bluuebunny/crossref_metadata_2025 huggingface dataset:
Theatrum Belli: Late-Restoration Comedy and the Rise of the Standing Army
Authors: Gardner Kevin J.
Published: July 2016

“Plays are but the Mirrours of our Lives,” wrote Colley Cibber in 1707, recognizing the special relevance of a timeless metaphor to the theatre of his own day. A man generally given to hyperbole, Cibber here underestimates the theatre's affective power for influencing and transforming society. Of all the many reflections and transformations one may see in the mirror of late-Restoration theatre, however, the most important, I believe, are the images of warfare. In the early eighteenth century, thetheatrum mundiwas indeed atheatrum belli, for the theatre of war was not confined to Vigo, Blenheim, and Malplaquet, to the fields of Sanders or Spain, but was enacted on the proscenium stages of Drury Lane, Lincoln's Inn fields, and the Haymarket. Nearly every new play written and produced on the London stages in the first decade of the eighteenth century has a Redcoat or a Tar in itsdramatis personaeor has topical references to the War of the Spanish Succession, to disbandment, to conscription, or to the debate over the issue of a standing army. Concurrent with the theatre's reflection of the nation's concern over the rise of the standing army is a transformation in the representation of army officers in stage comedies. After 1700, portrayals of military men shift so dramatically that they seem to attain an ideological significance; the historical causes and the aesthetic effects of this shift—which are the focal points of the ensuing essay—suggest a widespread ideological effort by writers to enlist public sympathy not only for the soldier but also for the notion of a standing army.
Technique and Tact: Nina Moise Directs the Provincetown Players
Authors: Black Cheryl
Published: July 2016

Historians of the Provincetown Players generally recognize Nina Moise as an individual who made a significant contribution to the company at a crucial period in its existence. Those who acknowledge her as an important member of the group commonly agree that Moise was Provincetown's first professional director and that her success as a director facilitated a shift away from amateurish collectivism toward more professional production techniques. That Nina Moise was largely responsible for this critical transformation in the company's production policies is not in dispute; the factors underlying her success, however, have not been examined. What were the qualities, personal and professional, that enabled Moise to make her significant contribution?
A comparison of dynamical models of the Andromeda Nebula and the Galaxy
Authors: Rubin V. C. , Ford W. K.
Published: July 2016

(1) From new radial velocities of 67 H II regions in M 31, rotational velocities and a mass model of M 31 are derived, and compared with the rotation curve and Schmidt mass model of our galaxy. (2) It is shown that in M 31 the distribution of H II regions as identified by Baade agrees with the distribution of neutral hydrogen determined from 21-cm observations. Also, the rotation curve derived from the H II velocities outside of the nucleus is similar to the rotation curve derived from 21-cm H I observations.
A peculiar neutral hydrogen concentration at lII = 280°, bII = −18°
Authors: Bajaja E. , Colomb F. R.
Published: July 2016

The observations discussed in this paper were obtained with the 30-m telescope of the Instituto Argentino de Radioastronomía.
Local stellar distribution and galactic spiral structure
Authors: McCuskey S. W.
Published: July 2016

Aside from the well-known spiral arm tracers such as the OB associations, young galactic clusters, WR stars and possibly the long-period classical cepheids, the more common stars in the neighborhood of the sun within 2 kpc show little or no relationship to the local spiral structure of the galaxy.
Galactic clusters and H II regions
Authors: Becker W. , Fenkart R.
Published: July 2016

The galactic clusters and the exciting stars of H II regions are powerful indicators of the spiral structure since these objects lie on or very close to the zero age main sequence (ZAMS). For clusters this behaviour can be confirmed by direct photometric observation. The exciting stars of H II regions are probably so young as not to have evolved from the ZAMS. The coincidence of these objects with the ZAMS indicates that there is little scattering in the absolute magnitudes and, as a consequence, little uncertainty in the determination of distance. This fact reveals itself very distinctly in the case of H II regions, whose exciting stars define the spiral structure considerably better than the stars of the same early spectral types but not connected with H II regions.
A new interpretation of the galactic structure from H II regions
Authors: G. Courtès Y.P. , Georgelin Y.M. , Monnet G.
Published: July 2016

