bluuebunny/crossref_metadata_2025_split huggingface dataset:
K-band Evolution of Elliptical Galaxies in the Cluster Abell 2390 at z=0.23
Authors: Alizadeh M. , Fritz A. , Da Rocha C. , Ziegler B. L. 
Published: April 2007

AbstractWe investigate the near-infrared K-band evolution of early-type galaxies in the cluster of galaxies Abell2390 at z = 0.23. Using the Omega-Prime camera at the 3.5-m Calar Alto telescope deep imaging (texp = 53 min) over a 6' × 6' field has been obtained. The measured K-band magnitudes of 28 galaxies are combined with the spectroscopic and morphological data of Fritz et al. (2005) to construct the Faber-Jackson and Fundamental Plane relations in the NIR. By comparing our distant galaxies to a local sample of cluster ellipticals (Pahre 1999), we find on average a mild luminosity evolution for both scaling relations (ΔMK ~ 0.6 − 0.7 mag) compatible with passive evolution of the stellar populations.
Non Adiabatic Evolution of Elliptical Galaxies by Dynamical Friction
Authors: Arena S.E. , Bertin G. , Liseikina T. , Pegoraro F. 
Published: April 2007

AbstractMany astrophysical problems, ranging from structure formation in cosmology to dynamics of elliptical galaxies, refer to slow processes of evolution of essentially collisionless self-gravitating systems. To determine the relevant quasi-equilibrium configuration at time t from given initial conditions, such slow evolution is often approximated in terms of adiabatic evolution. Here we focus on the slow process of evolution induced by dynamical friction of a spherical stellar system (the host galaxy) on a minority component of “satellites” (distributed in a spherical shell), to determine to what extent an adiabatic description might be applied.
Three-Dimensional MHD Simulations of a Subcluster Plasma Moving in Turbulent ICM
Authors: Asai N. , Fukuda N. , Matsumoto R. 
Published: April 2007

AbstractWe carried out 3D magnetohydrodynamic simulations of a subcluster moving in turbulent ICM by including anisotropic heat conduction. Since magnetic fields stretched along the subcluster surface suppress the heat conduction across the front, cold fronts are formed and sustained.
Automated Search for Gravitational Lensing Arcs and Interacting Galaxies in the Red Sequence Survey
Authors: Chiang P. S. , Chen S. Y. , Ip W. , Chen W. P. 
Published: April 2007

AbstractWe have developed a robust and efficient algorithm to identify gravitational lensing arcs and interacting galaxies. The algorithm has been applied to the Red Sequence Survey II (RCS II) data, and we demonstrate a few examples here.
AGES Observations of Abell1367 and its Outskirts
Authors: Cortese L. , Minchin R. F. , Auld R. R. , Davies J. I. , Catinella B. , Momjian E. , Rosenberg J. L. , O'Neil K. ,   The AGES Team
Published: April 2007

AbstractThe Arecibo Galaxy Environment Survey (AGES, Auld et al. 2006) will map ~200 square degrees over the next years using the ALFA feed array at the 305-m Arecibo Telescope. AGES is specifically designed to investigate various galactic environments from local voids to interacting groups and cluster of galaxies. AGES will map 20 square degrees in the Coma-Abell1367 supercluster including the Abell cluster 1367 and its outskirts (up to ~2 virial radii). In Spring 2006 we nearly completed the observations of 5 square degrees in the range 11:34< RA< 11:54, 19:20<Dec<20:20 covering all the cluster core and part of its infalling region reaching a 5 sigma detection limit of M(HI)~4×108M⊙ (assuming a velocity width ~200 km~s−1) at the distance of Abell1367 (~92 Mpc). An HI selected sample has been extracted from the datacube obtaining a catalogue of fluxes, recessional velocities, positions and velocity widths. We present a preliminary analysis of the properties of the HI sources and report the discovery of HI diffuse features within interacting groups at the periphery of Abell1367.
Galaxy Preprocessing in a Starbrusting Group Infalling into Abell1367
Authors: Cortese L. , Gavazzi G. , Boselli A. , Franzetti P. , Kennicutt R. C. , O'Neil K. , Sakai S. 
Published: April 2007

