Past Pizza Lunches

Número de entradas: 155

19
Octubre 2018

Primordial black hole formation and abundance: dependence on the shape of the inflationary power spectrum


Inicio: 12:15h
Ponente: Ilia Musco (Institut de Ciències del Cosmos (ICCUB))
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

Primordial black holes can form in the early Universe from the collapse of cosmological perturbations after the cosmological horizon crossing. They are possible candidates for the dark matter as well as for the seeds of supermassive black holes observed today in the centre of galaxies. In calculations…
Inicio: 12:15h
Ponente: Ilia Musco (Institut de Ciències del Cosmos (ICCUB))
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

Primordial black holes can form in the early Universe from the collapse of cosmological perturbations after the cosmological horizon crossing. They are possible candidates for the dark matter as well as for the seeds of supermassive black holes observed today in the centre of galaxies. In calculations of spherically symmetric collapse, using a large curvature perturbation in the super horizon regime, the initial conditions are specified using the gradient expansion approximation in the long wave length limit. The non linear evolution is then simulated using a Lagrangian relativistic hydrodynamical code. If the perturbation is larger than  a threshold depending on the equation of state and on the specific shape of the perturbation, a black hole is formed. In this talk I will discuss the dependence of PBH formation from the initial shape of the curvature profile showing the relation between the threshold amplitude and the steepness of the perturbation which is linked to the amplitude of the pressure gradients that are developing during the collapse. I will show how to derive the initial curvature profile form the shape of the inflationary power spectrum, which affects also the abundance of PBHs. Depending on the model, a proper calculation, using the shape of the power spectrum, shows that the abundance of PBHs is significantly increased by several order of magnitudes compared to previous estimations.
05
Octubre 2018

Bouncing cosmology from warped extra dimensional scenario


Inicio: 12:00h
Ponente: Tanmoy Paul (Indian Association for the Cultivation of Science (IACS))
Lugar: Alberto Lobo

From the perspective of four dimensional effective theory on a two brane warped geometry model,  we examine the possibility of "bouncing phenomena'' on our visible brane. Our results reveal that the presence of warped extra dimension lead to a non-singular bounce on the brane scale factor…
Inicio: 12:00h
Ponente: Tanmoy Paul (Indian Association for the Cultivation of Science (IACS))
Lugar: Alberto Lobo

From the perspective of four dimensional effective theory on a two brane warped geometry model,  we examine the possibility of "bouncing phenomena'' on our visible brane. Our results reveal that the presence of warped extra dimension lead to a non-singular bounce on the brane scale factor and hence can remove the "big-bang singularity''. We also examine the possible parametric regions for which this bouncing is possible.
29
Junio 2018

The Halo-Galaxy connection and how to model it


Inicio: 12:15h
Ponente: Ismael Ferrero (ICE)
Lugar: Alberto Lobo

I will present the results after analysing the ability of the standard cold dark matter model with cosmological constant (ΛCDM) to reproduce observational results of the dynamics of galaxies. Using rotation curves of dwarf galaxies compiled from the literature, it is shown that the galaxy formation…
Inicio: 12:15h
Ponente: Ismael Ferrero (ICE)
Lugar: Alberto Lobo

I will present the results after analysing the ability of the standard cold dark matter model with cosmological constant (ΛCDM) to reproduce observational results of the dynamics of galaxies. Using rotation curves of dwarf galaxies compiled from the literature, it is shown that the galaxy formation efficiency represents a severe challenge at the low stellar mass of dwarf galaxies for this prevailing cosmological model. I will also show what is the process of creating a synthetic catalogs of galaxies through the implementation of the halo occupation distribution (HOD) in cosmological simulations, an efficient way to model the halo-galaxy connection.
22
Junio 2018

Radial velocities of cool stars with rocky planets


Inicio: 12:15h
Ponente: Manuel Perger
Lugar: Sala Alberto Lobo

We are already able to detect potentially habitable, rocky planets with the precision of modern Doppler spectroscopy. At least if they orbit a low-mass star. In this domain however, magnetic phenomena of the host star affect the measurements and are even able to hide and mimic a true planetary signal.…
Inicio: 12:15h
Ponente: Manuel Perger
Lugar: Sala Alberto Lobo

We are already able to detect potentially habitable, rocky planets with the precision of modern Doppler spectroscopy. At least if they orbit a low-mass star. In this domain however, magnetic phenomena of the host star affect the measurements and are even able to hide and mimic a true planetary signal. A challenge in modern radial velocity planet searches is therefore the understanding of the different stellar contributions. In this talk I will explain how we measure and obtain high-precision radial velocities and how we can disentangle the different origins. With this focus, I will discuss the recent findings of exoplanets like GJ 3998b,c, GJ 3942b, and will give previews on my recent research target.
15
Junio 2018

Using the environment to infer supernova progenitor properties


Inicio: 12:15h
Ponente: Lluís Galbany (Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT PACC). Physics and Astronomy Department, University of Pittsburgh)
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

Integral Field Spectroscopy (IFS) applied to supernova (SN) environmental studies have shown the potential of this technique to directly characterize the galactic environmental parameters at SN locations, compare them to those at different locations of the galaxy, and put constraints on progenitor stars…
Inicio: 12:15h
Ponente: Lluís Galbany (Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT PACC). Physics and Astronomy Department, University of Pittsburgh)
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

Integral Field Spectroscopy (IFS) applied to supernova (SN) environmental studies have shown the potential of this technique to directly characterize the galactic environmental parameters at SN locations, compare them to those at different locations of the galaxy, and put constraints on progenitor stars for different SN types. Here, I will summarize current efforts from the PISCO compilation, Hi-KIDS, and the AMUSING survey, that have put together more than 500 SN hosts observed with IFS, and give details about published results from these 3 datasets.
08
Junio 2018

