Finalized Master theses

Número de entradas: 46

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

work
Estado: defended (06/09/2019)
Estudiante: Cesar Ramirez Perez
Supervisada por: Sergei D Odintsov ; Emilio Elizalde
Universidad: Universitat de Barcelona

work

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

work
Estado: defended (06/09/2019)
Estudiante: Gerard Navo Perez
Supervisada por: Emilio Elizalde ; Sergei D Odintsov
Universidad: Universitat de Barcelona

work

Study of S-bearing molecules in high-mass star-forming regions

Estado: defended (11/07/2019)
Estudiante: Santiago Ubach Ramirez
Supervisada por: Gemma Busquet ; Josep Miquel Girart Medina
Universidad: Universitat Autònoma de Barcelona


Sulfur-bearing molecules have been detected in different interstellar environments, from diffuse clousd to star-forming regions.  Observations show that the total sulfur conent in dense cores is depleted by several orders of magnitude in comparison with diffuse clouds. 
In this master thesis we analyze IRAM 30m data toward three high-mass star-forming regions to investigate the content of sulfur-bearing species during the earliest stages of massive and star cluster formation. 
Sulfur-bearing molecules have been detected in different interstellar environments, from diffuse clousd to star-forming regions.  Observations show that the total sulfur conent in dense cores is depleted by several orders of magnitude in comparison with diffuse clouds.  In this master thesis we analyze…
Estado: defended (11/07/2019)
Estudiante: Santiago Ubach Ramirez
Supervisada por: Gemma Busquet ; Josep Miquel Girart Medina
Universidad: Universitat Autònoma de Barcelona

Sulfur-bearing molecules have been detected in different interstellar environments, from diffuse clousd to star-forming regions.  Observations show that the total sulfur conent in dense cores is depleted by several orders of magnitude in comparison with diffuse clouds. 
In this master thesis we analyze IRAM 30m data toward three high-mass star-forming regions to investigate the content of sulfur-bearing species during the earliest stages of massive and star cluster formation. 

A search for Brown Dwarfs in the Taurus star-forming region

Estado: defended (08/10/2018)
Estudiante: Manuel Perger
Supervisada por: Martín, E.

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Estado: defended (08/10/2018)
Estudiante: Manuel Perger
Supervisada por: Martín, E.

...

Testing Weak Lensing magnification bias in the Euclid Flagship galaxy mock

Estado: defended (13/09/2018)
Estudiante: Cristian Nery Viglione Munoz
Supervisada por: Pablo Fosalba Vela; Blot, L.
Universidad: Universitat Autònoma de Barcelona

One of the major goals of observational cosmology is to map the large-scale structure of the universe. Traditionally this is performed using large surveys of galaxies. But these surveys only map the light distribution while most of the matter in the Universe appears to be dark. This is where gravitational…
Estado: defended (13/09/2018)
Estudiante: Cristian Nery Viglione Munoz
Supervisada por: Pablo Fosalba Vela; Blot, L.
Universidad: Universitat Autònoma de Barcelona

One of the major goals of observational cosmology is to map the large-scale structure of the universe. Traditionally this is performed using large surveys of galaxies. But these surveys only map the light distribution while most of the matter in the Universe appears to be dark. This is where gravitational lensing becomes a useful phenomenon to study the distribution of all the matter as the light's path is aected by the gravity of any kind of matter. The progress in the development of simulated catalogs has allowed the implementation of weak lensing observables. We can study and test predictions in order to understand these observables and prepare for the analysis of the information of future observational surveys. In this thesis we analyze and validate several lensing observables like the convergence and the detection angle coming from data of the simulated Flagship galaxy mock, the rst ocial pertaining to ESA's Euclid mission. Our main focus resides in the study and validation of the two competing eects of the magnication bias that change the number density counts of galaxy sources. We follow the methodology presented in the MICE Gran Challenge paper but using data of the Flagship simulation, a catalog with 10 times more galaxies than MICE-GC, extracted from the Cosmohub web portal. We also re-obtain the desired plots for MICE-GC to check our procedure and carry out comparisons. We couldn't capture, and therefore validate, the survey area distortion term, related to the lensed positions, of the magnications bias. So we discuss possibles causes to this issue in relation to resolution and systematic eects of Flagship's data.

Characterization of CARMENES M-dwarf spectral binaries

Estado: defended (15/09/2017)
Estudiante: Baroch, David
Supervisada por: Juan Carlos Morales Peralta; Ignasi Ribas Canudas
Universidad: Universitat Autònoma de Barcelona

In this project we analysed the radial velocities from the CARMENES project (an spectroscopic survey of 300 M-dwarf stars to look for exoplanets) of targets that turned out to be binary systems, with the aim of characterizing their orbital parameters and their physical properties. We also studied the…
Estado: defended (15/09/2017)
Estudiante: Baroch, David
Supervisada por: Juan Carlos Morales Peralta; Ignasi Ribas Canudas
Universidad: Universitat Autònoma de Barcelona

In this project we analysed the radial velocities from the CARMENES project (an spectroscopic survey of 300 M-dwarf stars to look for exoplanets) of targets that turned out to be binary systems, with the aim of characterizing their orbital parameters and their physical properties. We also studied the photometry of these systems to find the rotation period of the primary star and to look for possible eclipses between the components. All this data will help the CARMENES consortium when trying to find planets around these stars. We updated the multiplicity fraction of M dwarfs by including the binary stars that we have identified, which are presented in this work for the first time.

