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Anonymous (not verified) Hunting massive relic galaxies Anna Ferré-Mateu ICCUB aferremateu@icc.ub.edu It is assumed that massive galaxies grow in a two-phase formation mode, where a superdense compact massive core is formed very rapidly and violently up to z~2 (red nugget) and then it grows in size by adding material at its outskirts via merging events, becoming the large elliptical galaxies we see nowadays. However, because mergers are stochastic events, some of these red nuggets managed to skip the second phase of formation. Dubbed as massive relic galaxies, they have remained like frozen in time since z~2 and thus constitute a direct window into the properties of the early epochs of the Universe. However, their predicted number are scarce (0.01% of today's population) and only a handful of them have been confirmed to date.
In this talk I will summarise the quest to find these elusive relic galaxies and will explore the intriguing properties they show.
Anonymous (not verified) Title: Solar Energetic Particle events: Modelling and Prediction Angels Aran Departament de Física Quàntica i Astrofísica angels.aran@fqa.ub.edu European Union countries are jointly (and lately also individually) working towards developing an infrastructure for the monitoring and prediction of space weather. This includes the study of solar energetic particle (SEP) events, with the ultimate goal of predicting the particle radiation in the interplanetary space, and particularly at near-Earth environment. The most important contribution to radiation doses comes from protons > 10 MeV, although ions > 1 MeV/nuc may traverse typical shielding. About 100 SEP events with > 10 MeV protons are produced per solar cycle, and < 10 large events occur with fluences accounting for a significant fraction of the solar cycle's accumulated fluence.

Solar activity producing SEP events are mainly coronal mass ejections (CMEs) and flares, being the former the main sources in large events. Three-dimensional magnetohydrodynamic models describing the propagation of interplanetary (IP) shocks driven by CMEs are routinely run to estimate IP shocks arrivals at Earth. The combination of such models with SEP models of particle acceleration and transport is a hot topic in heliophysics and it is the necessary step to be undertaken for the forecasting of large SEP events in near-real time. The main difficulty is that the current knowledge of the mechanisms involved in the generation of these SEP events is not complete yet, rendering the prediction of individual SEP events difficult. However, first attempts are currently being developed. In addition to the models describing SEP events episodes, particle radiation models are used to estimate the accumulated fluence, maximum intensity and worse case scenarios that interplanetary missions may encounter during their orbits. These models are based on the statistical treatment of SEP data measured during the last 40 years, and they make assumptions on the variation of the SEP event size with the heliocentric radial distance from the Sun.

We present here the SEP models and prediction tools being developed in the Heliospheric Physics and Space Weather Group in collaboration with different European groups.
Anonymous (not verified) IRDC G14.2.UNRAVELING THE ROLE OF THE MAGNETIC FIELD. Nacho Añez-López Institut de ciències de l'espai (ICE-CSIC) anyez@icc.ub.edu The detailed process of the fragmentation of a high-mass core to form a cluster is not well understood yet, and important ingredients competing with gravity like turbulence, angular momentum, magnetic fields, and stellar feedback, must play an important role. In this work we aim to test the possibility that magnetic fields play a significant role in the fragmentation of gravitationally unstable cores. To do so, we have selected two prominent hubs in the IRDC G14.2. The physical properties of the two cores appear to be quite similar. However, they show a clear different level of fragmentation. We intend to estimate the importance of the magnetic field using the method developed by Koch et al. 2012 and thus understand the role of the magnetic field in the process of fragmentation.
Anonymous (not verified) Symmetry energy : From finite nuclei to neutron stars Chiranjib Mondal ICCUB chiranjib.mondal@icc.ub.edu Symmetry energy and specially its density dependence has been a major focus of research in modern day nuclear physics.
In this talk, I will try to give a simplistic overview how it plays a significant role in determining different
quantities of finite nuclei and neutron stars.
Anonymous (not verified) Cloud computing for research Carme Pineda Teixidó University of Barcelona cpineda@ub.edu Everyone has heard about cloud computing, and all of us have used one of the services offered by cloud computing: email, buy Amazon, share a google drive ... in this talk I'll explain to you The main reasons why it is recommended to use cloud computing for research, which are the main providers that offer cloud computing services and what is the IaaS framework agreement signed by GÉANT at European level.
Anonymous (not verified) Cloud Computing for reserach Carme Pineda Teixidó University of Barcelona cpineda@ub.edu Everyone has heard about cloud computing and all of us may have use it when we sent an email, bought something on Amazon or shared a Google Drive document. In this talk I will expose the main reasons why cloud computing is recommended for doing research, which are its main providers and what is the IaaS framework agreement signed by GÉANT at European level.
Anonymous (not verified) cosmology with massive neutrinos David Valcin ICCUB d.valcin@icc.ub.edu Massive neutrinos are a realy good probe of the beyond standard model physics. Cosmology is a valuable asset to measure or constrain their absolute mass. Before you take advantage of the information provided by this new physics, we need to rethink the current state of analysis to include massive neutrinos.
Anonymous (not verified) Dealing with systematics in next-generation galaxy surveys: DESI and the problem of missing observations Davide Bianchi ICC davide.bianchi@icc.ub.edu The forthcoming Dark Energy Spectroscopic Instrument (DESI) survey will provide us with an unprecedented wealth of cosmological information. For this information to be properly extracted, all possible systematic effects must be kept under control. I will briefly introduce the DESI survey and show how to circumvent one of its most critical sources of systematics: the problem of missing observations.
Anonymous (not verified) Stochastic approach to inflation and its faliure beyond slow-roll. Diego Cruces. ICCUB dcrucema7@icc.ub.edu After giving a pedagogical review of stochastic approach to inflation, I will clarify that this approach is generically reliable only at zeroth order in the (geometrical) slow-roll parameter ε1 if and only if ε1≪6/ε2, with the notable exception of slow-roll. This is due to the failure of the separate universe approach. As a byproduct, by keeping the formalism in its regime of validity, we show that quantum diffusion in ultra-slow-roll might only contribute to the power spectrum at sub-leading orders in slow-roll, and thus, it is irrelevant.

