Subvenciones relacionadas:
General
Las estructuras en el Universo, a todas las escalas de masa, se han formado de una forma jerárquica y principalmente producidas por fusiones de galaxias. Sin embargo, esta formación jerárquica de las galaxias está modulada por el entorno en el cual se crean y evolucionan. Mientras que las galaxias de campo presentan una evolución pasiva, los cúmulos de galaxias son entornos de muy alta densidad donde las galaxias interaccionan unas con otras y con el gas intracumular caliente (ICM). Además, la dinámica de los cúmulos está dominada por la alta densidad y cantidad de materia oscura presente en los mismos y que provoca elevados potenciales gravitatorios. Por todo ello, los cúmulos de galaxias son sistemas complejos con múltiples componentes (galaxias, ICM, materia oscura) que evolucionan de manera acoplada. La mezcla de todas estas componentes, así como sus interacciones, hacen de los cúmulos de galaxias laboratorios ideales donde estudiar una gran variedad de mecanismos que provocan que la evolución de galaxias en estos entornos de alta densidad sea muy diferente a la de las galaxias de campo.
El objetivo de este proyecto es estudiar la formación y evolución de las galaxias en estos entornos densos. Se pretende entender en que entorno domina cada uno de los mecanismos de transformación de galaxias propuestos por las simulaciones numéricas y como se produce la evolución de los diferentes tipos de galaxias (tanto brillantes como enanas) en los cúmulos. Cuantificar observacionalmente la eficiencia de estos mecanismos no es una tarea sencilla ya que se conoce que muchos de ellos actúan a la vez, lo hacen en escalas de tiempo muy diferentes, y en regiones del cúmulo también diversas. Sin embargo, hay una serie de evidencias observacionales que pueden ser directamente contrastadas: i) distribución morfológica y estructural de las galaxias de los cúmulos; ii) función de luminosidad de galaxias en cúmulos; iii) luz difusa (cantidad y distribución); iv) presencia de subestructuras galácticas dentro de los cúmulos; v) propiedades espectro-fotométricas de las galaxias enanas y brillantes; vi) propiedades del ICM. Todos estos observables proporcionan la información necesaria para entender la relación entre entorno y evolución galáctica. Estas son las cantidades que se mediran en este proyecto para muestras amplias de cúmulos de galaxias.
Miembros
Resultados
- Forma Intrínseca de las Barras Galácticas. Se encontró, por primera vez, que el 52% (16%) de los bulbos son más gruesos (más planos) que la barra circundante. Se sugiere que estos porcentajes podrían ser representativos de la fracción de bulbos clásicas y tipo disco en nuestra muestra, respectivamente.
- La Influencia del Medio Ambiente en la Parada de la Formación de Estelar. Nuestros resultados indican que en entornos de baja densidad, las galaxias post-starburst se forman por fusiones menores ricas en gas, mientras que en entornos de alta densidad, las PSB se producirían al eliminar los depósitos de gas de las galaxias de líneas de emisión por presión de arrastre.
- Propiedades Morfo-Cinemáticas de los Bulbos Galácticos. Se encontró que los diagnósticos fotométricos para separar diferentes tipos de bulbos (tipo disco vs clásico) podrían no ser útiles para galaxias S0. Usando las propiedades morfo-cinemáticas de los bulbos en S0, se sugiere que estos se forman principalmente por procesos disipativos a alto redshift.
Actividad científica
Publicaciones relacionadas
-
The Alhambra Survey: a Large Area Multimedium-Band Optical and Near-Infrared Photometric SurveyHere we describe the first results of the Advanced Large Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) survey, which provides cosmic tomography of the evolution of the contents of the universe over most of cosmic history. Our novel approach employs 20 contiguous, equal-width, medium-band filters covering from 3500 Å to 9700 Å, plusMoles, M. et al.
Fecha de publicación:
92008 -
Structural properties of disk galaxies. I. The intrinsic equatorial ellipticity of bulgesContext: A variety of formation scenarios have been proposed to explain the diversity of properties observed in bulges. Studying their intrinsic shape can help to constrain the dominant mechanisms at the epochs of their assembly. Aims: The structural parameters of a magnitude-limited sample of 148 unbarred S0-Sb galaxies were derived in order toMéndez-Abreu, J. et al.