From 6000 optical radial velocities of H II regions a new spiral structure (4 arms of pitch angle 20°) is found. The radial velocities of the observed H II regions are the same with the velocities of the H I regions. The kinematics of H II regions is similar to that of Cepheids and B stars.
Progress report of the current research on the galactic structure in Vela
Authors: Denoyelle J.
Published: July 2016

In order to find evidence for supporting or rejecting the idea of a major spiral feature in the direction of lII = 270°, as proposed by Velghe (1969), it is necessary to extend the limits of the survey both in longitude and in distance. The extension towards smaller longitudes was placed arbitrarily at lII = 257°, while in the direction of Carina, the investigation was confined to lII = 285°. In doing so, sufficient overlap was made with the studies by Velghe and by Graham and Lyngå (1965), in order to get a homogeneous and complete material in a large, but important section of the southern Milky Way. Following the same technique as outlined in the preceding paper, about 360 young type stars were selected from objective-prism plates, taken with the ADH-telescope of the Boyden Observatory. Later on (in 1966) a first series of UBV photoelectric measurements was carried out at the Boyden Observatory, however with insufficient accuracy. Before finishing the reductions, a second series was made with the 1m-photometric telescope of the ESO (La Silla, Chile) at the end of 1968. These (ESO)-values, in the Johnson UBV-system, will be available before long. In the definite form, they will be combined with the Boyden-measurements. The surface distribution of the stars in the whole section is shown in Figure 1. Many of the stars between lII = 273° and 282° are of rather late B-type, but they were included for the purpose of determining the absorption in this field. The space distribution will enable us to decide whether the edge of the Carina spiral feature is seen in this direction (Bok et al., 1969) and if there is any indication for a possible linkage from Carina to Puppis. To extend the distance limit, a search for faint blue stars, applying the idea of Bok (1966), is planned and some photoelectric sequences will be measured early in 1970 as standards for photographic photometry. As another approach to the galactic structure in this field a complete set of red objective-prism plates has been obtained since 1966, to pick out the objects with H α in emission. As for the reality of the association I Vel, some preliminary material on Radial Velocities will be collected also in 1970, using the Fehrenbach astrograph of the ESO at La Silla (Chile).
Small amplitude density waves on a flat galaxy
Authors: Kalnajs A. J.
Published: July 2016

By numerical methods we have found an unstable two-armed density wave on a flat galactic model. We present the results in a form of four plots, and briefly discuss the observational implications as well as the uncertainties involved in the models and the calculations.
The propagation and absorption of spiral density waves
Authors: Shu F. H.
Published: July 2016

An ‘anti-spiral theorem’ holds with limited validity for the neutral modes of oscillation in a stellar disk - namely, whenever the effects of stellar resonances can be ignored. In the regions between Lindblad resonances, a group of spiral waves will propagate in the radial direction with the group velocity found by Toomre. This propagation occurs with the conservation of ‘wave action’, wave energy, and wave angular momentum.
Neutral hydrogen in the Sagittarius and Scutum spiral arms
Authors: Burton W. B. , Shane W. W.
Published: July 2016

Observations of the neutral hydrogen in the first quadrant of galactic longitude have been analysed. The existence of large-scale streaming motions such as the streaming associated with the Sagittarius arm makes interpretation of the observations in terms of circular galactic rotation unsatisfactory. It is shown that application of the density-wave theory formulated by Lin et al. (1969) leads to a more satisfactory interpretation. Using kinematic models based on this theory the distribution and motion of the neutral hydrogen are studied. Failures of kinematic models based on circular rotation are pointed out. A map of the distribution of neutral hydrogen is produced. The Scutum arm is composed of inner and outer arcs both of which seem to be moving outward from the galactic center with velocities of the order of 30 km s−1.
On a corollary to the magnetic dipole theory of the origin of spiral structure
Authors: Pişmiş Paris
Published: July 2016

Some observable features of our Galaxy are explained in terms of a theory of the origin of spiral structure, whose basic feature is a gradually contracting gaseous subsystem with a magnetic dipole of which the axis is very close to the galactic plane.
Hubble Space Telescope Studies of the Dense Central Regions of Globular Clusters
Authors: Guhathakurta Puragra , Yanny Brian , Schneider Donald P. , Bahcall John N.
Published: July 2016