After giving a pedagogical review we clarify that the stochastic approach to inflation is generically valid only at zeroth order in the (geometrical) slow-roll parameter ε1 if and only if ε1≪6/ε22, with the notable exception of slow-roll. This is due to the failure of the separate universe approach. As a byproduct, by keeping the formalism in its regime of validity, we show that quantum diffusion in ultra-slow-roll might only contribute to the power spectrum at sub-leading orders in slow-roll, and thus, it is irrelevant
Anonymous (not verified) New involvement of ICCUB in international collaborations D. Gascon, J. Portell ICCUB dgascon@fqa.ub.edu The ICCUB has recently joined international collaborations as Virgo, IAXO and HERD. We will introduce the projects and we will describe the technological contributions of the ICCUB.
Anonymous (not verified) The effects of the stellar wind on the jets of high-mass microquasars Edgar Molina Universitat de Barcelona / ICCUB emolina@fqa.ub.edu High-mass microquasars (HMMQ) are X-ray binaries that host a massive star and a compact object (CO) from which jets are produced. In these systems, the stellar wind from the companion star can significantly influence the jet propagation, both because the jet has to propagate through a dense medium filled with wind material, and because the wind impact on the jet may deviate it away from the star. I will present a review on different numerical and analytical approaches performed so far in order to model the jet-wind interaction in HMMQ. I will specially focus in a semi-analytical model that we have recently developed to study the large scale effects of this interaction combined with the orbital motion, both from a hydrodynamical and a radiative point of view. To conclude, I will also mention some aspects of an ongoing work that will explore the jet-wind interaction at the binary system scale.
Anonymous (not verified) Gravitational waves and fundamental physics Roberto Emparan ICREA+ICCUB emparan@ub.edu I will present an overview of what we can learn about fundamental physics from upcoming observations of gravitational waves
Anonymous (not verified) Testing Dark Energy using spectroscopic galaxy surveys: BAO and RSD Hector Gil Marin ICCUB hectorgil@icc.ub.edu In this talk I will review the state-of-the-art techniques for measuring the expansion of the Universe using massive spectroscopic galaxy surveys datasets, focusing on the Baryon Acoustic Oscillation (BAO) and Redshift Space Distortion (RSD) techniques. I will also present the most relevant results from BOSS and eBOSS surveys, and the forecasts for upcoming surveys Euclid and DESI.
Anonymous (not verified) On $K^-NN$ absorption in nuclear medium J. Hrtankova, A. Ramos NPI Rez and University of Barcelona hrtankova@ujf.cas.cz In this contribution we report on our recent study of $K^-NN$ absorption in nuclear matter. We have developed a microscopical model describing the $K^-N$ and $K^-NN$ absorption in the medium using two-body $K^-N$ amplitudes derived from chiral meson-baryon interaction model. We take into account the in-medium modifications of the chiral amplitudes and study their effect on the total $K^-$ potential. We aim to confront our model with new experimental data published recently by AMADEUS collaboration [1,2] as well.

The importance of $K^-$ absorption on two or more nucleons in the medium was shown in previous self-consistent calculations of $K^-$ quasi-bound states in nuclear many-body systems [3,4]. In the calculations, the single-nucleon $K^-$ optical potential developed within several chiral meson-baryon coupled-channel interaction models was supplemented by a phenomenological potential representing $K^-$ multinucleon interactions. The multinucleon potential was fitted to kaonic atom data for each chiral $K^-N$ amplitude model separately and the total $K^-$ potential was further confronted with branching ratios of $K^-$ absorption at rest from bubble chamber experiments [5]. The resulting $K^-$ widths were considerablylarger than corresponding binding energies and the main contribution to the total $K^-$ width came from the multinucleon absorption.

