bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the Uccle-Brussels Coordinates in the BIH, NWL and EUR 50 Systems
Authors: Pâquet P. , Dejaiffe R. , Rop W. De , Verbeiren R. 
Published: July 2016

AbstractThe possibility exists at the Royal Observatory of Belgium (Uccle-Brussels) of comparing the coordinates of a well-defined point simultaneously obtainable in the BIH, NWL and EUR50 astronomical and geodetical systems.The following differences between these reference systems have been obtained:if the longitudes are positively measured westward.
2.3.3 Micrometeorite Impact Craters on Skylab Experiment S 149
Authors: Nagel K. , Fechtig H. , Schneider E. , Neukum G. 
Published: July 2016

AbstractDuring the Skylab experiment S 149 three different sets of areas were exposed. 71.5 cm2 were facing the sun for 46 days, and 36 cm2 for 33 days, whereas 77.5 cm2 were exposed in anti-solar direction for 34 days. A fourth set is currently being exposed with the hope of future recovery. The exposed surfaces consisted of stainless steel, aluminium, platinum, glass, and pyroxene. The recovered targets have been investigated with a light microscope and a scanning electron microscope. We found two groups of possible impact structures:1.) Five craters between 1 and 30 µm. These craters show clear signs of hypervelocity impact. Measurements yielded diameter to depth ratios between 2 and 3. Chemical investigations in the craters yielded an enhancement in aluminium in one case.2.) 44 crater-like structures between 1 and 4 (µm in diameter. These features have been found on 4 cm2 of pyroxene exposed in solar direction. They show diameter to depth ratios between 5 and 8. Chemical measurements of the interior of these structures indicate the elements of the pyroxene composition.The five impacts of the first group correspond to a cumulative flux of the order of 10−4 (m−2s−l) for masses of about 10−12 g. The second group may indicate a fragmentation process at altitudes around 450 km. Considering these 44 crater-like structures having been produced by fragments of one projectile, the impact rate could be comparable to that calculated for the first group. If individual projectiles had produced these structures, the corresponding flux could be 2 orders of magnitude higher.
2.3.5 Magellan Collections of Large Cosmic Dust Particles
Authors: Hallgren D. S. , Hemenway C. L. , Wlochowicz R. 
Published: July 2016

AbstractA new balloon collection technique, Magellan, for obtaining large cosmic dust particles > 50µ is described. The technique utilized a 40 m2 aperture funnel suspended 300 m below a balloon at an altitude of 25 km. First results indicate that the collected particles are diverse both chemically and physically.
3.6 Dust Emission from Comet Kohoutek (1973f) at Large Distances from the Sun
Authors: Grün E. , Kissel J. , Hoffmann H.-J. 
Published: July 2016

AbstractDuring a period of 60 days around the time when the HEOS 2 satellite penetrated the orbital plane of Comet Kohoutek (1973f) the micro-meteoroid experiment on board registered an excessive particle flux. These particles are identified with those originated in Comet Kohoutek. Orbit calculations show that their emission occurred outside 3.8 AU from the sun. The ratio of the force of radiation pressure to that of gravity of these particles was determined to ß =1 ± 0.1, their mass has been measured from the satellite data (10−13g to 10−11g). The velocity and the rate of dust particles emitted from the comet is studied on the basis of the theory of dust comets formulated by Finson and Probstein. An emission rate of appr. 1.2 × 1018particles per second in the size range corresponding to 0.9 ≤ ß < 1.1 and an emission velocity of appr. 0.5 km/sec match best the observed data.
Effets de Selection Dans La Decouverte De Systemes Multiples
Authors: Muller P. 
Published: July 2016

AbstractEn étudiant les systèmes multiples issus d’un couple de découverte ancienne grâce à l’emploi ultérieur d’un instrument plus puissant, on constate qu’un grand nombre d’étoiles doubles n’ont jamais été examinées avec un tel instrument; il en résulte que parmi ces couples plusieurs centaines sont des systèmes au moins triples que nous ignorons.
UBVRI Photometry of Stars in Trapezium Type Systems
Authors: Warman Josef , Echevarría Juan 
Published: July 2016

