bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of NLTE on research of early chemical enrichment of the dwarf galaxies
Authors: Mashonkina Lyudmila , Jablonka Pascale , North Pierre , Sitnova Tatyana 
Published: May 2016

AbstractBased on high-resolution observed spectra, the non-local thermodynamic equilibrium (NLTE) line formation, and precise stellar atmosphere parameters, we present the first complete sample of dwarf spheroidal galaxies (dSphs) with accurate chemical abundances in the very metal-poor (VMP) regime. The obtained stellar elemental ratios are compared with chemical enrichment models, and we show that NLTE is a major step forward for studies of the dSph and the Milky Way (MW) chemical evolution.
Globular clusters in M31, Local Group, and external galaxies
Authors: Larsen Søren S. 
Published: May 2016

AbstractThroughout most of the Local Group, globular clusters (GCs) remain recognisable as extended objects in ground-based images taken in good seeing conditions. However, studying the full extent of the GC systems is challenging because of the large sky area that needs to be surveyed and recent years have seen dramatic progress in our knowledge of GC populations in nearby galaxies, thanks to large imaging surveys. At the same time, techniques for deriving detailed abundances from integrated-light spectra of GCs are maturing so that detailed comparisons of the chemical composition for GCs in different galaxies can now be made. Such comparisons may shed important light on the properties of proto-galactic fragments that were accreted onto galaxy halos. Nevertheless, our census of Local Group GCs probably remains far from complete, in particular at low luminosities and for very extended clusters.
RR Lyrae stars as probes of the Milky Way structure and formation
Authors: Pietrukowicz Pawel ,   OGLE collaboration
Published: May 2016

AbstractRR Lyrae stars being distance indicators and tracers of old population serve as excellent probes of the structure, formation, and evolution of our Galaxy. Thousands of them are being discovered in ongoing wide-field surveys. The OGLE project conducts the Galaxy Variability Survey with the aim to detect and analyze variable stars, in particular of RRab type, toward the Galactic bulge and disk, covering a total area of 3000 deg2. Observations in these directions also allow detecting background halo variables and unique studies of their properties and distribution at distances from the Galactic Center to even 40 kpc. In this contribution, we present the first results on the spatial distribution of the observed RRab stars, their metallicity distribution, the presence of multiple populations, and relations with the old bulge. We also show the most recent results from the analysis of RR Lyrae stars of the Sgr dwarf spheroidal galaxy, including its center, the globular cluster M54.
The Milky Way's halo in 6D: Gaia's Radial Velocity Spectrometer performance
Authors: Seabroke George , Cropper Mark , Katz David , Sartoretti Paola , Panuzzo Pasquale , Marchal Olivier , Gueguen Alain , Benson Kevin , Dolding Chris , Huckle Howard , Smith Mike , Baker Steve 
Published: May 2016

AbstractGaia's Radial Velocity Spectrometer (RVS) has been operating in routine phase for over one year since initial commissioning. RVS continues to work well but the higher than expected levels of straylight reduce the limiting magnitude. The end-of-mission radial-velocity (RV) performance requirement for G2V stars was 15 km s−1 at V = 16.5 mag. Instead, 15 km s−1 precision is achieved at 15 < V < 16 mag, consistent with simulations that predict a loss of 1.4 mag. Simulations also suggest that changes to Gaia's onboard software could recover ~0.14 mag of this loss. Consequently Gaia's onboard software was upgraded in April 2015. The status of this new commissioning period is presented, as well as the latest scientific performance of the on-ground processing of RVS spectra. We illustrate the implications of the RVS limiting magnitude on Gaia's view of the Milky Way's halo in 6D using the Gaia Universe Model Snapshot (GUMS).
Very Metal-poor Stars Observed by the RAVE Survey
Authors: Matijevič Gal ,   the RAVE Collaboration
Published: May 2016

AbstractRadial Velocity Experiment (RAVE) observed ~500,000 southern sky stars between 2003 and 2013 in the infra-red calcium triplet (CaII) spectral region. In this study we extended the analysis of RAVE very metal-poor stars ([Fe/H] < −2) presented by Fulbright et al. (2010). We employed a novel method for identifying the metal-poor stars and developed a tool for modeling CaII lines where we also modeled the background noise to avoid systematical biases in the equivalent width (EW) measurements. Final metallicity values were derived with a flexible calibration approach using only 2MASS photometric data and EW measurements obtained from the RAVE spectra.
Disk dwarf galaxy as the progenitor of the Andromeda giant stream
Authors: Kirihara Takanobu , Miki Yohei , Mori Masao , Kawaguchi Toshihiro 
Published: May 2016

