bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma Dynamics in Mercury’s Magnetosphere
Authors: Ip Wing-Huen 
Published: March 2016

AbstractMercury is in all sense of the words still Terra Incognito, its magnetosphere is hence little known. The only source of knowledge came from the in-situ measurements by the Mariner 10 close encounters in 1974. This has been complemented since by ground-based observations of the atomic sodium and potassium emissions in the vicinity of the planetary disk. This series of optical observations has produced intriguing evidence of magnetospheric and/or solar wind effects on the surface-plasma interaction processes. In this review we will describe the current theories of the corresponding space weather effects.
Space Studies of the Black-Drop Effect at a Mercury Transit
Authors: Schneider Glenn , Pasachoff Jay M. , Golub Leon 
Published: March 2016

AbstractTransits of Mercury and Venus across the face of the Sun are rare. The 20th century had 15 transits of Mercury and the 21st century will have 14, the two most recent occurring on 15 November 1999 and 7 May 2003. We report on our observations and analysis of a black-drop effect at the 1999 and 2003 transits of Mercury seen in high spatial resolution optical imaging with NASA’s Transition Region and Coronal Explorer (TRACE) spacecraft. We have separated the primary contributors to this effect, solar limb darkening and broadening due to the instrumental point spread function, for the 1999 event. The observations are important for understanding historical observations of transits of Venus, which in the 18th and 19th centuries were basic for the determination of the scale of the solar system. Our observations are in preparation for the 8 June 2004 transit of Venus, the first to occur since 1882. Only five transits of Venus have ever been seen – in 1639, 1761, 1769, 1874, and 1882. These events occur in pairs, whose members are separated by 8 years, with an interval between pairs of 105 or 122 years. Nobody alive has ever seen a transit of Venus.
Formation of ω Centauri from an Ancient Nucleated Dwarf Galaxy
Authors: Bekki Kenji , Freeman K. C. 
Published: March 2016

AbstractWe present a self-consistent dynamical model in which ω Cen is formed from an ancient nucleated dwarf galaxy merging with the first generation of the Galactic thin disc in a retrograde manner with respect to the Galactic rotation. Our numerical simulations demonstrate that during merging between the Galaxy and the ω Cen’s host dwarf with MB ⋍ ‒14 mag and its nucleus mass of 107M⊙, the outer stellar envelope of the dwarf is nearly completely stripped whereas the central nucleus can survive from the tidal stripping because of its compactness. The developed naked nucleus is orbiting the young Galactic disc in a retrograde manner with its apocenter and pericenter distances of ~ 8 kpc and ~ 1 kpc, respectively, and thus have orbital properties similar to those of ω Cen. The Galactic tidal force can induce radial inflow of gas to the dwarf’s center and consequently triggers moderately strong nuclear starbursts in a repetitive manner. This result implies that efficient nuclear chemical enrichment resulting from the later starbursts can be closely associated with the origin of the observed relatively young and metal-rich stars in ω Cen. Dynamical heating by the ω Cen’s host can transform the young thin disc into the thick one during merging.
Perhaps They are not Globular Clusters After All
Authors: Karick A. M. 
Published: March 2016

AbstractOur 2dF Fornax Cluster Spectroscopic Survey (FCSS) and follow-up work in the Virgo Cluster have shown that the cores of both galaxy clusters contain a previously-unknown class of object, ultra-compact dwarf (UCD) galaxies. We present high resolution spectroscopy and deep multicolor imaging to show that these enigmatic objects are dynamically distinct from both globular clusters (GCs) and nucleated dwarf galaxies (dE,Ns). Our hypothesis for their origin may explain the observed high “specific frequency” of GCs in central cluster galaxies.
JD 7: The Sun and the Heliosphere as an Integrated System
Authors: Poletto Giannina , Suess Steven T. 
Published: March 2016

AbstractWe summarize here the oral contributions given at the Joint Discussion (JD) 7The Sun and the Heliosphere as an Integrated System, held on July 17, 2003, in Sydney, as part of IAU XXV and give a list of posters presented at the JD.
X-ray Cavities and Cooling Flows
Authors: Nulsen Paul E. J. , McNamara Brian R. , David Laurence P. , Wise Michael W. 
Published: March 2016

