bluuebunny/crossref_metadata_2025 huggingface dataset:
Maximum efficiency of wind turbine rotors using Joukowsky and Betz approaches
Authors: OKULOV V. L. , SØRENSEN J. N.
Published: April 2010

On the basis of the concepts outlined by Joukowsky nearly a century ago, an analytical aerodynamic optimization model is developed for rotors with a finite number of blades and constant circulation distribution. In the paper, we show the basics of the new model and compare its efficiency with results for rotors designed using the optimization model of Betz.
Extended self-similarity works for the Burgers equation and why
Authors: CHAKRABORTY SAGAR , FRISCH URIEL , RAY SAMRIDDHI SANKAR
Published: April 2010

Extended self-similarity (ESS), a procedure that remarkably extends the range of scaling for structure functions in Navier–Stokes turbulence and thus allows improved determination of intermittency exponents, has never been fully explained. We show that ESS applies to Burgers turbulence at high Reynolds numbers and we give the theoretical explanation of the numerically observed improved scaling at both the IR and UV end, in total a gain of about three quarters of a decade: there is a reduction of subdominant contributions to scaling when going from the standard structure function representation to the ESS representation. We conjecture that a similar situation holds for three-dimensional incompressible turbulence and suggest ways of capturing subdominant contributions to scaling.
Patient Groups and the Construction of the Patient-Consumer in Britain: An Historical Overview
Authors: MOLD ALEX
Published: April 2010

This article presents an historical overview of the changing meaning of the patient-consumer, and specifically the role played by patient groups in constructing the patient as consumer. It is argued that patient groups were central to the formation of the patient-consumer, but as health consumerism was taken on by the state, they lost control of this figure. Competing understandings of what it meant to be a patient-consumer developed, a shift that raises further questions about the unity of claims made in the name of the patient-consumer.
Study of the Helium Enrichment in Globular Clusters
Authors: Valcarce Aldo A. R. , Catelan Márcio
Published: April 2010

Globular clusters (GCs) are spheroidal concentrations typically containing of the order of 105 to 106, predominantly old, stars. Historically, they have been considered as the closest counterparts of the idealized concept of “simple stellar populations.” However, some recent observations suggest than, at least in some GCs, some stars are present that have been formed with material processed by a previous generation of stars. In this sense, it has also been suggested that such material might be enriched in helium, and that blue horizontal branch stars in some GCs should accordingly be the natural progeny of such helium-enhanced stars. In this contribution we show that, at least in the case of M3 (NGC 5272), the suggested level of helium enrichment is not supported by the available, high-precision observations.
MILES SSP Models
Authors: Vazdekis A. , Sánchez-Blázquez P. , Falcón-Barroso J. , Cenarro A. J. , Beasley M. A. , Cardiel N. , Gorgas J. , Peletier R.
Published: April 2010

We present SEDs for single-age, single-metallicity stellar populations (SSPs) covering the full optical spectral range at resolution (FWHM = 2.3Å). These SEDs can be regarded as our base models, as we combine scaled-solar isochrones with an empirical stellar spectral library (MILES), which follows the chemical evolution pattern of the solar neighbourhood. The models rely as much as possible on empirical ingredients as also employ extensive photometric libraries. Thanks to the unprecedented parameter coverage of the MILES library we synthesize SSP SEDs from intermediate- to very-old age regimes, and the metallicity from super-solar to [M/H] = −2.3, all for a suite of IMF shapes and slopes. We propose a new Line Index System (LIS), based on flux-calibrated spectra, to avoid the intrinsic uncertainties associated with the Lick/IDS system and provide more appropriate, uniform, spectral resolution.
Spectral Evolution Models for the Next Decade
Authors: Leitherer Claus
Published: April 2010

Spectral evolution models are a widely used tool for determining the stellar content of galaxies. I provide a review of the latest developments in stellar atmosphere and evolution models, with an emphasis on massive stars. In contrast to the situation for low- and intermediate-mass stars, the current main challenge for spectral synthesis models are the uncertainties and rapid revision of current stellar evolution models. Spectral libraries, in particular those drawn from theoretical model atmospheres for hot stars, are relatively mature and can complement empirical templates for larger parameter space coverage. I introduce a new ultraviolet spectral library based on theoretical radiation-hydrodynamic atmospheres for hot massive stars. Application of this library to star-forming galaxies at high redshift, i.e., Lyman-break galaxies, will provide new insights into the abundances, initial mass function and ages of stars in the very early universe.
A simple model to interpret the ultraviolet, optical and infrared SEDs of galaxies
Authors: da Cunha Elisabete , Charlot Stéphane , Elbaz David
Published: April 2010

We present a simple, largely empirical but physically motivated model, which is designed to interpret consistently multi-wavelength observations from large samples of galaxies in terms of physical parameters, such as star formation rate, stellar mass and dust content. Our model is both simple and versatile enough to allow the derivation of statistical constraints on the star formation histories and dust contents of large samples of galaxies using a wide range of ultraviolet, optical and infrared observations. We illustrate this by deriving median-likelihood estimates of a set of physical parameters describing the stellar and dust contents of local star-forming galaxies from the Spitzer Infrared Nearby Galaxy Sample (SINGS) and from a newly-matched sample of SDSS galaxies observed with GALEX, 2MASS, and IRAS. The model reproduces well the observed spectral energy distributions of these galaxies across the entire wavelength range from the far-ultraviolet to the far-infrared. We find important correlations between the physical parameters of galaxies which are useful to investigate the star formation activity and dust properties of galaxies. Our model can be straightforwardly applied to interpret observed ultraviolet-to-infrared spectral energy distributions (SEDs) from any galaxy sample.
Resolved maps of stellar mass and SED of galaxies from optical/NIR imaging and SPS models
Authors: Zibetti Stefano , Charlot Stéphane , Rix Hans-Walter
Published: April 2010

