Past Pizza Lunches

Número de entradas: 152

07
Junio 2019

Simulations on reverberating and superefficient pulsar wind nebulae


Inicio: 12:15h
Ponente: Tingting Lin (Institut de Ciències de l'Espai (CSIC-IEEC))
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Pulsar wind nebulae (PWNe) experience significant evolution in reverberation phase, when the reverse shock created by the supernova explosion travels back towards the pulsar, compressing the wind bubble. We numerically studied the radiative properties of the reverberation phase of several well-characterized…
Inicio: 12:15h
Ponente: Tingting Lin (Institut de Ciències de l'Espai (CSIC-IEEC))
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Pulsar wind nebulae (PWNe) experience significant evolution in reverberation phase, when the reverse shock created by the supernova explosion travels back towards the pulsar, compressing the wind bubble. We numerically studied the radiative properties of the reverberation phase of several well-characterized PWNe and discovered that even the Crab nebula, associated to the more energetic pulsar of the sample we consider, has a period in its future time evolution where the X-ray luminosity will exceed the spin-down power at the time. In fact, all nebulae in our sample are expected to have a period of radio, X-ray, and GeV superefficiency, and most will also have a period of TeV superefficiency. We then explored a broad range of PWN models to study their reverberation and superefficiency phases in a systematic way in order to analyze how many Galactic PWNe are expected to be reverberating, or in a superefficiency at any given time. We also provide predictions for the future evolution of the magnetar nebula J1834.9-0846 along the next 50 years. I will talk about the characterization of the superefficiency period we discovered in our numerical study.
31
Mayo 2019

Public communication of science. A portal to the public: IATE &OAC experience


Inicio: 12:15h
Ponente: Victoria Rubinstein (Observatorio Astronomico de Cordoba, Argentina)
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Science communication is a growing area of practice and research. During the past two decades, the number of activities, courses, and practitioners has steadily increased. But why is important to do Science Communication? In the 21st century, a general knowledge and understanding of scientific concepts…
Inicio: 12:15h
Ponente: Victoria Rubinstein (Observatorio Astronomico de Cordoba, Argentina)
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)


Science communication is a growing area of practice and research. During the past two decades, the number of activities, courses, and practitioners has steadily increased. But why is important to do Science Communication?
In the 21st century, a general knowledge and understanding of scientific concepts is required for making the best choices for our families, our society, our planet, and ourselves. Unfortunately, formal education often falls short on providing the necessary science-related skills, literacy, and proficiency for optimally navigating life. As such, informal science learning, often through effective science communication by research-active scientists, can play a vital role for a functioning society.
In my talk, I will show what are the activities that we carry out from the IATE and the OAC, in terms of public communication of science, outreach  and teaching. I will show the results of the practice of these activities, in social networks, media etc, and I will end with the idea of encouraging scientists to communicate their own research to the public.
24
Mayo 2019

The heart of darkness


Inicio: 12:15h
Ponente: Diego Torres (ICE)
Lugar: Alberto Lobo room

Can a molecular cloud beat?
Inicio: 12:15h
Ponente: Diego Torres (ICE)
Lugar: Alberto Lobo room

Can a molecular cloud beat?
17
Mayo 2019

Particle acceleration in protostellar jets: an observational approach


Inicio: 12:15h
Ponente: Adriana R. Rodriguez Kamenetzky (Instituto de Astronomía Teórica y Experimental, Córdoba, Argentina)
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Deeply embedded protostellar jets are well known to be dominated by the emission of thermal electrons. Interestingly, in the last decades, negative spectral indices have been detected at centimeter wavelengths in some protostellar jets, indicating the presence of a non-thermal component. Detecting non-thermal…
Inicio: 12:15h
Ponente: Adriana R. Rodriguez Kamenetzky (Instituto de Astronomía Teórica y Experimental, Córdoba, Argentina)
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Deeply embedded protostellar jets are well known to be dominated by the emission of thermal electrons. Interestingly, in the last decades, negative spectral indices have been detected at centimeter wavelengths in some protostellar jets, indicating the presence of a non-thermal component. Detecting non-thermal emission implies the existence of relativistic particles interacting with magnetic fields, and therefore, the action of a mechanism able to efficiently accelerate them. In this talk I will discuss the conditions that need to be met in order to produce efficient particle acceleration in these low energy systems, based on the analysis of radio continuum images of two representative young stellar objects, obtained with the Karl G. Jansky Very Large Array.
10
Mayo 2019

