bluuebunny/crossref_metadata_2025_split huggingface dataset:
JASMINE: constructor of the dynamical structure of the Galactic bulge
Authors: Gouda N. , Kobayashi Y. , Yamada Y. , Yano T. , Tsujimoto T. , Suganuma M. , Niwa Y. , Yamauchi M. ,   JASMINE Working Group
Published: July 2008

AbstractWe introduce a Japanese space astrometry project which is called JASMINE. JASMINE (Japan Astrometry Satellite Mission for INfrared Exploration) will measure distances and tangential motions of stars in the Galactic bulge with yet unprecedented precision. JASMINE will operate in z-band whose central wavelength is 0.9 micron. It will measure parallaxes, positions with accuracy of about 10 micro-arcsec and proper motions with accuracy of about 10 micro- arcsec/year for the stars brighter than z=14 mag. The number of stars observed by JASMINE with high accuracy of parallaxes in the Galactic bulge is much larger than that observed in other space astrometry projects operating in optical bands. With the completely new “map of the Galactic bulge” including motions of bulge stars, we expect that many new exciting scientific results will be obtained in studies of the Galactic bulge. One of them is the construction of the dynamical structure of the Galactic bulge. Kinematics and distance data given by JASMINE are the closest approach to a view of the exact dynamical structure of the Galactic bulge.Presently, JASMINE is in a development phase, with a target launch date around 2016. We comment on the outline of JASMINE mission, scientific targets and a preliminary design of JASMINE in this paper.
Uncloaking globular clusters of the inner Galaxy
Authors: Alonso-García Javier , Mateo Mario , Sen Bodhisattva 
Published: July 2008

AbstractWe intend to map the differential extinction and remove their effects in a sample of clusters in the direction of the inner Galaxy using a new dereddening technique. These observations and their analyses will let us produce high quality color-magnitude diagrams of these poorly studied clusters that will allow us to determine these clusters' relative ages, distances and chemistry and to address important questions about the formation and the evolution of the inner Galaxy.
Stellar proper motions in the Galactic bulge with ACS/WFC on HST
Authors: Clarkson Will , Sahu Kailash , Anderson Jay , Smith T. Ed , Brown Thomas M. , Casertano Stefano , Rich R. Michael , Bond Howard E. , Brown Timothy , Livio Mario , Minniti Dante , Panagia Nino , Renzini Alvio , Valenti Jeff , Zoccali Manuela 
Published: July 2008

AbstractIn 2004 the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) project undertook a very deep ACS/WFC exposure-set of the Sgr-I low-reddening window in the Galactic Bulge, with repeat observations 2.04 years later. The combination of superb first-epoch sampling, wide field of view and high PSF stability of ACS/WFC on Hubble allows proper motions to be extracted for more than 137,000 objects, over 85,000 to accuracy better than 0.3 mas yr−1. We present these proper motions and outline some of the uses to which they have been put, including the separation of a pure-Bulge sample and the inner Galactic rotation curve.
Red-giant branch morphology of metal-poor globular clusters in the Galactic bulge
Authors: Kim J. W. , Kim H. I. , Sohn Y. J. 
Published: July 2008

AbstractUsing the (J − K, K) color-magnitude diagrams (CMDs) of 16 metal-poor globular clusters in the Galactic bulge, we investigate the morphological properties of their red-giant branch (RGB), comparing with those of metal-rich clusters in the Galactic bulge and metal-poor clusters in the Galactic halo. The RGB morphological parameters, such as colors at fixed magnitudes, magnitudes at a fixed color, the RGB slope, and a difference of color indices at two fixed magnitudes have been derived from the near-IR CMDs for each cluster. Metal-poor Galactic bulge clusters follow the previous empirical relations between colors at fixed magnitudes and magnitudes at a fixed color of the RGB and the cluster's metallicity. However, the RGB slope and the color difference parameters of some bulge clusters deviate slightly from the previous empirical linear relations for the other globular clusters, implying that the metal-poor bulge clusters may have different formation origin from the other globular clusters in the Galaxy.
The evolution of the Galactic bulge from planetary nebulae
Authors: Maciel Walter J. , Costa R. D. D. , Escudero A. V. 
Published: July 2008