We report on the method developed by Zibetti, Charlot & Rix (2009) to construct resolved stellar mass maps of galaxies from optical and NIR imaging. Accurate pixel-by-pixel colour information (specifically g – i and i – H) is converted into stellar mass-to-light ratios with typical accuracy of 30%, based on median likelihoods derived from a Monte Carlo library of 50,000 stellar population synthesis models that include dust and updated TP-AGB phase prescriptions. Hence, surface mass densities are computed. In a pilot study, we analyze 9 galaxies spanning a broad range of morphologies. Among the main results, we find that: i) galaxies appear much smoother in stellar mass maps than at any optical or NIR wavelength; ii) total stellar mass estimates based on unresolved photometry are biased low with respect to the integral of resolved stellar mass maps, by up to 40%, due to dust obscured regions being under-represented in global colours; iii) within a galaxy, on local scales colours correlate with surface stellar mass density; iv) the slope and tightness of this correlation reflect/depend on the morphology of the galaxy.
The Virgo Stellar Stream: Extended sample
Authors: Duffau S. , Vivas A. K. , Zinn R. , Méndez R. A. , Ruiz M. T.
Published: April 2010

We have completed a spectroscopic study of the “12.4 hr clump”, the second largest substructure in the Quasar Equatorial Survey Team (QUEST) catalog. First discovered as an over-density of RR Lyrae stars (Vivas et al. 2001, ApJL 554 33), the region containing the “12.4 hr clump” has generated much interest (Newberg et al. (2002), Martinez-Delgado et al. (2007), Juric et al. (2008), amongst many others). Our first spectroscopic study of this clump revealed the presence of a sharp peak in the radial velocity histogram for the candidate stars (Duffau et al. 2006). The combination of this result and metal abundance estimates for the sample was then interpreted as a signature of the presence of a stellar stream within the clump. This sub-structure was named the “Virgo Stellar Stream” (VSS), given its location in the direction of the Virgo Constellation, at approximately 20 kpc from the Sun. Several other groups have studied this region and have suggested that the over-density containing the VSS could extend to larger areas of the sky (outside QUEST's observing range). We present the complete spectroscopic follow up of the clump candidates present in QUEST and the composite of the studies we performed along the same l.o.s., including data at brighter magnitudes (Vivas et al. 2008). Our study confirmed the nature of the VSS, revealed its likely extent within the QUEST survey and defined a number of its relevant properties.
Mild Velocity Dispersion Evolution of massive galaxies since z~2
Authors: Trujillo Ignacio , Cenarro A. Javier
Published: April 2010

Making use of public spectra from Cimatti et al. (2008), we measure for the first time the velocity dispersion of spheroid-like massive (M* ~ 1011M⊙) galaxies at z ~ 1.6. By comparing with galaxies of similar stellar mass at lower redshifts, we find evidence for a mild evolution in velocity dispersion, decreasing from ~240 kms−1 at z ~ 1.6 down to ~180 km s−1 at z ~ 0. Such mild evolution contrasts with the strong change in size (a factor of ~4) found for these type of objects in the same cosmic time, and it is consistent with a progressive larger role, at lower redshift, of the dark matter halo in setting the velocity dispersion of these galaxies. We discuss the implications of our results within the context of different scenarios proposed for the evolution of these massive objects.
The properties of a large sample of low surface brightness galaxies from SDSS
Authors: Liang Y. C. , Zhong G. H. , Chen X. Y. , Gao D. , Hammer F. , Liu F. S. , Hu J. Y. , Deng L. C. , Zhang B.
Published: April 2010

A large sample of low surface brightness (LSB) disk galaxies is selected from SDSS with B-band central surface brightness μ0(B) from 22 to 24.5 mag arcsec−2. Some of their properties are studied, such as magnitudes, surface brightness, scalelengths, colors, metallicities, stellar populations, stellar masses and multiwavelength SEDs from UV to IR etc. These properties of LSB galaxies have been compared with those of the galaxies with higher surface brightnesses. Then we check the variations of these properties following surface brightness.
Thousands of Milky Ways: galaxy satellites and building blocks
Authors: Padilla Nelson , Lagos Claudia , Cora Sofía
Published: April 2010

A semi-analytic model of galaxy formation with and without active galactic nuclei feedback is used to study the nature of possible building blocks (BBs) of z = 0 galaxies, including those of Milky-Way types. We find that BBs can show an important range of properties arising from environmental variables such as host halo mass, and whether a galaxy is a satellite within its host halo; the stellar formation histories are comparatively faster and the chemical enrichment is more efficient in BBs than in surviving satellites, in accordance with recent metallicity measurements for the Milky Way. These results can be used in combination with observational constraints to continue probing the ability of the cold dark-matter scenario to reproduce the history of galaxy demography in the Universe.
Quenching Star Formation in the Green Valley: The Mass Flux at Intermediate Redshifts
Authors: Gonçalves Thiago S. , Martin D. Christopher
Published: April 2010

We have obtained several hundred very deep spectra with DEIMOS/Keck in order to estimate the galactic mass flux density at intermediate redshifts (0.6 < z < 0.9) from the "blue cloud" to the red sequence across the so-called “green valley”, the intermediate region in the color-magnitude plot between those two populations. We use spectral indices (specifically Dn(4000) and Hδ, A) to determine star formation histories. Together with an independent measurement of number density of galaxies in each bin of the color-magnitude plot, one can infer the rate at which galaxies from a given sample are transiting through that bin. Measuring this value for all magnitude values, studies at lower redshift determined that the mass flux density in the green valley is comparable to both the mass build-up rate of the red sequence and the mass loss rate from the blue cloud. We show preliminary results for our intermediate redshift sample.
The Dark Energy Survey: perspectives for resolved stellar population studies
Authors: Santiago Basílio , Yanny Brian
Published: April 2010

