Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc
[eng] This thesis has as a main purpose the determination of the chemical composition of Open Clusters for the study of the chemical gradients in the Galactic disc with: Galactocentric radius, position above the plane, and age. In 3 years and a half we have acquired high-resolution spectra of stars...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/119036 |
| Acceso en línea: | https://hdl.handle.net/2445/119036 http://hdl.handle.net/10803/459148 |
| Access Level: | acceso abierto |
| Palabra clave: | Estels Galàxies Cúmuls d'estels Espectroscòpia astronòmica Via Làctia Stars Galaxies Clusters of stars Astronomical spectroscopy Milky Way |
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España |
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| dc.title.none.fl_str_mv |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc |
| title |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc |
| spellingShingle |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc Casamiquela, Laia Estels Galàxies Cúmuls d'estels Espectroscòpia astronòmica Via Làctia Stars Galaxies Clusters of stars Astronomical spectroscopy Milky Way |
| title_short |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc |
| title_full |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc |
| title_fullStr |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc |
| title_full_unstemmed |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc |
| title_sort |
Chemical and dynamical analysis of Open Clusters in the context of the Milky Way disc |
| dc.creator.none.fl_str_mv |
Casamiquela, Laia |
| author |
Casamiquela, Laia |
| author_facet |
Casamiquela, Laia |
| author_role |
author |
| dc.contributor.none.fl_str_mv |
Jordi i Nebot, Carme Carrera Jiménez, Ricardo Universitat de Barcelona. Departament de Física Quàntica i Astrofísica |
| dc.subject.none.fl_str_mv |
Estels Galàxies Cúmuls d'estels Espectroscòpia astronòmica Via Làctia Stars Galaxies Clusters of stars Astronomical spectroscopy Milky Way |
| topic |
Estels Galàxies Cúmuls d'estels Espectroscòpia astronòmica Via Làctia Stars Galaxies Clusters of stars Astronomical spectroscopy Milky Way |
| description |
[eng] This thesis has as a main purpose the determination of the chemical composition of Open Clusters for the study of the chemical gradients in the Galactic disc with: Galactocentric radius, position above the plane, and age. In 3 years and a half we have acquired high-resolution spectra of stars in 18 Open Clusters as a part of the OCCASO survey. We have used three fiber fed high-resolution spectrographs in the Observatorio del Roque de los Muchachos (La Palma, Spain) and the CAHA observatory (Almería, Spain). After a very accurate data reduction we have determined radial velocities, atmospheric parameters (effective temperature, surface gravity) and chemical abundances. Using the derived radial velocities and proper motions from the literature we have done a kinematic study of these clusters in the context of the Galactic disc and the position near the spiral arms. We have obtained radial velocities for OC never studied before with high-resolution spectroscopy: NGC 1907 (vr=2.3+- 0.5 km/s), NGC 6991 (vr=-12.3+-0.6 km/s) and NGC 7245 (vr=-74.0+-1.4km/s). We have computed the possible orbits that the clusters have followed using two models of the Galactic potential: an axysimmetric one, and a model with a bar and spiral arms featuring those of the Milky Way. With this, we have recovered the position of the clusters at birth. We have calculated temperatures, gravities and iron abundances using two different methodologies widely used in the literature. We have made an exhaustive comparison of the behaviour of both methods and the differences obtained among them. We obtained no systematics in effective temperature and surface gravity within the quoted errors, though with a large dispersion in surface gravity. As a sanity check we derived atmospheric parameters from BVI Johnson photometry for the stars from NGC 2420 and NGC 6791. We found systematic differences between spectroscopic and photometric determinations which change with slight variations of the assumed reddening, distance, age and metallicity to compute photometric parameters. Mean uncertainties in the final adopted in temperature and gravity are around 40 K and 0.1 dex. The comparison with literature values gives mean offsets well within uncertainties and dispersions. All these checks provide a study of the precision and accuracy of the obtained results. We have measured abundances of iron-peak elements (Fe, Ni, Cr) and the so-called α-elements (Si, Ca, Ti, Mg, O). From member stars we derive mean Fe cluster abundances with the two methods. We do an extensive star-by-star comparison with literature, showing good agreement. We also derived mean cluster Ni, Cr, Si, Ca and Ti abundances, and its abundance ratios respect to Fe. We see that all the clusters present small dispersions in abundance. The larger ones are 0.03 ([Ni/Fe]), 0.06 ([Cr/Fe]), 0.05 ([Si/Fe]), 0.07 ([Ca/Fe]), 0.05 ([Ti/Fe]) dex, excluding NGC~6791 (for which we have larger errors) We have compared the Galactocentric trend seen with OCCASO clusters with different theoretical models obtaining that the results for the oldest clusters favour a chemo-dynamical model instead of a pure chemical evolution model. Using OCCASO and two complementary samples (40 clusters in total), we have determined new values for the Galactocentric Fe gradient in three age bins, and the age-metallicity relation in four ranges of Galactocentric distance. In particular we have studied NGC 6705 in detail. We have seen that this cluster presents an unexpected α- enhancement for its location in the disc and its young age. We have derived the birth location of this cluster computing the possible orbits that it could have followed in the disc using different models. It seems that its α-enhancement cannot be explained by a very different place of birth of this cluster (i.e. the inner Galaxy), which from our calculations would be at most from a radii of 6.5 kpc. |
