Interplay between evolved massive stars and their circumstellar medium : a (SUB) millimetre view of luminous blue variable mass loss
Massive stars play a significant role in the shaping and evolution of the Galaxy. Their stellar winds and strong UV fields continuously alter the structure, dynamics and chemical composition of the surrounding ISM. Still, their impact becomes even more relevant once they leave the main sequence. They turn unstable and progressively lose a significant fraction […]
Study of the early stages in the formation of super star clusters
This thesis aims to study the earliest heavily obscured phases of massive star formation in starburst (SB) galaxies through a multi-line analysis of the HC 3 N rotational transitions from the ground and vibrationally excited states (HC 3 N). Due to its unique spectroscopic properties, we also discuss the potential of HC 3 N as […]
Spectroscopy of FGKM-type stars for the scientific exploitation of the CARMENES exoplanet search
The increased interest that sparks the search for exoplanets over the last few years has resulted in the design of high-resolution spectrographs such as CARMENES, installed at the 3.5 m telescope in the Calar Alto Observatory in Almería (Spain), in order to improve the radial-velocity measurements and, thus, to help detect Earth-type planets around stars […]
MONOS: Multiplicity of Northern O-type Spectroscopic Systems
One of the key pillars in our understanding of the chemical (Matteucci 2012) and dynamical evolution of galaxies is our knowledge about massive stars (Massey 2003), and the O-type stars (M ZAMS ⇠ 15/20 60/80 M ) in particular. Massive stars play a crucial role in shaping their environment due to their thrilling short lives […]
The first massive galaxies formed in the Universe: selection and characterization of optically faint, infrared-bright galaxies in the first 2 Gyr of the Universe
The ultimate goal in galaxy studies is having a complete picture of galaxy formation and evolution across the history of the Universe. A robust determination of the abundance of massive (an even quiescent) galaxies at high redshift is essential to constrain current models of galaxy formation and alleviate the tension between existing models and observations. […]
Interplay between evolved massive stars and their circumstellar medium: a (sub) millimetre view of luminous blue variable mass loss
Exocomets: a study of the gaseous environment of A-type main-sequence stars
En las estrellas de secuencia principal, los excesos fotométricos en el infrarrojo atribuidos a la presencia de polvo circunestelar en los discos conocidos como debris o escombro, ha sido la única prueba empírica indirecta de la existencia de cuerpos menores durante más de 40 años. No fue hasta 1987 cuando se encontró la primera evidencia de la […]
GALANTE: Photometric System and Galactic Plane Survey
GALANTE project has the goal to observe the Northern Hemisphere, 6 degrees wide, in the optical range. To reach this goal, 7 photometric bands have been selected to obtain the most complete information about the stellar physical variables. The new photometric system GALANTE has been designed using 4 J-PLUS bands in addition with 3 home-made […]
Nitrogen chemistry in the interstellar medium: fractionation and molecular complexity across the galaxy
In recent years, Astrochemistry (the field of Astronomy that studies the chemistry of molecules in space) has revealed the presence of large molecular organic species, both O-bearing and N-bearing, in the medium between stars (the interstellar medium or ISM). Some of these species are of pre-biotic interest due to their possible link to the emergence […]
Physical and Chemical Processes in Cloud-Cloud Collisions: Star Formation on the Making
Infrared Dark Clouds (IRDCs) are cold and dense regions in space, considered as the birthplace of high-mass stars and stellar clusters. Recent studies support the idea that the physical mechanisms leading to the formation of these IRDCs may also trigger high-mass star formation within the clouds. Fossil records of such formation mechanisms may be stored […]
A Far-Infrared Study of Low and Intermediate Mass Evolved Stars using Herschel PACS and SPIRE Spectroscopy
In this thesis, a far-infrared (FIR) study of evolved low and intermediate mass stars is presented. The characterization of these evolved stars is particularly interesting when we analyse their properties in the FIR and the sub-millimeter wavelength regions. Due to the very promising spectroscopic data of Herschel, PACS (50-220 μm) and SPIRE (200-600 μm) observations have been […]
Un sondeo espectroscópico de estrellas o galácticas
Los catálogos de clasificaciones espectrales de estrellas masivas que recopilan sus datos de diferentes fuentes, muestran una gran disparidad en las clasificaciones que contienen. Algunas de las discrepancias se deben a las diferentes resoluciones espectrales o relaciones señal-ruido (S/N), otras a la variabilidad en las estrellas (siendo las binarias espectroscópicas las principales culpables), y otros […]
The impact of metallicity on massive star evolution
