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Anonymous (not verified) Prova Ariadna ICCUB ariadna@icc.ub.edu abstract
Anonymous (not verified) Pealing off layers of data contamination when measuring the 3D galaxy power spectrum Benedict Kalus ICCUB benedict.kalus@icc.ub.edu I consider techniques to remove contaminants when calculating the 3D galaxy power spectrum. The commonly used naïve template subtraction technique estimates the power spectrum quickly but in a biased way. The mode deprojection scheme is designed to give an unbiased power spectrum, but it requires huge costly matrix operations. Prior to normalisation, template subtraction and mode deprojection yield identical results. I, therefore, argue that one can remove contaminants from the 3D galaxy power spectrum using template subtraction, and then remove the bias either using the normalisation of
the quadratic maximum likelihood (QML) estimator as one would do for mode deprojection, or to use a new and computationally cheaper method that is an extension to the FKP estimator and also debases the power
spectrum estimate, but slightly increases the error bars by not weighting each mode optimally. However, the increase of the error is small in the test cases that we analyse and is less severe than many
other sub-optimal assumptions commonly employed. I show how this can be applied to the systematic contaminants in BOSS galaxy data.
Anonymous (not verified) Type Ia Supernovae: The Search for the Progenitors Carles Badenes University of Pittsburgh / ICCUB badenes@pitt.edu Type Ia Supernovae are still the best standard candles for the measurement of cosmological distances, but the precise nature of their stellar progenitors remains a mystery. While we are reasonably sure that the exploding star is a white dwarf composed of carbon and oxygen, the mechanism by which this star becomes unstable and explodes has never been established. I will review the current observational evidence on Type Ia SN progenitors, the challenges in this field, and a few recent advances.
Anonymous (not verified) Core-crust transition and crustal properties in neutron stars Claudia Gonzalez Boquera University of Barcelona, ICCUB claugb@fqa.ub.edu An accurate determination of the core-crust transition is necessary in the modelling of neutron
stars for astrophysical purposes. The properties of the core-crust transition are
intimately related to the isospin dependence of the nuclear force at low baryon densities.
We obtain the core-crust transition density, asymmetry and pressure
by studying the thermodynamical stability of the core.
Next, we analyze the correlation of these transition properties with the
slope of the symmetry energy associated to the nuclear equation of state.
Finally, we integrate the Tolman-Oppenheimer-Volkov equations in order to
obtain the relation between the neutron star masses and radii.
Knowing the core-crust transition point,
we are also able to predict the mass, thickness and moment of inertia of the neutron star crust.
Anonymous (not verified) prova esther esther ICCUB estpallgui@icc.ub.edu Hola que tal
Anonymous (not verified) Gravitational waves and the nature of spacetime Gustavo E. Romero IAR, CONICET gustavo.esteban.romero@gmail.com Gravitational waves are a natural prediction of General Relativity. The direct detection of these waves has been a major confirmation that the theory can make accurate predictions in the strong gravity regime. In this talk I will review some of the implications of this discovery for the hypothesis that spacetime is a real entity.
Anonymous (not verified) TBD Lluis Mas Ribas University of Oslo lluismasribas@gmail.com TBD
Anonymous (not verified) The Connection Between Galaxies and the Intergalactic Medium Lluis Mas Ribas University of Oslo lluismasribas@gmail.com The evolution of galaxies and the large-scale intergalactic medium go hand in hand due to their interaction, which takes place in a region around galaxies called circumgalactic medium. I will present new approaches for probing this region, and how we can extract valuable information from it to reveal some cosmic properties across the history of our Universe.
Anonymous (not verified) Entanglement and squeezing of one and two impurities in a BEC M.A. García-March ICFO – Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spai garciamarchma@gmail.com Quantum Brownian motion represents a paradigmatic model of complex quantum system. It describes the dynamics of a quantum particle coupled to a bath made up by a huge number of harmonic oscillators. We employ such a model to investigate the physics of one impurity and two distinguishable impurities embedded in a Bose-Einstein condensate (BEC). The case of one particle resembles that of the Bose polaron and has been recently realized in experiments. In an open quantum system context the impurity plays the role of the Brownian particle and the bath is constituted by the Bogoliubov excitations of the condensate. We show that the motion of the impurity is described by means of a Langevin quantum equation, with a time non-local damping, i.e. carrying a certain amount of memory effects. We solve this stochastic equation for the case in which the impurity is trapped and the BEC is homogeneous. We find genuine position squeezing, i.e. the impurity position variance takes values lower than that imposed by the Heisenberg principle. This effect occurs at low temperatures and is enhanced by the strength of the interactions between the impurity and the BEC. We find the regimes of experimentally realistic parameters in which the model is valid and these effects can be observed. We also study a system of two distinguishable impurities in independent traps embedded in a BEC. We evaluate first how the impurity position variance is affected by the presence of the second impurity. We discuss the entanglement between the two impurities that occurs as a consequence of their independent interaction with the BEC. We detail how this entanglement depends on the distance between their traps, interactions, temperature, trapping frequency etc.
