Número de entradas: **54**

### A deep synoptic radio survey of high-mass precursors in infrared dark clouds

**Estado:** defended (09/09/2020)

**Estudiante:** Roger Grau Haro

**Supervisada por:** Gemma Busquet ; Josep Miquel Girart Medina

**Universidad:** Universitat Autònoma de Barcelona

**Estado:** defended (09/09/2020)

**Estudiante:** Roger Grau Haro

**Supervisada por:** Gemma Busquet ; Josep Miquel Girart Medina

**Universidad:** Universitat Autònoma de Barcelona

We present observations of the centimeter continuum emission toward the infrared dark cloud G14.225-506 carried out with the JVLA at two different wavebands, one centered at 3.6 cm and the other at 6 cm. We found a total of 82 sources, 36 in the G14.2-N field (21 detected only at the C-band, 2 detected only at the X-band and 13 detected at both frequency bands), and 45 in the G14.2-S field (10 detected only at the C-band, 15 detected only at the X-band and 22 detected at both bands), and one source which is detected in both regions. We studied the size and flux distribution of both regions, distinguishing between both wavebands, and found that most of the sources are compact sources and that they are really faint. Focusing on the hubs, at large scales both hubs present similar physical structure while at small scales they clearly present different levels of fragmentation. We found that inside a diameter of 0.4 pc, Hub-N presents 7 centimeter sources (or fragments) while Hub-S is associated with 10 centimeter sources. We also computed the statistical number of background sources in the FWHM field of view and inside the hub region and found that at C-band we expect about 10 sources and in the X-band about 5 for the FWHM field of view and 1 background source, at most, for the hub region at both wavebands. We estimated the spectral indices of the sources and obtained that the north region (G14.2-N) is mostly formed by non-thermal emitters while the south region is mostly associated with thermal emitters. Finally we have found counterparts of the detected centimeter sources and studied them in order to know the evolutionary stage of the stellar population in both hubs. This helped us understand the reason of the different fragmentation which could be explained as the two hubs having different evolutionary stages, being Hub-N more evolved than Hub-S, or because Hub-N is mainly forming intermediate-/high-mass stars, whereas Hub-S seems to be forming a cluster in which most of the cluster members are low-mass stars.
### Rotating hyperonic neutron
stars,

**Estado:** defended (18/12/2019)

**Estudiante:** Campoy, Anna

**Supervisada por:** Laura Tolos

**Universidad:** Universitat de Barcelona

**Estado:** defended (18/12/2019)

**Estudiante:** Campoy, Anna

**Supervisada por:** Laura Tolos

**Universidad:** Universitat de Barcelona

Neutron stars are among the most compact objects known in the Universe, with central

densities several times that encountered in the center of atomic nuclei. The properties

of neutron stars, such as their masses and radii, depend strongly on their internal composition,

and hence the equation of state, which is still an open question. Most neutron

stars are observed as pulsars, which rotate with periods as low as the millisecond. It is

therefore of fundamental importance to study how rotation affects its structure and this

is the main purpose of this project. To this aim, the TOV equations with the Hartle-

Thorne approach for rotating neutron stars are solved for different angular velocities of

rotation employing two different hadronic models: A pure nucleonic equation of state for

nuclear matter, widely used in the literature, and a recently developed hyperonic equation

of state, the FSU2H model, which allows two-solar-mass neutron stars with hyperons in

their cores. It is found that, due to its stiffer behaviour, the FSU2H equation of state

leads to smaller Keplerian frequencies than the pure nucleonic model (H&H) and, hence,

the FSU2H rotating neutron stars suffer bigger deformations and reach higher moments

of inertia. Particularly, the less massive neutron stars are the systems that experience the

larger effects due to rotation
### Sigma N --> Y N transitions in the decay of 6^He_Lambda Lambda

**Estado:** defended (18/12/2019)

**Estudiante:** Aixut, Ariadna

**Supervisada por:** Laura Tolos

**Universidad:** Universitat de Barcelona

**Estado:** defended (18/12/2019)

**Estudiante:** Aixut, Ariadna

**Supervisada por:** Laura Tolos

**Universidad:** Universitat de Barcelona

Sigma N --> Y N transitions in the decay of 6^He_Lambda Lambda
### On the relation between dark matter in halos and stellar mass in the Euclid Flagship galaxy mock