AbstractWe present UBVRI photometric data for 50 stars forming 14 systems of the trapezium type. Color-magnitude and color-color diagrams indicate the presence of ultraviolet excess and anomalous behavior in the infrared part of the spectrum. This is consistent with the dynamical ages for stars in trapezia.
The Formation of Multiple Systems by Dynamical Interaction in Clusters
Authors: Aarseth S. J. 
Published: July 2016

AbstractThis review is mainly devoted to a discussion of binary formation and evolution in stellar systems, as described by N-body techniques. The simplest formation mechanisms consist of ejection from bound triple systems and capture arising from hyperbolic three-body encounters. However, the large number of astrophysically close binaries cannot be accounted for in this way unless most stars are formed in compact groups. Numerical calculations show that the evolution of clusters containing several hundred members is invariably dominated by one central binary which absorbs a large fraction of the total energy. It is suggested that a visual binary in the core of the Hyades cluster may have been associated with this process.
Critical Evaluation of Photometric Data
Authors: Nicolet B. , Hauck B. 
Published: July 2016

AbstractSome problems encountered in the homogenization of photometric data (especially for the uvby$ and UBV systems) are presented: sources of inhomogeneity, method to obtain a homogeneous photometric value, establishment of a reference list, etc.In many cases a homogeneous photometric value is necessary, but cannot be simply an arithmetical mean, and for this purpose it is necessary to make a critical evaluation of the data.
Proposal for A Data Centre on Galactic Non-Stellar Objects
Authors: Lortet M. C. 
Published: July 2016

Bibliographic work was begun in 1969 on Interstellar Matter and Galactic Non-Stellar Objects, mainly those found in regions suspected to be favourable to star formation.We are contemplating the systematization and automatization of this work, taking advantage of the tools now worked out for stellar data at the Centre de Données Stellaires de Strasbourg.
Low Surface Brightness Galaxies in Deep Surveys
Authors: Ferguson Henry C. 
Published: July 2016

AbstractWe examine the constraints that can be placed on the space density of low-surface-brightness galaxies from deep HST images. Such images, while covering only a small solid angle, provide enough depth and spatial resolution to detect LSB galaxies at moderate redshift and distinguish them from galaxies of higher surface brightness.We consider five simple models of the non-evolving or slowly-evolving population of LSB galaxies, motivated by various discussions in the recent literature. The basic results are (1) models with a large space-density of giant LSB galaxies at moderate redshift do not look like the real world and, (2) models with a large space-density of dwarf LSB galaxies are consistent with HST data (that is, they do not produce more faint LSB galaxies per unit solid angle than are detected at magnitudes I ≳ 23), but these LSB dwarf galaxies do not contribute much to faint galaxy counts unless they formed their stars in a rapid burst.
Morphology and Stellar Populations in the Gas-Rich, Giant LSBGs
Authors: Knezek P. 
Published: July 2016

AbstractAn unexpected characteristic of low surface brightness galaxies (LSBGs) is that a significant number are massive and possess substantial amounts of atomic gas. We present preliminary results of an ongoing program to obtain BVRIJHK imaging, along with some nuclear spectroscopy, of a well-defined sample of LSBGs which are gas-rich and of similar size to giant, high surface brightness spiral galaxies (HSBGs). These LSBGs span the entire range of Hubble disk morphologies. While their disks are bluer, on average, than comparable HSBGs, the optical morphology of massive LSBGs indicates that many of these systems have undergone previous star formation episodes. They typically have long disk scale lengths, and range from MB = −16 to −22 (H0 = 75 km s−1 Mpc−1). About half of the LSBGs with bulges show evidence of nuclear activity, and ~30% appear to be barred. These massive, gas-rich LSBGs apparently have varied, and often complex, evolutionary histories.
Kinematics of Giant Low Surface Brightness Galaxies
Authors: Pickering T.E. 
Published: July 2016