We present results from an ongoing program to probe the dense central parts of Galactic globular clusters using multicolor Hubble Space Telescope images (WF/PC-I and WFPC2). Our sample includes the dense clusters M15, 47 Tuc, M30, NGC 6624, M3 and M13. The two main goals of our program are to measure the shape of stellar density profile in clusters (the slope of the density cusp in post core collapse clusters, in particular) and to understand the nature of evolved stellar populations in very dense regions and their variation as a function of radius. The latter includes studies of blue straggler stars and of the central depletion of bright red giants. Our recent WFPC2 study of M15 is described in detail.
Monte-Carlo Simulations
Authors: Giersz Mirek
Published: July 2016

The revision of the Stodółkiewicz's Monte-Carlo code is presented. It treats each superstar as a single star and follows the evolution and motion of all individual stellar objects. The first calculations, for equalmass N-body systems with three-body energy generation accordingly to Spitzer's formulae, show good agreement with the direct N-body calculations for N = 2000 and 10000 particles.
Comparison of X-Ray Sources in Old Open and in Globular Clusters
Authors: Verbunt Frank
Published: July 2016

Twelve bright (Lx ≳ 1036erg/s) X-ray sources have been detected in globular clusters: they are accreting neutron stars. Five of these are transients. Thirty less luminous sources have been detected in eighteen globular clusters. The luminosity function of these sources does not rise rapidly towards lower luminosities. The sources with Lx ∼ 1033 erg/s are probably transients in their low state; the least luminous sources currently detected may be cataclysmic variables. The old open cluster M 67 harbours chromospherically active binaries, with Lx ∼ 1030−31erg/s. Globular clusters contain fewer of these binaries than estimated by scaling with mass from M 67.
The Formation of Globular Clusters and of The Stars Within Them
Authors: Lin D.N.C. , Murray S.D.
Published: July 2016

We propose that proto-globular cluster clouds form in a collapsing protogalactic cloud as a consequence of thermal instability. The clouds are photoionized and heated by nearby massive stars. Most are not self-gravitating, but are confined by the residual hot gas in the protogalactic cloud. Their masses evolve as they undergo cohesive collisions with each other and erosion due to interaction with the residual halo gas. Collisions may also trigger thermal instability and fragmentation within protocluster clouds. The resulting cloudlets are pressure confined, and fall toward the center of the protocluster cloud due to inverse buoyancy. Their mass distribution is also regulated by coagulation and erosion. While most cloudlets have substellar masses, the largest become self-gravitating, and collapse to form protostellar cores without further fragmentation. The initial stellar mass function is established as these cores capture additional residual cloudlets. Energy dissipation from the mergers ensures that the cluster will remain bound in the limit of low star formation efficiency. Dissipation also promotes the formation and retention of the most massive stars in the cluster center.
Panel Discussion
Authors: King Ivan R. , Meylan Georges , Verbunt Frank , Hut Piet , Sugimoto Daiichiro
Published: July 2016

My first reaction, at the end of this conference, is that it has not produced nearly as much “Confrontation of Theory and Observations” as one might have wished. We have all made our separate presentations, but no one has yet made the connections that are so much to be desired. Perhaps it is just that we need time to absorb what we have heard, and react to it.
Exchange Cross Sections For Hard Binaries
Authors: Heggie Douglas C. , Hut Piet , McMillan Stephen L.W.
Published: July 2016

We present results on the exchange cross section for the interaction between a hard binary and a field of single stars, for arbitrary masses. The results are based partly on extensive numerical scattering experiments, and partly on analytic estimates of the mass-dependence of the cross section. They can be used to estimate the rate of exchange in an arbitrary mixture of masses, provided that the binary is hard.
The Orbital Eccentricities of Binary Millisecond Pulsars in Globular Clusters
Authors: Rasio Frederic A. , Heggie Douglas C.
Published: July 2016