Fecha de publicación:
22008 -
Stellar physics with the ALHAMBRA photometric systemThe ALHAMBRA photometric system was specifically designed to perform a tomography of the Universe in some selected areas. Although mainly designed for extragalactic purposes, its 20 contiguous, equal-width, medium-band photometric system in the optical wavelength range, shows a great capacity for stellar classification. In this contribution weAparicio Villegas, T. et al.
Fecha de publicación:
122011 -
Search for Blue Compact Dwarf Galaxies During Quiescence. II. Metallicities of Gas and Stars, Ages, and Star Formation RatesWe examine the metallicity and age of a large set of Sloan Digital Sky Survey/Data Release 6 galaxies that may be blue compact dwarf (BCD) galaxies during quiescence (QBCDs). The individual spectra are first classified and then averaged to reduce noise. The metallicity inferred from emission lines (tracing ionized gas) exceeds by ~0.35 dex theSánchez Almeida, J. et al.
Fecha de publicación:
62009 -
Revisiting the Hubble sequence in the SDSS DR7 spectroscopic sample: a publicly available Bayesian automated classificationWe present an automated morphological classification in 4 types (E, S0, Sab, Scd) of ~700 000 galaxies from the SDSS DR7 spectroscopic sample based on support vector machines. The main new property of the classification is that we associate a probability to each galaxy of being in the four morphological classes instead of assigning a single classHuertas-Company, M. et al.
Fecha de publicación:
12011 -
Quasi-stellar objects in the ALHAMBRA survey. I. Photometric redshift accuracy based on 23 optical-NIR filter photometryContext. Even the spectroscopic capabilities of today's ground and space-based observatories can not keep up with the enormous flow of detections (>105 deg-2) unveiled in modern cosmological surveys as: i) would be required enormous telescope time to perform the spectroscopic follow-ups and ii) spectra remain unattainable for the fainter detectedMatute, I. et al.
Fecha de publicación:
62012 -
Properties of the Photometric Components of Lenticular GalaxiesAfter almost one century since their definition, the origin of lenticular galaxies is still a matter of debate. Several formation processes have been proposed in order to explain the wide variety of their observational properties. These properties could indicate that the class of lenticulars is a family formed by galaxies with different formationsAguerri, J. A. L.
Fecha de publicación:
02012 -
Properties of the Dwarf Galaxy Population in Galaxy ClustersWe present the observational properties of the dwarf galaxy population (Mr>M*r+1) corresponding to one of the largest samples of spectroscopically confirmed nearby galaxy cluster members reported in the literature. We have observed that red dwarf galaxies (u-r>2.22) share the same cluster environment as the brightest cluster members (MrSánchez-Janssen, R. et al.
Fecha de publicación:
62008 -
Optimal Filter Systems for Photometric Redshift EstimationIn the coming years, several cosmological surveys will rely on imaging data to estimate the redshift of galaxies, using traditional filter systems with 4-5 optical broad bands; narrower filters improve the spectral resolution, but strongly reduce the total system throughput. We explore how photometric redshift performance depends on the number ofBenítez, N. et al.
Fecha de publicación:
22009 -
On the origin of dwarf elliptical galaxies: the fundamental planeContext: Early-type dwarf (dE) galaxies are the most common type of galaxies observed in the Universe. Their study has important cosmological implications because according to hierarchical galaxy evolution theories they are the progenitors of brighter galaxies. Nevertheless, the origin of this kind of system is still not well understood. Aims: TheAguerri, J. A. L. et al.
Fecha de publicación:
22009 -
Near-Infrared Galaxy Counts and Evolution from the Wide-Field ALHAMBRA SurveyThe ALHAMBRA survey aims to cover 4 deg2 using a system of 20 contiguous, equal width, medium-band filters spanning the range 3500 Å-9700 Å plus the standard JHKs filters. Here we analyze deep near-IR number counts of one of our fields (ALH08) for which we have a relatively large area (0.5 deg2) and faint photometry (J = 22.4, H = 21.3, and K = 20Cristóbal-Hornillos, D. et al.
