bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Value of Fabry-Perot Interferometry in Studying Long-Term Convective Line Shifts
Authors: McMillan Robert S. , Bressi T. H. , Montani J. L. , Moore T. L. , Perry M. L. , Tubbiolo A. F. 
Published: July 2016

AbstractSmall < 10 m s−1 variations of radial velocity (RV) with multi-year periods in solar-type stars may be indistinguishable from the effects induced on lines by stellar activity cycles (Dravins 1985; Saar & Donahue 1997). Dravins (1992) recommended a resolving power R > 3 × 105 to measure accurately the subtle changes in the shapes of bisectors of photospheric absorption lines driven by changes of granular convection in slowly rotating dwarf stars. Butler et al. (1996) measure impressively small amplitudes of RVs by using echelle spectrographs that cover a broad spectrum. However, to cover a broad spectrum the resolving power is typically limited to < 7 × 104, and the necessary presence of the iodine absorption spectrum may make it difficult to measure convective line shifts contemporaneously with the RV time series. Furthermore, to reach an RV accuracy of ± 3 ms−1 the whole profile of each line is used, thus maximizing the possibility that changes in the shapes of the lines’ C-bisectors could induce an apparent variation of RV.Dravins (1985) recommended the exclusive use of the steep flanks of photospheric absorption lines to minimize the effects of convection on apparent RV. McMillan et al. (1993, 1994) demonstrated that such RV measurements made with a Fabry-Perot etalon (FPE) interferometer in transmission can be stable in the presence of stellar line variations seen by other investigators whose measurements were not based exclusively on line flanks. Dravins also prescribed high resolving power, high signal-to-noise ratio, high instrumental contrast, and low instrumental wings to analyze the rest of the line profile for convectively-driven changes (Dravins 1978, 1987, 1992). A double- or multiple-pass FPE scanning whole line profiles can provide high R, high contrast, low wings, and a stable, symmetrical line spread function with small (portable) optics, although the low photon efficiency will restrict its use to a few carefully selected stars. The spectral classes of these stars should span the spectral classes of the stars being monitored by others for planets. We describe a possible implementation of this concept that has the potential for adequate photon flux: observing symbiotically through another instrument on a 6-m to 10-m class telescope.
20 Years of CORAVEL Monitoring of Radial-Velocity Standard Stars
Authors: Udry S. , Mayor M. , Maurice E. , Andersen J. , Imbert M. , Lindgren H. , Mermilliod J.-C. , Nordström B. , Prévot L. 
Published: July 2016

AbstractA preliminary analysis of a sample of more than hundred stars, used as radial-velocity standards and followed with the CORAVEL spectrographs over 1 to 2 decades, is presented. Stars with intrinsic variability or orbital motions are pointed out.
Combining High Angular Resolution Interferometry and Spectroscopy in Studies of Stars and Stellar Systems
Authors: Davis John 
Published: July 2016

AbstractA number of long baseline optical/infrared interferometers have commenced their scientific programs or are under development. These instruments will provide accurate measurements of the angular sizes of single stars and the angular separations of binary systems at resolutions impossible with conventional telescopes. The combination of interferometric data with the results of high-resolution spectroscopy will, for many classes of objects, provide a powerful method for studying them that neither technique can do alone. Examples include the combination of interferometric and spectroscopic data for spectroscopic binaries and, in particular, for double-lined binaries, and single-lined binaries of known parallax, to determine fundamental stellar quantities. Another example concerns the study of Cepheid variables, where the combination of the data can provide an independent calibration of the zero point of the luminosity scale. The requirements and potential of these combined interferometric-spectroscopic studies are discussed.
Properties of the Magellanic Type Galaxies
Authors: Odewahn S. C. 
Published: July 2016