Low-mass binary millisecond pulsars are born with very small orbital eccentricities, typically of order ei ∼ 10−6−10−3. In globular clusters, however, higher eccentricities ef ≫ ei can be induced by dynamical interactions with passing stars. Using both analytical perturbation calculations and numerical integrations, we have shown (Heggie & Rasio 1996) that the cross section for this process is much larger than previously estimated. This is because, even for initially circular binaries, the induced eccentricity ef for an encounter with pericentre separation rp beyond a few times the binary semi-major axis a declines only as a power-law, ef ∝ (rp/a)−5/2, and not as an exponential. We find that all currently known low-mass binary millisecond pulsars in globular clusters must have been affected by interactions, with their current eccentricities being at least an order of magnitude larger than at birth (Rasio & Heggie 1995).
The Energy Exchange between Different Masses in an Expanding Gravitating System
Authors: Zhou Yuan , Miyama Shoken M.
Published: July 2016

We investigate whether or not the energy exchange occurs between two species groups of particles in an expanding two-component gravitating system, and we derive the relaxation time scale for energy exchange in such a phase. This is accomplished by solving the dynamic equation coupled with Poisson's equation. We derive a characteristic time determined by the various mass and velocity ratios. When the expansion time does not exceed the characteristic time, energy exchange between the two components is possible and depends on the mass ratio. Once the characteristic time is exceeded, there is virtually no relaxation at all in system. When m2 ≫ m1, the transfer of energy becomes inefficient. Therefore, energy exchange between two species of particle in an expanding two-component gravitating system depends not only on the mass ratio but also on the expansion time.
Metallicity and Luminosity Functions of the Globular Clusters in NGC 4472
Authors: Lee Myung Gyoon , Kim Eunhyeuk , Geisler Doug
Published: July 2016

NGC 4472, the brightest elliptical galaxy in the Virgo cluster, has a rich globular cluster system. We present a study of the metallicity and luminosity functions of a large number of globular clusters in NGC 4472. Deep Washington CT1 photometry of a wide (16′ × 16′) field of NGC 4472 was obtained using Tek 2048 × 2048 CCD at the KPNO 4m telescope.
Grape-SPH Simulations of the Chemodynamical Evolution of Dwarf Galaxies
Authors: Mori Masao , Yoshii Yuzuru , Tsujimoto Takuji , Nomoto Ken'ichi
Published: July 2016

The central concentration of the luminosity distribution in dwarf elliptical galaxies (dEs) is weaker than that of giant elliptical galaxies (Es). In other words, the luminosity profiles in Es follow the de Vaucouleurs' law whereas dEs have exponential luminosity profiles. Athanassoula(1994) describes the one dimensional simulations of the formation of dEs that include the feedback effects from supernovae. The model with no dark matter halo is shown to be much better agreements with the observations than with dark matter halo. However no attempt has yet been made to reproduce much lower heavy element abundances in dEs than in Es. We calculate the chemodynamical evolution of a less massive gas cloud with an SPH+N-body three dimensional simulation code to explore the luminosity profile and chemical abundances in dEs.
The Chromospheres of Carbon Stars
Authors: Luttermoser Donald G.
Published: July 2016

Most oxygen-rich late-type giant stars show evidence for chromospheres in their visual spectra (e.g. Ca ii H & K emission features). Cool (i.e. N-type) non-Mira carbon stars, however, have never been observed to have chromospheric emission in their Ca ii H & K lines. However, faint Mg ii h & k lines were detected in emission in low-dispersion IUE spectra of the brightest cool carbon stars in the early 1980s. May 1984 saw the first (and only) successful high-dispersion IUE spectrum taken of a cool carbon star, TX Psc (N0; C6,2). Armed with this high-dispersion spectrum, as well as low-dispersion IUE and ground-based spectra, Luttermoser et al. (1989) made the first detailed attempt to semiempirically model the chromosphere of a cool carbon star. This model was successful in reproducing the Mg ii lines, but it was not well constrained due to the lack of other observed high-resolution chromospheric profiles for comparison. Modeling carbon star chromospheres can now be addressed more accurately with HST/GHRS high-resolution spectra. New fluoresced emission features have been discovered in the GHRS spectra of carbon stars that are not present in their oxygen-rich counterparts.
Spectral Characteristics of RV Tauri Stars
Authors: Giridhar Sunetra
Published: July 2016