AbstractHigh sensitivity H I observations now exist for six giant low surface brightness (LSB) disk galaxies including the two prototypes, Malin 1 (Bothun et al. 1987; Impey & Bothun 1989) and F568-6 (also known as Malin 2; Bothun et al. 1990). Their H I surface brightnesses are generally low, but proportionally not as low as their optical surface brightnesses. Their total H I masses and radial extents are quite large, however, with MHI ∼ 1010M⊙h−275 and with detectable H I out to 100 kpc h−175 or more in a couple of cases. The rotation curves of these systems rise slowly and are consistent with negligible disk contribution, similar to many previously observed dwarf galaxies. However, the peak rotation velocities of these galaxies are high (>200 km s−1) and infer high dynamical masses. These galaxies provide the some of the first examples of galaxies that are both massive and dark matter dominated.
The fate of LSB galaxies in clusters and the origin of the diffuse intra-cluster light
Authors: Moore Ben , Lake George , Stadel Joachim , Quinn Thomas 
Published: July 2016

AbstractWe follow the evolution of disk galaxies within a cluster that forms hierarchically in a standard cold dark matter N-body simulation. At a redshift z = 0.5 we select several dark matter halos that have quiet merger histories and are about to enter the newly forming cluster environment. The halos are replaced with equilibrium high resolution model spirals that are constructed to represent luminous examples of low surface brightness (LSB) and high surface brightness (HSB) galaxies. Whilst the models have the same total luminosity, ~ L*, they have very different internal mass profiles, core radii and disk scale lengths, however they all lie at the same place on the Tully-Fisher relation. Due to their “soft” central potentials, LSB galaxies evolve dramatically under the influence of rapid encounters with substructure and strong tidal shocks from the global cluster potential - galaxy harassment. As much as 90% of the LSB disk stars are tidally stripped and congregate in large diffuse tails that trace the orbital path of the galaxy and form the diffuse intra-cluster light. The bound stellar remnants closely resemble the dwarf spheroidals (dE’s) that populate nearby clusters, with large scale lengths and low central surface brightness.
The Connection Between dE and dI Galaxies
Authors: Miller Bryan W. 
Published: July 2016

AbstractWe combine specific globular cluster frequencies (SN) with newly measured surface brightness profiles to identify dEs that may be stripped dIs. Luminous dEs generally have higher surface brightnesses and steep central light profiles. Conversely, fainter dEs have low surface brightnesses and flatter central light profiles. The most likely candidates for stripped dIs have low SN and low central surface brightnesses.
Star Formation Thresholds in Low Surface Brightness Dwarf Galaxies
Authors: van Zee Liese 
Published: July 2016

AbstractThe results of a comparative study of star formation thresholds in gas-rich, low surface brightness, dwarf galaxies are presented. Approximately half the galaxies in the study were “high MH/LB” galaxies, which appear to have inefficient star formation properties. The comparison sample comprised of otherwise “normal” dwarf galaxies, with moderate current star formation rates. In all systems, sites of active star formation were associated with local peaks in the HI column density. For both types of galaxies, the azimuthally averaged gas column density is low. Similar to other LSB systems, the global gas densities are well below the critical threshold for star formation throughout the system. Thus, star formation is inhibited globally, but occurs locally in these gas-rich dwarf galaxies.
Testing environmental influences on star formation with a sample of Low Surface Brightness dwarf galaxies in the Vigo cluster
Authors: Heller Ana , Almoznino Elchanan , Brosch Noah 
Published: July 2016

AbstractWe analyze the star formation activity of an homogeneous LSB dwarf galaxy sample in the Virgo cluster, as a function of the radial velocity relative to the cluster mean velocity and the projected distance from the center of the cluster, using CCD images obtained at the Wise Observatory. The localized Hα emission in the HII regions of this sample is compared to that of an isolated gas-rich sample of LSB dwarf galaxies and that of a representative sample of Blue Compact Dwarf (BCD) galaxies in the cluster. We report preliminary results on the LSB dwarf star formation histories obtained from surface color distribution.
The Parkes Multibeam Blind HI Survey
Authors: Webster R.L. , Kilborn V. , O’Brien J.C. , Staveley-Smith L. , Putman M.E. , Banks G. 
Published: July 2016

AbstractA thirteen-beam HI receiver has been constructed for the Parkes radio telescope. When this instrument is used in active scanning mode, it can rapidly survey large areas of sky, with a relatively uniform sensitivity. The Multibeam Working Group, comprising about 30 astronomers from more than a dozen institutions, is undertaking a blind HI survey of the entire southern sky. The status of the survey is described, with some of the first scientific results.
Simulations of Lyα Absorption from Low Surface Brightness Galaxies
Authors: Linder Suzanne M. 
Published: July 2016