AbstractWe have used our dataset on the abundances of planetary nebulae (PN) to study the chemical evolution of the Galactic bulge. We have derived several relations involving the chemical abundances and computed three classes of models for the Galactic bulge: (i) one-zone, single-infall models, (ii) one-zone, double-infall models and (iii) multizone, double infall models. We conclude that part of the observational data can be understood in terms of the simpler models, but the full understanding of all observational constraints can only be explained by more complex multizone models.
Evidence of outflow from the Galactic bulge imprinted in stellar elemental abundances
Authors: Tsujimoto Takuji 
Published: July 2008

AbstractWe explore the elemental abundance features of metal-rich disk stars, highlighting the comparisons made with those of the recently revealed Galactic bulge stars. A similarity between two of the comparisons leads to a new theoretical picture of the bulge-disk connection in the Galaxy, where a supermassive black hole resides at the center. We postulate that a metal-rich outflow, triggered by feedback from a black hole, was generated and quenched the star formation, which had lasted several billion years in the bulge. The expelled gas cooled down in the Galactic halo without escaping from the gravitational potential of the Galaxy. The gas gradually started to accrete to the disk around five billion years ago, corresponding to the time of sun's birth, and replaced a low-metallicity halo gas that had been accreting over nearly ten billion years. The metal-rich infalling gas, whose elemental abundance reflects that of metal-rich bulge stars, mixed with the interstellar gas already present in the disk. Stars formed from the mixture compose the metal-rich stellar disk.
The position angle of the Galactic bulge
Authors: Vallenari A. , Ragaini S. , Bertelli G. 
Published: July 2008

AbstractWe present a study of the structure of the Galactic Bulge in the region −6° < b < 3°,−17° < l < 17° using 2MASS archive data. More than 100 fields are used. We make use of the red clump method to derive the distance of the Bulge in the studied regions. We derive a position angle of the Galactic Bulge going from 42° ± 11 to 35° ± 10 depending on the adopted bulge mass distribution.
Properties of luminous spheroids at redshiftsz~ 1 from Keck and HST
Authors: Koo David C. ,   DEEP and CATS Teams
Published: July 2008

AbstractThree new and still on-going surveys that combine the power of spectroscopy or adaptive optics from the Keck Telescopes with HST images are DEEP, AEGIS, and CATS. The advantages of each for the study of distant bulges are accompanied by a few highlights. We find that the vast fraction of luminous distant bulges appear very red, independent of the bulge luminosity, bulge fraction, disk color, and environment. Yet early-type galaxies appear to be relatively young at redshiftsz~ 1, are less numerous then, host many X-ray AGN's with some that are highly obscured, and have low but increasing dry-dry and dry-wet merger rates over time.
Star formation in bulges from GALEX
Authors: Yi Sukyoung K. 
Published: July 2008

AbstractEarly-type galaxies, considered as large bulges, have been found to have had a much-more-than-boring star formation history in recent years by the UV satellite GALEX. The most massive bulges, brightest cluster galaxies, appear to be relatively free of young stars. But smaller bulges, normal ellipticals and lenticulars, often show unambiguous sign of recent star formation in their UV flux. The fraction of such UV-bright bulges in the volume-limited sample climbs up to the staggering 30%. The bulges of spirals follow similar trends but a larger fraction showing signs of current and recent star formation. The implication on the bulge formation and evolution is discussed.
Young stellar populations in early-type galaxies in the SDSS
Authors: Nolan Louisa A. , Kabán Ata , Harva Markus , Benson Andrew , Raychaudhury Somak 
Published: July 2008

AbstractWe use a purely data-driven rectified factor analysis to identify early-type galaxies with young (≲ 4 Gyr) stellar populations in the Sloan Digital Sky Survey Spectroscopic Catalogue. We call these galaxies E+F galaxies, analogous to E+A galaxies. These galaxies lie in the ‘Green Valley’, between the blue cloud and the red sequence on the colour-magnitude diagram. As such, these galaxies may represent an important transient stage in the evolution of galaxies from blue and star-forming to red and passive. We investigate the distribution in projected local galaxy surface density of the E+F galaxies, and compare it with the environment of early-type and E+A galaxies. We find that i) the E+A distribution peaks strongly in projected local galaxy surface density, Σ5, at ~ 0.1−0.2 Mpc−2, ii) early-types have a flatter peak at ~ 0.06−0.2 Mpc−2, iii) the E+Fs lie somewhere in between, and iv) the distributions of the models do not agree well with the data, peaking at higher densities, and under-predicting the number of E+As at low (Σ5 < 0.3 Mpc−2) densities. The dearth of E+A and E+F galaxies in dense environments confirms that E+A and E+F galaxies are most likely the products of galaxy-galaxy merging or interactions, rather than star-forming galaxies whose star formation has been quenched by processes unique to dense environments, such as ram-pressure stripping or galaxy harassment. The similarity of the environments in which the E+F population and the E+A galaxy sample are found, together with the spectral evidence, suggests that E+F galaxies are E+A galaxies, which have evolved by a further ~ one to a few Gyr.
Galaxy scaling relations from the ACS Virgo and Fornax Cluster Surveys: no evidence for a dwarf-giant dichotomy
Authors: Côté Patrick , Ferrarese Laura , Jordán Andrés , Blakeslee John P. , Chen Chin-Wei , Infante Leopoldo , Mei Simona , Peng Eric W. , Tonry John L. , West Michael J. 
Published: July 2008