AbstractWe present a multiwavelength analysis of a compact group infalling at high speed (~1700 km s−1) into the dynamically young cluster Abell 1367. Peculiar morphologies and unusually high Halpha emission are associated with two giant galaxies and at least ten dwarfs/extragalactic HII regions, making this group the region with the highest density of star formation activity ever observed in the local clusters. Moreover Halpha imaging observations reveal extraordinary complex trails of ionized gas behind the galaxies, with projected lengths exceeding 100 kpc. These unique cometary trails mark the gaseous trajectory of galaxies, witnessing their dive into the hot cluster intergalactic medium. Under the combined action of tidal forces among group members and the ram-pressure by the cluster ambient medium, the group galaxies were fragmented and the ionized gas was blown out. The properties of this group suggest that environmental effects within infalling groups may have represented a preprocessing step of the galaxy evolution during the high redshift cluster assembly phase.
Dynamical Evolution in Hickson Compact Groups using Intragroup Light
Authors: Da Rocha C. , Ziegler B. L. , de Oliveira C. Mendes 
Published: April 2007

AbstractMost of the galaxies in the local universe are located in groups, in particular in small groups, and most of the transformations suffered by galaxies located in today's clusters are likely to have occurred in groups at higher redshifts. Understanding the formation and evolution of groups is essential to understand the whole picture of structures and galaxy build-up. Using multi-band photometry we studied the intragroup light component (IGL) observed in compact groups of galaxies in a subsample of Hickson's catalogue, an efficient tool for determining its stage of dynamical evolution and for mapping its gravitational potential. Applying the OV_WAV package, a wavelet based technique, we can identify the IGL independently of the main contaminating effects. The fractions of IGL detected range from 11% to 46%, with one group with no IGL detected. The colors are consistent with those for old stellar populations and the mean surface brightnesses range from 24.8 to 28.4 B mag arcsec−2. Using the IGL, along with other dynamical evolution indicators, we could establish an evolutionary sequence for our sample.
E+A Galaxies: Did They Lose The A to Become E?
Authors: De Rijcke Sven , Michielsen D. , Buyle P. , Pisano D. J. , Dejonghe H. , Freeman K. 
Published: April 2007

AbstractWe present deep HI observations of a sample of 9 nearby E+A galaxies (0.05 < z < 0.1). In 7 of them, we detected up to a few times 109 M⊙ of neutral gas, making the link between E+As and early-types less direct than previously thought.
The Different Environmental Dependencies and Evolutions of Giant and Dwarf Galaxies
Authors: Haines C.P. , Gargiulo A. , Mercurio A. , Merluzzi P. , La Barbera F. , Busarello G. , Capaccioli M. 
Published: April 2007

AbstractThe star-formation histories, masses and structural properties of galaxies are strongly dependent on their environment: massive, passively-evolving spheroids dominate cluster cores, while in field regions, galaxies are typically low-mass, star-forming and disk-dominated (e.g Blanton et al. 2005). Equally the global properties of galaxies have been found to be bimodally distributed around a stellar mass of ~3 × 1010 M⊙ (~M*+1) (e.g. Kauffmann et al. 2003). Large-scale spectroscopic surveys have shown that the evolution of massive galaxies is primarily driven by their merger history, rather than through direct interection with the cluster environment, as demonstrated by the finding of massive passively-evolving galaxies in all environments, mild observed environmental trends for their mean stellar ages, and the gradual SF-density relation in which star-formation is still seen to be suppressed in galaxies 3–4 virial radii from the nearest cluster. In contrast, in the dwarf regime (>M*+2) dramatic changes are seen in both the luminosity function and red galaxy fraction between those galaxies in the cores of clusters and those at the virial radius (Mercurio et al. 2006, Haines et al. 2006a).We have examined the origins of the bimodality observed in the global properties of galaxies by comparing the environmental dependencies of star-formation for giant and dwarf galaxy populations. Using SDSS DR4 spectroscopic data to create a volume-limited sample complete to M*+3, we find that the environmental dependences of giant and dwarf galaxies are quite different, implying fundamental differences in their evolution (Haines et al. 2006b). Whereas the star-formation histories of giant galaxies are determined primarily by their merger history, this is not the case for dwarf galaxies. In particular, we find that old or passive dwarf galaxies are ONLY found as satellites within massive halos (clusters, groups or giant galaxies), with none in the lowest density regions. This implies that star-formation in dwarf galaxies must be much more resilient to the effects of mergers, and that the evolution of dwarf galaxies is primarily driven by the mass of their host halo, through effects such as suffocation, ram-pressure stripping or galaxy harassment.
X-ray Morphology of Clusters of Galaxies and its Application
Authors: Hashimoto Y. , Boehringer H. , Henry J. P. , Hasinger G. , Szokoly G. 
Published: April 2007