[1] K. Piscicchia et al., Phys. Lett. B 782 (2018) 339.
[2] R. Del Grande et al., arXiv:1809.07212 [nucl-ex] (2018).
[3] J. Hrtankova, J. Mares, Phys. Lett. B 770 (2017) 342.
[4] J. Hrtankova, J. Mares, Phys. Rev. C 96 (2017) 015205.
[5] E. Friedman, A. Gal, Nucl. Phys. A 959 (2017) 66.
Anonymous (not verified) Exploring New Physics with Neutrinos Jordi Salvado Universitat de Barcelona jsalvado@icc.ub.edu In this talk I will show how neutrinos can be used to probe New Physics in different scenarios. In the second part I will present some concrete results using data from IceCube, and finally I will show the fist tomography of the planet Earth with neutrinos.
Anonymous (not verified) On robust aspects of the out-of-equilibrium dynamics Luca Tagliacozzo ICCUB luca.tagliacozzo@fqa.ub.edu In this talk I will discuss about the possible existence of robust phenomena out-of-equilibrium and the design of approximate methods able to unveil them in the context of 1D quantum-many-body systems.

Anonymous (not verified) Photons, neutrinos and cosmic rays from AGNs Matteo Cerruti ICCUB matteo.cerruti@icc.ub.edu The origin of ultra-high-energy cosmic-rays remains one of the most important open questions in astrophysics. Active galactic nuclei (AGNs), the observational effect of accretion of matter onto super-massive black-holes, have long been considered a prime candidate for cosmic-ray acceleration. A powerful tool to investigate the sources of cosmic rays is multi-messenger astronomy: if cosmic rays are accelerated in AGNs' jets, they interact with low-energy photons producing mesons which then decay to photons, leptons and neutrinos. The joint detection of photons and neutrinos from an AGN will thus represent the fingerprint of cosmic ray acceleration in the source. On 09/22/2017, IceCube and the gamma-ray instruments Fermi-LAT and MAGIC, observed the first evidence (at the 3 sigma level) of co-production of photons and neutrinos from the AGN TXS 0506+056. For the first time, theoretical models of hadronic emission from AGNs can thus be tested on both messengers. In this talk, I will briefly introduce the detection of IceCube-170922A / TXS0506+056, and the hadronic emission models. Then I will present a review of the studies on the modeling and interpretation of this unique event, showing the capability of multi-messenger campaigns to elucidate acceleration and emission mechanisms in AGNs jets.
Anonymous (not verified) Gaia data triggers the need for complex warp kinematic models Merce Romero-Gomez ICCUB-IEEC mromero@fqa.ub.edu In this talk we show the results from analyzing the kinematics of two different populations extracted from the Gaia Data Release 2, namely a young bright sample mainly formed by OB stars and another from the Red Giant Branch stars. We use two different, but complementary methods based on the Gaia observables, positions and proper motions, to extract the space and kinematic characteristics of the Galactic warp. We also relate our results with the ones from other related works on the Galactic warp found in the literature that use Gaia Data Release 2 data.
Anonymous (not verified) Ultracold atoms in confined geometries: a new tool for atom-based quantum technologies. M. Guilleumas Departament de Física Quàntica i Astrofísica, Facultat de Física i Institut de Ciències del Cosmos, Universitat de Barcelona. muntsa@fqa.ub.edu Recent advances in the preparation and control of ultracold atomic gases have fostered the appearence of the new field of atomtronics. It aims at producing the basic tools to develop quantum technologies with ultracold atoms confined by laser fields of different shapes and intensities.
The idea is to mimic the field of electronics with atomic devices, where the carriers instead of electrons are neutral atoms. The analog of electronic circuits are coupled primary atomtronic circuits capable of producing complex applications. For instance, transfer of quantum properties between diferent parts of the system or production of entangled states.
Atom-based quantum devices may be used to simulate intricate quantum systems, to develop finer sensors and to devise platforms for new routes to quantum technology.
Anonymous (not verified) Modeling dark matter halo substructure with the CUSP formalism. Ignacio Botella Lasaga UB nachobotella@ub.edu The ConflUent System of Peak trajectories (CUSP) is a rigorous analytic formalism allowing one to accurately recover the typical structural and kinematic properties of DM halos in hierarchical cosmologies. This is done by monitoring the ellipsoidal collapse and virialization (through shell-crossing) of their seeds, i.e. peaks in the initial Gaussian random field of density perturbations. In this talk I will show that CUSP also allows one to model halo substructure. Specifically, taking into account the statistics of peaks nested within other peaks, one can derive the properties of subhalos accreted onto halos and, by monitoring their tidal stripping by the halo potential well, one can reproduce the abundance and spatial distribution of stripped subhalos. In this way we recover the observed trends of halo substructure found in simulations and reveal the origin of the three conditions shown by Han et al. (2016) to explain such trends.
Anonymous (not verified) Primordial Black Holes with very small masses: Interactions with main sequence stars Marc Oncins Fernández Universitat de Barcelona (ICCUB) oncins@icc.ub.edu One of the most mysterious and abundant components of the current known universe is the so called Dark Matter. While we usually resort to physics beyond the Standard Model and new particles as possible explanations for it, we may not need to do so at all. Black Holes formed during or after inflation (thus "primordial") could end up being the majority of the Dark matter, thus solving the issue with already well known physics.

