Past Colloquia

Número de entradas: 5

26
Julio 2017

The physics and astrophysics of merging neutron-star binaries


Inicio: 12:00h
Ponente: Prof. Luciano Rezzolla (University of Frankfurt)
Lugar: Sala Alberto Lobo

I will argue that if black holes represent one the most fascinating implications of Einstein's theory of gravity, neutron stars in binary system are arguably its richest laboratory, where gravity blends with astrophysics and particle physics. I will discuss the rapid recent progress made in modelling…
Inicio: 12:00h
Ponente: Prof. Luciano Rezzolla (University of Frankfurt)
Lugar: Sala Alberto Lobo

I will argue that if black holes represent one the most fascinating implications of Einstein's theory of gravity, neutron stars in binary system are arguably its richest laboratory, where gravity blends with astrophysics and particle physics. I will discuss the rapid recent progress made in modelling these systems and show how the inspiral and merger of a binary system of neutron stars is more than a strong source of gravitational waves. Indeed, while the gravitational signal can provide tight constraints on the equation of state for matter at nuclear densities, the formation of a black-hole--torus system can explain much of the phenomenology of short gamma-ray bursts, while the the ejection of matter during the merger can shed light on the chemical enrichment of the universe.
05
Julio 2017

Neutron Stars: Physics Labs in extreme conditions


Inicio: 12:30h
Ponente: Jose Pons (U. Alicante)
Lugar: Sala d'Actes - Departament de Física (Edifici C5) UAB

Las estrellas de neutrones son unos laboratorios fantásticos para muchas ramas de la Física Fundamental que el Universo pone a nuestra disposición, y que nos permiten experimentar en unas situaciones extremas que no son reproducibles en los laboratorios terrestres por sus limitaciones. En esta charla…
Inicio: 12:30h
Ponente: Jose Pons (U. Alicante)
Lugar: Sala d'Actes - Departament de Física (Edifici C5) UAB

Las estrellas de neutrones son unos laboratorios fantásticos para muchas ramas de la Física Fundamental que el Universo pone a nuestra disposición, y que nos permiten experimentar en unas situaciones extremas que no son reproducibles en los laboratorios terrestres por sus limitaciones. En esta charla se describirá de forma divulgativa cuáles son las propiedades típicas de las estrellas de neutrones, cómo se observan, cómo se forman y evolucionan, y a qué tipo de fenómenos superenergéticos están asociadas. Discutiremos cómo se pueden usar como laboratorios de Física en condiciones extremas y por qué son interesantes para prácticamente todas las ramas de la Física.
31
Mayo 2017

Cherenkov Telescope Arrays for Optical Astronomy: Intensity interferometry and imaging of stellar surfaces


Inicio: 12:00h
Ponente: Dainis Dravins (Lund Observatory)
Lugar: Sala Alberto Lobo

Optical imaging with microarcsecond resolution will reveal details on and around stellar surfaces but requires kilometer-scale interferometers.  Intensity interferometry, electronically connecting independent telescopes, has an error budget that relates to electronic time resolutions of nanoseconds…
Inicio: 12:00h
Ponente: Dainis Dravins (Lund Observatory)
Lugar: Sala Alberto Lobo

Optical imaging with microarcsecond resolution will reveal details on and around stellar surfaces but requires kilometer-scale interferometers.  Intensity interferometry, electronically connecting independent telescopes, has an error budget that relates to electronic time resolutions of nanoseconds and light-travel distances of centimeters or meters (rather than scales of an optical wavelength), circumventing issues of atmospheric turbulence.  Once pioneered by Hanbury Brown and Twiss, digital versions of this quantum-optical technique have now been demonstrated in the laboratory, reconstructing diffraction-limited images from measurements over hundreds of optical baselines.  Baselines up to a few km will soon become available with the Cherenkov Telescope Array (primarily built for gamma-ray studies), thus realizing an optical interferometer in software, somewhat analogous to that of ALMA at radio wavelengths.
13
Marzo 2017