AbstractWe report our study of X-ray cluster morphology using a sample of 101 clusters of galaxies at redshift z~0.05-1 taken from the Chandra archive.
Extremely Red Galaxies in Abell 1835
Authors: Hempel A. , Schaerer D. , Richard J. , Egami E. , Pelló R. 
Published: April 2007

AbstractWe use multi-colour data of the gravitational lensing cluster Abell 1835 to search for high-z candidates (Richard et al. 2006) and extremely red galaxies.Applying a colour criteria of R-K ≥ 5.6 we have selected 12 EROs, of which 10(9) have no R(I)-band detection. Two of these sources posses multiple detections in the ACS z850 band, possibly gravitationally bound objects.Using the method of Pozzetti and Mannucci (2000) to classify an ERO either as evolved elliptical or dusty starburst, we find that two thirds of all objects have colours assigned to evolved ellipticals. One of the remaining 4 sources is the known sub-mm source SMMJ14009+0252.The spectral energy distributions of sources with no optical detection show strong similarities to the SED of the high-z object of Mobasher et al. (2005), i.e. a degeneracy between a low- and high-z solution. However, for objects we accept the low-z solution as the better fit.A detailed analyses of the colour properties and spectral energy distribution will be published in two forthcoming papers (Schaerer et al., Hempel et al.).
Nature of X-ray Sources From the Field of Nearby, Poor Cluster of Galaxies
Authors: Hudaverdi M. , Kunieda H. , Ercan E.N. 
Published: April 2007

AbstractA194 and A1060 are studied for the nature of point source properties. X-ray to optical luminosity ratios (Lx/Lb) are evaluated for selected galaxies. Cumulative log(N)-log(S) and intrinsic luminosity functions are applied for a comparative evaluation with Lockman Hole. 46 and 32 X-ray point sources are detected by EPIC-PN, for A194 and A1060 respectively. The XLF space density shows significant excess compared to field and local group space density. The result is interpreted as the fueling of AGNs as they enter the ICM from outskirts of the clusters and dimming of the very bright AGNs as they further proceed into cluster core.
The Structure and Interaction History of Moderate Luminosity Mergers
Authors: Hüttemeister Susanne , Manthey Eva 
Published: April 2007

AbstractInteraction and merging are the two most important driving forces of galaxy evolution. In contrast to the well studied major mergers of two large gas-rich disk galaxies, which may lead to Ultraluminous Infrared Galaxies (ULIRGs, LFIR>1012 L⊙), mergers between galaxies of unequal mass or a spiral and an elliptical (S+E mergers) are still poorly understood. These moderate luminosity mergers typically have LFIR > 1011 L⊙. Here, we present the results of our multiwavelength study of a sample of such kind of mergers, including interferometric HI and single-dish CO observations, optical and near-infrared imaging as well as optical spectroscopy.
New Kinematics for the Central Spheroid in Polar Disk Galaxy NGC4650A
Authors: Iodice E. , Arnaboldi M. , Saglia R. , Sparke L. , Gerhard O. 
Published: April 2007

AbstractWe have obtained high angular resolution spectra on the photometric axes of the stellar spheroid in the polar disk galaxy NGC4650A. We discuss the main implications by the new kinematics on the previous mass models for NGC4650A and on current formation scenarios of Polar Ring Galaxies (PRGs).
The Kelvin-Helmholtz Instability in Smoothed-Particle Hydrodynamics
Authors: Junk Veronika , Heitsch Fabian , Naab Thorsten 
Published: April 2007

AbstractSmoothed Particle Hydrodynamics (SPH) simulations are a powerful tool to investigate hydrodynamical processes in astrophysics such as the formation of galactic disks. Dense gas clouds raining on the forming disk are possibly disrupted by Kelvin-Helmholtz-Instabilities (KHI). To understand the evolution of the halo clouds, we have to ascertain the capability of SPH to treat the KHI correctly, since SPH-methods tend to suffer from an innate surface tension and viscosity effects, both of which could dampen the KHI. We analytically derive a growth rate of the KHI including surface tension and viscosity in the linear regime, and compare this growth rate to results of numerical simulations by an SPH method and a grid-based method. We find that SPH in some cases suppresses the KHI (Junk et al., in prep).
Mid- and Far-Infrared Study of X-ray-emitting Dusty Elliptical Galaxies
Authors: Kaneda H. , Onaka T. , Kitayama T. , Okada Y. , Sakon I. 
Published: April 2007