The Dark Energy Survey (DES) will cover 5000 sq. deg. in grizY filters. Although its main goals are related to cosmology, it will yield photometric measurements of over 108 stars, most of them belonging to the Galaxy. DES will increase the sampling depth of very low-luminosity stellar and sub-stellar species, such as white, red, and brown dwarfs, by a factor of several as compared to SDSS. The structure of the Galactic halo, including its complex sub-structures caused by accretion remnants and globular cluster tidal tails, will also be probed and analyzed. DES will also allow comparison of star counts between Northern and Southern Galactic hemispheres to unprecedented detail. Finally, a significant sample of stars in the outskirts of the Large Magellanic Cloud (LMC) will be studied, providing new light into the debate about the existence of an LMC spheroidal component. These, among other important research goals attainable with the DES stellar data, are discussed in this contribution.
SMART for the Next Decade
Authors: Lee Myung Gyoon , Yuk In-Soo , Lim Sungsoon
Published: April 2010

SMART is a model to derive both star formation history and chemical evolution simultaneously from color-magnitude diagrams of resolved stars in a galaxy. We present current progress and discuss the prospects of SMART for the next decade.
Spectrum Fitting Code for LAMOST ExtraGAlactic Surveys (LEGAS)
Authors: Kong Xu , Su Shanshan
Published: April 2010

The study of stellar populations in galaxies is entering a new era with the availability of large and high-quality data bases of both observed galactic spectra and state-of-the-art evolutionary synthesis models. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has a 4m primary, and a 5 degree field of view, accommodate as many as 4000 optical fibers. It can obtain the spectra of objects as faint as down to B = 20.5 mag with an exposure of 1.5 hour, promising a very high spectrum acquiring rate of ten-thousands of spectra per night. In this talk, we introduce the progress of the LAMOST project, its surveys and show the spectral synthesis code that we are developing for the LAMOST ExtraGAlactic Surveys (LEGAS).
Symbiotic Stars and Planetary Nebulae in the λ5007/Hβ vs. λ4363/Hγ Diagnostic Diagram
Authors: Baella N. O.
Published: April 2010

In this work the location of a sample of 174 flux measurements (planetary nebulae, S, D, D'-type Symbiotic Star (SS) and six peculiar objects) on the λ5007/Hβ vs. λ4363/Hγ diagnostic diagram are compared, in order to investigate possible differences in electron density and temperature among them. Helium abundances, electron density and temperature were obtained for five D'-type SS and HD149427 (PC 11). In order to calculate them, expressions normally used for objects with low density were modified, in such a way that they can be used in objects with higher densities.
Multi-wavelength characterization of the outskirts of spiral galaxies
Authors: Bakos Judit , Trujillo Ignacio
Published: April 2010

We have explored late-type spiral galaxies with truncated radial surface brightness profiles. Based on the study of optical color profiles, Bakos et al. (2008) suggested that truncated (TYPE II) galaxies have a generally older stellar population in their outer regions: one observable consequence of this would be a strong dependence of the structural parameters of the outer disk on the observing wavelength. To corroborate this result, we obtained surface brightness profiles using data from GALEX(UV), SDSS(optical), UKIDSS(NIR) and SPITZER-IRAC(IR). We have characterized the behaviour of the outer disk by obtaining the ratio of the inner and outer scale-lengths. Here we show the example of NGC0450. Our results suggest that there is an existing general trend of the scale-length ratio: from bluer to redder bands the scale-length ratio decreases, which is in accordance with the idea of the old smooth stellar disk in the outer disk.
The UV spectrum of the Galactic Bulge
Authors: Busso Giorgia , Moehler Sabine
Published: April 2010

The aim of this work is to investigate the possible existence of the UV-excess in the Milky Way bulge and its correlation with the presence of sdB stars in the bulge. The integrated spectrum of a bulge region from the UV to the optical was constructed. Results show that this bulge region has only a very weak UV excess
The Hot Molecular Core of G12.21–0.10: NH3(4, 4) Observations
Authors: de la Fuente Eduardo , Kurtz Stanley E. , Rodriguez-Rico Carlos A. , Trinidad Miguel A. , Araya Esteban , Kemp Simon , Porras Alicia , Hofner Peter , Franco José
Published: April 2010

In de la Fuente (2007; Ph. D. Thesis), the molecular clump associated with the ultracompact HII region G12.21–0.10 was confirmed as a large, hot, dense Hot Molecular Core nearby to the ionized gas. The density was confirmed by comparing low resolution NH3(2, 2) and (4, 4) VLA observations, with other molecular lines and radio–continuum observations. These results will be presented in detail in a forthcoming paper (de la Fuente et al. in preparation). In these works, for the first time, the spatial location of the Hot Molecular Core is presented. Here we present the NH3(4,4) observations from de la Fuente (2007; Ph. D. Thesis), confirming that the hotter and denser gas in the molecular core lies in a compact structure, of smaller scale than the NH3(2, 2) emission.
The star formation histories of fossil group galaxies
Authors: de la Rosa Ignacio G. , Proctor Robert N. , Mendes de Oliveira Claudia , Forbes Duncan A. , Cid Fernandes Roberto , Mateus Abilio
Published: April 2010