AbstractWe present a study of the morphology of a progenitor galaxy that has been disrupted and formed a giant southern stellar stream in the halo of Andromeda galaxy(M31). N-body simulations of a minor merger of M31 with a dwarf galaxy suggest that the progenitor's rotation plays an important role in the formation of an asymmetric surface brightness distribution of the stream.
Contributions to the Galactic halo from in-situ, kicked-out, and accreted stars
Authors: Sheffield Allyson A. , Johnston Kathryn V. , Cunha Katia , Smith Verne V. , Majewski Steven R. 
Published: May 2016

AbstractWe report chemical abundances for a sample of 66 M giants with high S/N high-resolution spectroscopy in the inner halo of the Milky Way. The program giant stars have radial velocities that vary significantly from those expected for stars moving on uniform circular orbits in the Galactic disk. Thus, based on kinematics, we expect a sample dominated by halo stars. Abundances are derived for α-elements and neutron capture elements. By analyzing the multi-dimensional abundance space, the formation site of the halo giants – in-situ or accreted – can be assessed. Of particular interest are a class of stars that form in-situ, deep in the Milky Way's gravitational potential well, but are “kicked out” of the disk into the halo due to a perturbation event. We find: (1) our sample is dominated by accreted stars and (2) tentative evidence of a small kicked-out population in our Milky Way halo sample.
Baryonic inflow and outflow histories in disk galaxies as revealed from observations of distant star-forming galaxies
Authors: Toyouchi Daisuke , Chiba Masashi 
Published: May 2016

AbstractGas inflow and outflow are the most important processes, which determine the structural and chemical evolution of a disk galaxy like the Milky Way. In order to get new insights into these baryonic processes in Milky Way like galaxies (MWLGs), we consider the data of distant star-forming galaxies and investigate the evolution of the radial density profile of their stellar components and the associated total amount of gaseous inflow and outflow. For this purpose, we analyze the redshift evolution of their stellar mass distribution, combined with the scaling relations between the mass of baryonic components, star formation rate and chemical abundance for both high- and low-z star-forming galaxies. As a result, we find the new relations between star formation rate and inflow/outflow rate as deduced from these distant galaxies, which will provide fundamental information for understanding the structural and chemical evolution of MWLGs.
Multiple populations in the Sagittarius nuclear cluster M 54 and in other anomalous globular clusters
Authors: Milone A. P. 
Published: May 2016

AbstractM 54 is the central cluster of the Sagittarius dwarf galaxy. This stellar system is now in process of being disrupted by the tidal interaction with the Milky Way and represents one of the building blocks of the Galactic Halo. Recent discoveries, based on the synergy of photometry and spectroscopy have revealed that the color-magnitude diagram (CMD) of some massive, anomalous, Globular Clusters (GCs) host stellar populations with different content of heavy elements. In this paper, I use multi-wavelength Hubble Space Telescope (HST) photometry to detect and characterize multiple stellar populations in M 54. I provide empirical evidence that this GC shares photometric and spectroscopic similarities with the class of anomalous GCs. These findings make it tempting to speculate that, similarly to Sagittarius nuclear cluster M 54, other anomalous GCs were born in an extra-Galactic environment.
Searching for planetary nebulae at the Galactic halo via J-PAS
Authors: Gonçalves Denise R. , Aparício-Villegas T. , Akras S. , Cortesi A. , Borges-Fernandes M. , Daflon S. , Pereira C. B. , Lorenz-Martins S. , Marcolino W. , Kanaan A. , Viironen K. , de Oliveira C. Mendes , Molino A. , Ederoclite A. ,   the J-PAS Collaboration
Published: May 2016