AbstractWe study nearby X-ray-emitting dusty elliptical galaxies in mid- and far-infrared by using the Spitzer Space Telescope and AKARI, the Japanese infrared astronomical satellite.
Metal Enrichment Processes in the ICM – Starbursts and Galactic Winds
Authors: Kapferer W. , Kronberger T. , Domainko W. , Schindler S. , van Kampen E. , Kimeswenger S. , Ruffert M. , Mair M. , Breitschwerdt D. 
Published: April 2007

AbstractWe present an investigation of the metal enrichment of the intra-cluster medium (ICM) by galactic winds and merger-driven starbursts. We use combined N-body/hydrodynamic simulations with a semi-numerical galaxy formation model. The inhomogeneities in the metal distribution caused by these processes are an ideal tool to reveal the dynamical state of a galaxy cluster. We show that X-ray weighted metal maps distinguish between pre- or post-merger galaxy clusters by comparing the metallicity distribution with the galaxy-density distribution: pre-mergers have a metallicity gap between the subclusters, post-mergers a high metallicity between subclusters.
Fossil Galaxy Groups; Scaling Relations, Galaxy Properties and Formation of BCGs
Authors: Khosroshahi Habib G. , Ponman T. J. 
Published: April 2007

AbstractWe study fossil galaxy groups, their hot gas and the galaxy properties. Fossils are more X-ray luminous than non-fossil groups, however, they fall comfortably on the conventional L-T relation of galaxy groups and clusters indicating that their X-ray luminosity and temperature are both boosted, arguably, as a result of their early formation. The central dominant galaxy in fossils have optical luminosity comparable to the brightest cluster galaxies (BCGs), however, the isophotal shapes of the central galaxy in fossils are non-boxy in contrast to the isophotes of majority of the BCGs.
Internal Kinematics of Modelled Isolated and Interacting Disc Galaxies
Authors: Kronberger T. , Kapferer W. , Schindler S. , Böhm A. , Kutdemir E. , Ziegler B. L. 
Published: April 2007

AbstractWe present a systematic investigation of the velocity fields of both isolated and interacting spiral galaxies in combined N-body/hydrodynamical simulations. Closely mimicking the procedures applied in observations of distant, small, and faint galaxies we extract rotation curves (RCs) and compare the results of the simulation directly to observations. Irregularities in the velocity field reflect disturbances in the gravitational potential of the galaxy. They can be used to trace the recent interaction history of a galaxy and give possible clues to the type of the respective interaction. In addition, identifying disturbances in the RCs is important for Tully-Fisher studies in order to accurately derive the maximum rotation velocity.
The Far-Infrared Properties of the Most Isolated Galaxies
Authors: Lisenfeld U. , Verdes-Montenegro L. , Sulentic J. , Leon S. , Espada D. , Bergond G. , García E. , Sabater J. , Santander-Vela J. D. , Verley S. 
Published: April 2007