A comparison is carried out among the star formation histories of early-type galaxies in fossil groups, clusters and low density environments. Although they show similar evolutionary histories, a significant fraction of the fossils are younger than their counterparts, suggesting that they can be precursors of the isolated ETG galaxies.
Age and metallicity of star clusters in the Small Magellanic Cloud from integrated spectroscopy
Authors: Dias Bruno , Coelho Paula , Kerber Leandro , Barbuy Beatriz , Idiart Thais
Published: April 2010

Analysis of integrated spectra of star clusters in the Magellanic Clouds can bring important information for studies on the chemical evolution of the Clouds. The aim of the present work is to derive ages and metallicities from integrated spectra of 15 star clusters in the Small Magellanic Cloud (SMC), some of them not studied so far. Making use of a full spectrum fitting technique, we compared the integrated spectra of the sample clusters to three different sets of single stellar population models available in the literature. We derived ages and metallicities for the sample clusters employing the codes STARLIGHT and ULySS. Out of the 15 clusters in our sample, 9 are old/intermediate age clusters and 6 are young clusters. We point out the results for the newly identified as old/intermediate age clusters HW1, NGC 152, Lindsay 3 and 11. We also confirm old ages for NGC 361, NGC 419 and Kron 3, and the oldest well-known SMC cluster NGC 121.
Superdense massive galaxies in the nearby universe
Authors: Ferré-Mateu Anna , Trujillo Ignacio
Published: April 2010

At high-z the most superdense massive galaxies are supposed to be the result of gas-rich mergers resulting in compact remnant (Khochfar & Silk (2006); Naab et al. (2007)). After this, dry mergers are expected to be the mechanism that moves these very massive galaxies towards the current stellar mass size relation. Whitin these merging scenarios, a non-negligible fraction (1-10%) of these galaxies is expected to survive since that epoch retaining their compactness and presenting old stellar populations in the past universe.Using the NYU Value-Added Galaxy Catalog (DR6), we find only a tiny fraction of galaxies (~0.03%) with re ≤ 1.5 kpc and M* ≥ 8x1010M⊙ in the local Universe (z~0.2). Surprisingly, they are relatively young (~2Gyr) and metal rich ([Z/H]~0.2) These results have been published in Trujillo et al. (2009)
M32: Is there an Ancient and Metal-poor Stellar Population?
Authors: Fiorentino Giuliana , Monachesi Antonela , Trager Scott C. , Lauer Tod R. , Saha Abhijit , Mighell Kenneth J. , Freedman Wendy , Dressler Alan , Grillmair Carl , Tolstoy Eline
Published: April 2010

We observed two fields near M32 with the ACS/HRC (Program GO-10572, PI: T. Lauer) on board the Hubble Space Telescope, located at distances of about 1.8' and 5.4' (hereafter F1 and F2, respectively) from the center of M32. To obtain a very detailed and deep color-magnitude diagram (CMD) and to look for short period variability, we obtained time-series imaging of each field in 32-orbit-long exposures using the F435W (B) and F555W (V) filters, spanning a temporal range of 2 days per filter. We focus on our detection of variability on RR Lyrae variable stars, which represents the only way to obtain information about the presence of a very old population (larger than 10 Gyr) in M32 from optical data. Here we present results obtained from the detection of 31 RR Lyrae in these fields: 17 in F1 and 14 in F2. We claim we detected 7+4−3 RR Lyrae variables belonging to M32 in F1 thus indicating the presence of a metal-poor ancient population in M32.
Mass dependent Evolution of Field Early-Type Galaxies Since z=1
Authors: Fritz Alexander , Jørgensen Inger , Schiavon Ricardo P.
Published: April 2010

We present the Fundamental Plane (FP) of field early-type galaxies at 0.5 < z < 1.0. Our project is a continuation of our efforts to understand the formation and evolution of early-type galaxies in different environments. The target galaxies were selected from the comprehensive and homogeneous data set of the Gemini/HST Galaxy Cluster Project. The distant field early-type galaxies follow a steeper FP relation compared to the local FP. The change in the slope of the FP can be interpreted as a mass-dependent evolution. Similar results have been found for cluster early-type galaxies in high redshift galaxy clusters at 0.8 < z <1. Therefore, the slope change of the FP appears to be independent of the environment of the galaxies.
Stellar Populations in Luminous and Ultraluminous Infrared Galaxies
Authors: Delgado R. M. González , Cid Fernandes R. , Pérez E. , Rodríguez-Zaurín J. , Tadhunter C. , Dors O. , Marín V. Muñoz , Villar-Martín M.
Published: April 2010

The goal of this work is to determine the properties of the stellar populations in a sample of LIRGs and ULIRGs. Using the ages as a clock we investigate: a) whether LIRGs-ULIRGs evolve into Radio Galaxies and QSOs; b) whether cool LIRGs-ULIRGs can evolve into warm LIRGs-ULIRGs; c) the merger sequence deduced from the morphological studies is reflected in the properties of the stellar populations. Using evolutionary synthesis models with high spectral resolution stellar libraries we have found that the intermediate age stellar population dominates at optical wavelengths. The stellar population in LIRGs is similar to ULIRGs and ULIRGs-QSOs transition objects.
Spectroscopic Hα and Hγ survey of field Be stars: 2004-2008
Authors: Grundstrom Erika , Aragona Christina , Boyajian Tabetha , Gies Douglas , Amber  , McSwain M. Virginia , Rachel  , Williams Stephen , Wingert David
Published: April 2010

Massive O- and B-type stars are “cosmic engines” in the Universe and can be the dominant source of luminosity in a galaxy. Be stars are rapidly rotating B-type stars that lose mass in an equatorial, circumstellar disk (Porter & Rivinius 2003) and cause Balmer and other line emission. Currently, we are unsure as to why these stars rotate so quickly but three scenarios are possible: they may have been born as rapid rotators, spun up by binary mass transfer, or spun up during the main-sequence evolution of B stars. In order to investigate these scenarios for this population of massive stars, we have been spectroscopically observing a set of 115 field Be stars with the Kitt Peak Coudè Feed telescope in both the Hα and Hγ wavelength regimes since 2004. This time baseline allows for examination of variability properties of the circumstellar disks as well as determine candidates for closer examination for binarity.