The accurate characterization of the physical properties of massive stars in very low-metallicity environments has important implications in our interpretation of the primitive Universe. The first population of stars, which are thought to have been very massive and extremely metal-poor, has been proposed as the responsible source of the re-ionization of the early Universe. Moreover, […]
Legacies of the Dust. A multiwavelength study of protoplanetary disks and young exoplanetary systems
The curtain opens. A cold and dark molecular cloud enters the stage, opaque, invisible to the eye. Suddenly, the light changes, and under an infrared filter, the audience can finally see. The cloud now shines, bright, its filaments, clumps, global structure, all bare. Cosmic rays and far ultra violet irradiation can not penetrate it, its […]
Molecular complexity in envelopes of evolved stars: detailed study of the molecular emissión of the objects IK Tau, OH231.8 + 4,2 and IRC + 10216
Evolved stars whose main sequence masses were comprised between approximately 1 and 8 solar masses, for example like our Sun will be after 4.5 billion years from now, are the main contributors to the enrichment of the interstellar medium. These stars create a circumstellar envelope around them during the asymptotic giant branch phase, which is […]
Infrared emission of active galaxies
La emisión infrarroja de galaxias activas Nowadays it is accepted that all galaxies with significant bulge component contain a supermassive black hole (SMBH) in their centres. This SMBH plays an important role in the formation of galaxies, being quiet in some galaxies and accreting material and growing in others. The latter phenomenon is referred to […]
The cycle of matter in the interstellar medium: energetic processing of dust and ice
The aim of this PhD thesis is to expand our knowledge of particular processes taking place in the interstellar medium (ISM). These processes are related in one way or another to the energetic processing of the interstellar dust grains and the ice mantles on top of them, and to the interplay between the solid and […]
A study of the X-ray and optical variability of the active galactic nucleus ESO 362-G18: from days to years
Estudio de la variabilidad del núcleo galáctico activo ESO 362-G18 en las bandas óptica y de rayos X : escalas de tiempo desde días a años El modelo unificado (UM) de los núcleos galácticos activos (AGN), establecido hace 30 años, se fundamenta en la existencia de una estructura toroidal, compuesta por gas y polvo, capaz […]
CARMENES-UCM: scientific preparation, multiplicity, chromospheric activity and kinematics
CARMENES-UCM: preparación científica, multiplicidad, actividad cromosférica y cinemática Las estrellas enanas de tipo M representan cerca de dos tercios de las estrellas en la Galaxia, lo que las convierte en objetivos perfectos para el estudio de formación y evolución estelar al final del diagrama Hertzsprung-Russell. El máximo de emisión de energía de las estrellas M […]
Cúmulos jóvenes masivos en el infrarrojo como sondas Galácticas
Los cúmulos jóvenes masivos (YMCs) espacialmente resueltos disfrutan de un singular conjunto de propiedades físicas, evolutivas y observacionales que los convierten en laborato- rios astrofísicos privilegiados. Están formados por una abundante población estelar coetánea, codistante, y de la misma composición química inicial, que muestrea toda o casi toda la función inicial de masas (IMF). Cada […]
Lessons from high-energy studies of AGN: X-ray absorption and its variability
Lecciones del estudio de AGN a altas energías: absorción de rayos X y su variabilidad This is a doctoral dissertation about the X–ray observational and theoretical study of active galactic nuclei (AGN). In the following paragraphs, the research lines addressed during my Ph. D. work are exposed. From a theoretical approach, my work belongs to […]
A Search For Neutral Gas Outflows In Nearby Luminous Star-Forming Galaxies
In the last decade, our understanding of the formation and evolution of galaxies over cosmic time has been significantly enhanced by large scale galaxy surveys. These surveys have drawn a detailed pic- ture of the global properties of the galaxies, establishing the galaxy stellar mass function and scaling relations (e.g., mass-metallicity). Galaxy evolution models attempt […]
Búsqueda IR de starburst y del toroide de polvo oscurecedor en QSO
Con el propósito de estudiar la contribución estelar y de un toroide de polvo nuclear a la emisión nuclear (. 1 kpc) en el cercano y mediano IR (2-20 μm) de cuásares (QSO, del inglés Quasi Stellar Object) hemos realizado observaciones en el Gran Telescopio CANARIAS de 10.4 m (GTC) de 20 QSO cercanos (z […]
Identification and characterization of low mass stars and brown dwarfs using virtual observatory tools
Identificación y caracterización de estrellas poco masivas y enenas marrones con el observatorio virtual Two thirds of the stars in our galactic neighborhood (d < 10 pc) are M-dwarfs which also constitute the most common stellar objects in the Milky Way. This property, combined with their small stellar masses and radii, increases the likelihood of […]
CARMENES science preparation: characterisation of M dwarfs with low-resolution spectroscopy and search for low-mass wide companions to young stars