Unveiling a cluster of protoplanetary disks around the massive protostar GGD27 MM1


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

Most stars, including our Sun, form in clusters embedded within molecular clouds. It is then important to characterize the protostellar disk population in dense environments to assess whether the environment plays a role in the subsequent evolution; specifically whether planet formation is altered with…
Inicio: 12:15h
Ponente: Gemma Busquet (Institut de Ciencies de l'Espai (CSIC-IEEC))
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

Most stars, including our Sun, form in clusters embedded within molecular clouds. It is then important to characterize the protostellar disk population in dense environments to assess whether the environment plays a role in the subsequent evolution; specifically whether planet formation is altered with respect to more isolated stars formed in dark clouds. In this talk, I’ll present ALMA observations at 1.14 mm towards the high-mass star-forming region GGD27, which harbors a B0-type young stellar object and it is surrounded by a cluster of infrared sources. The unprecedented angular resolution (40 mas) and sensitivity provided by ALMA has brought us to the serendipitous discovery of a cluster of disks from low-mass protostars in the vicinity of the massive protostar GGD27 MM1. I’ll present the properties of the disk population of the GGD 27 cluster and a comparison with the findings reported from nearby regions forming stars in isolation. 
01
Junio 2018

e-XTP: a near-future China-EU mission for X-ray timing and polarization


Inicio: 12:15h
Ponente: Margarita Hernanz Carbó
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

The enhanced X-ray Timing and Polarimetry mission (eXTP) is a China-led science space mission designed to study the state of matter under extreme conditions of density, gravity and magnetism. Its predicted launch date is 2025. eXTP will carry a unique and unprecedented suite of state-of-the-art instruments,…
Inicio: 12:15h
Ponente: Margarita Hernanz Carbó
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

The enhanced X-ray Timing and Polarimetry mission (eXTP) is a China-led science space mission designed to study the state of matter under extreme conditions of density, gravity and magnetism. Its predicted launch date is 2025. eXTP will carry a unique and unprecedented suite of state-of-the-art instruments, enabling for the first time ever the simultaneous spectral-timing-polarimetry studies of cosmic sources in the energy range from 0.5 to 30 keV. In addition to science contributions (previous LOFT and XIPE teams), at ICE we are leading the Wide Field Monitor instrument, which is the Spanish instrumental contribution to eXTP. I will explain the main scientific goals of the mission and its instrumentation, as well as our contribution to the payload. The current status of the mission (extended Phase A) and its forthcoming phases and scheduling details will be presented as well.
25
Mayo 2018

Radial velocities of cool stars with rocky planets


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

We are already able to detect potentially habitable, rocky planets with the precision of modern Doppler spectroscopy. At least if they orbit a low-mass star. In this domain however, magnetic phenomena of the host star affect the measurements and are even able to hide and mimic a true planetary signal.…
Inicio: 12:15h
Ponente: Manuel Perger (Institut de Ciencies de l'Espai (CSIC-IEEC))
Lugar: Sala Alberto Lobo (ICE building, Campus UAB)

We are already able to detect potentially habitable, rocky planets with the precision of modern Doppler spectroscopy. At least if they orbit a low-mass star. In this domain however, magnetic phenomena of the host star affect the measurements and are even able to hide and mimic a true planetary signal. A challenge in modern radial velocity planet searches is therefore the understanding of the different stellar contributions. In this talk I will explain how we measure and obtain high-precision radial velocities and how we can disentangle the different contributions. With this focus, I will discuss in length the recent findings of exoplanets like Proxima Centauri b, GJ 3998b,c, GJ 3942b, and will give previews on my recent research target. 
18
Mayo 2018

Sniffing Alien Atmospheres: Exoplanet spectrophotometry (from ground-, airborne- and space-based observatories)


Inicio: 12:15h
Ponente: Angerhausen, Daniel (Center for Space and Habitability (CSH), Bern University, Switzerland)
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

In my presentation I will give a short introduction to the science of extrasolar planets, in particular the technique of transit, eclipse and phasecurve spectro-photometry.  I will describe my various projects in this emerging field using state of the art spectroscopic and photometric instruments on…
Inicio: 12:15h
Ponente: Angerhausen, Daniel (Center for Space and Habitability (CSH), Bern University, Switzerland)
Lugar: Alberto Lobo Seminar Room (ICE, UAB Campus)

In my presentation I will give a short introduction to the science of extrasolar planets, in particular the technique of transit, eclipse and phasecurve spectro-photometry.  I will describe my various projects in this emerging field using state of the art spectroscopic and photometric instruments on the largest ground based telescopes, the 'flying telescope' SOFIA (Stratospheric Observatory for Infrared Astronomy) and the Kepler and Hubble space telescopes.
11
Mayo 2018

The PAU data management: from observations to science ready data


Inicio: 12:15h
Ponente: Santiago Serrano Elorduy (ICE-CSIC)
Lugar: Alberto Lobo

The data reduction of a large galaxy survey can be complex to design and orchestrate, due to its large dataset and a delicate calibration. In this talk I will explain the process that happens to the Physics of the Accelerating Universe (PAU) data, from the observations at the William Herschel Telescope…
Inicio: 12:15h
Ponente: Santiago Serrano Elorduy (ICE-CSIC)
Lugar: Alberto Lobo

The data reduction of a large galaxy survey can be complex to design and orchestrate, due to its large dataset and a delicate calibration.
In this talk I will explain the process that happens to the Physics of the Accelerating Universe (PAU) data, from the observations at the William Herschel Telescope up to the final calibrated catalogues of galaxies used by the scientists in the collaboration to perform the cosmological analysis.
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