AbstractRecent data have radically altered the X-ray perspective on cooling flow clusters. X-ray spectra show that very little of the hot intra-cluster medium is cooler than about 1 keV, despite having short cooling times. In an increasing number of cooling flow clusters, the lobes of a central radio source are found to have created cavities in the hot gas. Generally, the cavities are not overpressured relative to the intra-cluster gas, but act as buoyant bubbles of radio emitting plasma that drive circulation as they rise, mixing and heating the intra-cluster gas. All this points to the radio source, i.e., an active galactic nucleus, as the heat source that prevents gas from cooling to low temperatures. However, heating due to bubbles alone seems to be insufficient, so the energetics of cooling flows remain obscure. We briefly review the data and theory supporting this view and discuss the energetics of cooling flows.
Mass Loss, Kinematics, & Evolution of Super Star Clusters in the Antennae
Authors: Gilbert Andrea M. , Graham James R. 
Published: March 2016

AbstractThe youngest super star clusters (SSCs) in the merging Antennae Galaxies (NGC 4038/39) drive supersonic mass-loaded outflows from the HII regions in which they are embedded. High-resolution K-band Keck/NIRSPEC spectroscopy reveals broad, spatially extended Brγ emission in 16 targets. Simple wind models for the line profiles provide good fits and imply cluster mass-loss rates of up to 1.5 M⊙/year and terminal velocities of up to 205 km s−1. The emission-line clusters (ELCs) that drive these outflows constitute at least 15% of the star formation rate in the Antennae, and their high star formation efficiencies imply that they will probably evolve into bound SSCs. The youngest ELC outflows, which are driven primarily by stellar winds, very efficiently entrain ambient matter. The cluster winds transfer or dissipate a large fraction of their energy and momentum in a hot or cool medium that does not emit Brγ. ELCs are the individual engines that power galactic-scale superwinds, viewed in their earliest evolutionary stage.
Processed and Unprocessed Ices in Circumstellar Disks
Authors: Pontoppidan Klaus , Dishoeck Ewine van , Dartois Emmanuel , Thi Wing-Fai 
Published: March 2016

AbstractWe present 3-5 µm VLT-ISAAC spectroscopy showing the presence of methanol ices in edge-on disks of young embedded stars. Examples include the disks of L1489 IRS in Taurus and CRBR 2422.8-3423 in Ophiuchus, the last of which has the highest column density of solid CO known toward a YSO. Several additional low-mass sources in the Serpens and Chameleon molecular clouds exhibit abundant solid methanol although it is not clear if the ice is associated with a disk or with the envelope. These are the first detections of solid methanol in the disks and circumstellar environments of embedded young low-mass stars providing evidence that complex molecular species previously observed only in the solid state toward high-mass star forming regions are also present near solar-type young stars. The constraints on the formation mechanisms of methanol and the chemical evolution of ices as the material is incorporated into circumstellar disks are discussed.
Disk Chemistry and Cometary Composition
Authors: Markwick A. J. , Charnley S. B. 
Published: March 2016

AbstractWe describe a theoretical study of protoplanetary disk chemistry. By considering physical conditions similar to that of the protosolar nebula, we attempt to assess the contribution made by material from the cooler nebular regions to cometesimal composition. Calculations are presented which determine the spatial and temporal chemistry of the gas and dust within the 5-40 AU comet-forming region of the nebula. We show that there is little radial variation in the solid-state distribution of some molecules which could potentially be parents of the carbon-chain species observed in comets. We conclude that the apparent variation in abundance of C2 and C3 between long- and short-period comets is the result of chemical processing during their lifetimes and not differences in composition at the time of formation.
Crystallization of Silicate Particles By Shock Waves
Authors: Nakamoto Taishi , Miura Hitoshi 
Published: March 2016

AbstractCrystalline silicate dust particles have been found in some comets, though progenitors of those dust particles are thought to be amorphous. Here, the origin of the crystalline particles was investigated based on the shock-wave heating mechanism. We find that appropriate shock waves can crystallize amorphous dust particles and conditions of these shock waves (shock velocity and pre-shock gas density) are clarified.The gas density in the solar nebula and the shock velocity that may be induced in comet forming regions by some mechanisms were discussed. It was suggested that comets formed in a region closer than about 20 AU to the Sun can contain the crystalline particles, whereas comets formed in a further region can hardly have them.
Atomic Spectral Tables for the Chandra X-ray Observatory
Authors: Podobedova L. I. , Kelleher D. E. , Reader J. , Wiese W. L. 
Published: March 2016