Fecha de publicación:
52009 -
Intracluster light in the Virgo cluster: large scale distributionAims: The intracluster light (ICL) is a faint diffuse stellar component of clusters made of stars that are not bound to individual galaxies. We have carried out a large scale study of this component in the nearby Virgo cluster. Methods: The diffuse light is traced using planetary nebulae (PNe). The surveyed areas were observed with a narrow-bandCastro-Rodriguéz, N. et al.
Fecha de publicación:
112009 -
Globular cluster systems as tracers of environmental effects on Virgo early-type dwarfsEarly-type dwarfs (dEs) are by far the most abundant galaxy population in nearby clusters. Whether these objects are primordial, or the recent end products of the different physical mechanisms that can transform galaxies once they enter these high-density environments, is still a matter of debate. Here we present a novel approach to test theseSánchez-Janssen, R. et al.
Fecha de publicación:
82012 -
Fossil groups origins. I. RX J105453.3+552102 a very massive and relaxed system at z ~ 0.5Context. The most accepted scenario for the origin of fossil groups is that they are galaxy associations in which the merging rate was fast and efficient. These systems have assembled half of their mass at early epoch of the Universe, subsequently growing by minor mergers, and therefore could contain a fossil record of the galaxy structureAguerri, J. A. L. et al.
Fecha de publicación:
32011 -
Fossil group origins. II. Unveiling the formation of the brightest group galaxies through their scaling relationsContext. Fossil systems are galaxy associations dominated by a relatively isolated, bright elliptical galaxy, surrounded by a group of smaller galaxies lacking L∗ objects. Because of this extreme environment, fossil groups (FGs) are ideal laboratories for studying the mass assembly of brightest group galaxies (BGGs). Aims: We analyzed the nearMéndez-Abreu, J. et al.
Fecha de publicación:
12012 -
Expansion Velocities and Core Masses of Bright Planetary Nebulae in the Virgo ClusterThe line-of-sight velocities and [O III] 5007 Å expansion velocities are measured for 11 planetary nebulae (PNs) in the Virgo Cluster core, at 15 Mpc distance, with the FLAMES spectrograph on the ESO VLT. These PNs are located about halfway between the two giant elliptical galaxies M87 and M86. From the [O III] 5007 Å line profile widths, theArnaboldi, Magda et al.
Fecha de publicación:
22008 -
Evolution of Brightest Cluster Galaxy Structural Parameters in the Last ~6 Gyr: Feedback Processes Versus Merger EventsWe present results on the evolution of the structural parameters of two samples of brightest cluster galaxies (BCGs) in the last 6 Gyr. The nearby sample of BCGs consists of 69 galaxies from the WINGS survey spanning a redshift range of 0.04 z 0.07. The intermediate-redshift (0.3 z 0.6) sample is formed by 20 BCGs extracted from the HubbleAscaso, B. et al.
Fecha de publicación:
12011 -
Dissecting the morphological and spectroscopic properties of galaxies in the local Universe. I. Elliptical galaxiesAims: We revisit the scaling relations and star-forming histories of local elliptical galaxies using a novel selection method applied to the Sloan Digital Sky Survey DR7. Methods: We combine two probability-based automated spectroscopic and morphological classifications of ~600 000 galaxies with z 0.25 to isolate true elliptical galaxies. OurAguerri, J. A. L. et al.
Fecha de publicación:
42012 -
Constraining the formation of inner bars: photometry, kinematics and stellar populations in NGC 357Double-barred galaxies are common in the local Universe, with approximately one-third of barred spirals hosting a smaller, inner bar. Nested bars have been proposed as a mechanism to transport gas to the very central regions of the galaxy, trigger star formation and contribute to the growth of the bulge. To test this idea, we perform for the firstde Lorenzo-Cáceres, A. et al.
Fecha de publicación:
22012 -
Confirmation of a Kinematic Diagnostic for Face-On Box/Peanut-shaped BulgesWe present the results of high-resolution absorption-line spectroscopy of three face-on galaxies, NGC 98, NGC 600, and NGC 1703, with the aim of searching for box/peanut (B/P) shaped bulges. These observations test and confirm, for the first time, the prediction that face-on B/P-shaped bulges can be recognized by two minima in the profile along theMéndez-Abreu, J. et al.
Fecha de publicación:
62008