interferometric observations using the tclean task in CASA, the combination of images from two different arrays (ACA 7-m and Total Power), and the various techniques that can be applied. Additionally, I will explain the generation of spectral cubes and the construction of moment maps to trace different gas structures.

Extendemos la invitación a la comunidad a participar de este seminario que busca aportar a la comprensión sobre las huellas que van dejando las estrellas masivas en su entorno interestelar.

Inauguración del Año Académico “Inestabilidades mecánicas como explicación de la anti-adherencia vascular”

Te invitamos a participar del Inicio del Año Académico 2025 del Instituto de Física de la Pontificia Universidad Católica de Valparaíso, el día martes 20 de mayo desde las 11:00 AM en el Auditorio Otto Zollner de la Facultad de Ciencias, Campus Curauma. 

En el evento se dictará la charla “Inestabilidades mecánicas como explicación de la anti-adherencia vascular” junto a nuestro invitado Dr. Enrique Cerda Villablanca, profesor del departamento de Física de la Universidad de Santiago de Chile.

Seminario de Astrofísica: “Simulation of the Impact of Jupiter-Type Rogue Planets on Circumstellar Disks”

Seminario de Astrofísica en el IFIS. Este martes 13 de mayo, Patricio Messen, estudiante del Magíster en Física de la Pontificia Universidad Católica de Valparaíso, presentará “Simulation of the Impact of Jupiter-Type Rogue Planets on Circumstellar Disks” a las 14:30 horas en la Sala 208 del Instituto de Física, Campus Curauma.

Compartimos el abstract de la presentación:

Circumstellar disks are structures of gas and dust that surround young stars during the early stages of their evolution. These disks are thought to be the sites of planet formation, and observations have revealed complex substructures with unclear origins, such as prominent spirals, low-density rings, and high-density regions where material accumulates.

In this work, we perform two-dimensional hydrodynamic simulations using the FARGO3D code, where we perturb a circumstellar disk with a Jupiter mass planet undergoing a coplanar flyby. We compare cases where the planet follows a prograde or retrograde trajectory. Simulations are carried out using two different equations of state: isothermal and adiabatic. The disk morphology varies significantly depending on the planet’s trajectory, and in all models, spiral-shaped density waves are generated and propagate throughout the disk.

In the retrograde case, two relatively close spiral arms form, while in the prograde scenario, two nearly symmetric spirals appear with respect to the central object. Under the isothermal condition, the spirals exhibit a more compact and well-defined structure compared to the adiabatic case, due to the absence of local temperature variations that would affect gas pressure. When local temperature variations are considered in the adiabatic models, we find that in the prograde case, the region where the spiral arms intersect experiences a significant temperature increase compared to the retrograde case.

To assess the observable differences between these scenarios, we adopt an approximation assuming dust perfectly coupled to the gas, and generate a synthetic spectral energy distribution (SED). This reveals that the temperature peak leads to an increase in the disk’s emitted flux. By evaluating viscous dissipation terms, we find that these events produce changes in bolometric luminosity below 1%, with prograde cases yielding the largest variation.

All simulated cases produce a low-density ring (gap) at approximately 8 AU from the central object. Uniquely in the prograde case with an adiabatic equation of state, a high-density ring forms just outside the gap, potentially acting as a dust trap and possibly triggering planetesimal formation. Finally, we perform a purely morphological comparison with Elias 2-27, a system that exhibits spiral arms with features resembling those of our simulated disks in the prograde scenario, which may provide insight into the origin of Elias 2-27’s observed morphology.

Extendemos la invitación a la comunidad a participar de este seminario que busca aportar al entendimiento de los procesos de formación planetaria.