AbstractWe examine the photometric and structural properties of early-type galaxies derived from theACS Virgo and Fornax Cluster Surveys, supplementing these data with previously published or newly reanalysed data for additional early-type galaxies in Virgo, Fornax and the Local Group. As we have noted elsewhere, Sérsic models are found to provide accurate representations of the observed brightness profiles on scales greater than a few percent of the effective radius,Re. On smaller scales, the brightness profiles of bright (MB≳ −20) galaxies show centraldeficitswith respect to the inward extrapolation of the Sérsic models; fainter galaxies usually show centralexcesses. Fainter thanMB≈ −20, we find a continuity in the photometric and structural scaling relations: i.e., between absolute magnitude, central surface brightness, Sérsic index, effective radius, and the surface brightness measured at, and averaged within, the effective radius. There is no evidence for a “dwarf/giant dichotomy” — a conclusion consistent with a number of recent studies but contrary to some earlier claims.
The 6dF Galaxy Survey: a low-redshift benchmark for bulge-dominated galaxies
Authors: Colless Matthew , Jones Heath , Proctor Rob , Harrison Craig , Campbell Lachlan , Lah Philip 
Published: July 2008

AbstractThe 6dF Galaxy Survey provides a very large sample of galaxies with reliable measurements of Lick line indices and velocity dispersions. This sample can be used to explore the correlations between mass and stellar population parameters such as age, metallicity and [α/Fe]. Preliminary results from such an analysis are presented here, and show that age and metallicity are significantly anti-correlated for both passive and star-forming galaxies. Passive galaxies have strong correlations between mass and metallicity and between age and α-element over-abundance, which combine to produce a downsizing relation between age and mass. For old passive galaxies, the different trends of M/L with mass and luminosity in different passbands result from the differential effect of the mass–metallicity relation on the luminosities in each passband. Future work with this sample will examine the Fundamental Plane of bulge-dominated galaxies and the influence of environment on relations between stellar population parameters and mass.
Ages and metallicities of faint red galaxies in the Shapley Supercluster
Authors: Smith Russell J. , Lucey John R. , Hudson Michael J. 
Published: July 2008

AbstractWe present results on the stellar populations of 232 quiescent galaxies in the Shapley Supercluster, based on spectroscopy from the AAOmega spectrograph at the AAT. The key characteristic of this survey is its coverage of many low-luminosity objects (σ ~ 50 kms−1), with high signal-to-noise (~45 Å−1). Balmer-line age estimates are recovered with ~25% precision even for the faintest sample members. We summarize the observations and absorption line data, and present correlations of derived ages and metallicities with mass and luminosity. We highlight the strong correlation between age and α-element abundance ratio, and the anti-correlation of age and metallicity at fixed mass, which is shown to extend into the low-luminosity regime.
Finding galaxy clusters with spectro-photometric density in SDSS
Authors: Yoon Joo H. , Schawinski Kevin , Sheen Yun-Kyeong , Ree Chang H. , Yi Sukyoung K. 
Published: July 2008

AbstractWe have attempted to overcome the incompleteness of spectroscopic survey and found galaxy clusters by measuring the spectro-photometric density of galaxies.
The z = 0.8 precursors of today's bulges
Authors: Balcells Marc , Domínguez-Palmero Lilian 
Published: July 2008