General relativity and extreme-mass-ratio binaries


Inicio: 12:15h
Ponente: ((ICE, CSIC/IEEC))
Lugar: Alberto Lobo Room

In this talk, I will give a broad and largely non-technical overview of general relativity and strong gravitational two-body systems, from the status of their theoretical modeling to their observation via gravitational waves. I will focus on the problem of modeling binaries with extreme mass ratios,…
Inicio: 12:15h
Ponente: ((ICE, CSIC/IEEC))
Lugar: Alberto Lobo Room

In this talk, I will give a broad and largely non-technical overview of
general relativity and strong gravitational two-body systems, from the
status of their theoretical modeling to their observation via
gravitational waves. I will focus on the problem of modeling binaries with
extreme mass ratios, an ongoing effort among theorists today with which
our group is actively involved, and which is needed for their future
observation, promising unique astrophysical information, with planned
space-based gravitational wave detectors such as LISA.
03
Mayo 2019

Outflows from young stars


Inicio: 12:15h
Ponente: Manuel Fernández-López (Instituto Argentino de Radioastronomía)
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Outflows are ubiquitous in star-forming regions. They are associated with accretion events and trace the rich chemistry produced by shocks and heating surrounding protostars. Protostellar outflows yield a turbulent feedback that can be of relevance in the Galactic energy budget. We carried out morphological…
Inicio: 12:15h
Ponente: Manuel Fernández-López (Instituto Argentino de Radioastronomía)
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Outflows are ubiquitous in star-forming regions. They are associated with accretion events and trace the rich chemistry produced by shocks and heating surrounding protostars. Protostellar outflows yield a turbulent feedback that can be of relevance in the Galactic energy budget. We carried out morphological studies toward outflows in low and high-mass star-forming regions. All of these works are part of an effort to derive information on the accretion, feedback, ejection mechanisms, and the dynamics of the launching protostars in nearby environments using detailed interferometric observations. We will make a brief review on the subject and show some of our most interesting and recent results. 
26
Abril 2019

The discovery of a comet fragment inside a meteorite provides clues about water delivery


Inicio: 12:15h
Ponente: Josep M. Trigo-Rodríguez
Lugar: Sala Alberto Lobo

In our Meteorite Microscopy Clean Room we have discovered the first cometary fragment found inside a meteorite, precisely in the CR2 carbonaceous chondrite LaPaz 02342. This finding demonstrates that the class of meteorites known as carbonaceous chondrites contains clues to the composition of more fragile…
Inicio: 12:15h
Ponente: Josep M. Trigo-Rodríguez
Lugar: Sala Alberto Lobo

In our Meteorite Microscopy Clean Room we have discovered the first cometary fragment found inside a meteorite, precisely in the CR2 carbonaceous chondrite LaPaz 02342. This finding demonstrates that the class of meteorites known as carbonaceous chondrites contains clues to the composition of more fragile objects that formed in regions distant from the Sun, about 4,560 million years ago. The chemical and isotopic evidence suggests that the clast was probably subjected to cosmic ray irradiation, and accreted into the asteroid preserving an ice mantle, so it demonstrates wet accretion. The results are published in the journal Nature Astronomy: http://dx.doi.org/10.1038/S41550-019-0737-8
12
Abril 2019

EoS in neutron stars - recent results on cooling and tidal deformabilities


Inicio: 12:15h
Ponente: Laura Tolos
Lugar: Sala Alberto Lobo

We present our recent results on cooling and tidal deformabilities of neutron stars using a recently developed hadronic equation-of-state (EoS) for the neutron star interior. The hadronic EoS is obtained from a phenomenological approach that reproduces the properties of nuclear matter and finite nuclei,…
Inicio: 12:15h
Ponente: Laura Tolos
Lugar: Sala Alberto Lobo