AbstractUsing simulations of the low redshift galaxy population based upon galaxy observations, it is shown (Linder 1998) that the majority of Lyα absorbers at low redshift could arise in low surface brightness (LSB) galaxies. The contribution to absorption from LSB galaxies is large for any galaxy surface brightness distribution which is currently supported by observations. Lyα absorbers should become powerful tools for studying the properties and evolution of galaxies, but first it will be necessary to establish observationally the nature of the Lyα absorbers at low redshift. Further simulations, in which the absorbing galaxy population is ‘observed’ with some selection criteria, are used to explore how easy it is for an observer to test for a scenario in which LSB galaxies give rise to most of the Lyα absorbers. It is shown that absorption arising in LSB galaxies is often likely to be attributed to high surface brightness galaxies at larger impact parameters from the quasar line of sight.
First Results from the HI Parkes Zone of Avoidance Survey
Authors: Henning P.A. , Staveley-Smith L. , Kraan-Korteweg R.C. , Sadler E.M. 
Published: July 2016

AbstractThe HI Parkes Zone of Avoidance Survey is a 21 cm blind search with the multibeam receiver on the 64-m radiotelescope, looking for galaxies hidden behind the southern Milky Way. The first phase of the survey has uncovered 107 galaxies, two-thirds of which were previously unknown. The addition of these galaxies to existing extragalactic catalogs allows the connectivity of large-scale structures across the Zone of Avoidance within 3500 km s−1 to become evident. No nearby hidden “Andromeda-class” object was uncovered. Our census of the most dynamically important HI-bearing nearby galaxies is now complete, at least for those objects whose HI profiles are not totally buried in the Galactic HI signal. The full survey is ongoing, and is expected to produce a catalog of thousands of objects when it is finished.
Diffuse Ultraviolet Background Radiation
Authors: Henry Richard C. 
Published: July 2016

AbstractDiffuse ultraviolet background radiation may contain important information concerning the dark matter of the universe. I briefly review new Voyager observations of the diffuse background, which give a very low upper limit on the background radiation shortward of Lyman α, and I review the capabilities for detection and characterization of diffuse radiation that will be provided by a proposed new NASA mission. Low-surface-brightness radiation remains largely an unexplored frontier, particularly in the ultraviolet.
Southern triplets of galaxies
Authors: Karachentseva V. E. , Karachentsev I. D. 
Published: July 2016

AbstractUsing the ESO/SERC and POSS-I sky surveys we selected 76 isolated triple systems of galaxies with Dec. < −3°. For each triplet the equatorial coordinates, type of configuration, angular diameters, apparent angular separation of the components, morphological types, total magnitudes and some other characteristics are presented. 33 of 76 triplets have the measured radial velocities for all the components. The median values of basic dynamic parameters: a radial velocity dispersion, mean harmonic separation, an absolute magnitude of galaxies, mass-toluminosity ratio are very close to those obtained earlier for 83 northern isolated triple systems from the list of Karachentseva et al. (1979).
The Luminosity Function of Galaxies in Compact Groups
Authors: Hunsberger S. D. , Charlton J. C. , Zaritsky D. 
Published: July 2016

AbstractFrom R-band images of 39 Hickson compact groups (HCGs), we use galaxy counts to determine a luminosity function. We find that a single Schechter function is a poor fit to the data, so we use a composite function consisting of separate Schechter functions for the bright and faint galaxies. The decreasing bright end slope implies a deficit of intermediate luminosity galaxies in our sample and the faint end is slightly steeper than that reported for earlier HCG luminosity functions. Furthermore, luminosity functions of subsets of our sample reveal more substantial dwarf populations for groups with X-ray halos, groups with tidal dwarf candidates, and groups with a dominant elliptical or lenticular galaxy. Collectively, these results support the hypothesis that within compact groups, the initial dwarf galaxy population is replenished by “subsequent generations” formed in the tidal debris of giant galaxy interactions.
Objectively selected samples of galaxy multiplets: an analysis of observed properties
Authors: Kelm B. , Focardi P. , Palumbo G. G. C. 
Published: July 2016

