bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sun as a Laboratory Source for IR Molecular Spectroscopy
Authors: Sauval A. J. , Grevesse N.
Published: June 2019

The infrared solar spectrum is used to refine our knowledge of molecular constants of CH and CO and to test the accuracy of transition probabilities and dissociation energies of a few diatomic molecules.
A 4-meter McMath Telescope for the Infrared
Authors: Livingston W.
Published: June 2019

Having no window and a filled aperture, i.e., no occlusion by secondary optics, the all-reflective McMath telescope is a proven IR facility. Beyond about 2 μm, it is diffraction limited, however. Engineering studies show that the McMath building could accommodate an increase to a 4-m aperture with a 6-m alt-azimuth feed, permitting sub-arcsec resolution to 12 μm. The use of cooled, solid aluminum mirrors would eliminate “mirror seeing”, which plagues non-vacuum solar telescopes.
Interstellar Extinction in External Galaxies
Authors: Fitzpatrick Edward L.
Published: June 2019

In this paper I review the existing measurements of the wavelength dependence of interstellar extinction arising from dust situated outside the Milky Way galaxy. This paper emphasizes studies of extinction in the Large and Small Magellanic Clouds. I discuss the UV extinction properties, as well as the optical and near-IR properties as determined from ground-based photometry.
Infrared Emission from Reflection Nebulae
Authors: Sellgren K.
Published: June 2019

Observations of 1–25 μm. continuum emission and the interstellar infrared emission features in reflection nebulae are reviewed. These observations place important constraints on models of very small grains or large molecules such as PAHs, which these models must address in order to understand this fundamental component of interstellar dust.
Panel Discussion on the Quantum Statistical and Thermal Treatments of Processes in Molecule-Sized PAHs
Authors: Leach Sydney
Published: June 2019

This discussion followed the two talks, one by John Barker on “Grains or Molecules, Thermal or Non-Thermal,” the second, by Louis d'Hendecourt on “The Particle/Thermal Approach to the Physics of Emission from Interstellar PAHs.” The presentations discussed the factors involved in the process of absorption of an ultraviolet photon by a PAH molecule or ion, followed by infrared and/or visible emission. Model calculations were presented for various stages of those sequential events, as a function of PAH size. The material presented applied to large molecules in general and was not restricted to the PAH case. The models sought to investigate the radiative, and nonradiative intramolecular processes, including dissociation, that are competitive for conversion of the absorbed ultraviolet photon energy. The essential differences between the Barker and d'Hendecourt approaches were brought out by estimations of the range of physical parameters which delimited the approximate validity of a thermal treatment using Boltzmann statistics or the Planck function as compared with a more formally correct quantum statistical (i. e. non-thermal) approach to energy conversion and dissipation. It was concluded that the thermal approximation was reasonably satisfactory at high (absorbed) photon energies in explaining conversion to an infrared emission situation, but was unsatisfactory at low energies, when the (vibrational) excitation of the excited molecule was of the same order of magnitude as the emitted infrared photons. It was also not valid for discussions of the competitive unimolecular dissociation of excited PAHs, such as denydrogenation and fragmentation. In those cases the quantum statistical approach was required.
Pitfalls in Calculating Scattering by Small Particles
Authors: Huffman Donald R.
Published: June 2019

Comparisons between measured extinction on small particle systems and the same quantity derived from scattering calculations using bulk optical constants often show substantial disagreements. Based on such comparisons, certain pitfalls which have been recognized in such a process, as it applies to the modelling of interstellar dust properties, are pointed out. Illustrations are taken from laboratory work on SiC, graphitic carbon, and olivine-type silicates.
Bare Carbon/Silicate Theories
Authors: Mathis John S.
Published: June 2019

Several theories involving bare silicate grains, combined with carbon in either amorphous or graphitic form, are discussed and contrasted to the other grain theories outlined at this Symposium. The assumption of bare grains is justified, and power-law size distributions are strongly indicated from both theoretical and observational standpoints. Various successes and problems of these and other theories are discussed. All of the theories discussed in this Symposium can probably explain the observed extinction and polarization in general terms, but certain crucial observations, such as the wavelength behavior of the polarization and extinction in the wavelength range near the strong silicate absorption bands, will probably be able to discriminate among them.
Dust Destruction in the Interstellar Medium
Authors: McKee Christopher F.
Published: June 2019

Grains are injected into the interstellar medium (ISM) from evolved stars and supernovae; in addition, supernova ejecta may condense onto pre-existing grains before becoming well-mixed with the interstellar gas. Once in the ISM, grains can grow by accretion, but are also subject to destruction by interstellar shocks. The current status of the theory of shock destruction of interstellar grains is reviewed briefly. Small grains are destroyed by thermal sputtering in fast, nonradiative shocks; large grains are destroyed by grain-grain collisions and eroded by nonthermal sputtering in radiative shocks. The dominant shocks in the ISM are from supernova remnants (SNRs), and the mass of grains destroyed is proportional to the energy of the SNR. In a multiphase ISM, these shocks destroy the grains at a rate proportional to the volume filling factor of the phase; since the density of the hot phase is too low for efficient grain destruction, most of the destruction occurs in the warm phase. Not all SNRs are effective at destroying grains, however: some are above the gas disk, and some —Type IPs in associations—are highly correlated in space and time. The galactic SN rate is observed to about 2.2 per century (van den Bergh, 1983), but the effective supernova rate for grain destruction is estimated to be only about 0.8 per century. As a result, the timescale for the destruction of a typical refractory grain in the ISM is inferred to be about 4 × 108 yr for either a two-phase or a three-phase ISM. Most of the refractory material in the ISM (other than carbon) is injected by supernovae, not evolved stars; the net injection timescale is estimated as about 1.5 × 109 yr. Comparison of the destruction and injection timescales indicates that the fraction of grains injected by stars which survive in the ISM is only about 20%. Most of the refractory material in interstellar grains must, therefore, have accreted onto the grains in the ISM. Nonetheless, a significant fraction of dust formed in stars survives in the ISM and may be detectable in meteorites and interplanetary dust particles.
Quantitative Predictions of CMB Anisotropies and Distortions
Authors: Richard Bond J.
Published: June 2019

The increasing precision of experiments designed to detect angular anisotropies and spectral distortions of the microwave background has now brought us near to or below the levels predicted by most theories of the formation of structure in the universe. Here I review the quantitative theoretical results for anisotropies and distortions for a wide variety of models. Many of these were presented in the Monday afternoon discussion session on the microwave background held at IAU Symposium 130. Primary and secondary anisotropies (and the associated distortions) are considered for universes with structure arising from initially Gaussian perturbations, especially the scale-invariant ones predicted by inflation, from accretion onto cosmic strings, and from shells generated by explosive energy injection, including that from superconducting strings as well as from supernovae.
A Cut of Large-Scale Structure Across the Coma Supercluster
Authors: Karachentsev I.D. , Kopylov A.I.
Published: June 2019

Spectral survey of 245 galaxies with mB⩽17.5 in the narrow strip {+28° 20′>DEC>+28°10′, 15h28m0>R.A>10h42Mm0} confirms a bubble-like type of the large-scale structure around the coma supercluster, have been founded by Lapparent et al. (1986). A correlation function in the volume has the power index γ=1.5 and the correlation radius rO= 29 Mpc (H=75 Km/s Mpc). For the sample of 14 voids their mean diameter  equals to (33±3) Mpc. This value coincides with the correlation scale rO= 32 Mpc for Abell clusters, and also with the mean length of “God finger” for a rich cluster, 2√ 3σvH−1 = 32Mpc. We note a presence of a preferential orientation of voids toward the Coma supercluster, /= 1.15±0.8, that corresponds to a possible peculiar flow toward/outward Coma with Vpec∼400±200 (Km/s) at a scale ∼100 Mpc.
Constraints on the Biasing of Density Fluctuations
Authors: Szalay Alexander S.
Published: June 2019

A general nonlinear function G(X) describing the biasing of primordial Gaussian density fluctuations is considered. Arbitrary N-point correlations of the biased field are calculated in the form of a series expansion in terms of the correlations of the Gaussian field. The observed scaling of the three point correlations in the galaxy distribution is satisfied, but the scaling coefficient Q has a nontrivial value Q = J2/J12, where Jk is the k-th term in the Hermite expansion of G(X). The three point function is always accompanied by a cubic term Q3ξ1ξ2ξ3, independent of the functional form of the biasing. Its absence in the cluster 3-point correlations may be observable, in which case it rules out biasing as the major amplification mechanism of galaxy and cluster correlations.
Large Peculiar Velocities in the Hydra Centaurus Supercluster
Authors: Aaronson M. , Bothun G.D. , Budge K.G. , Dawe J.A. , Dickens R.J. , Hall P.J. , Lucey J.R. , Mould J.R. , Murray J.D. , Schommer R.A. , Wright A.E.
Published: June 2019

Six clusters forming part of the Hydra-Cen Supercluster and its extension on the opposite side of the galactic plane are under study at 21 cm with the Parkes radiotelescope. The infrared Tully-Fisher relation is used to determine the relative distances of the clusters. These clusters exhibit significant and generally positive peculiar velocities ranging from essentially zero for the Hydra cluster to as much as 1000 km/sec for the Pavo and Centaurus clusters. An upper limit of 500 km/sec was previously found in the study of clusters accessible from Arecibo. Data collection is not yet complete, however, and is further subject to unstudied systematic errors due to present reliance on photographic galaxy diameters. Nevertheless, these preliminary results support the notion of a large scale (and presumably gravitationally) disturbed velocity field in the second and third quadrants of the supergalactic plane.
The Orientation of Galaxies in Superclusters
Authors: Flin Piotr
Published: June 2019

The alignment of galaxies with the main plane of supercluster can contribute to recovering information on the structure origin. The positive result of the preliminary search for galaxy alignment in the Local Supercluster /Flin and Godlowski 1986, hereafter FG/ have stimulated further studies. Following Jaaniste and Saar /1977/, the both parameters, the position angle of the galaxy major axis p and the axial ratio b/a of the galaxy image, were used for the better determination of the actual spatial orientation of the galaxy disc. This approach also permit to consider “face-on” objects, whose discounting leads to obvious incompleteness of the analysed data. Each galaxy has two possible orientations and both were taken into account during calculations. The analysis is perfomed by transforming position angle p and coordinates α, δ of galaxies expressed in the equatorial coordinates into coordinate system connected with each parent supercluster separately, which gives parameters P, l and b respectively. The main supercluster plane should be determined, which resticts the present study to the three superclusters with a known spatial geometry, i.e. LSC /Tully 1982/, Perseus and Coma/A1367 /Chincarini et al. 1983/.
Cosmic Strings and Galaxy Formation
Authors: Turok Neil
Published: June 2019

The hot big bang theory of the early universe is rather well established. Among its successful predictions are the Hubble expansion, the microwave background radiation and the abundances of the light elements. It also fits in rather nicely with ideas from particle physics. According to these ideas (which are firmly based on experiment) at high energies particle interactions become more symmetrical and the apparently complicated particle spectrum today becomes very simple. It is an appealing notion that such a state of high symmetry was actually realised in the very early universe at very high temperatures, and the symmetry was broken as the universe expanded and cooled.
Large-Scale Structure of the Universe in Unstable Dark Matter Models
Authors: Doroshkevich A.G. , Klypin A.A. , Khlopov M.U.
Published: June 2019

Processes of the formation and the evolution of the large-scale structure are discussed in the framework of unstable dark matter models. Six numerical models are presented. The projected distribution of simulated galaxies on the sky, wedge diagrams, correlation functions and the mean linear scale of voids are presented. Physical background of the hypothesis of unstable particles and possible observational tests are discussed. The level of the microwave background fluctuations is estimated analytically. Special attention is given to late stage of supercluster evolution and galaxy formation.
The Formation of Disk Galaxies
Authors: Freeman K.C.
Published: June 2019

In this talk, I will discuss a few particular topics, rather than attempting a general review of the formation of disk galaxies. First recall the basic structure and kinematics of a disk galaxy like the Milky Way. The Table below lists the four main structural components as they are presently understood, and gives typical masses, and (if known) the characteristic rotational velocities (at the sun) and the radial velocity dispersion for each component. For more details, see Freeman (1987).
Explosive Origins of Large-Scale Structures
Authors: Ostriker Jeremiah P.
Published: June 2019

Large scale structures up to 5h−1 mpc, the galaxy-galaxy correlation length and the size of typical galaxy groups and clusters, can be produced quite naturally from explosions originating in young galaxies (Ostriker and Cowie, 1981: “OC”) or quasars (Ikeuchi, 1981: “I”) with energy output of 1061 ergs. But very large-scale structure in the 25 mpc −50 mpc range possibly indicated by cluster-cluster correlations (Bahcall, 1987a), can only be produced by much more energetic events of 1065 ergs which are far beyond the output of any objects currently known. This follows simply from the dimensional arguments which give R = c(Eσ/t2)0.2 implicit in the classic Seldov-Taylor solution and cosmological analogs (cf Ostriker, 1986). Thus very large scale structure can only be produced by explosions if many small ones can coalesce suitably at early epochs (OC) or single giant events are produced by exotic objects such as superconducting cosmic strings (Ostriker, Thompson and Witten 1986: “OTW”). If however these large events do occur, then many specific properties of very large-scale structures will be produced quite naturally (cf Bahcall, 1987b, Weinberg, Ostriker and Dekel, 1987 “WOD”). Before discussing these points, it is appropriate to say a few words on the importance of hydrodynamics in general and explosions in particular, since the latter will certainly be a consequence of galaxy formation even if they are not the primary cause.
Observations of Galaxy and QSO Clustering
Authors: Shanks T , Hale-Sutton D , Boyle B. J.
Published: June 2019

We present correlation function results from galaxy and QSO redshift surveys. The galaxy correlation function shows evidence for a possible ‘shoulder’ feature in ξ(s) at s = 2h−1 Mpc. At scales between 10 and 100h−1Mpc the correlation function remains close to zero and shows no evidence for any large scale galaxy clustering. The QSO correlation function detects strong QSO clustering for scales s < 10h−1 Mpc. At larger scales (10 < s < 1000h−1 Mpc) no evidence of significant QSO clustering is seen.
The Distribution of Faint Radio Sources at 6 cm
Authors: Kellermann K. I. , Fomalont E. B.
Published: June 2019

Deep radio source surveys made with the VLA at 6 cm wavelength show that the radio source count continues to converge down to microjansky flux densities, although there is some evidence of a flattening of the count in the range between 10 and 100 microjansky. The weak sources may be primarily an evolving population of active spiral galaxies.
Dipole Anisotropy in the Lick galaxy catalogue
Authors: Plionis Manolis
Published: June 2019

The Shane & Wirtanen (SW) galaxy catalog, as reduced by Seldner et al (SSGP), is used to calculate the dipole vector of the galaxy distribution. The catalogue covers 86% of the North and 53% of the South Galactic cap (totally 8.8 steradians) and contains about 810,000 galaxies binned in 10′ × 10′ cells with magnitude limit mB ∼ 18.8. Dipoles have been found in the IRAS and in an optical catalogue based on the ESO, UGC and MCG catalogues, with average depths of ∼ 100 h−1 and ∼ 50 h−1 Mpc respectively. The direction of these dipoles is consistent with that of the microwave background dipole which means that the structures responsible for the dipole are present within the limits of the shallower catalogue and dominate the large-scale morpology of the galaxy distribution in both catalogues. It can therefore be expected that these structures will be ‘washed out’ by more distant structures dominating the deeper SW catalogue. The characteristic depth of the SW catalogue is 360 h−1 and the median depth of a cluster sample, identified from the SW catalogue by an objective proccedure, is ∼ 180 h−1 Mpc. Even if a dipole is found there is no apparent reason for it to point towards the MWB dipole direction since other galaxy fluctuations, comparable in size with those responsible for the MWB dipole, should be present in the SW catalogue if the Cosmological Principle is relevant on scales traced by the catalogue.
Primordial Density Perturbations in Tepid Inflation
Authors: Lukacs B. , Paal G.
Published: June 2019

Density fluctuations needed for galaxy formation may have thermal origin in a tepid inflation.
Galaxy Clusters in the APM Survey
Authors: Maddox S. J.
Published: June 2019

We have completed a deep wide-field galaxy survey (the APM survey) using the Automatic Plate Measuring machine in Cambridge. The APM survey covers 4400 square degrees in the Southern hemisphere and is designed to be complete to a magnitude limit of bJ = 20.5. A more detailed description may be found elsewhere in these proceedings. We are using this survey to generate a new catalogue of galaxy clusters similar to that of Abell (Abell, G.O., 1958, Astrophys. J. Suppl., 3, 211.). Our cluster cataloge will represent a significant improvement over previous work, since we have detailed information on each individual galaxy including position, size profile and magnitude.
Hydra - Centaurus: A Redshift Survey
Authors: Chincarini G , da Costa L , Fairall A.P. , Pellegrini P , Vettolani G , Willmer C
Published: June 2019

The survey consists of 2 samples : SAMPLE A, 85% complete to B(T) = 14.0 in the region between 10 and 14 Hours in R.A. and between −20 and −50 degrees in DEC., SAMPLE B, complete to B(0) = 14.5 in two regions one between R.A. 13 and 14 hours, DEC between −25 and −33, the other between 11 and 12 hours, DEC from −33 to −27.
MRSP - The Muenster Redshift Project
Authors: Schuecker P , Horstmann H , Seitter W
Published: June 2019

ESO/SRC-J-Atlas plates (film copies) and film copies of UK-Schmidt objective prism J-plates (dispersion 246nm/mm at Hγ) were scanned with the microdensitometer PDS 2020 GM and reduced automatically with the software package ADAS developed at the Astronomical Institute of Muenster University. In a single field (30 square degrees) near the South Galactic Pole 150 000 objects are found up to the limiting magnitude Stars and galaxies are separated. Algorithms for quasar search among the star-like objects are applied and radial velocities determined from the identified emission lines. Follow-up observations with the ESO 3.6m telescope show fair agreement between the redshifts determined from the objective prism plate and from the slit spectra.
A New Catalog of Superclusters of Galaxies
Authors: Kalinkov M , Kuneva I.
Published: June 2019

A technique developed by us for searching for superclusters of galaxies (Kalinkov and Kuneva, 1985, 1986) has been applied to the both main catalogs of clusters of galaxies, as well as to some subcatalogs:

(i)

all Abell (1958) clusters,

(ii)

rich A-clusters (RG > 0),

(iii)

very rich A-clusters (RG > 1),

(iv)

X-ray A-clusters,

(v)

Zwicky et al. (1961–1968) clusters,

(vi)

A-clusters, identified in the Zwicky catalog.
Abell Clusters as Tracers of Large-Scale Structure: Alignments and Substructure
Authors: Rhee G. , Katgert P.
Published: June 2019

Binggeli (A & A, 107, 338, 1982) showed that neighbouring Abell clusters with pair distances less than 30 to 40 h50−1 Mpc show directional correlation. Binggeli's result is based on structure data of 44 Abell clusters (all with zspectr < 0.1). Binggelli's result was questioned by Struble and Peebles (A.J., 90, 582, 1985). They produce a visual estimate of the direction of cluster elongation for 237 clusters. They did not observe reduced probability for small D large Θ pairs.
A Possible Connection Between the Diffuse X-Ray Background and Large Scale Structures in the Universe
Authors: Daly Ruth A.
Published: June 2019

The diffuse x-ray background extends from about five to 200 keV. The spectrum is very well fit by a thermal bremsstrahlung emission spectrum characterized by a temperature of about (25–40)(l+z) keV, where z is the redshift at which the emission is produced.
Space Distribution of X-Ray Clusters of Galaxies
Authors: Cavaliere A. , Colafrancesco S.
Published: June 2019

The Intra-Cluster Plasma constitutes an archive of the past history of all clusters and of many groups of galaxies: statistical observations of their X-ray emission will set significant constraints on the dynamical, thermal and chemical events in these cosmic structures. Data on the local X-ray luminosity function N(L, z ≃ 0) were provided by the 1st generation X-ray surveys. HEAO II provided an integral of N(L, z) out to z ≃ 0.4, the counts from a subsample of the MSS (Gioia et al. 1984, Ap.J. 283, 495): these counts result very flat, cf. Fig. 2.
Merger Rates in Simulated and Observed Groups of Galaxies
Authors: Mamon Gary A.
Published: June 2019

The occurrence of mergers in simulated loose groups of galaxies (Barnes 1985; Mamon 1987) has generated the concern that mergers may be significantly more frequent in simulated groups than in observed groups (Ostriker 1987). I compare here quantitatively the rates of merging between a subset of 102 groups (Mamon 1986) of the CfA group catalog (Geller and Huchra 1983) and samples of 50 dynamically simulated groups of given initial density. The simulated groups start out virialized with galaxy luminosities pseudo-randomly generated from a Schechter function of index −1 and cutoff 0.5 L* (giving an average luminosity ∼ L*, close to the average in the CfA group catalog). The groups are evolved with the N-body code described in Mamon (1987). The merging time of the sample of 50 simulated groups is defined as the time at which the Tremaine-Richstone (1977) statistic T1 = σ(M1)/〈ΔM12〉 becomes smaller than 0.8. This value of T1 is significantly smaller than expected from a random realization of groups with the luminosity function given above (Mamon 1987).
Statistics of Galaxy Orientations: Morphology and the Large Scale Structure
Authors: Lambas D. G. , Groth E. J. , Peebles P. J. E.
Published: June 2019

Using the Uppsala General Catalog of bright galaxies (Nilson, 1973) and the northern and southern galaxy maps (Seldner, et al., 1977) made from the Lick counts (Shane and Wirtanen, 1967), we find statistical evidence of a morphology-orientation effect. Our results indicate that elliptical galaxies are preferentially oriented along the large scale features of the Lick maps. However, position angles of spiral and SO galaxies show no clear signs of non-random behavior. The angular scale of the detected alignment effect for ellipticals is θ ∼ 2 to 4°, which at a redshift of Z ∼ .03 (which comprises the depths of both catalogs) corresponds to a linear scale of ∼ 3 to 6 h−1 Mpc.
Theoretical Models for the Galaxy Angular Correlation Function
Authors: Couchman H.M.P. , Bond J.R.
Published: June 2019

The spatial two point galaxy correlation function, ξ(r), is, at present, the most useful statistic for comparing theoretical models to observational data. We have derived expressions for the dynamical evolution of ξ for structures arising from Gaussian initial conditions under the assumption that non-linear evolution may be described by the Zel'dovich approximation. The observed angular correlation function, w(θ), places constraints on the spectrum of initial fluctuations on large scales.
Does A Periodicity Exist in the Redshift Distribution of Quasars' Lyman-alpha Absorption Lines?
Authors: Zhu Xingfen , Chu Yaoquan
Published: June 2019

We have investigated the redshift distribution of the Ly-α absorption lines in a quite reasonable homogeneous sample compiled by Murdoch et al. (1986).
Evolution of Quasar Clustering
Authors: Iovino A , Shaver P.
Published: June 2019

Using three deep samples of quasars, we have found strong evidence for quasar clustering and its evolution.
Some Remarks on Observational Problems for Disk-Galaxy Evolution
Authors: Sanromà M. , Salvador-Solé E. , Solanes J.M.
Published: June 2019

Observational objections against an important role of evolution in morphological differentiation of disk - galaxies (Burnstein 1979, Dressier 1980b, Kent 1985) are summarized together with the results of their det ailed analysis (Salvador-Solé et al. 1987a and 1987b):

i)

Morphological segregation is independent on cluster characteristics.
The General Galaxy Luminosity Function
Authors: Martínez-González E. , Sanz J.L.
Published: June 2019

The general luminosity function of galaxies is believed to be well represented by the Schechter function with exponent α ≃ −1 and L* ≃ 1010L⊙, but with a wide range of variation from one sample to another. This function decreases exponentially at high luminosities and has a power law behaviour increasing towards low luminosities with no present evidence of turn over or cut-off.
Dark Matter Around the Local Group?
Authors: Giraud Edmond
Published: June 2019

The Hubble expansion rate measured in the short distance scale varies from 70–75 to 90 km s−1 Mpc−1 as the kinematic distance (corrected for in fall velocity toward Virgo) increases from Dv = 200–400 km s−1 to Dv ∼ 1300 km s−1. It should be observed in the long scale as well (starting from a lower value), if the same methods were used in the same way. The Malmquist bias for spiral galaxies in the range Dv ≤ 1300 km s−1 is very small or null. The velocity distribution of galaxies in the nearest groups compared with models of various rms velocity dispersions, suggests that at small distance, dispersions of 100 km s−1 or more do not fit the observations. The effect of the deceleration due to the mass of the Local Group on the very nearby velocity field is negligible beyond 2.5–3 Mpc. The low local value of Ho extends approximately over ∼ 6–7 Mpc.
Structure of Galaxies Embedded in Clouds of Dark Matter
Authors: Cowsik R.
Published: June 2019

The purpose of this poster is to draw attention to the recent papers of Cowsik and Ghosh (J.A.A. 7, 7, 1986 et seq. and Ap.J., 317, 26, 1987) where particles of dark matter, stars and galaxies are treated as collissionless gasses. The encounterless Boltzmann equations become coupled through the common gravitational potential in which they move. Assuming that the distributions have the Maxwellian or generalised Schwarzschild form, the potentials ϕg, ϕv due to the baryonic and dark matter are shown to satisfy the coupled equations:
Globular Clusters and Dark Clusters
Authors: Ashman Keith M.
Published: June 2019

Fall and Rees have suggested that thermal instability in the collapsing gas of a protogalaxy gives rise to cool clouds embedded in a hot medium. They argue that the temperature of the clouds cannot fall below 104K, since metals and molecular coolants are absent. Clouds with masses exceeding 106M⊙ are gravitationally unstable and are identified as the precursors of globular clusters. This model has difficulty in explaining high-metallicity globular clusters, since metals provide cooling down to ∼102K or below, thus considerably reducing the cloud Jeans mass. The same problem arises if H2 cooling occurs.
The Coupling of Modes and the Formation of Population III Objects
Authors: Mücket J.P. , Haubold H.J. , Gottlöber S. , Müller V.
Published: June 2019

We consider two density perturbation modes with significantly different length scales λ and L (λ ≪ L) in a homogeneous Universe within Newtonian approximation. For the two modes the coupling terms in the corresponding Euler-Lagrange and Poisson equations are taken into account within lowest order of approximation. We assume that the λ - nods (high-frequency mode) is superimposed on the large-scale mode in such way that by an appropriate averaging procedure, the global behaviour is determined only by the single L-mode. Locally (Δ x ≈ λ ≪ L) the space dependence of the L-mode can be neglected in comparison with the λ -mode, but its time evolution remains important for the evolution of the λ -mode perturbation δ. We obtain for δ the equation:

where , b is the sound velocity with respect to the undisturbed homogeneous natter distribution, H is the Hubble parameter, .
Gravitational Lensing and Cosmic Strings
Authors: Webster Rachel , Hewett Paul
Published: June 2019

Cosmic strings would be cosmologically interesting if they acted as seeds for rich cluster and galaxy formation. Most comological scenarios require the mean mass density per unit length of the string μ to be ∼ 2 × 10−6 for cosmic strings to act as seeds. If there is a population of long-lived cosmic strings which are either long loops or infinite strings, then they will gravit ationally lense background sources (Vilenkin 1984). We are undertaking a substantial survey for multiply imaged optical quasars. So far we have examined ∼ 2500 quasars and have no candidate multiply imaged quasars with separations ≳ 13″ (Webster et aJ. 1987). This sample will double over the next year. The survey will detect multiply imaged quasars with the image separations predicted if one has a population of cosmic strings with μ ∼ 2 × 10−6 acting as gravitational lenses. In due course, this survey will enable us to confirm or rule out the possibility that cosmic strings seed galaxy formation.
It is Not Easy to Replace Newtonian Gravitational Theory!
Authors: Gerbal D. , Siroussezia H.
Published: June 2019

The great amount of unseen dynamical matter in large scale structures is derived from: the Newton's law of inertia and the theory of gravitation. But none of these law has been tested on scale larger than r > 10Kpc. It is then tempting to modify them following:

where g(x) is a phenomenological function.
The Greenwich And Oxford Astrographic Telescopes 1958–1987
Authors: Jones D.H.P.
Published: June 2019

Improvements to the Greenwich Carte du Ciel telescope since its arrival at Herstmonceux are described. The original Oxford objective may be mounted on the same telescope. Both plate collections are held at Herstmonceux.
The Carte Du Ciel - The Australian Connection
Authors: White Graeme L.
Published: June 2019

This paper reviews the Australian involvement in the “Carte du Ciel”. Four Australian observatories - Sydney, Melbourne, Adelaide and Perth - undertook three zones of the Carte du Ciel project. This was about 18% of the total program and the Australian work took over 80 years to complete.
Documents Pour Une Exposition: La Carte Du Ciel
Authors: Debarbat S.
Published: June 2019

An exhibits entitled “La mesure du ciel - De la plaque photographique aux techniques spatiales” was held at the Observatoire de Paris in association with the Symposium 133, on the occasion of the centenary of the international enterprise which was named “Carte du Ciel” in 1887. Under the exception of some modern pieces such as maquettes of Ariane, of the Canada-France-Hawaii Telescope, of the Hipparcos Satellite, all other elements on display were from the resources of the Observatory. These case and some others, among the most recent ones, are analysed in view of studying the circumstances which allowed the objects and documents from the past to be still in our hands. The conditions through which they are still known and in existence are also reviewed. Based on such informations, some of the related problems are examined. In order to contribute to their solution, proposals could be made to the IAU Commission 41, in view of a study at the level of the International Astronomical Union. The author will be pleased to convey preliminary proposals to Commission 41.
Recovery of the Astrographic Catalogue
Authors: Stock J. , Abad C.
Published: June 2019

An almost fully automatic scheme has been developed which produces final positions in the system determined by the reference catalogue, cross identifications, and approximate magnitudes in a standard system. A plate-overlap method is used which permits inclusion of higher order terms either plate by plate or common to a subset of plates. Magnitude dependent errors are also included. The system has already been applied to more than 500 plates, most of them of the Paris zone, with smaller sets of the Oxford, Potsdam, and Helsingfors zones. The Paris zone yields consistent higher order and magnitude terms over the entire set analyzed so far.
Match Criteria for Automatic Alignment of Normal Astrograph and Schmidt Plate
Authors: Fresneau A.
Published: June 2019

The objective of the present study is to clarify the tests, checks and clues one may employ to determine whether a feature on a one century old plate is probably identical to a feature on a recent Schmidt plate. A test region of 40′ × 40′ around star HD 42088 was selected in order to detect a variability in nebulosities around Gem OB 1 stars.
Hipparcos: An Example Of Astrophysical Uses Of Astrometric Data
Authors: Gómez A.E. , Crifo F.
Published: June 2019

Hipparcos will measure positions, proper motions and parallaxes for about 110 000 stars brighter than B = 13, with an expected mean error of 2.10−3 arcsec in positions and parallaxes and 2.10−3 arcsec/year in proper motions. The contents of the first provisional catalogue with respect to astrophysical problems is described, and the star distribution versus spectral type, magnitude and distance is given. All types of stars are well represented (spectral types, various evolutionary stages, giants, white dwarfs, …). Precise parallaxes for 29 000 stars closer than 100 pc will provide a new base for luminosity calibration, and will allow accurate stellar masses to be determined from double stars with known orbits. Precise proper motions, in conjunction with the improved distances, will substantially improve our knowledge of galactic structure. All types of stars used for the cosmic distance scale calibration are well represented: Cepheids, RR Lyrae, supergiants, open cluster stars.
Proper Motions From Carte Du Ciel Plates
Authors: Luyten Willem J.
Published: June 2019

The existing data on proper motions from meridian catalogues and proper motion surveys appear to be reasonably complete for motions larger than 0.24 arc seconds per year and down to the 19th magnitude visual but for motions between 0.24 and 0.18 there exists a lacuna for stars between 8.5 and 11.5 visual which could easily be observed by repeating Carte du Ciel plates.
The Naval Observatory “Short” Plate Being Taken As Part Of The Palomar Sky Survey II
Authors: Monet David G.
Published: June 2019

The US Naval Observatory has commissioned a short exposure plate for each field in the Palomar Sky Survey II. These plates should provide the necessary intermediate reference frame for the determination of right ascension and declination for faint objects on the “deep” plates using catalog coordinates for bright stars measured on the “short” plate.
Mapping The Sky - Surveys With Schmidt Telescopes
Authors: Morgan D.H. , Tritton S.B.
Published: June 2019

This paper describes the sky surveys carried out over the past 30 years by the three large Schmidt Telescopes; the Palomar 1.2m Schmidt, the ESO 1m Schmidt and the UK 1.2m Schmidt. Developments in photographic technology, the reproduction of the surveys as sky atlases and problems associated with the storage of original plates are discussed. Brief reference is also made to limited purpose surveys which often address one specific research problem and to possible future developments in this branch of astronomy.
Astrometry And Data Centers
Authors: Jaschek C.
Published: June 2019

The paper tries to provide some background to answer the problem if old astrometric data should be stored. The cases of the AC and the CdC are examined, as well as the storage of some more recent catalogues on optical disc. Finally the necessity of producing general catalogues (of the SAO type) for non-astrometrists is underlined, to satisfy the needs of the astronomical community.
Astrometry With Carte Du Ciel Plates
Authors: Brosche P. , Geffert M.
Published: June 2019

Because of their early epochs, Carte du Ciel plates are ideal first epoch plates for the study of proper motions. We have tested the astrometric precision of some plates from different epochs using the accurate astrometric star catalogues of Praesepe and Pleiades.
Current Status Of The Second Cape Photographic Catalogue
Authors: de Vegt Chr. , Zacharias N. , Penston Margaret J. , Murray C. A.
Published: June 2019

Photography of the southern hemisphere for the Second Cape Photographic Catalogue (CPC2) was commenced in 1962 by R H Stoy, HM Astronomer at the Cape. During the following ten years nearly 6000 plates, each having two exposures and covering 4° × 4° with fourfold corner to centre overlap were obtained. All plates have been measured on the GALAXY measuring machine at the Royal Greenwich Observatory under the general direction of W Nicholson. A preliminary catalogue giving positions and magnitudes of more than 50 000 stars in the Cape Astrographic zone (−40° to −52°) has already been published (Nicholson et al. 1984), together with details of the programme. Measurement of the plates, initial identification of star images appearing on all overlapping plates, and photographic photometry have been carried out at RGO; the subseqent astrometric data reduction is being performed at Hamburg Observatory.
The Minnesota Automated Plate Scanner: A New User Facility
Authors: Pennington R.L. , Humphreys R.M. , Ghigo F.D.
Published: June 2019

The redevelopment of the Minnesota Automated Plate Scanner (APS) is complete and the system is being used as an astronomical visitor facility. The system consists of the original CDC-Luyten scanner with a new microprocessor-based motion control system, state of the art detection electronics, a PDP-11/60 data acquisition system with all relevant scanning parameters under software control, a Sun 3/110 computer for data reductions and a high speed link to the University of Minnesota Supercomputer Institute Cray 2 for reductions of very large projects. The redeveloped APS is among the fastest plate measuring machines in the world and features a variety of densitometric and isophotometric data acquisition modes. An ambitious project is being undertaken to scan all plates of the first epoch Palomar Sky Survey. Objects will be classified as stars, galaxies, plate flaws, etc., and accurate positions and magnitudes will be determined. This resulting catalog, as well as the raw data archive, will be made available to the astronomical community.
Precision Of Parallaxes From Automatic And Manual Measures From New Parallaxes Of The Hyades Cluster Region
Authors: Upgren A.R. , Weis E.W. , Fu H.-H. , Lee J.T.
Published: June 2019

Measures of 25 members of the Hyades and about 260 field stars have been made for parallax and proper motion in two ways, automatically using a PDS microdensitometer and manually using a conventional measuring machine. Reductions show the parallax errors from the former are about half those of the latter method.
The Space, Luminosity And Velocity Distribution Of Faint Stars
Authors: van Altena William F. , Lee John T. , Tsay Wean-Shun , Lu Phillip K.
Published: June 2019

The objective of this investigation is the determination of absolute parallaxes and proper motions with respect to faint galaxies for three fields at mid galactic latitudes and one field near the south galactic pole. The three mid galactic latitude fields were photographed on a IIIa-J + GG385 plate/filter combination by van Altena at the prime focus of the KPNO 4-meter in the mid 1970s, while the south polar region was photographed on a IIIa-F + RG610 plate/filter combination by van Altena and C.E. Lopez (Univ. of San Juan, Argentina) at the prime focus of the CTIO 4-meter; all plates were hypersensitized by baking and exposed to the sky limit. In this paper we report on the progress of an investigation of the mid galactic latitude field at R.A. = 7h 07m 31s and Dec. = +7o 19.7′ (1950) which contains the faint binary white dwarf LP543-32/33. Preliminary measurements of selected stars in this field were made some time ago and a parallax of the white dwarf binary were published by van Altena and Mora (1977). Those measurements showed that the plates were of very high astrometric quality and that it would be possible to obtain accurate parallaxes for very faint stars.
A Proposal For Mapping The Sky At Deka-Hectometer Wavelengths: The LFSA
Authors: Weiler K.W. , Dennison B.K. , Johnston K.J. , Simon R.S. , Spencer J.H. , Erickson W.C. , Kaiser M.L. , Cane H.V. , Desch M.D. , Hammarstrom L.M.
Published: June 2019