Spectroscopic properties of RV Tau variables are summarized. We report on our detailed spectroscopic investigation of a sample of RV Tau stars covering all three RV Tau subgroups. Though the observed abundance pattern is similar to those of a few post-AGB stars, we find considerable variation in the observed chemical compositions indicating that there is some non-homogeneity among subgroups of RV Tau variables. Possible scenarios of dust-gas separation in the material ejected by the dusty wind are discussed to explain the observed abundances. This mechanism would work better if the star happens to possess a binary companion. Interestingly, one of our sample stars, EP Lyr, shows long-term variations in radial velocity possibly caused by the presence of a companion.
Comparison of Mean Light Curve Parameters of M, S and C Mira and Semi-Regular Variable Stars Using 75 Years of AAVSO Data
Authors: Mennessier Marie-Odile , Boughaleb Hichame , Mattei Janet A.
Published: July 2016

Using 75 years of AAVSO data, mean light curve parameters of a sample of 350 long-period M, S and C Mira and semi-regular variable stars have been investigated. We compare M, S and C Mira and semi-regular stars, present a classification of the light curves of LPVs and give discriminant parameters.
Optical Spectroscopic Monitoring of the Carbon-Rich Post-AGB Star HD 56126: Pulsation and Shock Waves
Authors: Lèbre Agnès , Mauron Nicolas , Gillet Denis , Barthès Dominique
Published: July 2016

A spectroscopic monitoring of the post-AGB star HD 56126 was performed as regularly as possible over a 14-month interval in order to study atmospheric motions that could be associated with shock wave propagation through the stellar atmosphere. Some spectral features are strongly variable on a timescale of a few days. Radial velocity variations are also good evidence for complex atmospheric dynamics, in agreement with the recently found photometric variability. The data point to a pulsating nature for HD 56126, with a main period of 27.3 days.
Nucleating Dust in Carbon-Rich AGB Stars
Authors: Cherchneff I.
Published: July 2016

Chemical models of the inner circumstellar envelope of a typical carbon-rich AGB star are presented. The effect of pulsation-driven shocks on the gas close to the stellar photosphere is considered. The chemistry of dust condensation nuclei formation is described and applied to the gas layers close to the star. We derive formation yields for polycyclic aromatic hydrocarbon (PAH) species and their dimers and discuss their role in the condensation of dust.
Modelling the Spectral Energy Distributions of AGB Stars in the LMC
Authors: Groenewegen M. A. T. , Van Loon J. Th. , Whitelock P. A. , Wood P. R. , Zijlstra A. A.
Published: July 2016

The spectral energy distributions of 16 AGB stars in the LMC are fitted. The 6 known oxygen-rich stars are well fitted with silicate dust. Due to the completely different absorption properties of silicate and carbonaceous dust we argue that of the 10 stars of unknown spectral type, 1 is probably O-rich while the other 9 are probably C-rich.

The Period-Luminosity relation is discussed. Both the O- and C-rich LPVs in this study appear to lie on extensions of P-L relations derived for stars with much shorter periods.
Scattered Light from Envelopes around N-type Stars
Authors: Gustafsson Bengt , Eriksson Kjell , Kiselman Dan , Olander Nils , Olofsson Hans , Schwarz Hugo E.
Published: July 2016

Circumstellar emission in the Na I and K I resonance lines has been detected from three carbon stars using high-resolution spectroscopy. Some properties of the circumstellar envelopes are discussed.
Asymmetries around Luminous Red Variables
Authors: Magalhães Antonio Mário , Nordsieck Kenneth H.
Published: July 2016

Departures from spherical symmetry are known to exist around Luminous Red Variables (LRVs). One of the earliest pieces of evidence came from the discovery that light from these objects is polarized. Additional evidence comes from other techniques and observations of related objects. This talk briefly reviews these data and focuses on the mechanisms that produce polarization in LRVs. Emphasis is given on recent spectropolarimetric monitoring data of selected key objects and what we have learned about the LRV environment from such data.
Nucleosynthesis in Intermediate-Mass Stars
Authors: Lattanzio John C. , Frost Cheryl A. , Cannon Robert C. , Wood Peter R.
Published: July 2016

We discuss nucleosynthesis within 6 M⊙ models with Z = 0.02, 0.008 and 0.004. The emphasis is on the AGB phase of evolution, with particular reference to thermal pulses and Hot Bottom Burning. We find strong CN cycling, with substantial Al production, especially at low metallicities.
Studies of discrete cosmic X-ray sources at M.I.T.: (Invited discourse)
Authors: Clark George W.
Published: July 2016