Preparación científica de CARMENES : caracterización de enanas M con espectroscopía de baja resolución y búsqueda de compañeros separados poco masivos de estrellas jóvenes The mass ratio between rocky planets and M-type dwarfs is much lower than between rocky planets and stars like the Sun. This fact has made them prime targets for the detection […]
Submillimetric study of nearby galaxies
Estudio submilimétrico de galaxias cercanas The formation of molecules in the Interstellar medium is possible under the condition of high densities in a given region as the consequence of the occurrence of collisions between atoms. Moreover, a molecule can be dissociated by an UV photon. Interestelar dust can act as a pro- tection against dissociation […]
Search for planetary nebulae around hot subdwarf stars. Analysis and characterization of these peculiar systems
Hace apenas un año del 250 aniversario del descubrimiento de la primera nebulosa planetaria (NP), la nebulosa Dummbell o M27, por Charles Messier en 1764. Sin embargo, no fue hasta unos años más tarde (en 1780) cuando el término nebulosa planetaria fue acuñado por primera vez por el astrónomo británico William Herschel. A pesar de […]
Protoplanetary disk evolution in nearby star-forming regions
The main aim of this work is to better understand the evolution of protoplanetary disks around young stars in the solar neighborhood. It comprises three rst authored published papers, a fourth paper about to be submitted, and additional research as participation in six other refereed papers, which I coauthored during the period of this thesis. […]
Characterization of the planet-host stars WTS-1 and WTS-2, and detection of the secondary eclipses of WASP-10b and Qatar-1b
Ya se han confirmado cientos de exoplanetas desde el descubrimiento del primero que orbitaba alrededor de estrellas de tipo solar (Mayor y Queloz 1995), con muy distintas características. Así, la ecología exoplanetaria se ha ido diversificando y se han encontrado muy diversos nichos: desde planetas gigantes gaseosos hasta de tamaño similar a la Luna, o […]
Planetary systems across different niches Synergies between Kepler and Calar Alto observatories
Since the discovery of the first extrasolar planets around two decades ago, more than a thousand of these worlds have been confirmed and characterized. The wide and unexpected diversity of properties shown by these planetary systems suggest the complexity of the planet formation and evolution processes. Apart from providing indications on the formation of the […]
Optical and high-energy monitoring of variable sources observed with INTEGRAL/OMC
Since the discovery of the first variable stars in the 16th century, their study has been one of the principal areas of astronomical research. During the 20th century and the beginning of the 21st, many optical photometric surveys have been carried out with the aim of understanding the physical mechanisms producing the observed variations of […]
Caracterización de la cinemática de los vientos y los discos circunestelares ionizados de regiones UC HII con emisión máser en líneas de recombinación de hidrógeno
Aunque las estrellas masivas han jugado un papel clave en la evolución de las galaxias, todavía no hay un consenso acerca de cómo se forman y de cuáles son los procesos físicos que afectan a su evolución temprana. Con el objetivo de avanzar en el conocimiento de estos procesos, hemos estudiado la cinemática de las […]
Multi-wavelength study of the population of galaxies in intermediate-redshift clustersthe case of rxj1257.2+4738 at z~0.9
“Clusters of galaxies are the largest virialised systems in the Universe” is one of the most common statements in the framework of galaxy clusters research. This occurs because such gravitationally bound structures become ideal laboratories to directly study their baryon content (intracluster medium and galaxies) and to indirectly measure their dark matter content. In the […]
Química en las nubes moleculares del Centro Galáctico
La investigación que se desarrolla en esta tesis doctoral se centra en el estudio de dos de los principales complejos del Centro Galáctico (CG), Sagitario (Sgr) B2 y Sgr A, a través de la medición de la emisión/absorción procedente de estas fuentes en el rango de longitudes de onda centimétricas-submilimétricas. El CG se encuentra a […]
The role of low-mass star clusters in the formation of massive stars
Massive stars (M>8M⊙) are the main source of energy and turbulence injection into the interstellar medium (ISM) of galaxies. Despite their importance, their formation process is still not well understood, being one of the most debated topic in modern Astrophysics. Several theories have been proposed to explain the formation of the most massive stars: i) […]
Complejidad física y química en la nube molecular orión KL
El medio interestelar constituye un importante campo de investigación, especialmente para la Astrofísica Molecular. Las grandes cantidades de gas molecular presentes en el medio interestelar, ISM, que se agrupan formando complejos de nubes moleculares, son un laboratorio único para conocer en detalle su composición a través de la Astroquímica. Esta rama de la ciencia representa […]
2D kinematic characterization of a representative sample of local (U)LIRGs: A “kinemetry” analysis based on VIMOS/VTL Integral Field Spectroscopy