We find that 90% of the observed stars show some variability with only 4% showing significant variability over the 4-year baseline. Such values may be compared with the significant variability seen in some clusters such as NGC 3766 (McSwain 2008). Also, while 20% of the sample consists of known binaries, we find that another 15-30% of the sample shows indications of binarity.

This work has been supported in part by a grant from the Vanderbilt University Learning Sciences Institute, NASA grant # NNX08AV70G, and NSF Career grant AST-0349075.
Population synthesis from clustered star formation
Authors: Haas M. R. , Anders P.
Published: April 2010

In recent years, a series of papers (Kroupa & Weidner 2003, Weidner & Kroupa 2004, Weidner & Kroupa 2005 and Weidner & Kroupa 2006, WK06 from now on) have proposed that the stellar content of an entire galaxy may not be well described by the same initial mass function (IMF) that describes the distribution of stellar masses in the star clusters, where these stars form. The reason is that star clusters also form with a cluster mass function (CMF), which is a power law with a power law index of ~−2. If the lowest mass clusters are of masses smaller than the physical upper mass limit for stars they will be deficient in high mass stars. Therefore, if the stellar content of all clusters is added together, making up the Integrated Galactic Initial Mass Function (IGIMF), the distribution of stellar masses may be steeper at the high mass end, depending on the exact shape of the CMF.
Luminous Red Galaxies at Redshifts, z=0.4-0.5
Authors: Heap Sara R. , Lindler Don
Published: April 2010

We describe and analyze the color dispersion of LRG's at redshifts, z=0.4-0.5.
A rate study of Type Ia supernovae with Subaru/XMM-Newton Deep Survey
Authors: Ihara Yutaka , Doi Mamoru , Morokuma Tomoki , Pain Raynald , Takanashi Naohiro , Yasuda Naoki , Aldering Greg , Dawson Kyle , Goldhaber Gerson , Hook Isobel , Lidman Chris , Perlmutter Saul , Spadafora Anthony , Suzuki Nao , Wang Lifan
Published: April 2010

We present a measurement of the rate of high-z Type Ia supernovae (SNe Ia) using multi-epoch observations of Subaru/XMM-Newton Deep Field (SXDF) with Suprime-Cam on the Subaru Telescope. Although SNe Ia are regarded as a standard candle, progenitor systems of SNe Ia have not been resolved yet. One of the key parameters to show the progenitor systems by observations is the delay time distribution between the binary system formation and subsequent SN explosion. Recently, a wide range of delay time is studied by SN Ia rates compared with an assumed cosmic star formation history. If SNe Ia with short delay time are dominant, the cosmic SN Ia rate evolution should closely trace that of the cosmic star formation. In order to detect a lot of high-z SNe Ia and measure SN Ia rates, we repeatedly carried out wide and deep imaging observations in the í-band with Suprime-Cam in 2002 (FoV~1 deg2, mi < 25.5 mag). We obtained detailed light curves of the variable objects, and 50 objects are classified as SNe Ia using the light curve fitting method at the redshift range of 0.2 < z < 1.3. In order to check the completeness and contamination of the light curve classification method, we performed Monte Carlo simulations and generated ~100,000 light curves of SNe Ia and II from templates. The control time and detection efficiency of the SN survey are also calculated using the artificial light curves. We derived an increasing trend of rates at around z ~ 1.2. Our results are almost consistent with other SN Ia rate results from low-z to high-z. Our results are the first results of high-z SN Ia rates with large statistics using light curves obtained by ground based telescopes, and give us visions of the SN rate studies for the future.
Angular Momentum Loss in Polars
Authors: Kalomeni Belinda
Published: April 2010

We discuss the possible angular momentum loss mechanisms in AM Her type cataclysmic variables and their corresponding mass loss rates using the observed physical parameters of them.
Metallicity gradients in dwarf elliptical galaxies
Authors: Koleva Mina , Prugniel Philippe , De Rijcke Sven , Zeilinger Werner W.
Published: April 2010

We discuss the relations between the metallicity gradients and the other characteristics of a set of dwarf elliptical galaxies in different environments. We suggest that dEs have typically metallicity gradients of −0.30 ± 0.25 dex/re, unrelated to their mass. Dwarf elliptical galaxies with embedded disks, or dS0, may have flat metallicity gradients.
GALEV evolutionary synthesis on the web – current state and future plans
Authors: Kotulla Ralf , Anders Peter , Weilbacher Peter , Fritze Uta
Published: April 2010

GALEV evolutionary synthesis models describe the evolution of stellar populations in general, of star clusters as well as of galaxies, both in terms of resolved stellar populations and of integrated light properties over cosmological timescales of >13 Gyr from the onset of star formation shortly after the Big Bang until today. A new web-interface now allows to run customized GALEV models with user-defined parameters. This web-interface, all data, and many more features to come, can be found at http://www.galev.org.
What does the IMF really tell us about star formation?
Authors: Kouwenhoven M. B. N. , Goodwin S. P.
Published: April 2010