| publishDate |
2017 |
| dc.date.none.fl_str_mv |
2017 |
| dc.type.none.fl_str_mv |
info:eu-repo/semantics/doctoralThesis info:eu-repo/semantics/publishedVersion |
| format |
doctoralThesis |
| status_str |
publishedVersion |
| dc.identifier.none.fl_str_mv |
https://hdl.handle.net/2445/119036 http://hdl.handle.net/10803/459148 |
| url |
https://hdl.handle.net/2445/119036 http://hdl.handle.net/10803/459148 |
| dc.language.none.fl_str_mv |
Inglés |
| language_invalid_str_mv |
Inglés |
| dc.rights.none.fl_str_mv |
cc-by-sa, (c) Casamiquela, 2017 http://creativecommons.org/licenses/by-sa/3.0/ info:eu-repo/semantics/openAccess |
| rights_invalid_str_mv |
cc-by-sa, (c) Casamiquela, 2017 http://creativecommons.org/licenses/by-sa/3.0/ |
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openAccess |
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application/pdf |
| dc.publisher.none.fl_str_mv |
Universitat de Barcelona |
| publisher.none.fl_str_mv |
Universitat de Barcelona |
| dc.source.none.fl_str_mv |
Tesis Doctorals - Departament - Física Quàntica i Astrofísica reponame:Dipòsit Digital de la UB instname:Universidad de Barcelona |
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Universidad de Barcelona |
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Dipòsit Digital de la UB |
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Dipòsit Digital de la UB |
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1869416213371682816 |
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Chemical and dynamical analysis of Open Clusters in the context of the Milky Way discCasamiquela, LaiaEstelsGalàxiesCúmuls d'estelsEspectroscòpia astronòmicaVia LàctiaStarsGalaxiesClusters of starsAstronomical spectroscopyMilky Way[eng] This thesis has as a main purpose the determination of the chemical composition of Open Clusters for the study of the chemical gradients in the Galactic disc with: Galactocentric radius, position above the plane, and age. In 3 years and a half we have acquired high-resolution spectra of stars in 18 Open Clusters as a part of the OCCASO survey. We have used three fiber fed high-resolution spectrographs in the Observatorio del Roque de los Muchachos (La Palma, Spain) and the CAHA observatory (Almería, Spain). After a very accurate data reduction we have determined radial velocities, atmospheric parameters (effective temperature, surface gravity) and chemical abundances. Using the derived radial velocities and proper motions from the literature we have done a kinematic study of these clusters in the context of the Galactic disc and the position near the spiral arms. We have obtained radial velocities for OC never studied before with high-resolution spectroscopy: NGC 1907 (vr=2.3+- 0.5 km/s), NGC 6991 (vr=-12.3+-0.6 km/s) and NGC 7245 (vr=-74.0+-1.4km/s). We have computed the possible orbits that the clusters have followed using two models of the Galactic potential: an axysimmetric one, and a model with a bar and spiral arms featuring those of the Milky Way. With this, we have recovered the position of the clusters at birth. We have calculated temperatures, gravities and iron abundances using two different methodologies widely used in the literature. We have made an exhaustive comparison of the behaviour of both methods and the differences obtained among them. We obtained no systematics in effective temperature and surface gravity within the quoted errors, though with a large dispersion in surface gravity. As a sanity check we derived atmospheric parameters from BVI Johnson photometry for the stars from NGC 2420 and NGC 6791. We found systematic differences between spectroscopic and photometric determinations which change with slight variations of the assumed reddening, distance, age and metallicity to compute photometric parameters. Mean uncertainties in the final adopted in temperature and gravity are around 40 K and 0.1 dex. The comparison with literature values gives mean offsets well within uncertainties and dispersions. All these checks provide a study of the precision and accuracy of the obtained results. We have measured abundances of iron-peak elements (Fe, Ni, Cr) and the so-called α-elements (Si, Ca, Ti, Mg, O). From member stars we derive mean Fe cluster abundances with the two methods. We do an extensive star-by-star comparison with literature, showing good agreement. We also derived mean cluster Ni, Cr, Si, Ca and Ti abundances, and its abundance ratios respect to Fe. We see that all the clusters present small dispersions in abundance. The larger ones are 0.03 ([Ni/Fe]), 0.06 ([Cr/Fe]), 0.05 ([Si/Fe]), 0.07 ([Ca/Fe]), 0.05 ([Ti/Fe]) dex, excluding NGC~6791 (for which we have larger errors) We have compared the Galactocentric trend seen with OCCASO clusters with different theoretical models obtaining that the results for the oldest clusters favour a chemo-dynamical model instead of a pure chemical evolution model. Using OCCASO and two complementary samples (40 clusters in total), we have determined new values for the Galactocentric Fe gradient in three age bins, and the age-metallicity relation in four ranges of Galactocentric distance. In particular we have studied NGC 6705 in detail. We have seen that this cluster presents an unexpected α- enhancement for its location in the disc and its young age. We have derived the birth location of this cluster computing the possible orbits that it could have followed in the disc using different models. It seems that its α-enhancement cannot be explained by a very different place of birth of this cluster (i.e. the inner Galaxy), which from our calculations would be at most from a radii of 6.5 kpc.