The following is a brief summary of some of the recent results obtained at M.I.T. which bear on the properties of various discrete X-ray sources, both galactic and extragalactic. Most of the work referred to has been described in publications which contain more complete descriptions.
X-ray flux from discrete sources
Authors: Rao U. R. , Chitnis E. V. , Prakasarao A. S. , Jayanthi U. B.
Published: July 2016

Preliminary results of two rocket flights carrying X-ray payloads conducted from Thumba Equatorial Rocket Launching Station (TERLS), Trivandrum, India, on November 3, 1968, and November 7, 1968, respectively, are presented. The results indicate the first evidence for the existence of low energy X-ray flux in the energy range 2–20 keV from Cen-X2 source since the reported extinction in May, 1967. The energy spectrum and the absolute flux of X-rays from Cen-X2, Sco-X1 and Tau-X1 are presented and compared with other observations.
Properties of individual X-ray sources: (Invited discourse)
Authors: Giacconi Riccardo
Published: July 2016

In the past 2 years the group at American Science & Engineering, Inc., including Gursky, Gorenstein, Kellogg and me, has been engaged in a program of rocket launches aimed at the solution of several outstanding questions in X-ray astronomy. Of four rocket launches, one was almost totally unsuccessful due to a mechanical failure; one was only partially successful due to a failure of the ACS (Attitude Control System); and two performed as planned. Notwithstanding the delays induced by this run of bad luck, a considerable amount of data has been gathered and analyzed. The major results obtained in the flights on October 11, 1966, and on February 2, 1968, have been published. It is my intent today to report on preliminary results of a recent flight (December 5, 1968) and briefly summarize conclusions from previous flights, and comment on a few selected topics to which this experimental program may contribute.
The flux of hard radiation from M87
Authors: Fishman G. J. , Harnden F. R. , Haymes R. C.
Published: July 2016

This paper reports upon an observation of hard X-radiation from the direction of M87. Earlier (Haymes et al., 1968a), we reported the apparent detection of hard radiation from the general direction of Virgo; the experiment discussed here, conducted 16 months later, recorded approximately the same flux from a smaller region of sky that tends to isolate M87 as the most likely candidate for the source.
The possible detection of iron line emission from Sco X-1
Authors: Holt S. S. , Boldt E. A. , Serlemitsos P. J.
Published: July 2016

A rocket-borne measurement carried out on March 3, 1969 has yielded a net (dead-time-corrected) exposure of 104 cm2 sec to the differential spectrum of X-radiation from Sco X-1. The data are fully consistent with radiation from an optically thin thermal source, even to the extent that K-emission from high ionization states of iron appears to be present. Such iron emission is consistent with cosmic abundance at the measured temperature.
OAO observations of Sco X-1
Authors: Bless R. C. , Code A. D. , Houck T. E. , Lillie C. F. , Mcnall J. F.
Published: July 2016

On several occasions in the past month we attempted to observe the bright X-ray source in Scorpio using the OAO 8-inch photometers. These instruments isolate ultraviolet spectral bands by means of interference filters which have half-widths of about 300 Å. Digital and analog outputs both are available and integration times of 8 and 64 sec were used. The length of observing time was about 30 min per orbit. Sky background measurements about 30 arc min away from Sco X-1 source were interspersed with those of the X-ray source, enabling the large contribution of the background to be subtracted. These OAO observations are near the limit of our equipment and are therefore rather noisy. A sudden increase in the intensity of Sco X-1 less than 25% would be undetectable in the OAO photometers. During the observations described here, which were made on April 9, 11h14m UT to 11h43m UT, simultaneous observations were made by Dr. Jerome Kristian with the 200-inch telescope and multichannel photometer. Kristian observed a slow decrease in the flux from Sco X-1 during the first several minutes of simultaneous observations. We also observed such a decrease in intensity but did not see a 10% flare which the 200-inch saw at 5550 Å.
An X-ray pulsar in the Crab Nebula
Authors: Rossi Bruno
Published: July 2016