AbstractA method of searching for multiplets in a large catalogue of galaxies with measured redshifts is described. Compact Groups samples having different local and global characteristics are generated when the algorithm is applied to ZCAT catalogue. Both local and environmental galaxy density have been computed thus allowing to define truly isolated compact groups as well as compact groups in dense and medium dense environments. We find 40% of our compact groups to be isolated while as much as 20% are identified in high density structures.
The Nature of Hickson Compact Group 18
Authors: Plana Henri , de Oliveira Claudia Mendes , Amram Philippe , Balkowski Chantal 
Published: July 2016

AbstractWe present new observations of Hα emission of the Hickson Compact Group 18 (HCG 18) obtained with a scanning Fabry-Perot interferometer. The velocity field does not show motions of individual group members but instead a complex common velocity field of H18b, c and d. The gas distribution is very clumpy with blobs coinciding with group members but located also elsewhere. Comparing Hα with H ɪ data we reached the conclusion that HCG 18 seems to be an irregular galaxy containing several clumps of star formation sites.
Morphological Characteristics of Compact High-Velocity Clouds Revealed by High-Resolution WSRT Imaging
Authors: Burton W. B. , Braun R. 
Published: July 2016

AbstractA class of compact, isolated high–velocity clouds which plausibly represents a homogeneous subsample of the HVC phenomenon in a single physical state was objectively identified by Braun and Burton (1999). Six examples of the CHVCs, unresolved in single–dish data, have been imaged with the Westerbork Synthesis Radio Telescope. The high–resolution imaging reveals the morphology of these objects, including a core/halo distribution of fluxes, signatures of rotation indicating dark matter, and narrow linewidths constraining the kinetic temperature of several opaque cores. In these regards, as well as in their kinematic and spatial deployment on the sky, the CHVC objects are evidently a dynamically cold ensemble of dark–matter–dominated H ɪ clouds accreting onto the Local Group in a continuing process of galactic evolution.
Galaxies and the intergalactic medium in groups
Authors: Ponman Trevor J. , Lloyd-Davies Ed , Helsdon Stephen F. 
Published: July 2016

AbstractThe study of the relationship between the hot gas in groups and the galaxies they contain can help to constrain the evolution of both galaxies and groups. Here we present evidence that the intergalactic medium in groups has been strongly affected by preheating associated with galaxy formation which mostly preceded group collapse. The presence of this effect appears to be unrelated to the morphology of group galaxies, which supports models in which galaxy types are not primordial. We also present preliminary evidence that early-type galaxies in groups are not underluminous in the X-ray compared to isolated galaxies, suggesting that their dark halos may not have been substantially stripped.
Ab Initio Formation of Galaxies, Groups and Large-Scale Structure
Authors: Diaferio Antonaldo 
Published: July 2016

AbstractFor the first time, the combination of semi-analytic modelling of galaxy formation and N-body simulations of cosmic structure formation enables us to model, at the same time, both the photometric and the clustering properties of galaxies. Two Cold Dark Matter Universes provide a reasonable fit to the observed properties of galaxies, groups and clusters, including luminosities, colours, density and velocity biases. We show how the properties of galaxies and groups on small scales are inextricably connected with the global properties of the Universe.
The Connection with B[e] stars
Authors: Zickgraf Franz-Josef 
Published: July 2016

AbstractThe characteristics of the various types of B[e] stars are discussed and compared with those of classical Be stars. Both groups of stars are characterized by the presence of emission lines in their spectra, in particular of hydrogen. However, there are also significant differences between these classes. Classical Be stars lack hot circumstellar dust and strong forbidden low-excitation emission lines, which are typical characteristics produced by B[e]-type stars. While classical Be stars are a rather uniform group of early-type stars, B[e]-type stars form a quite heterogeneous group, very often of poorly known evolutionary status, comprising such diverse types of objects as near main-sequence objects, evolved lowmass proto-planetray nebulae and massive evolved hot supergiants. Even pre-main sequence Herbig Ae/Be stars sometimes find their way into the group of B[e] stars. However, despite these dissimilarities classical Be stars and B[e]-type stars, share a common property, namely the nonsphericity of their circumstellar envelopes.