AbstractTables of wavelengths, line classifications, and transition probabilities have been critically compiled for ionized spectra of neon (Ne V-VIII), magnesium (Mg V-X), silicon (Si VI-XII), and sulfur (S VIII-XIV) in the 20 Å-170 Å region. The tables provide basic atomic data for about 3300 transitions in support of astronomical studies from the Chandra X-ray Observatory.
The Astrophysical Plasma Emission Database: Progress and Plans
Authors: Smith Randall K. , Brickhouse Nancy S. , Liedahl Duane A. 
Published: March 2016

AbstractThe Astrophysical Plasma Emission Database (APED) contains atomic data for the 14 most abundant astrophysical elements, collected from the literature. Although APED was originally designed for use in calculating a collisional-equilibrium X-ray spectrum suitable for analysis of high-resolution data, it is in a general format which can be efficiently used to calculate absorption spectra, photoionization models, and non-equilibrium collisional models. We emphasize original sources; each transition, rate, and energy level in APED contains a bibliographic reference. The APED can be downloaded from http://cxc.harvard.edu/atomdb/, or our website WebGUIDE (http://obsvis.harvard.edu/WebGUIDE/) can be used to search for individual lines or transitions. We are continually working to expand APED (current version 1.3.1) and regularly issue updated collections.
High-Resolution Optical Observations of Interstellar Absorption Lines
Authors: Welty Daniel E. 
Published: March 2016

AbstractWe briefly note several current topics concerning the properties of interstellar clouds for which high-resolution optical spectra play a significant role: (1) the recognition and characterization of small-scale (sub-pc) structure in both atomic and molecular gas; (2) the discovery of variations in the 7Li/6Li isotopic ratio in the nearby Galactic ISM; (3) the determination of atomic and molecular abundances and physical conditions for heavily reddened (“translucent”) Galactic sightlines; and (4) studies of interstellar clouds in the LMC and SMC.
The Deuterium Balmer Series
Authors: Hébrard Guillaume 
Published: March 2016

AbstractThe first detection and identification of deuterium Balmer lines were recently reported in H ii regions, using high spectral resolution data secured at CFHT and VLT. The Di lines appear as faint, narrow emission features in the blue wings of the H i Balmer lines and can be distinguished from high-velocity Hi emission. The identification as deuterium and the excitation mechanism as fluorescence are both established beyond doubt. The deuterium Balmer series might lead to a new, optical method of deuterium abundance measurement in the interstellar medium. This may be the only way to observe atomic deuterium in objects like the Magellanic Clouds or low metallicity blue compact galaxies.
Probing Physics and Chemistry in Circumnuclear Torus with OH
Authors: Zhi-yao Yu 
Published: March 2016

AbstractWe observed OH maser emission at 18cm in a circumnuclear torus surrounding the center of IRAS10173+0828 using the 7 telescopes of MERLIN, together with the Lovell antenna. IRAS10173+0828 is a distant super-luminous far-infrared galaxy. The OH maser emission is remarkably narrow (FWHP = 39km s_1) for its strength, and the 1667 and 1665 MHz lines are well separated. The 1667 transition shows two distinct peaks displaced from one another by 100 km s−1. Using our MERLIN observational results we probe the physics in the circumnuclear torus surrounding the center of IRAS10173+0828, obtain the kinematic properties of the torus, and study the central source.
Newly detected H2O Masers in Seyfert and Starburst Galaxies
Authors: Peck A. B. , Tarchi A. , Henkel C. , Nagar N. M. , Braatz J. , Moscadelli L. 
Published: March 2016