**Estado:** defended (28/11/2019)

**Estudiante:** Gonzalez Reina, J.

**Supervisada por:** Pablo Fosalba Vela

**Universidad:** Universidad Internacional de Valencia

**Estado:** defended (28/11/2019)

**Estudiante:** Gonzalez Reina, J.

**Supervisada por:** Pablo Fosalba Vela

**Universidad:** Universidad Internacional de Valencia

In this work the verification of Euclid Consortium Flagship mock galaxy catalogue based on 2 trillion Dark Matter particles cosmological simulation performed on Piz Daint Supercomputer at Swiss National Supercomputing Center has been carried out by comparison with results from SDSS and COSMOS thorough the works that proposed analytic fitting functions in the near and far Universe, even though the work concentrates efforts in the calibration in near universe.
### Hot Neutron Rich Nuclear Matter Studied with the BCPM NuclearEnergy Density Functional

**Estado:** defended (20/09/2019)

**Estudiante:** Clara Dehman

**Supervisada por:** Xavier Viñas; Mario Centelles; Artur Polls

**Universidad:** Universitat de Barcelona

**Estado:** defended (20/09/2019)

**Estudiante:** Clara Dehman

**Supervisada por:** Xavier Viñas; Mario Centelles; Artur Polls

**Universidad:** Universitat de Barcelona

The main purpose of the master thesis was to study the thermal properties of a recently formulated nuclear energy density functional. The functional has been successfully used to describe finite nuclei and cold neutron stars. This functional is known as BCPM (Barcelona-Catania-Paris-Madrid) and it is based on microscopic calculations using the realistic Argonne v_{18} potential plus three-body forces of Urbana type. In the first part of the thesis, the main focus is on the thermodynamical properties of symmetric nuclear matter at zero and finite temperature using the BCPM functional. This study is next generalized to the case of asymmetric nuclear matter, where the thermodynamic properties will be investigated at zero and finite temperature. Later on, we investigate the properties of uniform β-stable matter, for the neutrino-free scenario at zero and finite temperature, and for the neutrino-trapped scenario at a fixed temperature and entropy. The β-stable matter is a key ingredient to perform different astrophysical applications of the BCPM functional, namely, the mass-radius relation and the tidal deformability for proto-neutron stars and for hot neutron stars.
### Probing cosmology and gravity theories through topological statistical descriptors

**Estado:** defended (12/09/2019)

**Estudiante:** Carballosa, A.

**Supervisada por:** Pablo Fosalba Vela

**Universidad:** Universitat Autònoma de Barcelona

**Estado:** defended (12/09/2019)

**Estudiante:** Carballosa, A.

**Supervisada por:** Pablo Fosalba Vela

**Universidad:** Universitat Autònoma de Barcelona

The morphological features of a given field such as the dark matter density field in the large scale structure of the Universe can be quantified through a set of statistical descriptors known as the Minkowski Functionals (MF). These descriptors contain information on all the N-point correlation functions, which turns them into a powerful tool to probe departures from Gaussianity and a strong complement to other statistical observables in the task of improving the constrains in the parameters of different cosmological models. In this work, we investigate to which point the Minkowski Functionals can be used to differentiate between two theories of gravity, General Relativity and Modified Gravity, through the analysis of pixelated all-sky maps generated from large N-body lightcone simulations
### Constraining modified gravity models through the turnaround radius