Anonymous (not verified) GGD 27 MM1: is it an archetype of an accretion disk around a massive YSO? Nacho Añez Institut de Ciències de l'Espai anyez@ice.csic.es The massive star forming region GGD27(IRAS -181622048) is located at a distance of 1.7Kpc. It shows the spectacular and highly collimated radio jet known, HH 80-81-80N, with is powered by a massive (early B-type) protostar. We have found for first time evidences of the presence of an accretion disk surrounding the massive protostar, through (sub)millimetre high-angular resolution interferometric observations. HH80-81 represents a unique case showing that high-mass protostar form through an accretion disk.
We modeled accretion disk around massive protostar GGD27 MM1 using the irradiated Alpha-acretion disk models with dust settling developed by D’Alession et al. 2006 and updated latter in Osorio et al 2016. In this model the temperature and density structure is calculated self-consistently and the main heating sources are stellar irradiation and viscous dissipation.
By comparing the models with high angular resolution observation at 1.1 mm with ALMA we find a very massive disk, what could mean that relationship between stellar and disk mass is different in massive stars.
We found significant substructure in the disk. Here, we compare these substructures with the ones found in low mass disks.
Anonymous (not verified) Primordial Black Holes in Cosmology Nicola Bellomo ICCUB nicola.bellomo@icc.ub.edu The model in which Primordial Black Holes (PBHs) constitute a non-negligible fraction of the dark matter has (re)gained popularity after the first detections of binary black hole mergers. Most of the observational constraints to date have been derived assuming a single mass for all the PBHs, although some more recent works tried to generalize constraints
to the case of extended mass distributions (EMD). In this talk we present a general methodology to obtain constraints for any PBHs EMD and any observables in the desired mass range, starting from those obtained for a monochromatic distribution. We apply this methodology to the study of PBHs effects on the cosmic microwave background in order to put constraints on the fraction of dark matter in PBHs, not only for monochromatic PBH mass distributions but also for popular EMD. Finally we present a way to discriminate if BHs progenitors has primordial or stellar origin by using galaxy surveys.
Anonymous (not verified) Mass-loading and non-thermal emission from AGN jets interacting with stellar populations Núria Torres-Albà Universitat de Barcelona (ICCUB) ntorres@fqa.ub.edu
Supermassive blackholes, present in the innermost regions of galaxies, may accrete the material surrounding them, becoming AGN. Some AGN produce jets, which propagate through the complex environment characteristic of the central regions of the host galaxy. This may lead to the jet interacting with a variety of obstacles; including stars, gas and dense clouds. These interactions may affect the jet dynamically, mass-loading and even decelerating it. In addition, when the jet collides with the obstacles, a shock is formed in which particles can be accelerated to relativistic speeds, emitting non-thermal high-energy radiation, potentially detectable for nearby sources.
Anonymous (not verified) Breaking of Translational Invariance in AdS/CFT Tomas Andrade University of Barcelona tandradew@gmail.com Motivated by applications to condensed matter physics, we introduce breaking of translational invariance in the context of AdS/CFT. On the gravity side,
this entails constructing black branes solutions which are not homogeneous along the directions parallel to the brane. We discuss some applications
such as the presence of holographic phonons and the appearance of metal-insulator transitions.
Anonymous (not verified) Open Clusters in the Milky Way with Gaia Tristan Cantat-Gaudin ICCUB tcantat@fqa.ub.edu Open Clusters are convenient tracers of the properties and structure of the Milky Way, because their ages and distances can be estimated more easily than individual stars. The upcoming second data release of the Gaia mission will provide data of unprecedented quality for more than a billion stars, enabling us to better characterise stellar clusters and to discover new ones, providing more insight on the history and structure of our Galaxy.