AbstractWe report new detections of three H2O megamasers and one kilomaser using the Effelsberg 100-m telescope. Isotropic luminosities are ~50, 300, 1, and 230 L⊙ for Mrk 1066, Mrk 34, NGC 3556, and Arp 299, respectively. Mrk 34 contains the most distant H2O megamaser ever detected in a Seyfert. Our targets in this survey were chosen to fit one of the following criteria: 1) to have a high probability of interaction between the radio jet and the ISM within the central few parsecs of the radio galaxy, yielding masers which arise in local molecular clouds; or 2) to have very bright IRAS sources in which massive star forming regions might yield powerful masers. The ‘jet maser’ sources can provide detailed information about the conditions in the ISM in the central 1-10 pc of AGN. The extra-galactic ‘star formation masers’ can be used to pinpoint and characterize locations of high mass star formation in nearby galaxies. In addition, these sources will help to provide a better understanding of the chemical properties of molecular clouds in extra-galactic systems.
Young Star Clusters: Metallicity Tracers in External Galaxies
Authors: Anders Peter , Alvensleben Uta Fritze – v. , de Grijs Richard 
Published: March 2016

AbstractStar cluster formation is a major mode of star formation in the extreme conditions of interacting galaxies and violent star bursts. These newly-formed clusters are built from recycled gas, pre-enriched to various levels within the interacting galaxies. Hence, star clusters of different ages represent a fossil record of the chemical enrichment history of their host galaxy, as well as of the host galaxy’s violent star formation history. We present a new set of evolutionary synthesis models of our GALEV code, specifically developed to include the gaseous emission of presently forming star clusters, and a new tool to analyze multi-color observations with our models. First results for newly-born clusters in the dwarf star-burst galaxy NGC 1569 are presented.
The Nuclear Starburst in NGC 4945
Authors: Wang M. , Henkel C. , Chin Y.-N. , Whiteoak J. B. , Hunt Cunningham M. , Mauersberger R. 
Published: March 2016

AbstractNGC 4945 is with D ~3-4 Mpc one of the nearest starburst galaxies known and a goldmine for molecular cloud research. A multi-line mm-wave study has been carried out towards its nuclear region with the Swedish-ESO Sub-millimetre Telescope (SEST). The study covers the frequency range from 82 GHz to 354 GHz and includes 80 transitions of 19 molecules, including rare isotope-bearing species. Applying a Large Velocity Gradient (LVG) code to the data, H2 densities and column densities of 22 molecular species are calculated. Many of these species indicate the presence of a prominent high density interstellar gas component characterized by nH2 ~105cm-3. Abundances of molecular species are calculated and compared with abundances observed toward the starburst galaxies NGC 253 and M 82 and galactic sources. Apparent is an ‘overabundance’ of HNC and CN in the nuclear environment of NGC 4945. NGC 4945 is the second known starburst galaxy with an HNC/HCN abundance ratio ≥1. Carbon, nitrogen, oxygen and sulfur isotope ratios are also determined. The data indicate that high 18O/17O, low 16O/18O and 14N/15N and perhaps also low 32S/34S ratios (6.4±0.3, 195±45, 105±25 and 13.5±2.5, respectively) are characteristic properties of a starburst environment in an advanced evolutionary stage.
Extragalactic Ammonia
Authors: Henkel C. , Menten K.M. , Braatz J. , Mauersberger R. , Weiß A. , Lebrón M. , Tarchi A. , Peck A. B. , Carilli C. L. , Lubowich D. A. 
Published: March 2016

AbstractMulti-line data of ammonia (NH3) are presented for Maffei 2, IC 342, and the starburst galaxies NGC 253 and M 82. While in M 82 the NH3 emitting gas is cool, presumably arising from well shielded dense cores deeply embedded in an environment dominated by Photon Dominated Regions, the other galaxies show ‘warm’ and ‘hot’ components that may be heated by shocks, ion-slip or cosmic rays. Interferometric observations show the detailed large scale distribution of NH3 in galaxies for the first time. The first multi-line studies of ammonia at significant redshifts (z = 0.65 and 0.89) are also reported and rotational temperatures, measures of the kinetic temperature of the emitting gas, are derived for all sources.
Large Changes in Pluto’s Atmosphere Revealed by Stellar Occultations
Authors: Sicardy Bruno , Widemann Thomas , Lellouch Emmanuel , Roques Françoise , Gendron Eric , Veillet Christian , Cuillandre Jean-Charles , Colas François , Beisker Wolfgang , Kretlow Mike , Hainaut Olivier R. , Lidman Chris 
Published: March 2016