We computed the radial velocities of both stars of the binary systems from their spectra using TODMOR. It uses two spectrum templates that are shifted with different velocities until they best match the observed spectra. The fit of an orbital solution to the measured radial velocities is obtained with the SBOP code, which computes an orbital solution and their physical parameters. We made periodograms of the photometry to find the rotation period of the stars, and we used the BLS webtool to look for eclipses.

We studied a total of 12 binary systems, of which 9 are double-lined spectral binaries (SB2’s) and 3 are single-lined (SB1). We defined with low relative errors the period of 5 systems, of which 3 have periods shorter than 10 days and 2 have periods between 100 and 200 days. It has been possible to estimate a period for other 4 systems, although they have large relative uncertainties and more observations are needed to constrain them better. For the remaining 3 systems, we only determined lower and upper period limits due to their long orbits. The study of the residuals of one of the SB1’s resulted in the detection of a signal at 1.69 days compatible with a planet of a minimum mass of 13.4 M⊕, though the signal is not significant yet and more observations are needed to confirm it. We gave the rotation period of 7 stars, an estimation of the individual masses of all the SB2’s and upper and lower limits of the individual masses of SB1’s, assuming several constraints. We estimated a lower limit for the multiplicity fraction of M dwarf stars of 41±3%. 

Extending BeSPP Capabilities for Asteroseismic Analysis of Solar-like Stars: How Bayesian Prior Constraints and the Application of Frequency Ratios Allows for Precise Determination of Fundamental Stellar Parameters

Estado: defended (11/09/2017)
Estudiante: Walker, Oliver
Supervisada por: Aldo Serenelli
Universidad: Universitat Autònoma de Barcelona

This thesis utilises a Bayesian pipeline known as BeSPP, designed to output stellar parameters for the purposes of analysis, in order to constrain the masses, ages, radii and densities on the Sun and 66 solar-like stars from the Kepler asteroseismic legacy sample. The work outlines both the positive…
Estado: defended (11/09/2017)
Estudiante: Walker, Oliver
Supervisada por: Aldo Serenelli
Universidad: Universitat Autònoma de Barcelona

This thesis utilises a Bayesian pipeline known as BeSPP, designed to output stellar parameters for the purposes of analysis, in order to constrain the masses, ages, radii and densities on the Sun and 66 solar-like stars from the Kepler asteroseismic legacy sample. The work outlines both the positive effect of Bayesian statistics, in particular priors, on constraining parameters, as well as the effect of taking frequency separation ratios from individual frequencies of model data, an action that effectively removes the large turbulent convective zone that features greatly in solar-like stars. BeSPP is extended to cater for these ratios and a normalisation is applied to the likelihood to produce histograms of fundamental parameters ready for discussion. The pipeline was found to greatly constrain all standard deviations of histograms concerning each stellar parameter with the increase in ratios applied (r02, r01, and r10), and a table containing all histogram data can be found in Appendix A. Also highlighted is the strong correlation between ratios by way of applying a covariance matrix to normalisation factors. The work concludes with examples of the benefits of the ratios in matters such as constraining parameters of globular clusters and stellar population, and the influence on galactic archaeology.

Describing the sources of meteor activity in May 2015: Eta Aquarids from 1P/Halley

Estado: defended (08/09/2017)
Estudiante: Real, K.
Supervisada por: Josep M. Trigo-Rodríguez
Universidad: Universitat Autònoma de Barcelona

The deceleration of asteroid and cometary particles in the Earth’s atmosphere pro- duces their ablation as luminous columns of ionized gas.  This master thesis de- scribes the general reduction procedure of the multi-station detection of meteors and fireballs, in order to reconstruct their atmospheric…
Estado: defended (08/09/2017)
Estudiante: Real, K.
Supervisada por: Josep M. Trigo-Rodríguez
Universidad: Universitat Autònoma de Barcelona

The deceleration of asteroid and cometary particles in the Earth’s atmosphere pro-
duces their ablation as luminous columns of ionized gas.  This master thesis de-
scribes the general reduction procedure of the multi-station detection of meteors
and fireballs, in order to reconstruct their atmospheric trajectories, velocities and he-
liocentric orbits and determine their potential origin. This thesis will exemplify the
different steps by analysing two meteor events which were recorded by the SPMN
in early May 2015. One event was determined to be a part of the Eta Aquarid fireball
outburst in May 2015 and it had a deduced apparent radiant of αg = 340.1 ± 0.7º ,
and δg = −0.6 ± −0.7 º and a pre-atmospheric velocity v∞ =  64.8 ± 0.5 km/s, both of
which were consistent with previous research. The second event was found to be a
sporadic meteor with an absolute visual magnitude of -9. Its apparent radiant and
pre-atmospheric velocity were calculated to be αg = (0.4 ± 0.8)º , δg = (66.3 ± 0.8)º and
v∞ = 40.7 ± 0.5 km/s, respectively. The computed orbital elements indicated that
it was most likely associated with a sun-grazer comet.