After the discovery of gravitational waves by LIGO, there's been a lot of focus on Intermediate Mass Black Holes of more than 10 solar masses, and after various tests it is currently believed they could not make up more than 1% of the DM. However, as different experiments continue to probe these possibilities, one window in much smaller masses still remains. PBHs of masses around 1 pico solar mass are small enough to not have any noticeable dynamical effect, while their size makes most lensing experiments ineffective. Thus, they could still make up the entirety of DM.

One of the few ways in which such a small objects could be probed would be in their capture by bigger astrophysical objects, in particular by main sequence stars. In this talk we will show how such interactions would work, including the approximate chances of capture, what would happen to the star afterwards and how we might observe the results.
Anonymous (not verified) Gaia as the Storyteller of the star formation history of the Milky Way disc Roger Mor Dept. Física Quàntica i Astrofísica, Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí Franquès 1, E080 rmor@fqa.ub.edu We developed a new theoretical framework, the Besançon Galaxy Model Fast Approximate Simulations (BGM FASt), that combined with approximate Bayesian computation techniques allows us to address fundamental questions of the Galactic structure and evolution performing multi-parameter inference. Here we use Gaia DR2 magnitudes, colours and parallaxes for stars with G<12 to explore a 15-dimensional space that includes simultaneously the stellar initial mass function (IMF) and a non-parametric star formation history (SFH) for the Milky Way disc. We find in Gaia DR2 data an imprint of a star formation burst in the Galactic thin disc region 2-3 Gyr ago and a present SFR of 1Msun/yr. Our results show a decreasing trend of the star formation rate (SFR) from 10 Gyr to about 6 Gyr ago that is consistent with the behaviour of the cosmological star formation quenching. This decreasing trend is followed by a SFR enhancement detected during a period from 5 Gyr to 1 Gyr ago. We estimate, from our best fit model, that about the 50% of the stellar mass of the Galactic thin disc was formed during this period. The timescale and the amount of stellar mass generated during the SFR enhancement event leads us to hypothesise that its origin is not intrinsic to the disc and that an external perturbation would be needed for its explanation.
Anonymous (not verified) An Initial State with shear and vorticity for non-central heavy ion collisions V.K. Magas FQA, University of Barcelona vladimir@fqa.ub.edu Recent experimental and theoretical developments indicate that a strong initial angular momentum, which is present in non-central collisions, has to be taken into account for a detailed simulation of the reactions. As a consequence of this large initial angular momentum we observe not only a overall system rotation, but also a strong fluid shear in the initial state, which leads to large flow vorticity and subsequent particle polarization: a significant Λ polarization was detected and analyzed in detail in the RHIC BES program [1].

More than 15 years ago an effective string rope model was proposed [2] to construct nucleus-nucleus collision initial state for realistic 3+1D relativistic fluid dynamical models. This model reflected correctly not only the energy-momentum, but also angular momentum, conservations, initial shear flow and local vorticity [3]. On the other hand, recent developments in parton kinetic and field dominance models provide a rather different initial state configuration, more compact for non-central collisions, see for example [4], what makes us revisit the our initial state model in that direction [5].


[1] L. Adamczyk et al. (The STAR Collaboration), Nature 548 (2017) 62.
[2] V.K. Magas, L.P. Csernai, D.D. Strottman, Phys. Rev. C64 (2001) 014901; Nucl. Phys. A712 (2002) 167.
[3] L.P. Csernai, V.K. Magas, D.J. Wang, Phys. Rev. C87 (2013) 034906.
[4] L.G. Pang, H. Petersen, G.Y. Qin, V. Roy and X.N. Wang, Nucl. Phys. A956 (2016) 272.
[5] V.K. Magas, J. Gordillo, D.D. Strottman, Y.L. Xie and L.P. Csernai, Phys. Rev. C97 (2018) no.6, 064903.