AbstractThe Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow-band imaging, very wide field cosmological survey. It will last 5 years and will observe 8500 sq. deg. of the sky. There will be 54 contiguous narrow-band filters of 145Å FWHM, from 3,500 to 10,000Å. Two broad-band filters will be added at the extremes, UV and IR, plus the 3–g, r, and i– SDSS filters. Thus, J-PAS can be an important tool to search for new planetary nebulae (PNe) at the halo, increasing their numbers, because only 14 of them have been convincingly identified in the literature. Halo PNe are able to reveal precious information for the study of stellar evolution and the early chemical conditions of the Galaxy. The characteristic low continuum and intense emission lines of PNe make them good objects to be searched by J-PAS. Though covering a significantly smaller sky area, data from the ALHAMBRA survey were used to test our J-PAS strategy to search for PNe. Our first results are shown in this contribution.
Exploring the early Universe with extremely metal-poor stars
Authors: Hansen Terese T. , Christlieb Norbert , Hansen Camilla J. , Beers Timothy C. 
Published: May 2016

AbstractThe earliest phases of Galactical chemical evolution and nucleosynthesis can be investigated by studying the old metal-poor stars. It has been recognized that a large fraction of metal-poor stars possess significant over-abundances of carbon relative to iron. Here we present the results of a 23-star homogeneously analyzed sample of metal-poor candidates from the Hamburg/ESO survey. We have derived abundances for a large number of elements ranging from Li to Pb. The sample includes four ultra metal-poor stars ([Fe/H] < −4.0), six CEMP-no stars, five CEMP-s stars, two CEMP-r stars and two CEMP-r/s stars. This broad variety of the sample stars gives us an unique opportunity to explore different abundance patterns at low metallicity.
Stellar halos and the link to galaxy formation
Authors: Helmi Amina 
Published: May 2016

AbstractI present a brief overview of how stellar halos may be used to constrain the process of galaxy formation. In particular, streams and substructure in stellar halos trace merger events but can also be used to determine the mass distribution of the host galaxy and hence put constraints on the nature of dark matter. Much of the focus of this contribution is on the Milky Way, but I also present an attempt to understand the kinematics of the globular cluster system of M31.
Dual Stellar Halos in Early-type Galaxies and Formation of Massive Galaxies
Authors: Lee Myung Gyoon , Jang In Sung 
Published: May 2016

AbstractM105 in the Leo I Group is a textbook example of a standard elliptical galaxy. It is only one of the few elliptical galaxies for which we can study their stellar halos using the resolved stars. It is an ideal target to study the structure and composition of stellar halos in elliptical galaxies. We present photometry and metallicity of the resolved stars in the inner and outer regions of M105. These provide strong evidence that there are two distinct stellar halos in this galaxy, a metal-poor (blue) halo and a metal-rich (red) halo. Then we compare them with those in other early-type galaxies and use the dual halo mode formation scenario to describe how massive galaxies formed.
Globular Clusters, Dwarf Galaxies, and the Assembly of the M87 Halo
Authors: Peng Eric W. , Zhang Hong-Xin , Liu Chengze , Liu Yiqing 
Published: May 2016

AbstractAt the center of the nearest galaxy cluster, the Virgo cluster, lies the massive cD galaxy, M87 (NGC 4486). Using data from the Next Generation Virgo Cluster Survey, we investigate the relationship between M87, its globular clusters (GCs), and satellite dwarf galaxies. We find that the kinematics of GCs and ultra-compact dwarfs (UCDs) are different, indicating that UCDs are not simply massive GCs. We also identify a morphological sequence of envelope fraction around UCDs correlated with cluster-centric distance that suggest UCDs are the result of tidal stripping. Lastly, we find that the [α/Fe] abundance ratios of low-mass early-type galaxies in Virgo exhibit a strong negative gradient within ~ 400 kpc of M87, where the galaxies closest to M87 have the highest values. These satellite galaxies are likely the surviving counterparts of accreted dwarfs that contribute stars to the metal-poor, α-rich stellar halos of massive galaxies. Together, these results describe a dense environment that has had a strong and continuing impact on the evolution of its low-mass neighbors.
Study of the Milky Way's hot coronal gas with its dwarf galaxies
Authors: Pasetto Stefano , Cropper Mark , Fujita Yutaka , Chiosi Cesare , Grebel Eva K. 
Published: May 2016