Obtaining accurate measurements of the initial mass function (IMF) is often considered to be the key to understanding star formation, and a universal IMF is often assumed to imply a universal star formation process. Here, we illustrate that different modes of star formation can result in the same IMF, and that, in order to truly understand star formation, a deeper understanding of the primordial binary population is necessary. Detailed knowledge on the binary fraction, mass ratio distribution, and other binary parameters, as a function of mass, is a requirement for recovering the star formation process from stellar population measurements.
Comparing six evolutionary population synthesis models
Authors: Liang Y. C. , Chen X. Y. , Hammer F. , Rodrigues M. , Zhao Y. H. , Zhong G. H.
Published: April 2010

We compare six evolutionary population synthesis (EPS) models, which have been popularly used in stellar populations analyses for galaxies. The resulted stellar populations of star-forming galaxies and E+A galaxies from these EPS models show that the dominated contribution (fraction) from young, intermediate and old populations to their lights are consistent, although the individual numbers may change significantly, 3-30%, which could relate to the different ingredients in EPS models, such as the stellar library, the stellar evolution tracks etc.
Stellar populations in brightest cluster galaxies
Authors: Loubser S. I. , Sánchez-Blázquez P. , Soechting I. K. , Sansom A. E.
Published: April 2010

We present the results of an investigation of a large sample of brightest cluster galaxies (BCGs), their kinematic and stellar population properties and the relationships between these and the properties of the host clusters. We have obtained high signal-to-noise, long-slit spectra of 49 BCGs in the nearby Universe with the Gemini and WHT telescopes. From this, we have measured the radial velocity and velocity dispersion profiles, and used the Lick system of absorption indices to derive Single Stellar Population (SSP)-equivalent ages, metallicities and α-abundance ratios. The results were systematically compared with those of large samples of ordinary elliptical galaxies in the same mass range. In addition, the derived properties were tested for possible correlations with the internal properties of the galaxies (mass, rotation and luminosity) and the properties of the host clusters (density, mass, distance to X-ray peak and cooling flows). We address the following questions: how the kinematic and stellar population properties differ from those of ordinary giant elliptical galaxies; and whether these properties are more influenced by the internal parameters of the BCGs or the properties of the clusters.
Ages and metallicities of early-type galaxies
Authors: Ogando Ricardo , Maia Marcio , Pellegrini Paulo , da Costa Luiz
Published: April 2010

The study of stellar populations in early-type galaxies give us clues on how they form and evolve. We calculate age, [Z/H], and [α/Fe] ratio for 162 early-type galaxies using the SSP models from Thomas, Maraston, & Bender (2003) applied to Lick indices measurements, such as Hβ, Mgb, Fe5270 and Fe5335. Those were obtained from longslit spectra observed in the ESO 1.52m telescope as described in Ogando et al. (2008). We study the relations between the SSP parameters and velocity dispersion, as well as the influence of environment on these relations. We find that age, [Z/H], and [α/Fe] correlate well with velocity dispersion, so that more massive galaxies, have on average, higher metallicities, ages and abundance ratios than that of the low-mass ones. Galaxies in high density regions are older and more metal-rich than those in regions with low number of neighbors. These results are not consistent with standard predictions of hierarchical clustering. In the last decade, this “anti-hierarchical” behavior has also been generally tagged as downsizing and has challenged the current theoretical framework of galaxy formation, calling for new ways of star formation regulation in early-type galaxies.
HI-selected Galaxies As a Probe of Quasar Absorption Systems
Authors: Okoshi K. , Nagashima M. , Gouda N. , Minowa Y.
Published: April 2010

We investigate the properties of local HI-selected galaxies detected in blind radio surveys by using semi-analytic galaxy formation models in the hierarchical structure formation scenario. By drawing a detailed comparison between the properties of the HI-selected galaxies and the quasar absorption systems, we investigate a link between the local galaxy population and the quasar absorption systems, particularly for Damped Lymanα absorption (DLA) systems (NHI ≥ 1020.3 cm−2) and sub-DLA systems (1019 < NHI < 1020.3 cm−2).

We find that DLA galaxies, in which the HI column densities are as high as those of DLA systems, contribute primarily to the population of local HI-selected galaxies at MHI ≥ 108M⊙. By contrast, in the low-mass range MHI ≤ 107M⊙, sub-DLA galaxies replace DLA galaxies as the dominant population. The HI-selected galaxies would be a strong probe of DLA/sub-DLA systems.
The stellar populations of the AGN/Starburst galaxy NGC7582
Authors: Ricci T. V. , Steiner J. E. , Menezes R. B. , Garcia-Rissmann A. , Cid Fernandes R.
Published: April 2010

NGC 7582 is defined as a Starburst/AGN galaxy, since its optical and X-Ray spectra reveal both characteristics. In this work, we show the results of a stellar population modeling in a datacube taken with the Gemini South telescope. We found that ~ 90% of the light in the field of view is emitted by stars that are less than 1 billion years old. A strong burst occurred about ~ 6 million years ago and has nearly solar metallicity. We also found a Wolf-Rayet cluster.
A spectroscopic survey of FHB stars near the south galactic pole
Authors: Rossi Silvia , Ortiz Roberto , Wilhelm Ronald , Costa Roberto , Beers Timothy C.
Published: April 2010