[cat] La present tesi té com a objectiu principal la determinació de la composició química de cúmuls oberts per l'estudi del gradient químic en el disc galàctic, tant amb la distancia al centre galàctic, com amb la posició sobre el disc, com amb l'edat. Durant 3 anys i mig s'han adquirit espectres d'alta resolució d'estrelles en 18 cúmuls oberts dins del projecte OCCASO. Així, després d'una acurada reducció de dades, s'han pogut determinar velocitats radials, paràmetres físics (temperatura efectiva, gravetat superficial) i abundàncies químiques. Amb les velocitats obtingudes i moviments propis de la literatura s'ha realitzat un estudi cinemàtic d'aquests cúmuls en relació amb el disc galàctic segons la seva posició a prop dels braços espirals. En concret s'han computat les possibles òrbites que han tingut els cúmuls a partir de dos models del potencial galàctic. S'han calculat temperatures, gravetats i abundàncies de ferro a partir de dues metodologies àmpliament usades a la literatura. S'ha fet una exhaustiva comparació del comportament dels dos mètodes i de les diferències obtingudes, aportant així un estudi de la precisió dels resultats obtinguts. S'han mesurat abundàncies químiques d'elements del pic del ferro (Fe, Ni, Cr) i d'elements anomenats α (Si, Ca, Ti, Mg, O). S'ha comparat la tendència dels cúmuls OCCASO amb diferents models teòrics i s'ha vist que els resultats dels cúmuls vells afavoreixen el model d'evolució químic-dinàmic front d'un model on només es contempli l'evolució química. Amb aquests resultats d'OCCASO i dues mostres complementaries (en total 40 cúmuls), s'han determinat nous valors pel gradient galactocèntric de Fe en tres rangs d'edat, i la relació edat-metal·licitat en quatre rangs de distancia galactocèntrica. En especial, s'ha estudiat en detall el cúmul NGC 6705. Aquest presenta una sobreabundància d'elements α inesperada per la seva localització en el disc i per ser tant jove. S'ha fet una investigació del lloc de procedència d'aquest cúmul computant les òrbites que podria haver seguit el cúmul en el disc amb diferents models. S'ha descartat que provingui d'un lloc intern de la galàxia que pugui explicar aquesta anomalia en els patrons químics.[spa] La presente tesis tiene como objetivo principal la determinación de la composición química de cúmulos abiertos para el estudio del gradiente químico en el disco galáctico, tanto con la distancia al centro galáctico, como con la posición sobre el disco, como con la edad. Durante 3 años y medio se han adquirido espectros de alta resolución de estrellas en 18 cúmulos abiertos dentro del proyecto OCCASO. Así, después de una acurada reducción de datos, se ha podido determinar velocidades radiales, parámetros físicos (temperatura efectiva, gravedad superficial) y abundancias químicas. Con los resultados de velocidades radiales y los movimientos propios de la literatura se ha realizado un estudio cinemático de dichos cúmulos según su posición en los brazos espirales. En particular se han computado las órbitas a partir de dos modelos del potencial galáctico. Se han calculado temperaturas, gravedades y abundancias de hierro a partir de dos metodologías. Se ha hecho una exhaustiva comparación del comportamiento de los dos métodos y las diferencias que se obtienen, aportando así un estudio de la precisión de los resultados obtenidos. Se han medido abundancias químicas de elementos del pico del hierro (Fe, Ni, Cr) y elementos llamados α (Si, Ca, Ti, Mg, O). Se ha comparado la tendencia de los cúmulos de OCCASO con diferentes modelos teóricos y se ha visto que los resultados de los cúmulos más viejos favorecen el modelo de evolución químico-dinámico frente a un modelo dónde solo se contemple la evolución química. Con estos resultados de OCCASO y dos muestras complementarias (40 cúmulos en total) se han determinado nuevos valores para el gradiente galactocéntrico de Fe en tres rangos de edad, y la relación edad-metalicidad en cuatro rangos de distancia galactocéntrica. En concreto, se ha estudiado con detalle el cúmulo NGC 6705. Éste presenta una sobreabundancia de elementos α inesperada por su localización en el disco y su joven edad. Se ha hecho una investigación del lugar de procedencia de éste cúmulo mediante diferentes modelos. Se ha descartado que provenga de un sitio interno de la Galaxia que pueda explicar esta anomalía en los patrones químicos.Universitat de BarcelonaJordi i Nebot, CarmeCarrera Jiménez, RicardoUniversitat de Barcelona. Departament de Física Quàntica i Astrofísica2017info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/119036http://hdl.handle.net/10803/459148Tesis Doctorals - Departament - Física Quàntica i Astrofísicareponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaIngléscc-by-sa, (c) Casamiquela, 2017http://creativecommons.org/licenses/by-sa/3.0/info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1190362026-05-27T06:46:51Z |
| score |
15,300719 |