**Estado:** defended (06/09/2019)

**Estudiante:** Cesar Ramirez Perez

**Supervisada por:** Sergei D Odintsov ; Emilio Elizalde

**Universidad:** Universitat de Barcelona

**Estado:** defended (06/09/2019)

**Estudiante:** Cesar Ramirez Perez

**Supervisada por:** Sergei D Odintsov ; Emilio Elizalde

**Universidad:** Universitat de Barcelona

work
### Effective field theory methods for chiral plasmas

**Estado:** defended (06/09/2019)

**Estudiante:** Marc Comandran Casas

**Supervisada por:** Cristina Manuel Hidalgo

**Universidad:** Universitat Autònoma de Barcelona

**Estado:** defended (06/09/2019)

**Estudiante:** Marc Comandran Casas

**Supervisada por:** Cristina Manuel Hidalgo

**Universidad:** Universitat Autònoma de Barcelona

The physics of extremely hot and/or dense relativistic plasmas is extremely rich. Quantum field theory computations for these systems have revealed to be cumbersome, as the standard quantum loop expansion valid at zero temperature ceases in this case to correspond to a gauge coupling constant expansion. In these plasmas there is a well-defined hierarchy of energy scales, defined by the temperature and/or chemical potential, as well as derived energy scales, obtained by multiplying the above by the gauge coupling constant. This fact gives the basic playground to use effective field theory techniques. In this thesis we will use and develop effective field theory techniques for the study of hot and/or dense plasma, and show how one can compute many properties of theses plasmas at high accuracy. We will mainly focus in plasmas where there is a chiral fermion imblance, and compute the photon polarization tensor, and check that we can describe the chiral magnetic effect.
### Bounce cosmology from F(R,T) modified gravity

**Estado:** defended (06/09/2019)

**Estudiante:** Gerard Navo Perez

**Supervisada por:** Emilio Elizalde ; Sergei D Odintsov

**Universidad:** Universitat de Barcelona

**Estado:** defended (06/09/2019)

**Estudiante:** Gerard Navo Perez

**Supervisada por:** Emilio Elizalde ; Sergei D Odintsov

**Universidad:** Universitat de Barcelona

work
### Design of an antenna for the detection of kHz electromagnetic disturbances on-board LISA

**Estado:** defended (12/07/2019)

**Estudiante:** Ho, J.J

**Supervisada por:** Miquel Nofrarias Serra; J. Ramos-Castro

**Universidad:** Universitat Politècnica de Catalunya

**Estado:** defended (12/07/2019)

**Estudiante:** Ho, J.J

**Supervisada por:** Miquel Nofrarias Serra; J. Ramos-Castro

**Universidad:** Universitat Politècnica de Catalunya

The Laser Interferometer Space Antenna (LISA) is a mission led by the European Space Agency that seeks to be the first space-based observatory capable to detect and measure gravitational waves. Since it is a pioneer investigation, some of the required technologies have been never proved before in a space environment, but just on-ground, arising then the need of launching a technology demonstrator for the mission, the LISA Pathfinder (LPF). The scope was to prove that the technology was able to detect differential acceleration noises between two test masses in nominal free-fall up to 30 fm·s-2/√Hz. After two years of testing, the spacecraft provided the data of the performances of each of the units contributing to the payload, the so-called LISA Technology Package (LTP). The results confirmed that the experiment was successful – even better than expected – because LPF detected differential acceleration noises below the requirements. Nonetheless, several glitches of unknown sources were found throughout the overall noise spectrum and had to be removed from the data in order to provide the results. Otherwise, the peaks add an excess noise in the low frequencies. Since this effect is not negligible, many hypotheses have been proposed and discarded until the present day to try to explain the physical phenomena. One of them is related to the magnetic contribution, and asserts that the origin is given by the down-conversion of a high frequency (kHz) amplitude modulating magnetic field into the LISA measureable bandwidth, located in the low frequency region (mHz). These time varying signals will be detected with audio-range sensors. Hence, the objective of this work is to design the most feasible sensor capable to detect the offending signals, considering the LISA requirements, the distribution of the units onboard the spacecraft, the modulation of the respective magnetic fields, or the sensor design specifications. The results prove that a simple air-cored search coil can be used as the demanded sensor, achieving sensitivities below the required and, therefore, capable to detect amplitude modulating magnetic fields of different intensities and distances from the test masses.

We present observations of the centimeter continuum emission toward the infrared dark cloud G14.225-506 carried out with the JVLA at two different wavebands, one centered at 3.6 cm and the other at 6 cm. We found a total of 82 sources, 36 in the G14.2-N field (21 detected only at the C-band, 2 detected…