We present the results of a medium-resolution spectroscopic survey of 43 field horizontal-branch (FHB) candidates carried out near the south galactic pole, selected from the original list of FHB candidates compiled by Beers et al. (2007). The observation list includes only stars classified as “high-probability” candidates, according to their 2MASS infrared colours. Atmospheric parameters of some stars have been obtained by comparing some spectral features with theoretical models provided by Kurucz (1993). A comparison between the grid of model atmospheres with some parameters of the Hδ line allowed the determination of log g, whilst [Fe/H] was estimated by the equivalent widths of the MgII 4481 and Caii lines. About 77% of the sample have been classified as FHB stars, 10% as subdwarfs, whilst the remaining 13% are probably main-sequence A-type stars far from the Galactic plane.
Stellar archeology of the nearby LINER galaxies NGC 4579 and NGC 4736
Authors: Steiner J. E. , Menezes R. B. , Ricci T. V. , de Oliveira A. S.
Published: April 2010

Stellar archeology of nearby LINER galaxies may reveal if there is a stellar young population that may be responsible for the LINER phenomenon. We show results for the classical LINER galaxies NGC 4579 and NGC 4736 and find no evidence of such populations.
CNO abundance pattern in the red clump stars of the Milky Way
Authors: Tautvaišienė G. , Puzeras E. , Chorniy Y. , Barisevičius G. , Ilyin I.
Published: April 2010

Hipparcos orbiting observatory has revealed a large number of helium-core- burning “clump” stars of the Galactic field. These low-mass stars exhibit signatures of extra-mixing processes that require modeling beyond the standard stellar theory. In this contribution we overview available results of 12C, 13C, N and O abundances obtained by high-resolution spectra for clump stars and discuss them in the light of current predictions of stellar evolution models.
Using stellar population studies to determine the progenitors of GRBs and SNe
Authors: Thöne Christina C. , Christensen Lise , Fynbo Johan P. U.
Published: April 2010

We present spatially resolved emission line studies of three nearby GRB and SN hosts with longslit and/or IFU observations. We compare the environment of the GRBs/SNe with those of other star-forming regions in the host galaxy and try to get informations on the progenitor from stellar population models and metallicities.
Disentangling Nitrogen and Carbon Abundances in Early-Type Galaxies
Authors: Toloba Elisa , Sánchez-Blázquez Patricia , Gorgas Javier , Gibson Brad K.
Published: April 2010

The near-UV NH3360 feature has been measured in a sample of 35 early-type
galaxies in a wide range of masses and environments. We found that, contrary to
what is seen with Mg- and C-sensitive Lick-style indices, NH3360 does not vary
significantly with galaxy velocity dispersion. When compared with solar-scaled
stellar population models N/Fe appears mildly enhanced. We do not detect any
difference in the NH3360 index between galaxies in different environments. We
outline the important implications of these conclusions for our understanding of
the origin of carbon and nitrogen, and the star formation histories of
early-type galaxies.
Stellar populations in star forming galaxies in the Sloan Digital Sky Survey
Authors: Westera Pieter , Cuisinier François , Rabaça Carlos R.
Published: April 2010

We examine the star forming phenomenon as it can be encountered in galaxies in the Sloan Digital Sky Survey, which possibly contains the largest homogeneous sample of star forming galaxy spectra to date.

After eliminating all spectra with an insufficient signal-to-noise ratio, without strong emission lines, and without the [OII] λ3727 Å line, which is necessary for the determination of the gas metallicity (which excludes galaxies with redshift ≲ 0.024–0.025), our sample contains ~6000 spectra of star forming galaxies.

Through a detailed stellar population analysis employing evolutionary synthesis methods we determined the stellar composition of these galaxies, that is, the masses, ages and metallicities of their partial stellar populations.

We find that most, possibly all, galaxies of our sample contain, apart from the presently bursting, ionising young generation (≤ 107 yrs), old (≥ 109 yrs) and intermediate (between 107 and 109 yrs) populations, whereas the old population dominates the stellar mass (but not the light).

We also find that high (stellar) mass galaxies have higher gas metallicities and lower present star formation rates relative to their total (stellar) masses, than low mass galaxies, indicating a higher chemical evolution degree for high mass galaxies.

Furthermore, we find that gas enrichment mechanisms in star forming galaxies do not vary with galactic mass, being the same for low- and high-mass galaxies on average. Gas enrichment mechanisms seem to present a greater variety at the high-mass end, though, indicating a more complex assembly history for high-mass galaxies.
HERMES – An instrument of the future
Authors: Wylie-de Boer Elizabeth , Freeman Kenneth
Published: April 2010

HERMES is a new, multi-object high resolution spectrometer for the 3.9m Anglo Australian Telescope, using the existing 2dF positioner. The primary goal of the HERMES survey is to unravel the history of the Galaxy from detailed elemental abundances for about 1.2 million individual stars. The HERMES chemical tagging survey concentrates on the 5000 to 8000 Å window at a resolving power of 30,000 in order to identify dissolved star formation aggregates and ascertain the importance of mergers throughout the history of the Galaxy.
MI-RSB 48
Authors: Unterrainer Human-Friedrich , Huber Helmuth-Paul , Ladenhauf Karl Heinz , Wallner-Liebmann Sandra Johanna , Liebmann Peter Michael
Published: April 2010