AbstractLate-type Magellanic spiral galaxies possess high surface brightness stellar bars whose centers are often offset from the photometric and kinematic disk centers derived from stellar and HI distributions. Since these systems represent the transitional stage between the pure disk and irregular galaxies, and because the spiral arm and bar properties of these systems present many unique aspects, an understanding of their properties will benefit our understanding of the physics underlying the Hubble sequence as well as the mechanisms associated with bar formation. I review detailed photometric and kinematic studies of several important SBm galaxies. Statistical studies using large samples drawn from the Third Reference Catalog of Bright Galaxies support the idea that scenarios invoking the formation of offset bars and/or dominant spiral arms through some tidal interaction mechanism might be attractive, since a common trait among the Magellanic spirals appears to be the presence of a physical neighbor.
Hubble Space Telescope Images of Nuclear Rings in Barred Galaxies
Authors: Barth Aaron J. , Ho Luis C. , Filippenko Alexei V. , Gorjian Varoujan , Malkan Matthew A. , Sargent Wallace L. W. 
Published: July 2016

AbstractWe present new and archival Hubble Space Telescope (HST) images of circumnuclear star-forming rings in barred spiral galaxies. We find that nuclear rings in barred galaxies are composed of large numbers of super star clusters similar to those found recently in other types of starburst systems. In NGC 1097 and NGC 6951, the young clusters have absolute magnitudes of up to Mv = −14 or −15, depending on highly uncertain extinction corrections, and effective radii of 2–3 pc. The images (especially that of NGC 6951) also show intricate spiral dust lane structure interior to the rings.
Morphology of Dust Lanes in Bars
Authors: Regan Michael W. , Vogel Stuart N. 
Published: July 2016

AbstractGiven that dust and molecular gas tend to concentrate at the locations of either shocks or orbit crowding, the study of the dust morphology of barred spirals can give insight into the kinematics of the galaxies. In order to do this, we present a sample of barred galaxies for which we have obtained near infrared and optical photometry and BIMA interferometer observations of CO emission. We obtain the dust extinction and relative scale height of the dust and stars using a radiative transfer model to interpret the photometry. We find that the scale height of the stars compared to the dust is generally larger in the central regions compared to further out in the bar dust lanes. The morphology of the dust extinction regions closely resembles the distribution of CO emission. An analysis of a larger sample of galaxies with IR data indicates that dust column densities appear larger in the nuclear regions than in the bar dust lanes. The sample also shows that the distribution of dust is not symmetrical along the bar with one side of the bar usually having a larger column density of dust than the other side.
The Pattern Speed of NGC 936 by the Tremaine-Weinberg Method
Authors: Kuijken Konrad , Merrifield Michael R. 
Published: July 2016

AbstractWe describe a kinematic measurement of the pattern speed in the classic SB0 galaxy NGC 936. While the practicalities of this method remain difficult, allowance for non-Gaussian velocity distributions enables more reliable measurements than hitherto possible. The bar of NGC 936 appears to end just inside its corotation radius.
CO in NGC 4314: The Detection of Inflow Along the Bar
Authors: Benedict G. Fritz , Smith Beverly J. , Kenney J. D. P. 
Published: July 2016

AbstractWe present CO(1-0) interferometer data with × spatial resolution and 13 km s−1 velocity resolution acquired at the Owens Valley Radio Observatory. These data reveal a clumpy circumnuclear ring of gas. We also find a central peak of CO within 2″ of the optical center. Deviations from circular motion are seen where the dust lanes along the leading edge of the bar intersect the nuclear ring, consistent with gas inflow along the bar. Hα maps of this galaxy show bright HII regions near the ends of this inflow region, indicating triggering of star formation by the inflow.
Bar Formation, Evolution and Destruction
Authors: Sellwood J. A. 
Published: July 2016

AbstractI review the various mechanisms for creating bars in rotating stellar disks, and conclude that the swing-amplified feed-back loop, which produces rapidly tumbling bars, remains the most probable. The bar continues to evolve after its formation in a number of ways; here I discuss what appears to be inevitable thickening normal to the plane, continued spiral activity in the outer disk and also underscore the increasingly important problem presented by angular momentum loss to the halo. Finally, I examine possible means, excluding interaction, by which bars in galaxies could be destroyed.
Evolution of Bars in Isolated and in Interacting Disk Galaxies
Authors: Athanassoula E. 
Published: July 2016