We present observations of the centimeter continuum emission toward the infrared dark cloud G14.225-506 carried out with the JVLA at two different wavebands, one centered at 3.6 cm and the other at 6 cm. We found a total of 82 sources, 36 in the G14.2-N field (21 detected only at the C-band, 2 detected only at the X-band and 13 detected at both frequency bands), and 45 in the G14.2-S field (10 detected only at the C-band, 15 detected only at the X-band and 22 detected at both bands), and one source which is detected in both regions. We studied the size and flux distribution of both regions, distinguishing between both wavebands, and found that most of the sources are compact sources and that they are really faint. Focusing on the hubs, at large scales both hubs present similar physical structure while at small scales they clearly present different levels of fragmentation. We found that inside a diameter of 0.4 pc, Hub-N presents 7 centimeter sources (or fragments) while Hub-S is associated with 10 centimeter sources. We also computed the statistical number of background sources in the FWHM field of view and inside the hub region and found that at C-band we expect about 10 sources and in the X-band about 5 for the FWHM field of view and 1 background source, at most, for the hub region at both wavebands. We estimated the spectral indices of the sources and obtained that the north region (G14.2-N) is mostly formed by non-thermal emitters while the south region is mostly associated with thermal emitters. Finally we have found counterparts of the detected centimeter sources and studied them in order to know the evolutionary stage of the stellar population in both hubs. This helped us understand the reason of the different fragmentation which could be explained as the two hubs having different evolutionary stages, being Hub-N more evolved than Hub-S, or because Hub-N is mainly forming intermediate-/high-mass stars, whereas Hub-S seems to be forming a cluster in which most of the cluster members are low-mass stars.

Neutron stars are among the most compact objects known in the Universe, with central densities several times that encountered in the center of atomic nuclei. The properties of neutron stars, such as their masses and radii, depend strongly on their internal composition, and hence the equation of state,…

Neutron stars are among the most compact objects known in the Universe, with central

densities several times that encountered in the center of atomic nuclei. The properties

of neutron stars, such as their masses and radii, depend strongly on their internal composition,

and hence the equation of state, which is still an open question. Most neutron

stars are observed as pulsars, which rotate with periods as low as the millisecond. It is

therefore of fundamental importance to study how rotation affects its structure and this

is the main purpose of this project. To this aim, the TOV equations with the Hartle-

Thorne approach for rotating neutron stars are solved for different angular velocities of

rotation employing two different hadronic models: A pure nucleonic equation of state for

nuclear matter, widely used in the literature, and a recently developed hyperonic equation

of state, the FSU2H model, which allows two-solar-mass neutron stars with hyperons in

their cores. It is found that, due to its stiffer behaviour, the FSU2H equation of state

leads to smaller Keplerian frequencies than the pure nucleonic model (H&H) and, hence,

the FSU2H rotating neutron stars suffer bigger deformations and reach higher moments

of inertia. Particularly, the less massive neutron stars are the systems that experience the

larger effects due to rotation

Sigma N --> Y N transitions in the decay of 6^He_Lambda Lambda

Sigma N --> Y N transitions in the decay of 6^He_Lambda Lambda

In this work the verification of Euclid Consortium Flagship mock galaxy catalogue based on 2 trillion Dark Matter particles cosmological simulation performed on Piz Daint Supercomputer at Swiss National Supercomputing Center has been carried out by comparison with results from SDSS and COSMOS thorough…

In this work the verification of Euclid Consortium Flagship mock galaxy catalogue based on 2 trillion Dark Matter particles cosmological simulation performed on Piz Daint Supercomputer at Swiss National Supercomputing Center has been carried out by comparison with results from SDSS and COSMOS thorough the works that proposed analytic fitting functions in the near and far Universe, even though the work concentrates efforts in the calibration in near universe.

The main purpose of the master thesis was to study the thermal properties of a recently formulated nuclear energy density functional. The functional has been successfully used to describe finite nuclei and cold neutron stars. This functional is known as BCPM (Barcelona-Catania-Paris-Madrid) and it is…

The main purpose of the master thesis was to study the thermal properties of a recently formulated nuclear energy density functional. The functional has been successfully used to describe finite nuclei and cold neutron stars. This functional is known as BCPM (Barcelona-Catania-Paris-Madrid) and it is based on microscopic calculations using the realistic Argonne v_{18} potential plus three-body forces of Urbana type. In the first part of the thesis, the main focus is on the thermodynamical properties of symmetric nuclear matter at zero and finite temperature using the BCPM functional. This study is next generalized to the case of asymmetric nuclear matter, where the thermodynamic properties will be investigated at zero and finite temperature. Later on, we investigate the properties of uniform β-stable matter, for the neutrino-free scenario at zero and finite temperature, and for the neutrino-trapped scenario at a fixed temperature and entropy. The β-stable matter is a key ingredient to perform different astrophysical applications of the BCPM functional, namely, the mass-radius relation and the tidal deformability for proto-neutron stars and for hot neutron stars.