The Spanish participation in the SKA


Inicio: 12:00h
Ponente: Lourdes Verdes-Montenegro (Instituto de Astrofísica de Andalucía, CSIC. Coordinator of the Spanish participation in the SKA)
Lugar: Sala Alberto Lobo

The Square Kilometre Array (SKA) will be a radio interferometer aiming to answer fundamental questions in Astrophysics, Fundamental Physics, and Astrobiology. It will be composed of thousands of antennas distributed over distances of more than 3000 kilometres on both Africa and Australia. The SKA has…
Inicio: 12:00h
Ponente: Lourdes Verdes-Montenegro (Instituto de Astrofísica de Andalucía, CSIC. Coordinator of the Spanish participation in the SKA)
Lugar: Sala Alberto Lobo

The Square Kilometre Array (SKA) will be a radio interferometer aiming to answer fundamental questions in Astrophysics, Fundamental Physics, and Astrobiology. It will be composed of thousands of antennas distributed over distances of more than 3000 kilometres on both Africa and Australia. The SKA has been recently identified as a Landmark Project in the European Strategy Forum on Research Infrastructures (ESFRI) roadmap. Spain has been participating in SKA-related activities since the 1990s, coordinated since 2011 by the Instituto de Astrofísica de Andalucía (IAA-CSIC). Currently, 20 researchers participate in 7 out of the 11 main SKA Science Working Groups, and a total of 119 researchers from 40 Spanish centres have participated in the Spanish SKA White Book, published in 2015. From a technological point of view, more than 20 research centres and companies are contributing to the design of the SKA as part of 7 international consortia.  This Spanish technological participation in the SKA, with an estimated financial value of ~€2M, has been officially acknowledged by the SKA Board. Since October 2013 a representative of the Spanish government has been regularly invited to participate in the SKA Board meetings. Furthermore, at the beginning of 2014, the Board of the Spanish Astronomy Infrastructures Network endorsed the recommendation issued by the Radio Astronomy Infrastructures working group on the interest of the scientific community and industry that Spain explores the possibility to join the SKA project as Full Member before the construction phase starts. In December 2015, the Spanish Secretary of State of Research, Development and Innovation sent a letter to the SKA Organisation Director General proposing to establish a dialogue in order to explore scenarios for Spain to join the SKA, what constitutes a further motivation for the Spanish community to continue its efforts. The aim of this talk is providing a retrospective view of the Spanish participation in SKA project and explain the current status of its participation and opportunities of involvement.
19
Diciembre 2016

The Origin of High-Energy Photons in Blazar Jets


Inicio: 15:00h
Ponente: Lorenzo Sironi (Columbia University)
Lugar: Sala Alberto Lobo

We investigate the origin of high-energy photons in blazar jets, by means of first-principles particle-in-cell (PIC) fully-kinetic simulations. In magnetically-dominated jets, magnetic reconnection is often invoked as a mechanism to transfer the jet magnetic energy to the emitting particles, thus powering…
Inicio: 15:00h
Ponente: Lorenzo Sironi (Columbia University)
Lugar: Sala Alberto Lobo

We investigate the origin of high-energy photons in blazar jets, by means of first-principles particle-in-cell (PIC) fully-kinetic simulations. In magnetically-dominated jets, magnetic reconnection is often invoked as a mechanism to transfer the jet magnetic energy to the emitting particles, thus powering the observed non-thermal emission. With 2D and 3D PIC simulations, we show that magnetic reconnection in blazar jets satisfies all the basic conditions for the emission: extended non-thermal particle distributions (with power-law slope between -2 and -1), efficient dissipation and rough equipartition between particles and magnetic field in the emitting region. In addition, we demonstrate from first principles that relativistic magnetic islands generated by reconnection in the jet can power the ultra-fast bright flares observed from a number of TeV blazars.
Institute of Space Sciences (IEEC-CSIC)

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An institute of the Consejo Superior de Investigaciones Científicas

An institute of the Consejo Superior de Investigaciones Científicas
Affiliated with the Institut d'Estudis Espacials de Catalunya

Affiliated with the Institut d'Estudis Espacials de Catalunya