Start year
2004
Organizational Unit
Organizing institutions
Grants related:
General
Description
Galaxies in the universe can be located in different environments, some of them are isolated or in low density regions and they are usually called field galaxies. The others can be located in galaxy associations, going from loose groups to clusters or even superclusters of galaxies. One of the foremost challenges of the modern Astrophysics is to achieve a complete theory about galaxy evolution. This theory should explain the relation between the environment and galaxy evolution. Galaxy clusters are high density environments where galaxies interact one to each other and with the intracluster material (ICM). In addition, the cluster dynamics is driven by the high density and quantity of dark matter present in them. Therefore, galaxy clusters are complex systems with multiple components (galaxies, ICM, dark matter) which are tightly bounded. The mix of all these components, as well as their interactions, makes galaxy clusters ideal laboratories to study the different mechanisms which cause the different evolution of galaxies in this high density environments with respect to field galaxies.
The objective of this project is to study the formation and evolution of galaxies in these dense environments. The ‘Galaxy Evolution in Clusters’ group intend to understand in what environment each of the mechanisms proposed by numerical simulations to transform the galaxies dominates and how the evolution of the different types of galaxies (both bright and dwarf) occurs in the clusters. Quantifying observationally the efficiency of these mechanisms is not an easy task since many of them act at the same time, they do it in very different time scales, and in diverse regions of the cluster. However, there are some observational evidences that can be directly contrasted: i) morphological and structural distribution of the galaxies of the clusters; ii) luminosity function of galaxies in clusters; iii) diffuse light (quantity and distribution); iv) presence of galactic substructures within the clusters; v) spectro-photometric properties of dwarf and bright galaxies; vi) ICM properties. All these observables provide the necessary information to understand the relationship between environment and galactic evolution. These are the quantities this project aims at measuring for large samples of galaxy clusters.
Members
Principal investigator
Jairo
Méndez Abreu
Project staff
Rafael Delfin
Barrena Delgado
Casiana
Muñoz Tuñón
Claudio
Dalla Vecchia
Dr.
Walter Boschin
José Alfonso
López Aguerri
LILIAN FÁTIMA
DOMÍNGUEZ PALMERO
Collaborators
Dr.
E.M. Corsini
Dr.
L. Morelli
Dr.
J.M. Vílchez
Dr.
J. Iglesias
Dr.
C. del Burgo
Dr.
E. Jiménez Bailon
Dr.
S. Sánchez
Dr.
S. Borgani
Dr.
A. Biviano
Dr.
V. Debattista
Dr.
E. D'Onghia
Dr.
M. Arnaboldi
Dr.
O. Gerhard
Dr.
R. Sánchez Janssen
Dr.
A. Diaferio
Dr.
V. Wild
Dr.
S. Zarattini
Dr.
A. Aragón Salamanca
Dr.
R. Peletier
Dr.
S. Trager
Dr.
G. Dalton
Dr.
M. Girardi
Dr.
L. Constatin
Results
- Intrinsic Shape of Galactic Bars. We find, for the first time, that 52% (16%) of bulges are thicker (flatter) than the surrounding bar. We suggest that these percentages might be representative of the fraction of classical and disc-like bulges in our sample, respectively.
- The Influence of the Environment in the Star Formation Quenching. Our results indicate that in low-density environments, post-starburst galaxies are formed by gas-rich minor mergers or accretions, whereas for high-density environments PSBs would be produced by the removal of the gas reservoirs of emission line galaxies by ram-pressure stripping.
- Morpho-Kinematic Properties of Galactic Bulges. We find that photometric diagnostics to separate different types of bulges (disc-like versus classical) might not be useful for S0 galaxies. Using the morpho-kinematics properties of S0 bulges derived in this paper we suggest that they are mainly formed by dissipational processes happening at high redshift.
Scientific activity
Related publications
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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.
Advertised on:
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.
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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.
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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.
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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.
Advertised on:
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.
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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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
Advertised on:
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.
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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.
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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.
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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.
Advertised on:
62008
![Izquierda - Imagen RGB de la nebulosa de Orión y M43 obtenida filtros estrechos con la cámara WFC en el INT: H alfa (rojo), [S II] 6716+30 (verde), [O III] 5007 (azul). Derecha - Imagen en falso color de la nebulosa planetaria NGC 6778. En azul se ve la emisión en la línea de O II tomada con el filtro sintonizable azul del instrumento OSIRIS en el GTC; en verde imagen con el filtro estrecho de [O III] del Nordic Optical Telescope (NOT).](/sites/default/files/styles/crop_square_2_2_to_320px/public/images/project/imagen_web.jpg?itok=fsBmV9CO "Izquierda - Imagen RGB de la nebulosa de Orión y M43 obtenida filtros estrechos con la cámara WFC en el INT: H alfa (rojo), [S II] 6716+30 (verde), [O III] 5007 (azul). Derecha - Imagen en falso color de la nebulosa planetaria NGC 6778. En azul se ve la emisión en la línea de O II tomada con el filtro sintonizable azul del instrumento OSIRIS en el GTC; en verde imagen con el filtro estrecho de [O III] del Nordic Optical Telescope (NOT).")