AbstractWe study the color structure of disk galaxies in the Groth strip at redshifts 0.1 < z < 1.2. Our aim is to test formation models in which bulges form before/after the disk. We find smooth color distributions with gentle outward blueing across the galaxy image: bulges are not distinctly redder than their disks; and bulge colors strongly correlate with global colors. The results suggest a roughly coeval evolution of bulges and disks. About 50% of the nuclei of galaxies with central light excesses above the outer exponential profile hold passively evolving red populations. The remainder 50% are galaxies with central blue colors similar to their disks. They may be bulges in formation, or the central parts of disks with non-exponential surface brightness profiles.
Adaptive optics imaging of Lyman break galaxies as progenitors of spheroids in the local Universe
Authors: Akiyama M. , Minowa Y. , Kobayashi N. , Ohta K. , Iwata I. 
Published: July 2008

AbstractIn order to reveal the stellar mass distribution of z ~ 3 galaxies, we are conducting deep imaging observations of U-dropout Lyman Break Galaxies (LBGs) with Adaptive Optics (AO) systems in K-band, which corresponds to rest-frame V-band of z ~ 3 galaxies. The results of the Subaru intensive-program observations with AO36/NGS/IRCS indicate that 1) the K-band peaks of some of the LBGs brighter than K = 22.0 mag show significant offset from those in the optical images, 2) the z ~ 3 $M_{V}^{*}$ LBGs and serendipitously observed Distant Red Galaxies (DRGs) have flat profiles similar to disk galaxies in the local universe (i.e., Sérsic with n < 2), and 3) the surface stellar mass densities of the $M_{V}^{*}$ LBGs are 3-6 times larger than those of disk galaxies at z = 0 − 1. Considering the lack of n > 2 systems among the luminous z ~ 3 LBGs and DRGs, and their strong spatial clustering, we infer that the dense n < 2 disk-like structures evolve into the n > 2 spheroids of nearby galaxies through relaxations due to major merger events.
Spitzer view of Lyman break galaxies
Authors: Magdis Georgios E. , Rigopoulou Dimitra 
Published: July 2008

AbstractUsing a combination of deep MID-IR observations obtained by IRAC, MIPS and IRS on board Spitzer we investigate the MID-IR properties of Lyman Break Galaxies (LBGs) at z~3, establish a better understanding of their nature and attempt a complete characterisation of the population. With deep mid-infrared and optical observations of ~1000 LBGs covered by IRAC/MIPS and from the ground respectively, we extend the spectral energy distributions (SEDs) of the LBGs to mid-infrared. Spitzer data reveal for the first time that the mid-infrared properties of the population are inhomogeneous ranging from those with marginal IRAC detections to those with bright rest-frame near-infrared colors and those detected at 24μm MIPS band revealing the newly discovered population of the Infrared Luminous Lyman Break Galaxies (ILLBGs). To investigate this diversity, we examine the photometric properties of the population and we use stellar population synthesis models to probe the stellar content of these galaxies. We find that a fraction of LBGs have very red colors and large estimated stellar masses M∗>5×1010M⊙. We discuss the link between these LBGs and submm-luminous galaxies and we report the detection of rest frame 6.2 and 7.7 μm emission features arising from Polycyclic Aromatic Hydrocarbons (PAH) in the Spitzer/IRS spectrum of an infrared-luminous Lyman break galaxy at z=3.01.
Symposium summary: dynamics
Authors: Binney James 
Published: July 2008

AbstractPseudobulges form from unstable disks, while classical bulges form in violent episodes of star formation when a merger sweeps cold gas to a galactic centre. It seems unlikely that smashed disks contribute much to classical bulges. During mergers central black holes make cusps shallower and inflate kinematically decoupled cores. The abundance of galaxies with no detected classical bulge can perhaps be understood if galaxies exchange gas with the IGM more freely than is often supposed.
Colours of intermediate z bulges in Groth and GOODS-N
Authors: Domínguez-Palmero Lilian , Balcells Marc 
Published: July 2008