AbstractA large amount (5 × 1010 M⊙) of hot gas is thought to exist in an extended (≈ 200 kpc) hot diffuse halo around the Milky Way. We investigate the competitive role of the different dissipative phenomena acting on the onset of star formation of this gravitationally bound systems in this external environment. Ram pressure, Kelvin-Helmholtz and Rayleigh- Taylor instabilities, and tidal forces are accounted for separately in an analytical framework and compared in their role in influencing the star forming regions. We present an analytical criterion to elucidate the dependence of star formation in a spherical stellar system on its surrounding environment, useful in observational applications as well as theoretical interpretations of numerical results. We consider the different signatures of these phenomena in synthetically realized colour-magnitude diagrams (CMDs) of the orbiting system, thus investigating the detectability limits and relevance of these different effects for future observational projects. The theoretical framework developed has direct applications to the cases of our MW system as well as dwarf galaxies in galaxy clusters or any primordial gas-rich star cluster of stars orbiting within its host galaxy.
Did globular clusters contribute to the stellar population of the Galactic halo?
Authors: Charbonnel Corinne , Krause Martin 
Published: May 2016

AbstractThe origin of Galactic halo stars and the contribution of globular clusters (GC) to this stellar population have long been (and still are) debated. The discovery of multiple stellar populations with peculiar chemical properties in GCs both in the Milky Way and in Local Group galaxies recently brought a renewal on these questions. Indeed most of the scenarios that compete to reproduce the present-day GC characteristics call for fast expulsion of both gas and low-mass stars from these clusters in their early infancy. In this framework, the initial masses of GCs could have been 8 to 25 times higher than their present-day stellar mass, and they could have contributed to 5 to 20 % of the low-mass stars in the Galactic halo. Here we revisit these conclusions, which are in tension with observations of dwarf galaxies and of young massive star clusters in the Local Group. We come back in particular on the paradigm of gas expulsion from massive star clusters, and propose an alternative interpretation of the GC abundance properties. We conclude by proposing a major revision of the current concepts regarding the role massive star clusters play in the assembly of galactic haloes.
IAU Symposium 317 Summary
Authors: Gratton Raffaele G. 
Published: May 2016

AbstractThe assembly of the halo yields fundamental information on the formation and evolution of galaxies: this was quite exhaustively discussed at this very important symposium. I present a brief personal summary of the meeting, outlining those points that I found more exciting and suggestive. I also remarked a few areas that were possibly not enough expanded. I found this research field extremely interesting and I think there are great expectations for new developments in the next few years, thanks to the new large spectroscopic surveys and the ESA GAIA satellite.
Die Effekte der Interessendiagnostik mittels Self-Assessments auf die Studienwahl
Authors: Aldrup Karen , Köller Michaela , Klusmann Uta 
Published: May 2016

Zusammenfassung. Berufliche Interessen determinieren neben der Studienfachwahl auch Zufriedenheit und Erfolg im Studium. Viele Schüler/innen treffen bei der Einschätzung ihrer Interessen jedoch auf Schwierigkeiten. Ein Angebot zur Verbesserung dieser Einschätzung stellen sogenannte Self-Assessments dar: Auf Basis von Interessenfragebögen wird das individuelle Interessenprofil ermittelt und dazu passende Studiengänge vorgeschlagen. Die vorliegende Studie untersucht in einem experimentellen Prä-Post-Kontrollgruppen-Design mit N = 430 Schüler/innen Effekte der Self-Assessments was-studiere-ich.de und EXPLORIX® auf den Studienwahlprozess im Vergleich zu einer allgemeinen Studieninformation. Varianzanalysen mit Messwiederholung zeigen, dass sich durch die Bearbeitung der Self-Assessments die studienwahlbezogene Selbstwirksamkeit, die Entschlossenheit, die Zufriedenheit mit der Entscheidung, das Wissen über die berufliche Umwelt und die Selbstkenntnis erhöhen. Die Selbstkenntnis steigt durch die Bearbeitung der Self-Assessments stärker an als durch die Studieninformation. Die Rückmeldung der individuellen Interessen im EXPLORIX® führt außerdem dazu, dass mehr Schüler/innen mit ihren Interessen kongruente Studienwünsche äußern als zuvor.
Deorphanization and characterization of the ectopically expressed olfactory receptor OR51B5 in myelogenous leukemia cells
Authors: Manteniotis S , Wojcik S , Göthert J R , Dürig J , Dührsen U , Gisselmann G , Hatt H 
Published: May 2016