AbstractI use N-body simulations to follow the evolution of bars in both isolated and interacting disk galaxies. The pattern speeds of bars evolving in isolated galaxies decline gradually with time, due to transfer of angular momentum from the bar to other components in the galaxy. Both the form and amount of this decline depend on the model used. The fate of a bar in an interacting disk galaxy depends on the mass, central concentration and orbit of the perturber. The pattern speed, form and amplitude of the bar may change, the bar can become off-centered, or, more drastically, it can disappear altogether. Finally I propose a scenario for the evolution of NGC 7217, which could, if proven correct, explain the formation of the rings in that galaxy and also, at least qualitatively, the existence of a retrograde population.
Non-Linear Excitation of Warps by Spiral Waves in Galaxies
Authors: Masset F. , Tagger M. 
Published: July 2016

AbstractWe present a mechanism to explain the permanent excitation of warps in spiral or barred galaxies. We show that non-linear mode coupling with the spiral wave can be very efficient to drive two warp waves. We derive an expression of the coupling coefficient in the WKB approximation. We show that the coupling is too weak in the stellar disk, except at the Outer Lindblad Resonance where the spiral slows down and is efficiently coupled to warp waves. There, the spiral can almost completely transfer its energy and angular momentum to a ”transmitted“ warp, which we can observe in HI, and a ”reflected“ one, which we can observe as a corrugation. Our mechanism reproduces the observed amplitudes of the warp and of the corrugation.We first present side results concerning the propagation of warps in moderately thick disks.
The Florida Barred Galaxy Program
Authors: Hunter J. H. , Gottesman S. T. 
Published: July 2016

AbstractFor more than a decade, a group at the University of Florida has been constructing models of barred spiral galaxies that we have observed at the VLA. Group members include: S. T. Gottesman, G. Contopoulos, J. H. Hunter, several Ph.D. students, and collaborators at other institutions. The HI distributions in our galaxies are either gas rich, or nearly devoid of gas, in their bar regions. Initially, we deduced density distributions and potentials of the stellar disks and bars from near infrared observations, modeled the gas response assuming different pattern speeds, etc., and compared the models with our HI observations. This simple approach is successful in some cases, such as NGC 3359, but less successful in others. More recently, our approach has been toward selfconsistent models, including stars and gas. Our techniques range from the Contopoulos-Grosbøl-Kaufmann stellar dynamical approach to methods exploiting grid codes and SPH tree codes. Some of our observations and models will be reviewed, and some new results will be presented.
The 65 cm PZT of the U. S. Naval Observatory
Authors: Klepczyński W. J. 
Published: July 2016

AbstractThe Time Service Division of the U.S. Naval Observatory has undertaken a program to construct and install at Washington, D. C. (latitude +39°) a 65 cm photographic zenith tube (PZT) telescope to be used in studies pertaining to the rotation of the Earth. It is expected to improve the precision with which the rate of rotation of the variation of latitude can be determined by photographic techniques and, in addition, will make possible more frequent determinations of these qualities. Due to itp larger field of view, direct intercomparison with the results obtained with other instruments near latitude, +39° will be feasible. Also, it is expected to contribute to studies of the proper motions of stars near declination +39°.
2.3.2 Analysis of Impact Craters from the S-149 Skylab Experiment
Authors: Hallgren D.S. , Hemenway C.L. 
Published: July 2016

AbstractAnalysis of craters found on polished plates exposed during Skylab has provided data for a flux measurement over the mass range 10−15 to 10−7 gms. Chemical analysis of residues in the craters shows a high incidence of aluminium. A variety of morphological forms are described.
5.5 Temperature Distribution and Lifetime of Interplanetary Ice Grains
Authors: Lamy Ph. , Jousselme M.F. 
Published: July 2016

AbstractAn improved solution of the temperature distribution of interplanetary ice grains is presented using the refractive index measured at 100° K. The efficiency factors for absorption are obtained from Mie theory and the calculation is carried out for micronic and submicronic grains at 50, 100 and 150° K; corresponding lifetimes are given.
5.7 Rotational Bursting of Interplanetary Dust Particles
Authors: Paddack Stephen J. , Rhee John W. 
Published: July 2016

AbstractSolar radiation pressure can cause rotational bursting and eventual elimination from the solar system of small asymmetric interplanetary particles by a windmill effect. The life span determined by this process for stony meteoritic material or tektite glass with radii of 1 cm is on the order of 105 years. Same size material which contains iron, nickel or aluminum, with properties such that it is subject to 5 percent of the amount of spin damping as pure metals, can be removed from the solar system on the order of 106 years by this process. Ordinary chondritic material, despite its high resistivity, is subject to a type of magnetic spin damping, in addition to the normal spin damping, with the consequent result that this type material cannot be removed from the solar system by this process. This depletion mechanism appears to work faster than the traditional Poynting-Robertson effect by approximately two orders of magnitude for the nonmetallic particles and one order of magnitude for the metallic particles.
6.5 Final Remarks
Authors: Whipple F.L. 
Published: July 2016