AbstractThe chronology of bulge and disk formation is a major unsolved issue in galaxy formation, which impacts on our global understanding of the Hubble sequence. We present colours of the nuclear regions of intermediate-redshift disk galaxies, with the aim of obtaining empirical information of ages of bulges at intermediate z. We work with a sample of 248 galaxies (123 inclined + 125 face-on) from the HST Groth Strip Survey (Groth et al. 1994) and another one with 404 objects (214 inclined + 190 face-on) from the HST GOODS-N field (Giavalisco et al. 2004), covering redshifts 0.1 < z < 1.3. Those samples are apparent-diameter limited at R > 1.4″. We find that, as in the Local Universe, the minor axis color profiles are negative (bluer outward), and fairly gentle, indicating that bulge colours are not distinctly different from disk colours. We apply a conservative criterion to identify bulges and potential precursors of present-day bulges, based on nuclear excess surface brightness above the exponential profile of the outer parts. For galaxies with central brightness excesses, rest-frame colour distributions show a red sequence that confirms the finding of very red bulges by Koo et al. (2005), using independent methods. In contrast, galaxies without central brightness excesses show typical colours of star-forming populations. Clearly, something had truncated star formation in many high-density cores, already at z ~ 1. The truncation epoch is uncertain, 1.5 < z < 10. The colour-magnitude distribution of intermediate-z bulges shows more colour dispersion than that of bulges in the Local Universe. About 50% of bulges are as red as local bulges, while the remainder are significantly bluer, a possible sign of late bulge formation. We also find that bulge colours correlate with integrated galaxy colours and with their disk colours.
Intense starbursts at z~5: first significant stellar mass assembly in the progenitors of present-day spheroids
Authors: Verma Aprajita , Lehnert Matthew , Schreiber Natascha Förster , Bremer Malcolm , Douglas Laura 
Published: July 2008

AbstractHigh redshift galaxies play a key role in our developing understanding of galaxy formation and evolution. Since such galaxies are being studied within a Gyr of the big bang, they provide a unique probe of the physics of one of the first generations of large-scale star-formation. We have performed a complete statistical study of the physical properties of a robust sample of z~5 UV luminous galaxies selected using the Lyman-break technique. The characteristic properties of this sample differ from LBGs at z~3 of comparable luminosity in that they are a factor of ten less massive (~few×109 M⊙) and the majority (~70%) are considerably younger (<100Myr). Our results support no more than a modest decline in the global star formation rate density at high redshifts and suggest that ~1% of the stellar mass density of the universe had already assembled at z~5. The constraint derived for the latter is affected by their young ages and short duty cycles which imply existing z~5 LBG samples may be highly incomplete. These intense starbursts have high unobscured star formation rate surface densities (~100s M⊙ yr−1 kpc−2), suggesting they drive outflows and winds that enrich the intra- and inter-galactic media with metals. These properties imply that the majority of z~5 LBGs are in formation meaning that most of their star-formation has likely occurred during the last few crossing times. They are experiencing their first (few) generations of large-scale star formation and are accumulating their first significant stellar mass. As such, z~5 LBGs are the likely progenitors of the spheroidal components of present-day massive galaxies (supported by their high stellar mass surface densities and their core phase-space densities).
Taming the binaries
Authors: Pourbaix D. 
Published: July 2008

AbstractAstrometric binaries are both a gold mine and a nightmare. They are a gold mine because they are sometimes the unique source of orbital inclination for spectroscopic binaries, thus making it possible for astrophysicists to get some clues about the mass of the often invisible secondary. However, this is an ideal situation in the sense that one benefits from the additional knowledge that it is a binary for which some orbital parameters are somehow secured (e.g. the orbital period). On the other hand, binaries are a nightmare, especially when their binary nature is not established yet. Indeed, in such cases, depending on the time interval covered by the observations compared to the orbital period, either the parallax or the proper motion can be severely biased if the successive positions of the binary are modelled assuming it is a single star. With large survey campaigns sometimes monitoring some stars for the first time ever, it is therefore crucial to design robust reduction pipelines in which such troublesome objects are quickly identified and either removed or processed accordingly. Finally, even if an object is known not to be a single star, the binary model might turn out not to be the most appropriate for describing the observations. These different situations will be covered.
A new all-sky catalog of stars with large proper motions
Authors: Lépine S. , Shara M. M. , Rich R.-M. , Wittenberg A. , Halmo M. , Bongiorno B. 
Published: July 2008

AbstractA new all-sky catalog of stars with proper motions μ > 0.15″ yr−1 is presented. The catalog is largely a product of the SUPERBLINK survey, a data-mining initiative in which the entire Digitized Sky Surveys are searched for moving stellar sources. Findings from earlier proper motions surveys are also incorporated. The new all-sky catalog supersedes the great historic proper motion catalogs assembled by W. J. Luyten (LHS, NLTT), and provides a virtually complete > 98% census of high proper motion stars down to magnitude R = 19.