AbstractPluto’s tenuous nitrogen atmosphere was detected by stellar occultations in 1985 and 1988. This atmosphere is poorly known, however, due to the rarity of these events. We report here the first Pluto occultations observed since 1988, on 20 July and 21 August 2002. Our analysis reveals drastic changes undergone by the atmosphere since 1988, namely a two-fold pressure increase, the probable effect of seasonal changes on Pluto over this fourteen year interval.
Results from the South Pole Infra-Red EXplorer Telescope
Authors: Rathborne J. M. , Burton M. G. 
Published: March 2016

AbstractThe SPIREX telescope, located at the Amundsen-Scott South Pole Station, was a prototype system developed to exploit the excellent conditions for IR observing at the South Pole. Observations over two winter seasons achieved remarkably deep, high-resolution, wide-field images in the 3-5 μm wavelength regime. Several star forming complexes were observed, including NGC 6334, Chamaeleon I, η Chamaeleontis, the Carina Nebula, 30 Doradus, RCW 57, RCW 38, as well as the Galactic Center. Images were obtained of lines at 2.42/μm H2, 3.29/μm PAH and 4.05/μm Br α, as well as 3.5/μm L-band and 4.7 μm M-band continuum emission. These data, combined with near-IR, mid-IR, and radio continuum maps, reveal the environments of these star forming sites, as well as any protostars lying within them. The SPIREX project, its observing and reduction methods, and some sample data are summarized here.
An Introduction to the Nomenclature Problem
Authors: Mason Brian D. , Hartkopf William I. 
Published: March 2016

AbstractThe new observing and reduction techniques available to astronomers have led to remarkable changes in the field of double and multiple stars. New classes of companions, such as brown dwarfs and exoplanets, have been discovered. Binaries which previously constituted distinct classes are now observable by multiple techniques. With many long-baseline optical interferometers operational or planned, with improvements in other techniques, and with astrometric space-based missions in various states of planning and funding, the situation is likely to become more complicated. The result is greater understanding for the scientist, but greater challenges for the cataloger!The “problem” is that purveyors of different techniques use different nomenclature, both in terms of root designation and component identifier. It is this latter inconsistency which causes the most confusion and is the topic of this Special Session.This talk will illustrate some of the many designation ambiguities and summarize efforts made during the past few years to address this problem.
Textbooks for K-12 Astronomy
Authors: Pasachoff Jay M. 
Published: March 2016

AbstractI report on American textbooks for kindergarten through highschool grades. Middle school, up through approximate age 15, is the last time American students are required to take science, and I provide statistics on the narrowing of the funnel containing those taking physics. I describe some recent curriculum and standards projects, and I discuss the recent “less is more” trend. I conclude with comments on whether textbooks are necessary and useful and discuss possible content and style of an ideal textbook.
Shielding of the Geomagnetic Field Alters Actin Assembly and Inhibits Cell Motility in Human Neuroblastoma Cells
Authors: Mo Wei-Chuan , Zhang Zi-Jian , Wang Dong-Liang , Liu Ying , Bartlett Perry F. , He Rong-Qiao 
Published: March 2016

AbstractAccumulating evidence has shown that absence of the geomagnetic field (GMF), the so-called hypomagnetic field (HMF) environment, alters the biological functions in seemingly non-magnetosensitive cells and organisms, which indicates that the GMF could be sensed by non-iron-rich and non-photo-sensing cells. The underlying mechanisms of the HMF effects on those cells are closely related to their GMF sensation but remain poorly understood so far. Previously, we found that the HMF represses expressions of genes associated with cell migration and cytoskeleton assembly in human neuroblastoma cells (SH-SY5Y cell line). Here, we measured the HMF-induced changes on cell morphology, adhesion, motility and actin cytoskeleton in SH-SY5Y cells. The HMF inhibited cell adhesion and migration accompanied with a reduction in cellular F-actin amount. Moreover, following exposure to the HMF, the number of cell processes was reduced and cells were smaller in size and more round in shape. Furthermore, disordered kinetics of actin assemblyin vitrowere observed during exposure to the HMF, as evidenced by the presence of granule and meshed products. These results indicate that elimination of the GMF affects assembly of the motility-related actin cytoskeleton, and suggest that F-actin is a target of HMF exposure and probably a mediator of GMF sensation.