We present our recent results on cooling and tidal deformabilities of neutron stars using a recently developed hadronic equation-of-state (EoS) for the neutron star interior. The hadronic EoS is obtained from a phenomenological approach that reproduces the properties of nuclear matter and finite nuclei, while fulfilling the restrictions on high-density matter deduced from heavy-ion collisions, measurements of massive 2Msun neutron stars, and neutron star radii below 13 km. On the one hand, we perform cooling simulations and find that the cooling observations are compatible with a soft EoS close to saturation density, hence it generates small neutron star radii. However, our model favors large stellar masses, above 1.8Msun, to explain the colder isolated neutron stars that have been observed, even if nucleon pairing is present. On the other hand, we analyze the possibility of a phase transition leading to twin stars fulfilling the information following the gravitational-wave event GW170817. We find that the data from GW170817 could be interpreted as produced by the merger of a binary system of hybrid stars, or of a hybrid star with a neutron star. Indeed, our results seem to favor the presence of a hybrid star in the inspiral phase if future gravitational-wave detections measure chirp masses smaller than 1.2Msun and tidal deformabilities of 1.4 Msun less than 400.
 
05
Abril 2019

White dwarfs in the Gaia era


Inicio: 12:15h
Ponente: Alberto Rebassa Mansergas (Universitat Politècnica de Catalunya)
Lugar: Sala Alberto Lobo

The vast majority of stars will end, or have ended, their lives in the form of a white dwarf. These objects have the average size of the Earth, however they can be more massive than the Sun. This makes white dwarfs to be extremely dense and to have exceptional properties. In this talk we will study the…
Inicio: 12:15h
Ponente: Alberto Rebassa Mansergas (Universitat Politècnica de Catalunya)
Lugar: Sala Alberto Lobo

The vast majority of stars will end, or have ended, their lives in the form of a white dwarf. These objects have the average size of the Earth, however they can be more massive than the Sun. This makes white dwarfs to be extremely dense and to have exceptional properties. In this talk we will study the physical characteristics of these exotic objects and we will see how the data provided by the Gaia satellite is helping us to significantly increase our understanding of white dwarfs.
 
22
Marzo 2019

Does the size matter?: The case of HH80-81 disk


Inicio: 12:15h
Ponente: Nacho Añez López (Institut de Ciències de l'Espai (CSIC-IEEC))
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Understanding how high-mass stars form and evolve is one of the hot topics in astrophysics, due to the high impact that these objects have in the life of a galaxy. It is well known that low-mass stars are formed through an accretion disk which transport gas and dust from the envelope of the system…
Inicio: 12:15h
Ponente: Nacho Añez López (Institut de Ciències de l'Espai (CSIC-IEEC))
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Understanding how high-mass stars form and evolve is one of the hot topics in astrophysics, due to the high impact that these objects have in the life of a galaxy. It is well known that low-mass stars are formed through an accretion disk which transport gas and dust from the envelope of the system to the protostar. HH80-81 seems to be very similar to the disk-jet systems found in low- and intermediate-mass protostars presenting a highly collimated and well-defined jet, a compact dust disk clearly perpendicular to the jet and possible rotating motions of the molecular gas around the massive protostar. The linear polarization of the dust emission is detected almost all along the disk, and its properties suggest that dust polarization is produced mainly by selfscattering. Polarization characteristic suggest that dust settling has not occurred yet with a maximum dust grain size between 50 and 500 microns. We applied disk models that have been successfully explained disks around low-mass prototstars as those developed by D'Alessio et al. (2001, 2006). These models satisfactorily explain the ALMA image at 1.14 mm with a massive central object (~20 Msun) and a massive disk (~7 Msun). The models shows that in first approximation the high-mass star formation process seems to be a scale up version of the low-mass star-formation scenario.
Institute of Space Sciences (IEEC-CSIC)

Campus UAB, Carrer de Can Magrans, s/n
08193 Barcelona.
Phone: +34 93 737 9788
Email: ice@ice.csic.es
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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