Nakhla Meteorite in context of Martian achondrites

Estado: defended (07/09/2017)
Estudiante: Donoso Linares, J.A.
Supervisada por: Josep M. Trigo-Rodríguez
Universidad: Universitat Autònoma de Barcelona

The Nakhla martian meteorite fell in Egypt on June 28,1911 and was re- covered soon after its fall. This master thesis is focused on the study of this martian achondrite by using several analytical techniques: petrographic mi- croscopy, scanning electron microscopy and EDX, and Raman spectroscopy. A…
Estado: defended (07/09/2017)
Estudiante: Donoso Linares, J.A.
Supervisada por: Josep M. Trigo-Rodríguez
Universidad: Universitat Autònoma de Barcelona

The Nakhla martian meteorite fell in Egypt on June 28,1911 and was re-
covered soon after its fall. This master thesis is focused on the study of this
martian achondrite by using several analytical techniques: petrographic mi-
croscopy, scanning electron microscopy and EDX, and Raman spectroscopy.
A thin sample of Nakhla was selected for the study, and an overall character-
ization of the mineral composition was done at selected regions of interest.
Bulk mineralogy of Nakhla is similar to the one described in scientific liter-
ature, but specific attention was given to describing the nature of secondary
minerals that are known to be the result of aqueous alteration.  Clear evi-
dence of Nakhla being formed under the presence of water was found. This
evidence is compared with scientific literature describing recent results ob-
tained by instrumentation aboard spacecrafts and rovers.  Finally, by using
Raman spectroscopy evidence of shock in the meteorite was presented and
put into context for the possible origin and ejection from the martian surface.

The Lambdac(2940)+ as a molecular D*N (Ds*Lambda) state

Estado: defended (25/07/2017)
Estudiante: Montaña, G.
Supervisada por: Laura Tolos ; Ramos, A.
Universidad: Universitat de Barcelona

Upon the assumption of being a resonance with spin-parity J = 3=2-, the Lambda_c(2940)+ is described
in this thesis as a vector meson-baryon molecule. Also, a visible signal of this resonance
is found in the invariant mass spectrum of the Lambda_b -> pi D0 p decay. This is achieved after a
complete study of the interaction of pseudoscalar mesons and vector mesons with baryons in
the charm C = 1 sector within a coupled-channel approach in SU(4), using the hidden gauge
formalism to implement the interaction through a vector meson exchange model. The results of
the model presented here predict the Lambdac(2940)+ as a state with basically rho Sigma_c and K*Xi'c components,
but also coupling to the D*N and D*sLambda channels. It is the coupling to these latter
vector meson-baryon systems which allows the appearance of a peak in the D0p invariant mass
distribution of the b decay, signalling the presence of the Lambdac(2940)+. The study of the details
of the weak decay and the hadronization process leads to a clear signal of this resonance, as well
as other interesting features, which make the Lambda_b -> pi D0 p decay an interesting process to be
observed experimentally, both for validating the molecular nature of the Lambdac(2940)+ and for the
observation of new exotic hadron states.
Upon the assumption of being a resonance with spin-parity J=3/2-, the Lambda_c(2940)+ is described in this thesis as a vector meson-baryon molecule. Also, a visible signal of this resonance is found in the invariant mass spectrum of the Lambda_b -> pi D0 p decay. This is achieved after a complete…
Estado: defended (25/07/2017)
Estudiante: Montaña, G.
Supervisada por: Laura Tolos ; Ramos, A.
Universidad: Universitat de Barcelona

Upon the assumption of being a resonance with spin-parity J=3/2-, the Lambda_c(2940)+ is described
in this thesis as a vector meson-baryon molecule. Also, a visible signal of this resonance
is found in the invariant mass spectrum of the Lambda_b -> pi D0 p decay. This is achieved after a
complete study of the interaction of pseudoscalar mesons and vector mesons with baryons in
the charm C = 1 sector within a coupled-channel approach in SU(4), using the hidden gauge
formalism to implement the interaction through a vector meson exchange model. The results of
the model presented here predict the Lambdac(2940)+ as a state with basically rho Sigma_c and K*Xi'c components,
but also coupling to the D*N and D*sLambda channels. It is the coupling to these latter
vector meson-baryon systems which allows the appearance of a peak in the D0p invariant mass
distribution of the b decay, signalling the presence of the Lambdac(2940)+. The study of the details
of the weak decay and the hadronization process leads to a clear signal of this resonance, as well
as other interesting features, which make the Lambda_b -> pi D0 p decay an interesting process to be
observed experimentally, both for validating the molecular nature of the Lambdac(2940)+ and for the
observation of new exotic hadron states.
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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