Coloquio IFIS: “New Zealand Radio Astronomy: Past, present, and perspectives of NZ-Chile collaboration”

El próximo miércoles 7 de mayo, a partir de las 11:00 AM, Sergei Gulyaev, profesor de Astronomía en la Escuela de Ingeniería, Informática y Ciencias Matemáticas de la Universidad Tecnológica de Auckland, Nueva Zelanda, presentará “New Zealand Radio Astronomy: Past, present, and perspectives of NZ-Chile collaboration” en un nuevo Coloquio del IFIS PUCV. El encuentro tendrá lugar en la sala 208 del Instituto de Física.

Te dejamos el abstract de la presentación:

New Zealand radio astronomy has experienced two defining periods: an early emergence in the 1940s alongside the birth of the field, and a resurgence in the 21st century with the creation of the Warkworth Radio Astronomical Observatory at AUT. In this talk, Prof. Gulyaev will present current projects and instruments, recent changes post-pandemic, and future prospects — especially regarding the collaboration between AUT and the PUCV Institute of Physics.

Seminario de Astrofísica: “Bias Function and the Cosmic-Web connection”

Seminario de Astrofísica en el IFIS. Este martes 6 de mayo, Constanza Soto estudiante de Doctorado de Ciencias Físicas de la PUCV y UTFSM, presenta “Bias Function and the Cosmic-Web connection” desde las 14:30 en la Sala 208 del Instituto de Física PUCV.

Revisa el abstract de la presentación:

The spatial distribution of galaxies and dark matter haloes is not random and carries crucial information about the evolution of the universe. When referring to large-scale structure (LSS), we describe an inhomogeneous universe whose nature is studied through the evolution of perturbations in the density field. On larger scales, the evolution of these fluctuations, driven by the gravitational interaction of matter, gives rise to the formation of complex structures such as nodes, filaments, voids, and walls, collectively known as the cosmic web. Following this idea, the relation between the distribution of galaxies or dark matter haloes and the underlying matter density field is referred to as bias. The primary dependence of halo clustering is on halo mass, such that more massive haloes are more clustered than their less massive counterparts. However, secondary properties, at fixed halo mass, also influence clustering, leading to the so-called secondary bias. In this study, using the TNG300 hydrodynamical simulation, we employed an individual halo bias estimator, leveraging its advantages over traditional methods. With this estimator, we constructed the halo bias function, defined as the relation between the average individual bias per halo mass bin. By analyzing the halo bias function across different environments, we found that the trend varies for each environment, indicating that haloes located in the outskirts of nodes are highly clustered, in contrast to haloes in voids and walls. Similarly, linking to galaxy properties, we observed that haloes hosting red galaxies are more clustered, across all environments, than those hosting blue galaxies. Additionally, at low masses (log10(Mhost) < 12.5 h−1M⊙), red galaxies are significantly influenced by nearby massive haloes (log10(Mhost) > 13.5h−1M⊙)) within a radius of 5 h−1Mpc.

Coloquio IFIS: “The anomalous magnetic moment of the muon and what it can teach us”

Este miércoles 30 de abril desde las 10:30 AM, Anton Rebhan, profesor de física teórica de la Universidad Tecnológica de Viena, Austria, presentará “The anomalous magnetic moment of the muon and what it can teach us” en un nuevo Coloquio del IFIS PUCV. El evento se llevará a cabo en la sala 208 del Instituto de Física.

Te dejamos el abstract de la exposición:

The magnetic moment of the muon will soon be measured with a precision of 11 digits, with results from an experiment at Fermilab to be released in the coming weeks. Its anomaly, the deviation from the value given by the Dirac equation, is one of the most stringent tests of the Standard Model of particle physics. At this level of precision, quantum fluctuations make it sensitive to potential physics beyond the Standard Model at scales that are even beyond reach of high-energy collider experiments. For nearly two decades, a persistent discrepancy between theory and experiment has been interpreted as an indication of New Physics. Recently it became clear, however, that at least a substantial part of this mismatch is due to an insufficiently precise understanding of hadron physics. After reviewing the state of affairs, I will discuss how methods derived from string theory have helped to sort out some of the open problems.