Luminous and ultraluminous infrared galaxies (i.e., LIRGs, LIR = [8-1000 μm] = 1011 – 1012 L⊙, and ULIRGs, LIR > 1012 L⊙, respectively) host the most extreme star-forming events in the present universe. Although they are rare in the local universe, they are much more numerous at high-z and are relevant contributors to the whole past star formation beyond z ∼ 1. Local (U)LIRGs […]
A VLT-SINFONI study of local Luminous and Ultraluminous infrared galaxies
Estudio de galaxias luminosas y ultraluminosas en el infrarrojo con VTL-SINFONI The importance of Luminous (LIRGs) and Ultraluminous (ULIRGs) infrared galaxies in the context of galaxy evolution has been clearly established since their discovery in the early 70’s. This new class of “infrared galaxies” is characterised by emitting more energy in the mid- and far-infrared […]
Vacuum-Ultraviolet Spectroscopy and Photodesorption of Interstellar Ice Analogues
Subjects: Espectroscopía ultravioleta – Tesis doctorales; Materia interestelar; Física
Evolution of gas and dust incircumstellar environments: from protoplanetary discs to the formation of planets
Understanding the evolution of gas and dust in circumstellar discs is a major topic in present day astronomy, linked to one of the most interesting challenges: understanding the formation of planets. Circumstellar discs can be found around stars at different ages, and circumstellar matter follows an evolutionary path that links the different kinds of discs […]
A search for low-mass objects in young star-forming regions
The object of this thesis is find new low-mass objects in Taurus in order to get new insights on its mass function. The investigated area in this work is located 5 deg north of the main clouds and covers around 25 sq:deg. Thus, we also contribute to answer the question whether the low-mass objects have […]
Star formation and high-energy emission in starburst galaxies
Starbursts are conspicuous star formation events which are characterized by a prompt production of massive stars. They dominate the emission of the host galaxies in most of the electromagnetic spectrum over several million years and observationally appear similar to HII regions (Sargent & Searle 1970). The strong UV emission from these stars is more powerful […]
Estudio experimental del procesamiento fotónico y térmico de hielos interestelares
El medio interestelar (ISM) es el espacio que hay entre las estrellas, dentro del ISM se puede distinguir el medio difuso, compuesto principalmente por hidrógeno atómico. Si la densidad sigue aumentando se empezarían a formar las nubes moleculares que se componen principalmente por hidrógeno molecular y polvo. Dentro de una nube molecular la densidad de […]
Star Formation and Nuclear Activity of Local Luminous Infrared Galaxies
Luminous infrared galaxies (LIRGs) and ultraluminous infrared galaxies (ULIRGs) are galaxies with infrared (IR) luminosities (LIR) in the range between 1011 and 1012 L⊙, and >1012 L⊙, respectively. Intense star-formation bursts and/or an active galactic nucleus (AGN) are the power sources of these galaxies. These galaxies are unusual in the local universe, they represent less than 6 % of […]
Accretion and circumstellar properties of Herbig Ae/Be stars
This work focuses on the massive counterparts of classical T-Tauri stars, the so-called Herbig Ae/Be (HAeBe) stars. These are the most massive objects to experience an optically visible pre-main sequence (PMS) phase, bridging the transition between low and high-mass young stars. Our knowledge about the HAeBe properties is much more limited than that for lower-mass […]
Fotometría óptica desde el espacio: la cámara OMC a bordo de INTEGRAL
El trabajo que presentamos en esta tesis tiene como finalidad la operación, calibración y análisis de datos ópticos del instrumento OMC (Optical Monitoring Camera) a bordo del satélite INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory). La cámara OMC ofrece, por primera vez, la oportunidad de realizar observaciones fotométricas de larga duración en el rango óptico, simultáneamente con […]
Optically selected stellar regions and tidal dwarf galaxies in (ultra)luminous infrared galaxies
Galaxy mergers can transform the type of the parent galaxy into another and, dur- ing their occurrence, drive phenomena that are extraordinary compared to the pro- cesses that take place in quiescent galaxies. Specifically, simulations and observa- tions show that they trigger star formation events, and young objects at least as massive as globular clusters […]
The Lambda Orionis star forming region. Spectroscopic Characterization
The Lambda Orionis Star Forming Region is part of the Orion molecular cloud complex, it is located about 15 degree north of the center of the complex (δ ∼ 10 degrees). λ Ori, itself is the brightest member of Collinder 69, a well-defined, compact open cluster at the center of the star forming region. Two other already identified and […]
The Lambda Orionis star forming region: A multi wavelength approach
The Head of Orion or Lambda Orionis Star Forming Region is part of the Orion molecular cloud complex, but at δ ∼ +10 ◦, it is located about 15◦ north of the center of the complex. The star λ Ori is the brightest member of Collinder 69, a well-defined, compact open cluster at the center of the star forming region. Two other […]