The morphological features of a given field such as the dark matter density field in the large scale structure of the Universe can be quantified through a set of statistical descriptors known as the Minkowski Functionals (MF). These descriptors contain information on all the N-point correlation functions,…

The morphological features of a given field such as the dark matter density field in the large scale structure of the Universe can be quantified through a set of statistical descriptors known as the Minkowski Functionals (MF). These descriptors contain information on all the N-point correlation functions, which turns them into a powerful tool to probe departures from Gaussianity and a strong complement to other statistical observables in the task of improving the constrains in the parameters of different cosmological models. In this work, we investigate to which point the Minkowski Functionals can be used to differentiate between two theories of gravity, General Relativity and Modified Gravity, through the analysis of pixelated all-sky maps generated from large N-body lightcone simulations

work

work

The physics of extremely hot and/or dense relativistic plasmas is extremely rich. Quantum field theory computations for these systems have revealed to be cumbersome, as the standard quantum loop expansion valid at zero temperature ceases in this case to correspond to a gauge coupling constant expansion. In these plasmas there is a well-defined hierarchy of energy scales, defined by the temperature and/or chemical potential, as well as derived energy scales, obtained by multiplying the above by the gauge coupling constant. This fact gives the basic playground to use effective field theory techniques. In this thesis we will use and develop effective field theory techniques for the study of hot and/or dense plasma, and show how one can compute many properties of theses plasmas at high accuracy. Applications of these methods for both astrophysical and cosmological settings will be addressed.

The physics of extremely hot and/or dense relativistic plasmas is extremely rich. Quantum field theory computations for these systems have revealed to be cumbersome, as the standard quantum loop expansion valid at zero temperature ceases in this case to correspond to a gauge coupling constant expansion.…

The physics of extremely hot and/or dense relativistic plasmas is extremely rich. Quantum field theory computations for these systems have revealed to be cumbersome, as the standard quantum loop expansion valid at zero temperature ceases in this case to correspond to a gauge coupling constant expansion. In these plasmas there is a well-defined hierarchy of energy scales, defined by the temperature and/or chemical potential, as well as derived energy scales, obtained by multiplying the above by the gauge coupling constant. This fact gives the basic playground to use effective field theory techniques. In this thesis we will use and develop effective field theory techniques for the study of hot and/or dense plasma, and show how one can compute many properties of theses plasmas at high accuracy. We will mainly focus in plasmas where there is a chiral fermion imblance, and compute the photon polarization tensor, and check that we can describe the chiral magnetic effect.

work

work

The Laser Interferometer Space Antenna (LISA) is a mission led by the European Space Agency that seeks to be the first space-based observatory capable to detect and measure gravitational waves. Since it is a pioneer investigation, some of the required technologies have been never proved before in a space…

The Laser Interferometer Space Antenna (LISA) is a mission led by the European Space Agency that seeks to be the first space-based observatory capable to detect and measure gravitational waves. Since it is a pioneer investigation, some of the required technologies have been never proved before in a space environment, but just on-ground, arising then the need of launching a technology demonstrator for the mission, the LISA Pathfinder (LPF). The scope was to prove that the technology was able to detect differential acceleration noises between two test masses in nominal free-fall up to 30 fm·s-2/√Hz. After two years of testing, the spacecraft provided the data of the performances of each of the units contributing to the payload, the so-called LISA Technology Package (LTP). The results confirmed that the experiment was successful – even better than expected – because LPF detected differential acceleration noises below the requirements. Nonetheless, several glitches of unknown sources were found throughout the overall noise spectrum and had to be removed from the data in order to provide the results. Otherwise, the peaks add an excess noise in the low frequencies. Since this effect is not negligible, many hypotheses have been proposed and discarded until the present day to try to explain the physical phenomena. One of them is related to the magnetic contribution, and asserts that the origin is given by the down-conversion of a high frequency (kHz) amplitude modulating magnetic field into the LISA measureable bandwidth, located in the low frequency region (mHz). These time varying signals will be detected with audio-range sensors. Hence, the objective of this work is to design the most feasible sensor capable to detect the offending signals, considering the LISA requirements, the distribution of the units onboard the spacecraft, the modulation of the respective magnetic fields, or the sensor design specifications. The results prove that a simple air-cored search coil can be used as the demanded sensor, achieving sensitivities below the required and, therefore, capable to detect amplitude modulating magnetic fields of different intensities and distances from the test masses.

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