AbstractThe ectopic expression of olfactory receptors (ORs) in the human body has been of major interest in the past decade. Several studies have reported the expression of ORs not only in healthy tissues such as heart, sperm or skin cells, but also in cancerous tissues of the liver, prostate or intestine. In the present study, we detected the expression of OR51B5 in the chronic myelogenous leukemia (CML) cell line K562 and in white blood cell samples of clinically diagnosed acute myelogenous leukemia (AML) patients by reverse transcription-PCR and immunocytochemical staining. The known OR51B5 ligand isononyl alcohol increased the levels of intracellular Ca2+ in both AML patient blood cells and K562 cells. With calcium imaging experiments, we characterized in greater detail the OR51B5-mediated signaling pathway. Here, we observed an involvement of adenylate cyclase and the downstream L-type and T-type calcium channels. In addition, the activation of OR51B5 leads to an inhibition of cell proliferation in K562 cells. In western blot experiments, we found that incubation with isononyl alcohol led to a reduction in p38-MAPK (mitogen-activated protein kinase) phosphorylation that might be responsible for the decreased cell proliferation. In the present study, we characterized the OR51B5-mediated signaling pathway downstream of the activation with isononyl alcohol, which leads to reduced proliferation and therefore provide a novel pharmacological target for CML and AML, the latter of which remains difficult to treat.
Repositioning of a cyclin-dependent kinase inhibitor GW8510 as a ribonucleotide reductase M2 inhibitor to treat human colorectal cancer
Authors: Hsieh Y-Y , Chou C-J , Lo H-L , Yang P-M 
Published: May 2016

AbstractColorectal cancer (CRC) is the second leading cause of cancer-related death in males and females in the world. It is of immediate importance to develop novel therapeutics. Human ribonucleotide reductase (RRM1/RRM2) has an essential role in converting ribonucleoside diphosphate to 2′-deoxyribonucleoside diphosphate to maintain the homeostasis of nucleotide pools. RRM2 is a prognostic biomarker and predicts poor survival of CRC. In addition, increased RRM2 activity is associated with malignant transformation and tumor cell growth. Bioinformatics analyses show that RRM2 was overexpressed in CRC and might be an attractive target for treating CRC. Therefore, we attempted to search novel RRM2 inhibitors by using a gene expression signature-based approach, connectivity MAP (CMAP). The result predicted GW8510, a cyclin-dependent kinase inhibitor, as a potential RRM2 inhibitor. Western blot analysis indicated that GW8510 inhibited RRM2 expression through promoting its proteasomal degradation. In addition, GW8510 induced autophagic cell death. In addition, the sensitivities of CRC cells to GW8510 were associated with the levels of RRM2 and endogenous autophagic flux. Taken together, our study indicates that GW8510 could be a potential anti-CRC agent through targeting RRM2.
Plasticity within non-cerebellar pathways rapidly shapes motor performance in vivo
Authors: Mitchell Diana E. , Della Santina Charles C. , Cullen Kathleen E. 
Published: May 2016

AbstractAlthough cerebellar mechanisms are vital to maintain accuracy during complex movements and to calibrate simple reflexes, recent in vitro studies have called into question the widely held view that synaptic changes within cerebellar pathways exclusively guide alterations in motor performance. Here we investigate the vestibulo-ocular reflex (VOR) circuitry by applying temporally precise activation of vestibular afferents in awake-behaving monkeys to link plasticity at different neural sites with changes in motor performance. Behaviourally relevant activation patterns produce rapid attenuation of direct pathway VOR neurons, but not their nerve input. Changes in the strength of this pathway are sufficient to induce a lasting decrease in the evoked VOR. In addition, indirect brainstem pathways display complementary nearly instantaneous changes, contributing to compensating for the reduced sensitivity of primary VOR neurons. Taken together, our data provide evidence that multiple sites of plasticity within VOR pathways can rapidly shape motor performance in vivo.
Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator
Authors: Krantz Philip , Bengtsson Andreas , Simoen Michaël , Gustavsson Simon , Shumeiko Vitaly , Oliver W. D. , Wilson C. M. , Delsing Per , Bylander Jonas 
Published: May 2016

AbstractWe propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185±15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing.