bluuebunny/crossref_metadata_2025 huggingface dataset:
The Prospects for High Sensitivity Gravitational Antennae
Authors: Braginsky V. B.
Published: June 2019

The sensitivity of a resonant gravitational wave detector which is necessary for the detection of pulses from asymmetric stellar collapses or from black-hole collisions in nearby galaxies is examined. Limitations on this sensitivity due to the resonating quality of the detector, thermal noise, and reaction of the detection system upon the detector are studied. No severe difficulties for the detection of the above-mentioned pulses are expected. For the detection of pulses from a cluster at the galactic center, a nonresonant system based on Doppler ranging to a drag-free satellite would be more appropriate. At present the sensitivity of Doppler-ranging is still two orders of magnitude below the requirements.
Observations with Wide-band Gravitational Radiation Detectors
Authors: Drever R. W. P. , Hough J. , Bland R. , Lessnoff G. W.
Published: June 2019

The principles and operation of wide-band gravitational radiation detectors are described. In 7 months of coincidence observations, one signal which fulfills requirements set for a gravitational wave event was recorded, and details are presented. The experiment sets an upper limit to millisecond pulses of gravitational radiation of 0.9±2.1 per month at a 25% threshold of 0.3kT in 300 kG bars, which appears inconsistent with the flux implied by Weber's 1970 results if these are due to such pulses.
The Stability of Relativistic Systems
Authors: Chandrasekhar S.
Published: June 2019

The stability of relativistic systems is reviewed against the background of what is known in the corresponding contexts of the Newtonian theory. In particular, the importance of determining whether Dedekind-like points of bifurcation occur along given stationary axisymmetric sequences is emphasized: the occurrence of such points of bifurcation may signal the onset of secular instability induced by radiation-reaction. (At a Dedekind-like point of bifurcation, the system can be subject, quasistationarily, to a non-axisymmetric deformation with an e2iϕ-dependence on the azimuthal angle ϕ.)

A formalism is described in terms of which the normal modes of axisymmetric oscillation of axisymmetric systems can be determined. Specialized to neutral modes of oscillation the formalism provides an alternative proof of Carter's theorem and clarifies the minimal requirements for its validity. A parallel formalism is described for ascertaining whether an axisymmetric system can be subject to a quasi-stationary non-axisymmetric deformation. The possibility of applying this latter formalism to determining whether a Dedekind-like point of bifurcation occurs along the Kerr sequence is considered.
Recent Work on Kerr Stability and Superradiant Wave Scattering
Authors: Press William H.
Published: June 2019

As a stopgap measure until a rigorous analytic determination is made, Teukolsky and I have tested the dynamical stability of the Kerr metric under small perturbations numerically (Press and Teukolsky, 1973). We find that it is stable for all a ≤ M. We have also computed the magnitude of electromagnetic and gravitational-wave amplification in superradiant scattering, and Bardeen has independently obtained identical results (Teukolsky, 1973; Teukolsky et al., 1974). The amplification ranges up to ~2% for electromagnetism (l=m=1) and up to 140% for gravitation (l=m=2); these values are also consistent with Starobinsky's (1973) results for the value of critical frequencies.
Electromagnetic Waves in the Exterior of a Schwarzschild Black Hole
Authors: Stephani H. , Herlt E.
Published: June 2019

Using the technique of Debye potentials, the regular (nonstatic) EM fields are found to behave at r = M either as purely ingoing or as purely outgoing waves. After separation the radial equation is treated in the short wavelength approximation.
Magnetization, Matter-Antimatter Symmetry and the Baryon-Photon Ratio in the Universe
Authors: Melvin M. A.
Published: June 2019

It is shown that the universal magnetic field, or sufficiently extended intergalactic fields, of magnitude ≳ 10-9 G would have aligned the magnetic moments of all leptons at an early time. Unless an upper limit to temperature exists, the alignment of all nucleons would also have occurred at an earlier time when the temperature was mN/me~2000 times higher. Possible inferences of this early magnetization of the matter in the universe for observation are discussed. The one selected for particular analysis is the parameter
expressing the inverse ‘hotness’ of the universe. The matter-anti-matter symmetric theory of η given by Omnes, amended by Steigman and Kundt is reviewed. The effect of the large scale magnetic alignment on the value of η resulting from the annihilation era is then discussed by means of a model in which matter and antimatter droplets or filaments are in quasi-equilibrium under magnetization and effective surface forces. The magnetized droplets affect the diffusion of neutrons, which is dominant in the annihilation era.
Gravitational Deviation Reaction
Authors: Sejnowski Terrence J.
Published: June 2019

A gravitational radiation reaction tensor is calculated for a point quadrupole source in the fast motion approximation. The calculation is in direct analogy with Dirac's original calculation of electromagnetic radiation reaction. In the gravitational case a tidal deviation reaction tensor results which is linear in the fifth derivatives of the source quadrupole moments.
Complex Maxwell and Einstein Fields
Authors: Newman Ezra T.
Published: June 2019

We consider the class of regular (in a certain precise sense) null vector fields, lμ which have the following properties; they are (1) tangent to geodesics, (2) diverging, (3) shear free, (4) twist (or curl) free. It is well known that the vacuum Einstein fields whose principle null vector field (pnvf) satisfies (1)–(4) are the Robinson-Trautman (1962) (RT) metrics and those which satisfy (1)–(3) are the algebraically special twisting metrics, (Kerr, 1963). To understand these metrics better we ask for those Maxwell fields (in flat space) whose pnvf also satisfy conditions (1)–(4) and (1)–(3). It can be shown that (1)–(4) imply (and are implied by) that the Maxwell field is a Lienard-Wiechart (LW) field. (This establishes the analogy between the RT metrics and the LW fields.) Conditions (1)–(3) imply that the Maxwell field is a complex LW field. (We mean by this that if the Maxwell equations are complexified (Newman, 1973) (in complex Minkowski space) then the real solution in question is induced from the complex solution which is associated with a charged particle moving along an arbitrary complex world line.) Finally it can be shown that the Einstein equations can be complexified and that the algebraically special twisting metrics can be interpreted as if they had a point source moving in the complex manifold and are thus analogous to the complex LW fields.
On Black and White Holes
Authors: Markov M. A.
Published: June 2019

Various possible cases of spherically systems the matter of which is localized in a domain smaller than the corresponding gravitational radius is considered.

The metic of the Friedmann closed world or of a part of it with an external continuation is suggested as a model of these systems.

There can exist black holes which are described by semi-closed metrics (black holes of the second kind). The class of systems in question may be both in the state of collapse and in the state of anti-collapse (including the state of ‘white holes’).

There are some grounds to suppose that collapse of celestial bodies should stop in the domain h/mvc, where mv is the mass of the vector meson, and that the pair production effect due to collapse of a charged sphere should conserve the Laplace determinism of the process.

The role of the charges of sources of different fields (electromagnetic, meson vector, scalar long-range, scalar meson, various versions of neutrino fields) in the deformation of the external and internal metric of black and white holes is analysed.

In this consideration a number of problems arises (the absence of horizon in the case of any small charges of scalar fields, the presence of the generalized Gauss theorem for vector meson field etc.), which provide evidence that the assertion ‘Black hole has no hair’ needs further investigations. In particular, the inverse process of formation of hair (e.g. vector-meson, scalar fields) in the process of anti-collopose has not been studied yet.

For the limiting case of the Nordström-Reissner metric m = e (more correctly m → e) two essentially different possibilities of continuing to the internal metric are considered (the Papapetrou case and the case which we called ‘friedmon metric’ describing charged black holes of the second kind (friedmons)).

In the case of charged holes of the second kind (friedmons) the occurance of quantum effects (pair productions) can reduce the horizon surface and violate the Hawking theorem.

The notion of black holes may turn out to be essential in elementary particle theory: among the intermediate states in elementary particle theory there are states the characteristic feature of which is the localization of arbitrary large energies (masses) in a domain smaller than the gravitational radius.
Binary X-ray Sources
Authors: Giacconi Riccardo
Published: June 2019

The observational data concerning binary X-ray sources is reviewed, with emphasis placed on Her X-1, Cen X-3 and Cyg X-1. In particular, the evidence for the identification of Cyg X-1 as a black hole is discussed.
Origin of Cosmic Rays, Atomic Nuclei and Pulsars in Explosions of Massive Stars
Authors: Arnett W. David
Published: June 2019

Explosions of massive stars (8 ≲ M/M⊙ ≲ 70) are examined as the source of galactic cosmic rays. Detailed nucleosynthetic and evolutionary calculations suggest that these massive stars produce the heavy elements (carbon and above) in their proper relative abundances. This is particularly significant because lower mass stars (in particular the 4–8 M⊙ range) are not able to produce the observed abundances of C and O relative to the iron peak. A small (~ 1.4 M⊙) dense remnant star (a neutron star) left after the explosion may provide a location for an electromagnetic acceleration mechanism. Those abundance ratios which can now be predicted (He, C, O, Ne, Mg) for the material to be accelerated by the pulsar give a reasonable match to the observed cosmic ray data. The conditions at the outer edge of the remnant and the inner edge of the ejected material may be appropriate for an r-process to occur; the high Z cosmic rays seem to show an enrichment of r-process material. It appears that these stars may be the astrophysical source for the galactic cosmic rays. The questions of rotation and black hole formation were discussed. It appears that the most straight-forward result of evolution of a close massive binary is a massive star and a neutron star in a low eccentricity orbit, in agreement with observation.
Black Holes in the Early Universe
Authors: Carr Bernard J. , Hawking Stephen W.
Published: June 2019

The existence of galaxies indicates that the early universe must have been inhomogeneous and might have been highly chaotic. This could have lead to regions of the size of the particle horizon undergoing gravitational collapse to produce black holes with initial masses from 10-5 g upwards. Radiation pressure in the early Universe would cause these black holes to grow by accretion. However, despite previous expectations, this accretion would not be very much unless the initial conditions of the Universe were arranged in a special and a causal manner. Observations indicate that, at the most, only a small fraction of the matter in the early Universe can have undergone gravitational collapse.
The Magnetic Fields of Pulsars
Authors: Sedrakian D. M.
Published: June 2019

Two generation mechanisms of magnetic fields in pulsars are considered.

If the temperature of a star is more than 108K, the star consists of a normal fluid of neutrons, protons and electrons. Because the angular velocity of pulsars is not constant dω/dt ≠0, inertia effects can occur, and generate magnetic fields through the relative motion of charged particles with different masses. The kinematic viscosity of electrons is 30 times larger than that of protons; hence electrons move with the crust, but the proton-neutron fluid will move relative to the electrons. The magnetic momentum can be calculated by the following formula
where Meff = Mp + Mn(Nn/Np), R = radius of the star, σ = conductivity. For typical neutron stars we have dω/dt~ 10-8 s-2, R~106 cm, σ~1029 s-1 and we get a magnetic field of the order of 1010 G.
Infrared Background Starlight: Observations and Galaxy Models
Authors: Fazio G. G. , Dame T. M. , Kent S.
Published: June 2019

The near-infrared region of the spectrum is a particularly advantageous window for observing the distribution of old, evolved stars in the galactic disk and bulge. These stars are important because they provide an excellent tracer of the overall stellar mass distribution. At shorter wavelengths extinction is a serious problem, and at longer wavelengths the flux is dominated by dust emission. A summary of the large-scale diffuse near-infrared observations of the Galaxy is presented, as is a summary of the results obtained from these data on the structure of the galactic disk and bulge. The importance of combining CO and near-infrared maps of similar resolution to determine a three-dimensional model of galactic extinction is demonstrated. The Spacelab-2 Infrared Telescope (IRT) data are used in conjunction with a proposed galactic model to make preliminary measurements of the global scale parameters of the Galaxy.
The Bochum Milky Way Surface Photometry: An Overview
Authors: Schmidt-Kaler Theodor
Published: June 2019

Photoelectric photometry is inherently much more accurate than photographic work. But large time variations of airglow, inaccurate elimination of bright stars, and the problematic adding-up of different scans may destroy this advantage in the case of surface photometry. On the other hand, the low internal accuracy of photographic photometry and its problematic nonlinearity can be overcome by a sufficient number of plates and by careful photoelectric calibrations. Such measures allow us to take full advantage of the high homogeneity of super-wide-angle photographs over extremely large areas, their global calibration, and their direct imaging. When I started this work, no charge-coupled device or similar device was available. But even today, with such detectors problems would arise for surface photometry in flat-fielding, zero-points, and bright star elimination. Our camera (Schlosser and Schmidt-Kaler 1977) followed the Henyey-Greenstein design with a f/4.3 Zeiss UV-Sonnar lens (with constant focus from 2000 Å up to 10000 Å) and f/0.4 spherical mirror of 30 cm ⊘, giving an effective f=18 mm. The angular resolution, limited by optics and plate, is 4′ in the center, 7′ in the average, and about 20′ at the edges of the field of view (=140°).
A Model of the 8–25 μm Point Source Infrared Sky
Authors: Wainscoat Richard J. , Cohen Martin , Volk Kevin , Walker Helen J. , Schwartz Deborah E.
Published: June 2019

We have constructed a detailed model for the infrared (IR) point source sky that comprises geometrically and physically realistic representations of the galactic disk, bulge, stellar halo, spiral arms (including the “local arm”), molecular ring, and the extragalactic sky. We represent each of the distinct galactic components by up to 87 types of galactic source, each fully characterized by scale heights, space densities, and absolute magnitudes at BVJHK, 12, and 25 μm, and a spectrum from the IRAS Low Resolution Spectrometer (LRS). Our model has been guided by a parallel Monte Carlo simulation of the Galaxy at 12 μm. The content of our galactic source table constitutes an excellent match to the 12 μm luminosity function in the simulation, as well as to the luminosity functions at V and K. We are able to predict differential and cumulative IR source counts for any bandpass lying fully within the IRAS LRS range (7.7–22.7 μm) as well as for the IRAS 12 and 25 μm bands. These source counts match the IRAS observations extremely well. The model can be used to predict the character of the point source sky expected for observations from future IR space experiments (e.g., ISO, SIRTF, LDR).
Monte Carlo Simulations of the Galaxy at 12 μm: Implications for Galactic Structure
Authors: Volk K. , Wainscoat R. J. , Cohen M. , Walker H. J. , Schwartz D. E.
Published: June 2019

We present an all-sky star count model at 12 μm based upon the Infrared Astronomical Satellite (IRAS) observations that characterize both the 12 μm luminosity function and the geometrical parameters of the galaxy. The model includes five galactic components: the bulge, the spheroid, the exponential disk, the spiral arms, and the molecular ring. The distribution of the brighter IRAS sources along the galactic plane required that the model include sources within the spiral arms and the molecular ring to produce an acceptable fit. We do not support the conclusion of Habing (1988) that the galactic disk ends just outside the solar circle, and do not require a thick disk to match the observations. We suggest that Habing's sample includes IRAS sources in the spiral arms but his model for the galactic disk does not include this critical component.
Light from Dark Clouds
Authors: Stüwe Joachim A.
Published: June 2019

The purpose of the present investigation was to find out how far the existing photographic sky surveys can be used to derive physical parameters of dark clouds, without the need of new observations. In a recent paper a method of distance determination and extinction mapping of dark clouds by automated star counts on microphotometric raster scans of the ESO/SRC Southern Sky Survey (Stüwe, 1989, hereafter Paper I) is presented. The present paper does a second step, which is based on the fact that dark clouds are marked by an intrinsic surface brightness (Barnard, 1927).
Luminescence from Small Carbonaceous Dust Grains
Authors: Friedemann Christian , Reimann Hans-Georg
Published: June 2019

A relationship exists between the amount of the ultraviolet (UV) extinction and the relative strength of the very broad structure (VBS) in the 500–600 nm wavelength region (5000–6000 Å) of the interstellar extinction curve. It is based on observations of OB stars distributed along the Milky Way. By examining E(B-V), we found that larger-than-mean values of the UV extinction correspond to larger-than-mean strengths of the VBS and vice versa. This feature is thought to be an emission arising from photoluminescence (PL) of small amorphous carbonaceous grains.
Galaxy Count Models and the Extragalactic Background Light
Authors: Shanks T.
Published: June 2019

In this review we first discuss the various ingredients of the non-evolving models for galaxy count observations. These ingredients include the K-corrections, the galaxy luminosity function and its dependence on galaxy colour, the local space density of galaxies and the cosmological deceleration parameter. Comparing the updated count model with the most recent galaxy count observations, the conclusion is still that at B>22m the B (and the R) counts require very significant amounts of evolution to fit the observed, steep n(m) relations. We review models of galaxy luminosity evolution and also discuss the current debate as to whether B≈23m galaxies have z ≈1 or z ≈3.

We also consider recent suggestions that the form of Tyson's counts at B=27m may constrain the cosmological deceleration parameter; contrary to the suggestion of Koo (1989), it is proposed here that if the turnover seen in Tyson's B counts is real then this argues for high values of qo and/or low galaxy formation redshifts. Finally, we consider the implications of these results for observations of the extragalactic background light (EBL) and conclude that in the ultraviolet (UV) and in the optical the contribution of faint galaxies to the EBL is likely to be small if the turnover in Tyson's counts is real. The galaxy count evidence gives less clear indications about the contribution of galaxies to the infrared EBL.
A New Catalogue of Faint Galaxies
Authors: Infante Leopoldo
Published: June 2019

A new catalogue of faint galaxies on a 3 deg2 area near the North Galactic Pole (NGP), complete to J =24.5 and F =23.5, has been obtained from nine Canada France Hawaii Telescope prime focus plates. The angular correlation function has been measured for the first time to separations ~1°. Preliminary results indicate a power law slope of ≈ −0.8 at small separations and no sharp break for θ ≤ 1°. We also find some evidence that the power law slope flattens to fainter limiting magnitudes.
Extended Halos in the Cluster Abell-426
Authors: Kelemen Janos , Mollenhoff Claus
Published: June 2019

During 1987 and 1988, we obtained 12 long-exposure Schmidt plates of the cluster Abell-426 at the Konkoly Observatory. The pictures were digitized with a microdensitometer and added with a computer. The resulting blue images clearly show extended envelopes around the bright cluster members.
Dust in Nearby Groups of Galaxies?
Authors: Girardi M. , Giuricin G. , Mardirossian F. , Mezzetti M.
Published: June 2019

The excess of higher redshift galaxies relative to the brightest member, found by several authors in poor, loose groups, is found to be present also in nearby, small groups identified by Geller and Huchra (1983) in the Center for Astrophysics Survey. This effect is explained as being due to the presence of diffuse intragroup dust together with an early evolutionary stage of nearby galaxy groups. An expected negative correlation between color excesses of galaxies and the velocity relative to the brightest member is found to be highly significant for both B-V and U-B colors. The optical depth produced by dust in groups turns out to be on the order of one, with a density of about 10−29 g/cm3.
Explaining the Infrared and Submillimeter Backgrounds by Decaying Particles
Authors: Wang Boqi , Field George B.
Published: June 2019

We propose that photons produced by decaying particles may account for the recently observed isotropic infrared background (IRB) between 1 and 5 μm. We find that for decaying particle masses mx between 5 and 18 keV, lifetime τd between 2 and 7 × 1010 s, and photon branching ratio Bγ between 4 and 9 × 10−4, the observed spectrum of decay photons is consistent with the observed spectrum of the IRB. The same parameters can explain the submillimeter background.
Properties of the Surface Brightness Distribution of the Cosmic X–Ray Background
Authors: De Zotti G. , Franceschini A. , Persic M. , Danese L. , Boldt E. A. , Marshall F. E. , Palumbo G. G. C.
Published: June 2019

The HEAO–1 A2 scanning survey has provided small field-of-view data characterized by a full width zero intensity of 3° along the scan direction (at approximately constant ecliptic longitude λ) and of 6° perpendicular to it. We have used independent fields taken from scanning circles separated by Δλ = 6° and whose centers are separated by Δβ = 3°. After having excluded all fields at | β | < 60° or at | b | ≤ 20°, only 905 of the total turned out to be not significantly contaminated by diffuse galactic emission or by known discrete sources. The flux intensity at each field's central position was evaluated by fitting a point source plus a constant background. The sample average C (θ) of the products dI (θ) x dI'(θ + Δθ) of positive and negative intensity fluctuations computed for angular separations of 3°, 6°, …, and 27° provides the X-ray background (XRB) angular correlation function.
Luminosity Inhomogeneity of Quasars and the Upper Limit of the Density Fluctuation in the Universe
Authors: Chu Yaoquan , Fang Lizhi
Published: June 2019

An upper limit to the amplitude of the overall density fluctuation has been found by means of the gravitational lensing effect of the density inhomogeneity on luminosity of quasars with large redshifts. The observed differences of luminosities of quasars located at different directions are partially given by the lensing effect; therefore, a useful upper limit to the inhomogeneity can be derived.
ISO's Capabilities for IR Background Measurements
Authors: Lemke D.
Published: June 2019

Although designed as a pointed infrared observatory for detailed studies of selected objects, the ISO satellite has remarkable capabilities for studying faint surface brightness sources and for helping to disentangle the overlaying background components. The 1993 launch of ISO is timely as it follows the COBE mission and offers a large guest observer program for which preparations can now be made.
Imaging Large– and Small–Scale Structures of the Far Ultraviolet Background with the Faust Instrument
Authors: Lampton M. , Bowyer S. , Deharveng J. M.
Published: June 2019

The FAUST telescope is an ultraviolet survey instrument that features a wide 8° field of view, ~1′ angular resolution, and a photon counting detector. Operating in the 1400–1800 Å band, it will be sufficiently sensitive to detect blue mv =17 objects in a single 20 minute night. The instrument is part of the ATLAS-1 shuttle mission, presently scheduled for flight in May 1991. A substantial number of high galactic latitude fields will be investigated, with particular emphasis on studies of the origin of the diffuse far UV background.
Far–Ultraviolet Background Studies with the Pan–American Astrophysics Explorer (PAX)
Authors: Martin C. , Steiner J.
Published: June 2019

We describe a proposed far-ultraviolet (FUV) photometric and spectroscopic survey covering the 1300–2000 Å band with a sensitivity comparable to that of the Palomar Sky Survey. Among the numerous scientific objectives of this mission, many have direct bearing on the nature of the FUV background.
The Potential of the Wide Field Camera on ROSAT for Investigations of the XUV Background
Authors: Harris Alan W. , Walker Helen J. , Sumner Timothy J.
Published: June 2019

The ROSAT X-ray astronomy satellite, due to be launched in early 1990, will carry two separate and complementary grazing-incidence telescopes with co-aligned axes. The German X-ray telescope (XRT) will cover the soft X-ray region in the range 0.15–2 keV (6–80 Å), while the U.K. XUV Wide Field Camera (WFC) will extend coverage to beyond 200 Å. The WFC is a joint project of Leicester and Birmingham Universities, the Mullard Space Science Laboratory, and the authors' institutes. The primary objective of ROSAT is to perform an all-sky survey over a period of six months. This will be followed by a guest-observer, “pointed” phase. We briefly discuss the sensitivity of the WFC to the soft X-ray/XUV background (SXRB) and the problems and techniques associated with distinguishing the astronomical background from other sources of background.
Summary: The Galactic Background Radiation
Authors: Puget J. L.
Published: June 2019

The most striking aspect of this conference with respect to galactic studies has been the confrontation between wavelengths. The study of the background radiation requires absolute measurements of low brightness over very extended regions. Such measurements are known to be extremely difficult. We now can confront data on the galactic background at all frequencies. The data from far ultraviolet to submillimeter give particularly useful constraints on both the direct interpretation of the data and on their astrophysical interpretation.
II.—The Chronicle of the Conquest
Authors: Tozer H. F.
Published: June 2019

The Greek Chronicle, which brought to light the feudal organisation of the Frank Principality, and is the principal authority for the first century of its existence, was first printed from the manuscript in the Paris library in 1841 by M. Buchon in his Chroniques étrangères relatives aux Expéditions françaises pendant le treizième Siècle. Its existence had long been known, for Ducange in his Greek Lexicon refers to it under the title De bellis Francorum in Morea; and the frequency of his quotations from it attests its value for linguistic purposes, so that it appears in some cases to be the earliest, and in some the only, authority for certain mediaeval Greek words. Ducange also intended to publish it, but was prevented by death, and no use was made of it as a historical document until Buchon's time. When it was first published, the editor believed that it was an original work; but this opinion he was led to alter by the discovery in 1845 of a French text in the library at Brussels, entitled Le Livre de la Conqueste de la Princée de la Morée. The view that this was the earlier of the two, and that the Greek version was derived from it, is now generally accepted, though it was doubted by so excellent a critic of Byzantine literature as the late Dr. Ellissen, who published extracts from the Greek poem, with a verse translation into German and historical notes, in the second volume of his Analekten der mittel- und neugriechischen Literatur, in 1856. The French chronicle was printed as vol. i. of Buchon's Recherches historiques sur la Principauté française de Morée, while the second volume of that work contained another Greek text, taken from a manuscript discovered at Copenhagen. This latter is undoubtedly superior to the text of the Paris manuscript, as it is fuller, and supplies many of its lacunae; but it is inferior in respect of orthography and metre: in the following pages, however, the references are made to the Copenhagen text, and the quotations are taken from it, unless the contrary is stated, because in it alone the lines are numbered. The poem, as edited by Buchon from the Copenhagen manuscript, supplemented in parts by the other, contains 9219 lines of ‘political’ verse, of which 1332 belong to the Prologue, and the remaining 7887 to the Conquest of the Morea. Its title is Χρονικὰ τῶν ἐν Ῥωμανίᾳ καὶ μάλιστα ἐν τῷ Μωρέᾳ πολέμων τῶν Φράγκων; for though the editor has given to the whole work the title Βιβλίον τῆς κουγκέστας, by which it is generally known, and to the part that follows the prologue the separate heading Τὸ πῶς οἱ Φράγκοι ἐκέρδισαν τὸν τόπον τοῦ Μωραίως, which is a line from the poem itself, yet these convenient appellations are his own invention. The Livre de la Conqueste carries the history twelve years further down than the Greek chronicle, for it continues to A.D. 1304, while the Greek manuscripts end in 1292.
III.—Topographical Notices
Authors: Tozer H. F.
Published: June 2019

The following descriptions of the position and present state of some of the most interesting places connected with the history of the Frank Principality are the result of a journey through the Peloponnese, made with the object of investigating the remains of that period. The ordinary routes through the peninsula, which are followed by tourists naturally anxious to visit the classical antiquities, lead to but few of those sites, and therefore it is almost necessary to undertake a special journey in order to explore them. No doubt the mediaeval fortifications of Patras, Corinth, Argos, and Nauplia, which are frequently visited, are among the finest in the country; but these, as we have seen, are but little associated with the history of the Principality, Patras and Corinth having followed for the most part an independent policy of their own, while Argos and Nauplia were attached as a fief to the dukedom of Athens, and remained in the hands of the family of Brienne even after their expulsion by the Catalans from their possessions in northern Greece. The same thing is true of the maritime fortresses of Modon and Coron in the south-west corner of the Peloponnese, for they were almost from the first in the hands of Venice. Hence the parts of the country which deserve especial attention in connection with this period are the north-western, the central, and the southern districts—or, to adopt the ancient names, Elis, Arcadia, and Laconia, together with the eastern portion of Messenia. The course of my own tour was from Corinth by way of Argos, Nikli (Tegea), and Mistra, to Monemvasia on the extreme south-east coast; thence by Passava in Maina and Kalamata through the pass of Makriplagi to Karitena and Akova in north-western Arcadia; and finally through Elis, visiting Khlemoutzi, Klarentza, and Andravida, to Patras. In what I have now to say, however, I prefer to invert this order, and to commence with the western portion, which formed the headquarters of the Principality. Some of the places to be noticed have been visited by Leake, others by Ernst Curtius; Buchon, also, who was indefatigable in every branch of his subject, made a journey in 1840 and 1841 in quest of these Frankish antiquities, an account of which is given in his interesting volume, entitled La Grèce continentale et la Morée. But the majority of the sites are so little known, and the subject has attracted so little attention, that a succinct account of them, which is the result of personal inspection, may not be without value.
VII.—Tombs
Authors: Hogarth D. G. , James M. R.
Published: June 2019

Tombs of all periods were opened during the past season, a few archaic ones at Leontari Vouno, which have been described by Mr. James in his account of that site, and others at Kuklia of all subsequent ages, down to the very latest. They are usually cut in the rock or earth of a gentle slope, in many cases, as in the Xylino valley at Kuklia, tier above tier: but they are also found in level ground, approached by a sloping passage now filled with earth. The whole plateau to the east of Kuklia above the is honey-combed with earth-tombs of this kind, consisting mainly of one or two vaulted chambers, leading one out of the other, without niches for the bodies, and entered by a vaulted opening closed by a slab. Such are probably tombs of the poor: the richer Cypriotes were for the most part laid in rock-tombs, such as abound in the plain north of New Paphos, and were found by us at Old Paphos on the slopes between the Temple of Aphrodite and the sea. From their greater durability and accessibility the latter were often used two or three times over, being sometimes sanctified at last for Christian burial by innumerable crosses, cut over the niches, as is the case at Cape Drepano: thus they are usually less profitable to the explorer of to-day than the earth-chambers, which were left undisturbed in the possession of their original tenants, and were not so easily detected by the τυμβωρύχος of the early centuries of our era. Of the work of the latter we found ample evidence at Kuklia: tomb after tomb was opened on the eastern slopes, in which broken glass and pottery were lying in a huge heap either in the middle or near the door, what the thieves did not want having apparently been wantonly destroyed: the lids of the sarcophagi were either hewn in pieces or wrenched aside, and even, in some cases, in order probably to evade notice, carefully replaced in statu quo. The door was by no means the favourite place of ingress, for we often dug down to find the slab quite undisturbed, while the tomb was in the state described above, and search would reveal the presence of a hole or passage cut through the solid rock from above or at the side.
Dedication to Arcadio Poveda
Authors: Abt Helmut A.
Published: June 2019

It is appropriate that this meeting about double and multiple stars be dedicated to Arcadio Poveda, who has derived so many results about such systems. This dedication mentions some of those results, as well as some other details of his research and accomplishments.
Binary Statistics Among Population II Stars
Authors: Zinnecker H. , Köhler R. , Jahreiß H.
Published: June 2019

Population II stars are old, metal-poor, Galactic halo stars with high proper motion. We have carried out a visual binary survey of 164 halo stars in the solar neighborhood (median distance 100 pc), using infrared speckle interferometry, adaptive optics, and wide field direct imaging. The sample is based on the lists of Population II stars of Carney et al. (1994) and Norris (1986), with reliable distances from HIPPARCOS measurements.

At face value, we found 33 binaries, 6 triples, and 1 quadruple system. When we limit ourselves to K-band flux ratios larger than 0.1 (to avoid background contamination), the numbers drop to 9 binaries and 1 triple, corresponding to a binary frequency of 6–7% above our angular resolution limit of about 0.1 arcsec. If we count all systems with K-band flux ratios greater than 0.01, we obtain 15 more binaries and 3 more triples, corresponding to a binary frequency for projected separations in excess of 10 AU of around 20 %. This is to be compared with the frequency of spectroscopic binaries (up to a period of 3000 days) of Population II stars of about 15 % (Latham et al. 2002). We also determined a semi-major axis distribution for our visual Population II binary and triple systems, which appears to be remarkably different from that of Population I stars. Second epoch-observations must help confirm the reality of our results.
The Mass Distribution of Secondaries to Solar-Type Stars
Authors: Abt Helmut A. , Willmarth Daryl W.
Published: June 2019

Two previous studies of the secondary mass function in spectroscopic binaries by Abt & Levy (1976) and by Duquennoy & Mayor (1991) are shown to be in good agreement if they are both plotted with the same abscissa scale. A new study of 271 main-sequence stars later than F6 V made with a radial-velocity accuracy of ±0.10 km s-1 yielded 10 new sets of orbital elements in addition to the 59 published ones. The resulting secondary mass function is nearly flat and shows that 2.2±1.5% of the primaries have low-mass (0.01–0.10 M⊙) companions. In contrast, the secondary mass function for visual binaries with separations >500 AU fits a van Rhijn function, as was shown previously by Abt and Levy.
Are Binary Separations Related to their System Mass?
Authors: Sterzik Michael F. , Durisen Richard H.
Published: June 2019

We compile most recent multiplicity fractions and binary separation distributions for different primary masses, including very low-mass and brown dwarf primaries, and compare them with dynamical decay models of small-N clusters. The model predictions are based on detailed numerical calculations of the internal cluster dynamics, as well as on Monte-Carlo methods. Both observations and models reflect the same trends: (1) The multiplicity fraction is an increasing function of the primary mass. (2) The mean binary separations are increasing with the system mass in the sense that very low-mass binaries have average separations around ≈ 4AU, while the binary separation distribution for solar-type primaries peaks at ≈ 40AU. M-type binary systems apparently preferentially populate intermediate separations. Similar specific energy at the time of cluster formation for all cluster masses can possibly explain this trend.
Observations of Hipparcos Double Stars with the WiynTelescope
Authors: Horch Elliott P. , Meyer Reed D. , van Altena William F. , MacKnight Meridith
Published: June 2019

A program of follow-up observations of HIPPARCOS Double Stars has been started using the WIYN 3.5-m Telescope at Kitt Peak, Arizona. Observations are made with the recently-completed RYTSI speckle camera, which is capable of determining reliable magnitude differences at various wavelengths down to the diffraction limit of the telescope. Thus in addition to precise relative astrometry, component magnitudes and colors can be obtained in a survey mode for all systems observed. Preliminary results and system capabilities are described. The benefits of a sustained program of observations of the HIPPARCOS Double Stars include populating the mass-luminosity relation with many more points (once the orbital status of these stars is known and orbital parameters are determined in sufficient detail for gravitationally bound pairs), robust tests of stellar evolution calculations in cases where at least one component has evolved off the main sequence, and a more complete picture of the nearby field binary population.
Spectroscopic Binaries among a Complete Sample of Hipparcos M Giants
Authors: Jorissen A. , Famaey B. , Dedecker M. , Pourbaix D. , Mayor M. , Udry S.
Published: June 2019

We present the first eccentricity-period diagram for binaries among nearby field M giants, where an observed frequency of at least 8% of spectroscopic binaries is found.
High-Mass X-Ray Binaries and OB Runaway Stars
Authors: Kaper L. , Van der Meer A. , Tijani A.H.
Published: June 2019

High-mass X-ray binaries (HMXBs) represent an important phase in the evolution of massive binary systems and provide fundamental information on the properties of the OB-star primaries and their compact secondaries (neutron star, black hole). Recent observations indicate that the neutron stars in some of these systems (Vela X-1, 4U 1700-37) are more massive than the canonical mass of 1.35 M⊙. These observations have important consequences for the equation of state at supranuclear densities and the formation mechanism(s) of neutron stars and black holes: supernovae and gamma-ray bursts. As a consequence of the supernova explosion that produced the compact star in these systems, HMXBs have high space velocities and thus are runaways. Alternatively, OB-runaway stars can be ejected from a cluster through dynamical interactions. Observations obtained with the Hipparcos satellite indicate that both scenarios are at work.
Spectroscopic Binaries in Southern Open Clusters
Authors: Levato H. , González J.F. , Malaroda S. , Grosso M.
Published: June 2019

This is a report on an ongoing program about binaries in southern open clusters. The long-term purpose of this project is to contribute to understanding the formation and evolution of spectroscopic binaries, providing observational constraints that will permit tests of some of the current theories on binary formation in open clusters.
The Possible Belts for Extrasolar Planetary Systems
Authors: Jiang Ing-Guey , Duncan M. , Lin D.N.C.
Published: June 2019

More than 100 extrasolar planets have been discovered since the 1990s. Unlike those of the solar system, these planets’ orbital eccentricities cover a huge range from 0 to 0.7. Incidentally, the first Kuiper belt object was discovered in 1992. Thus an interesting and important question will be whether extrasolar planetary systems could have structures like the Kuiper belt or asteroid belt. We investigate the stability of these planetary systems with different orbital eccentricities by similar procedures to Rabl & Dvorak (1988) and Holman & Wiegert (1999). We claim that most extrasolar planetary systems can have their own belts at the outer regions. However, we find that orbits with high eccentricity are very powerful in depletion of these populations.
The Impact of Large Databases on the Knowledge of Late-Type Close Binaries
Authors: Maceroni C.
Published: June 2019

This paper presents some results of the analysis of the eclipsing binaries samples that came out as by-products of the OGLE microlensing surveys. These experiments monitored millions of stars in the direction of the galactic bulge (OGLE-I), and of the Small Magellanic Cloud (OGLE-II). Their completeness allowed the discovery of rare and interesting systems. An example is a new group of long period binaries in the SMC with presumably a giant component in contact with the critical lobe, which dominates the systemic light variation (“β -contacts”). These systems obey a period-luminosity-color relation and could be used as an auxiliary, but independent, tool for distance determination. Another very interesting object, for its implications in the studies of angular momentum loss processes by magnetic braking and of stellar activity, is the system of shortest known period with M dwarf components, discovered by OGLE-I, BW3 V38, that is the target of a spectroscopic follow-up. The perspectives for close binary star research in view of future space missions, such as COROT and Eddington are briefly discussed.
What can the SB9 Database do for you?
Authors: Pourbaix D. , Jancart S. , Boffin H.M.J.
Published: June 2019

This paper illustrates different kinds of problems that can be tackled with SB9, the 9th catalogue of spectroscopic binary orbits.
VLBI Observations of SN 1979C and SN 1986J
Authors: Bartel N. , Bietenholz M.F.
Published: June 2019

We summarize our results on multi-epoch VLBI observations of SN 1979C in the galaxy M100 in Virgo, and of SN 1986 in the galaxy NGC 891. From t = 3.7 to 22 yr after the explosion, SN 1979C expands ∝ tm, almost freely, with m = 0.95 ± 0.03. For a total kinetic energy of 3 × 1051 erg, the expansion result requires a mass-loss to wind-velocity ratio for the progenitor of only 1 × 10−5 M⊙ yr−1per 10 km s−1, an order of magnitude smaller than estimated from radio light-curve fitting. We show a first image with slightly discernible structure of the supernova. For SN 1986J we present five images from 1987 to 2002 and show our result on moderately to strongly decelerated expansion with m = 0.71 ± 0.11. We comment on our result of an inversion of the radio spectrum in terms of the emergence of a possible pulsar nebula.
A Most Energetic Type Ic Supernova: SN 2003L
Authors: Soderberg Alicia M.
Published: June 2019

We present extensive radio observations of SN2003L, the most luminous and energetic Type Ic radio supernova with the exception of SN 1998bw. Using radio data, we are able to constrain the physical parameters of the supernova, including the velocity and energy of the fastest ejecta, the temporal evolution of the magnetic field, and the density profile of the surrounding medium. We highlight the extraordinary properties of the radio emission with respect to the supernova’s normal characteristics within optical bands. We find that although the explosion does not show evidence for a significant amount of relativistic ejecta, it produces a radio luminosity which is comparable to that seen in the unusual SN1998bw. Using SN2003L as an example, we comment briefly on the broad diversity of type Ic properties and the associated implications for progenitor models.
Synthetic Spectra of the Type Ia SN 2002bo
Authors: Stehle M. , Mazzali P.A.
Published: June 2019

SN 2002bo, a type Ia supernova in NGC 3190, is the first object of the European Supernova Collaboration (ESC). It was discovered on 09 March 2002 and is one of the earliest observed SNe. An almost complete set of spectra and photometry is available from 13 days before maximum B light until a few days after. An analysis using synthetic spectra is presented, focusing on the controversial issue of the reddening of SN 2002bo.
Optical Spectroscopy of Type Ia Supernovae
Authors: Matheson Thomas
Published: June 2019

The supernova (SN) group at the Harvard-Smithsonian Center for Astrophysics has been using the facilities of the F. L. Whipple Observatory to gather optical photometric and spectroscopic data on nearby supernovae for several years. The collection of spectra of Type Ia SNe is now large enough to allow a comprehensive analysis. I will present preliminary results from a study of a subsample of the CfA Type Ia spectroscopic database, with over 200 spectra of 31 Type Ia SNe. The SNe selected all have well-calibrated light curves and cover a wide scope of luminosity classes. The epochs of observation range from fourteen days before maximum to fifty days past maximum. All of the spectra were obtained with the same instrument on the same telescope, and were reduced using the same techniques. With such a large, homogeneous data set, the spectroscopic similarities and differences among Type Ia SNe become readily apparent.
Late Light Curves of Type Ia SNe
Authors: Milne Peter A. , Williams G.Grant
Published: June 2019

At late times, the energy deposition in the ejecta of type Ia supernovae is dominated by the slowing of energetic positrons produced in 56Co → 56Fe decays. Through comparisons of simulations of energy deposition in SN Ia models with observed light curves from supernovae, we study the positron transport and thus the magnetic fields of SNe Ia. In this paper, we summarize the current status of these investigations, emphasizing the observations made of two recent SNe Ia, 1999by and 2000cx.