My summary will certainly leave out much fine work but will stress a few of the points that impressed me.First, I note remarkable progress since 1967 when I last worried about the interplanetary complex, particularly the new observations from space and of very small particles. I am delighted to see the ground based Zodiacal Light observers, like Weinberg and Dumont, converging on their observations both of polarization and of intensity. The larger particles are clearly the major contributors particularly away from the Sun. This forces the theoreticians and the laboratory people to find out how these larger particles produce the observed polarization including the negative polarization. Theoreticians always can prove the answer when it is known.
Some Thoughts on Multiple Stars
Authors: Evans David S. 
Published: July 2016

AbstractThe occultation and spectroscopic approaches to the discovery of multiple stars are reviewed, and the technique of spectroscopic measurement recapitulated. A notation for multiple stars is proposed. An examination of the gravitational interaction levels suggests an average value of ∆ log P for one hierarchical step close to 3.0 and ∆ log a near 2.0 consistent with a binding ratio near 1 : 10000. The distribution for B stars seems to differ from other types and it is conjectured that they cannot be old enough to be residues of clusters. In general few multiple systems seems to show evidence of age sufficient for advanced evolution of the components.
Statistical Properties of Trapezium Systems
Authors: Allen Christine , Tapia Mauricio , Parrao Laura 
Published: July 2016

AbstractA catalogue of more than 900 multiple systems of trapezium type has recently been completed. In constructing the catalogue an attempt was made to exclude optical systems. We study the galactic distribution of trapezia of different spectral types, and we compare it with that of ordinary multiple systems and of visual binaries from the IDS. An estimate is made of the expected number of pseudo-trapezia among each spectral type. This study shows that most of our trapezia are true trapezia and should therefore be young. This conclusion holds for trapezia of all spectral types.
Stable Orbits in the Circular Plane Restricted Three-Body Problem
Authors: Benest Daniel 
Published: July 2016

AbstractWe investigate by numerical exploration the extended regions of stability for retrograde satellites when the mass of the less massive body increases up to μ = 0.5. A preliminary study is made of the characteristic and stability properties of the families of periodic orbits; then the general case of non-periodic orbits is considered. Those numerical explorations show that for stable large non-periodic orbits, the motion can be decomposed into a fast “reference motion” and slow libration; we study theoretically this libration in Hill’s case for which the “reference motion” is elliptic.
Retrieval Techniques and Graphics Displays using A Computerized Stellar Data Base
Authors: Mead Jaylee , Nagy Theresa A. 
Published: July 2016

AbstractA computerized astronomical data retrieval system, based on the Goddard Cross Index of star catalogs and operable from a remote terminal, has been developed. It permits retrieval of stellar data as a function of the object’s identification numbers, descriptive parameters (magnitude and/or spectral type), or position in the sky. In addition, software has been developed to retrieve the full data entry from any of the eleven catalogs currently included in the Goddard Cross Index, such as the Yale Bright Star Catalog (YBS), the Boss General Catalog (GC), and others all in one computer run.Four catalogs (Smithsonian Astrophysical Observatory Star Catalog (SAO), The Revised New General Catalogue of Non-stellar Astronomical Objects (RNGC), Reference Catalogue of Bright Galaxies, and Two-Micron Sky Survey) have been sorted by Palomar Sky Survey plate area and precessed to the epoch of the specific plate. For any set of coordinates covered by the Palomar Survey and the Whiteoak Extension, the computer can provide all the plate numbers on which the position can be found. These plate areas can be immediately accessed by computer; listings or plots to any desired scale of any or all of the objects from the four catalogs can be provided.
Survey of Existing Facilities
Authors: Jaschek C. 
Published: July 2016