The concept is developed for a scientific space mission to survey the entire sky and to image individual sources at frequencies between 1.5 and 26.3 MHz, a frequency range over which the Earth's ionosphere transmits poorly or not at all. The required technology already exists and there are many important scientific goals which can be attained with high sensitivity, high resolution space observations at the lowest frequencies available to astronomy from within the absorbing interstellar plasma of our own Galaxy.
Mapping The Radio Sky: Compact Radio Quasars From The Parkes 2.7 GHz Survey
Authors: Jauncey David L. , White Graeme L. , Harvey Bruce R. , Batty Michael J. , Wright Alan E. , Savage Ann , Peterson B.A. , Peters W.L. , Reynolds J.E. , Gulkis S. , Preston R.A. , Morabito D.D. , Tzioumis A.K. , Condon J.J. , Malin D.F. , Nicolson G.D. , Nothnagel A. , Argue A.N. , Stolz A.
Published: June 2019

We are investigating a complete sample of flat-spectrum extragalactic radio quasars drawn from the Parkes 2.7 GHz survey. The sample is being used to map the space distribution of radio quasars and to determine their luminosity function. Accurate positions are being measured for a selection of the brighter quasars in order to establish an extragalactic position reference frame in the Southern Hemisphere.
Comparison Of The Effect Of Various Solar System Ephemerides On Equator And Equinox Solutions From Six-inch Transit Circle Observations Of The Sun
Authors: Yao Zhen-Guo , Smith Clayton
Published: June 2019

Using observations of the sun made with the Washington six-inch transit circle from 1911 to 1971, equator and equinox corrections based on Newcomb's, DE102, and DE200 ephemerides are given for each of six catalogs of results of observations made during that period. Each of these catalogs was observed and discussed fundamentally, that is, in such a way as to decouple the system of the catalog positions from dependence on previously given systems of catalog positions and proper motions.

Variations of the solutions for the equator and equinox corrections and of earth orbital parameters including corrections to the ephemeris mean longitude of the sun, the mean obliquity of the ecliptic, the mean longitude of perihelion, and the mean eccentricity of the earth's orbit are discussed for solutions based on the independent catalog systems and on the catalog systems referred to the FK4 and to an improved FK4 in which an epoch dependent correction to the right ascension zero point has been applied.
Ultraviolet Observations of Planetary Nebulae
Authors: Gurzadyan G.A.
Published: June 2019

The ultraviolet spectra of gaseous nebulae have for long been arresting the attention of astrophysicists. The 60's saw the first attempts at plotting the expected spectra of planetary nebulae between 3000 and 912 Å (Code 1960; Aller 1961). This was followed by an examination of the expected forbidden lines (about thirty of them) in the ultraviolet, and of their relation to physical parameters (Gurzadyan 1965; Osterbrock 1963). Even more accurate calculations were made for the intensities of stronger lines in highly excited nebulae (Flower 1968). At the same time preliminary estimates were being made of atomic parameters for various transitions - the collision strengths, the probabilities of forbidden transitions, etc. (Czyzak et al. 1968; Garstang 1968). The computations of various models for planetary nebulae also bear on the above studies (Harrington 1968; Kirkpatrick 1970).
The Detailed Spectrophotometry of 8 Planetary Nebulae in the Spectral Region λλ6,000–11,000
Authors: Noskova R.I.
Published: June 2019

The detailed spectral study in the region λλ6,000–11,000 of eight planetary nebulae: NGC 6210, 6572, 6891, 7662, IC 2149, 4593, 4997 and BD+30° 3639 was carried out at the Crimean Station of Sternberg Astronomical Institute, using the 125-cm parabolic reflector with the contact image tube.
ATOMIC and Molecular Data
Authors: Dalgarno A.
Published: June 2019

Excitation, ionization and recombination processes are discussed elsewhere in this volume by Seaton (1977). I will restrict my attention to those processes involving heavy particles that may modify the ionization structure of planetary nebulae and that may affect the molecular composition of condensations and of the transition regions between the ionized nebulae and the surrounding interstellar gas.
The Ionisation Structure of IC 418
Authors: Atherton P.D. , Hicks T.R. , Reay N.K. , Worswick S.P.
Published: June 2019

Isophotal contour maps pröduced from monochromatic electronographic exposures of the low excitation planetary nebula IC 418 are interpreted in terms of a three-dimensional non-spherical gas distribution.
Spectrophotometry of Six Planetary Nebulae
Authors: Hua C.T.
Published: June 2019

In addition to numerous emission lines arising from the ionization of chemical elements, well-exposed nebular spectrograms reveal a Balmer continuum in emission hitherto attributed to the second level radiative recombination of the hydrogen atoms and to the two-photon contribution. The very intense lines with regard to the adjacent continuous spectrum have been easily measured by many workers for identification, Balmer decrements, line ratios … whereas few data are available involving continuum measurements. As well as the mean slope of the continuum, the Balmer discontinuity is very sensitive to the physical conditions prevailing and the presence of dust in the nebulae.