AbstractWe describe the mid- (MIR) and far- (FIR) infrared properties of a large (~1000) sample of the most isolated galaxies in the local Universe. This sample is intended as a “nurture-free” zero point against which more environmentally influenced samples can be compared. We reprocess IRAS MIR/FIR survey data using the ADDSCAN/SCANPI utility for 1030 out of 1050 galaxies from the Catalogue of Isolated Galaxies (CIG) as part of the AMIGA project. We focus on diagnostics (FIR luminosity LFIR, R = log(LFIR/LB) and IRAS colours) thought to be sensitive to effects of environment or interaction. The distribution of log(LFIR) is sharply peaked from 9.0–10.5 with very few (<2%) galaxies above 10.5. Review of available optical images of the most FIR luminous galaxies finds the majority to be, likely, interacting systems missed in our earlier morphological reevaluation. The optically normalised luminosity diagnostic R = log(LFIR/LB) shows a distribution sharply peaked between 0.0 and −1.0. These results were compared to the magnitude limited CfA sample that was selected without environmental discrimination. This modestly (e.g. compared to cluster, binary galaxy and compact group samples) environmentally affected sample shows significantly higher mean log(LFIR) and R, whereas the mean log(LB) is the same. Our sample shows a strong LFIR vs. LB correlation, with a slope steeper than one (LFIR ∝ L1.41B). Interacting galaxies were found above this correlation, showing an enhancement in LFIR. With respect to the IRAS colours, we found higher F60/F100 value for ellipticals and late-type galaxies than for spirals, indicating a higher dust temperature. The mean value of F60/F100 was found to be lower than for interacting samples from the literature. The results indicate that the FIR emission is a variable enhanced by interaction, and that our sample probably shows the lowest possible mean value. This attests to the utility of our sample for defining a nurture-free zero point. More details can be found in the paper (The AMIGA sample of isolated galaxies, III. IRAS data and infrared diagnositics, U. Lisenfeld et al.) which is accepted for publication in Astronomy & Astrophysics.
Nuclear Activity in UZC Compact Groups
Authors: Martinez M. A. , del Olmo A. , Focardi P. , Perea J. 
Published: April 2007

AbstractWe have analyzed the level and type of nuclear activity in 720 galaxies belonging to a large complete sample of Compact Groups (UZC-CGs). We have found that most (67%) galaxies show emission lines and that the most frequent (43%) nuclear activity is AGN. AGNs are mainly hosted in bright early type galaxies and early spirals, at variance with HII which reside in late spirals of lower luminosity. CGs which have a dominant content of AGNs and TOs have larger σv and lower Rp than CGs dominated by HII.
Galaxy Transformations in Different Environments of the Shapley Supercluster
Authors: Mercurio A. , Merluzzi P. , Haines C. P. , Gargiulo A. , Busarello G. , La Barbera F. , Capaccioli M. 
Published: April 2007

AbstractWe studied ~ 2 deg2 region in the Shapley Supercluster (SSC) core at z~0.05 in two bands (B and R). By studying the galaxy luminosity function (LF) and the colour distribution of galaxies we find that processes directly related to the supercluster environment are responsible for transforming faint galaxies, rather than galaxy merging.
Galaxy Evolution Traced by Multiple Galaxies from the BIG Sample
Authors: Mickaelian Areg M. 
Published: April 2007

AbstractOptical identifications of all IRAS PSC sources at high galactic latitudes by means of the First Byurakan Survey (FBS) in the area with +61° < δ < +90° at galactic latitudes |b|>15° have been carried out with a total surface of 1487 deg2. 1577 sources have been optically identified, 1178 sources corresponding to galaxies. The BIG sample (Byurakan-IRAS Galaxies) was constructed of 1178 newly identified galaxies and 789 other IRAS galaxies in the same area, known before, altogether 1967 galaxies. Studies of the BIG objects include: spectroscopic follow-up for the brighter (<18m) objects; discovery and study of new AGN; discovery and study of new ULIRGs; deep imagery of the most interesting objects and the “empty fields”; 2D spectroscopy of interacting/merging systems; search for obscured IRAS galaxies (with the Spitzer Space Telescope), etc. The BIG objects are a rich source for new AGN, high-luminosity IR galaxies (hence, starburst activity), and interacting/merging systems. All these phenomena are crucial for understanding the galaxy evolution and their interrelation, as well as the triggering of the powerful IR radiation. In frame of the redshift survey of these galaxies, spectroscopic observations have been carried out for the BIG objects (including the pairs and multiples) by means of the Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m, and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. It is shown that, without an exception, all double/multiple BIG systems are physical pairs or groups, and they are mostly interacting and/or merging systems. From the high IR luminosities derived from the observations, one can conclude that perhaps the ULIRG/HLIRG phenomenon is connected with galaxy interactions/merging. We find an evolution in luminosity function of these objects with respect to their redshift distribution.Existence of AGN among the multiple BIG objects provides a chance for study of the galaxy evolution in sense of interrelationship between the three phenomena: starburst, interactions/merging, and nuclear activity. We have shown (Mickaelian et al. 2001) that the maximum IR luminosity of a single spiral galaxy may not be larger than 1012 Solar luminosities. Hence, all high-L IRAS galaxies are interacting pairs/multiples or mergers. But what is the relation of the active nucleus to the starburst (i.e. IR) activity?