The purpose of the present paper is to present a review of the existing data centers.If one knows nothing about a subject, one makes an enquiry, and this is exactly what I have done. The list of addresses to start with was provided by Dr. G.A. Wilkins, chairman of the Working Group on Numerical Data of IAU Commission 5, who had collected a list of data services. I want to thank all colleagues who have answered the questionnaire, which is the basis of the present paper; the answers (and the questionnaire itself) are reproduced in Appendix A of this paper.
Optical and Near-IR Field Luminosity Functions
Authors: Loveday Jon 
Published: July 2016

AbstractWe present preliminary measurements of the bJ and K-band luminosity functions (LFs) of field galaxies obtained from optical and K-band imaging of a sample of galaxies selected from the Stromlo-APM Redshift Survey. The bJ LF is consistent with that previously published from photographic data. The K-band LF has been estimated over a range of 12 magnitudes and is reasonably well fit by a Schechter function with faint-end slope α = −1.2.
A dichotomy between HSB and LSB galaxies
Authors: Verheijen Marc , Tully Brent 
Published: July 2016

AbstractA complete sample of spiral galaxies in the Ursa Major cluster is imaged at various optical wavelengths and in the Near-Infrared K′-band. HI rotation curves were obtained for all gas rich systems. The Near-Infrared surface brightness distribution of disk galaxies turns out to be bimodal; galaxies avoid a domain around mag/arcsec2. This bimodality is particularly striking when only the more isolated, non-interacting systems are considered. The Luminosity Function of the HSB family of galaxies is truncated well above the completion limit while the Luminosity Function of the LSB family is still sharply rising at our limiting magnitude. Near-Infrared mass-to-light ratios suggest that HSB galaxies are close to a kinematic maximum-disk situation while LSB galaxies are dark matter dominated at all radii. Assuming equal Near-Infrared mass-to-light ratios for both HSB and LSB systems, we find that the gap in the surface brightness distribution corresponds to a situation in which the baryonic mass is marginally self-gravitating. We finally conclude that the luminosity-line width relation is a fundamental correlation between the amount and distribution of dark matter mass and the total luminosity, regardless of how the luminous mass is distributed within the dark mater halo.
Found: High Surface Brightness Compact Galaxies
Authors: Drinkwater M.J. , Phillipps S. , Jones J.B. , Gregg M.D. , Parker Q.A. , Smith R.M. , Davies J.I. , Sadler E.M. 
Published: July 2016

AbstractWe are using the 2dF spectrograph to make a survey of all objects (“stars” and “galaxies”) in a 12 deg2 region towards the Fornax cluster. We have discovered a population of compact emission-line galaxies unresolved on photographic sky survey plates and therefore missing in most galaxy surveys based on such material. These galaxies are as luminous as normal field galaxies. Using Hα to estimate star formation they contribute at least an additional 5% to the local star formation rate.
HST WFPC-2 Imaging of Four Nearby LSB Galaxies
Authors: O’Neil Karen 
Published: July 2016

AbstractBetween May, 1996 and January, 1997 HST WFPC-2 images of four nearby LSB galaxies were taken through both the 8140Å and 3000Å filters. The first galaxy imaged, UGC 12695, is a nearby (z~0.021) LSB disk galaxy. UGC 12695 has an unusual morphology, consisting of a Y-shaped nucleus surrounded by a faint spiral arm. Additionally, numerous HI regions are spread throughout the galaxy. One of the surprising discoveries with the WFPC2 imaging was that a number of what were previously believed to be structural peculiarities in the galaxy are actually background galaxies. Once the effects of these galaxies are removed, the resultant U—I color of UGC 12695 is only −0.2, making it possibly the bluest galaxy in the local universe. When combined with the metallicity studies of McGaugh (1992), these colors indicate UGC 12695 to be a highly unevolved galaxy.The other three galaxies imaged - V1L4, V2L8, and V7L3 - are dwarf elliptical galaxies located in the Virgo cluster. The intent of their images was to determine the galaxies’ small scale structure and place limits on the density and type of giant branch stars within each galaxy. Placed at the distance of the Virgo cluster, luminosity fluctuations indicate the galaxies to contain only from 4 – 13 stars per pixel, coinciding with a K/M giant ratio ranging from 6 to ∞ (no M giant stars). Additionally, we found no evidence for stellar clumping in these galaxies although an extremely red, extremely small bulge was found at the core of V2L8.