Zusammenfassung. In interdisziplinärer Zusammenarbeit wurde ein mehrdimensionales Messinstrument zu Religiosität und Spiritualität (MI-RSB 48) im Erleben von körperlicher und psychischer Gesundheit und Krankheit entwickelt, um das Konstrukt zum religiös-spirituellen Befinden zu erfassen. Im Deutungsrahmen des bio-psycho-sozio-spirituellen Modells kann nach einer Darstellung des Hintergrunds des Forschungsanliegens bzw. der Phasen der Testentwicklung eine vorläufige Endversion des Fragebogens präsentiert werden. Das Inventar wurde an einer Stichprobe von 200 Studierenden erprobt und an einer Stichprobe entsprechend der österreichischen Allgemeinbevölkerung validiert (N = 263). Ausgehend von der Fragestellung zum Zusammenhang von Religiosität, Spiritualität und psychischer Gesundheit werden die Ergebnisse der Befragung zum religiös-spirituellen Befinden im Kontext anderer Konzepte zum Wohlbefinden im bio-psycho-sozialen Raum dargestellt. Einbezogen werden der Kohärenzsinn im salutogenetischen Ansatz nach A. Antonovsky bzw. das Ausmaß an subjektiver Zufriedenheit mit der Befriedigung von Mangel- und Wachstumsbedürfnissen im Sinne A. H. Maslows.
Eine psychometrische Analyse der ZAREKI-R mittels Rasch-Modellen
Authors: Koller Ingrid , Alexandrowicz Rainer W.
Published: April 2010

Zusammenfassung. Die neuropsychologische Testbatterie für Zahlenverarbeitung und Rechnen bei Kindern (ZAREKI-R; von Aster, Weinhold & Horn, 2006 ) ist ein Verfahren zur Erkennung von Dyskalkulie. Es wurde an Kindern aus Deutschland und der deutschsprachigen Schweiz unter Verwendung klassisch testtheoretischer Methoden überprüft. Ausständig war bislang jedoch eine Überprüfung auf Gültigkeit des Rasch-Modells, was anhand einer Stichprobe von 341 Kindern aus zweiten bis vierten Klassen von fünf Kärntner Grundschulen in der vorliegenden Forschungsarbeit durchgeführt wurde. Für sechs der insgesamt 16 Subskalen konnte Modellgültigkeit angenommen werden. Nach Ausscheiden von nicht modellkonformen Items konnte dies auch für weitere sechs Subskalen a-posteriori erzielt werden. Damit konnte gezeigt werden, dass die ZAREKI-R mit einigen Abänderungen (und vorbehaltlich einer Kreuzvalidierung) den Anforderungen des Rasch-Modells genügt.
Das Konfliktlösungsstil-Inventar für Paare (KSIP)
Authors: Herzberg Philipp Yorck , Sierau Susan
Published: April 2010

Zusammenfassung. Vorgestellt wird eine deutsche Übersetzung des „Conflict Resolution Styles Inventory” (CRSI, Kurdek, 1994 ). Der Fragebogen erfasst mit 32 Items vier Dimensionen von Konfliktlösungsstilen: Kämpferischer Konfliktstil, Positive Konfliktlösung, Rückzug und Nachgiebigkeit jeweils in der Selbst- und Partnerbeurteilung. Die faktorielle Struktur und die Messinvarianz für Frauen und Männer sowie die Messäquivalenz zur amerikanischen Originalversion wurden mittels konfirmatorischer Faktoranalyse geprüft. Die Ergebnisse bestätigen die postulierte vierfaktorielle Struktur des Fragenbogens und deren Messinvarianz und Messäquivalenz. Die psychometrischen Eigenschaften der Skalen sind gut. Die konvergente und diskriminante Validität wurde an den globalen Faktoren der Persönlichkeit, der Partnerschaftszufriedenheit sowie der selbst- und fremdwahrgenommenen Belastung untersucht und belegt eine theoretisch fundierte Einbettung in das nomologische Netzwerk von Konfliktlösungsstilen. Die Ergebnisse zeigen, dass mit der deutschsprachigen Übersetzung des CRSI eine reliable, ökonomische und valide Erfassung von Konfliktlösungsstilen in der Selbst- und Partnerbeurteilung geleistet werden kann.
Temporal Cueing of Target-Identity and Target-Location
Authors: Wagener Annika , Hoffmann Joachim
Published: April 2010

In four experiments either a short or a long foreperiod preceded the presentation of one of two targets, presented either in the center of the screen (Experiment 1) or at one of two locations (Experiments 2–4). Participants were to identify the presented target by pressing a left or a right button as quickly as possible. In Experiment 1, each of the two targets and in Experiment 2, each of the two locations appeared frequently after one and infrequently after the other foreperiod. Experiments 3 and 4 explored the combined effects of disparate frequency distributions of targets and locations to the two foreperiods. Reaction times and error rates revealed faster processing and/or less errors for respectively those targets and locations which were frequent after the current foreperiod. The data suggest that besides location-specific target expectancies ( Hoffmann & Kunde, 1999 ) also time-specific expectancies for those targets and target-locations are formed which are likely at the respective point in time.
The Brightness-Weight Illusion
Authors: Walker Peter , Francis Brian J. , Walker Leanne
Published: April 2010

Bigger objects look heavier than smaller but otherwise identical objects. When hefted as well as seen, however, bigger objects feel lighter (the size-weight illusion), confirming that the association between visual size and weight has a perceptual component. Darker objects also look heavier than brighter but otherwise identical objects. It is uncertain, however, if this association also has a perceptual element, or if it simply reflects the fact that, in English at least, the same verbal label (light) is applied to both surface brightness and weight. To address this, we looked for a brightness equivalent of the size-weight illusion. Paired-comparison judgments of weight were obtained for balls differing only in color. Based on vision alone, darker objects were judged to be heavier. When the balls were hefted as well as seen, this association was reversed (i.e., a brightness-weight illusion), consistent with it having a perceptual component. To gauge the strength of the illusion (in grams), a white and a black ball (both 129 g) were each compared against a set of mid-gray balls varying in weight. When the balls were hefted as well as seen, the white ball felt approximately 8 g heavier than the black ball, a difference corresponding to 6.2% of their actual weight. Possible environmental origins of the association between surface lightness and weight are considered.