I wish to report the preliminary results obtained by Hale Bradt, William Mayer and Saul Rappaport of MIT in a recent rocket flight devoted entirely to the observation of the X-ray emission from the Crab Nebula. The flight had been planned originally for April 3. Because of administrative difficulties, it was delayed until April 26.
Predicted X-ray fluxes of stellar coronas
Authors: De Loore C. , De Jager C.
Published: July 2016

Models of convection zones and corresponding mechanical energy fluxes were computed for 90 stellar photospheres with effective temperatures ranging from 2500 K to 41 600 K and acceleration of gravity values between 1 and 105. The most intense X-ray fluxes may be expected from stars with T ≈ 7200 K and logg ≈ 4. Detectable X-ray fluxes could be expected from Procyon, α Cen and β Cas.
Spark-chamber observation of galactic γ-radiation
Authors: Hutchinson G. W. , Pearce A. J. , Ramsden D. , Wills R. D.
Published: July 2016

A γ-Ray telescope incorporating an acoustic spark chamber is included in the payload of the OGO-5 spacecraft. The performance of the instrument, which is sensitive to photons of energy 25 to 100 MeV, is discussed.

Observations are limited to a portion of the sky near Cygnus, but the first month's data indicate a variation of intensity showing a maximum in the direction of the galactic plane. If this plane contains a line source of radiation, its intensity is found to be (9 ± 5) × 10−4 photons cm−2 sec−1 rad−1 above an energy of 40 MeV.
γ-ray astronomy balloon results
Authors: Fichtel C. E. , Kniffen D. A. , Ogelman H. B.
Published: July 2016

The significance of high energy (≳ 30 MeV) γ-Ray astronomy and its relationship to cosmic rays and many of the high energy processes of the universe has been realized for over a decade. Through the last six to eight years, searches for point sources, mostly from balloon experiments, but also Explorers 11 and OSO-3, have been unsuccessful in clearly establishing the existence of any point source. Recently on OSO-3, Clark et al. (1968) have obtained positive evidence for a celestial γ-Ray flux which is anisotropic with a higher intensity in the direction of the galactic center region. In this talk, I wish to summarize our balloon results relating to both of these questions and indicate what we hope to accomplish with our new large γ-Ray detector over the coming months.
Intensity and galactic absorption of soft background X-rays
Authors: Bunner A. N. , Coleman P. L. , Kraushaar W. L. , Mccammon D. , Palmieri T. M. , Shilepsky A. , Ulmer M.
Published: July 2016

Measurements of the soft X-ray background intensity show that the intensity is largest in that part of the sky where the columnar atomic hydrogen density is smallest. In the direction bII =-60°, lII = 10° the intensity is found to be 195 ± 20 photons cm−2 sec−1 ster−1 keV−1 near 0.26 keV and 20 ± 3 photons cm−1 sec−1 ster−1 keV−1 near 0.9 keV. The intensity in the galactic plane is unexpectedly large.
Origin of the cosmic X-ray background:(Invited discourse)
Authors: Setti G. , Rees M. J.
Published: July 2016

In this paper we review the theories which have been proposed to account for the extra-galactic X-ray background. Although there is still no detailed theory, one may devise reasonable models which account in a natural way both for the intensity and the spectral shape over the whole energy band, provided that cosmological evolutionary effects are included. A model based on Compton scattering of cosmic black body photons by relativistic electrons in radio sources at large redshifts (z≳ 4) seems to give the most satisfactory explanation. However, the data are not yet good enough to discriminate against alternative models.

A discussion of the recent observations in the soft X-ray region (< 1 keV), and their relevance to the physics of interstellar and intergalactic gas, is given. The available data are somewhat confusing, but it seems that this part of the spectrum may still be consistent with a simple extrapolation of the non-thermal spectrum at higher energies, though various workers have claimed the detection of a new component probably due to hot intergalactic gas. If this interpretation is correct one may deduce interesting conclusions about the state of ionization and composition of the intergalactic gas, because of the importance of the absorption effects in this energy band.

Also it appears that the Galaxy is more transparent than one would deduce from 21-cm observations. However, due to the lack of observational data, no firm conclusions can be reached.
Cosmic background X-rays produced by intergalactic innerbremsstrahlung
Authors: Hayakawa Satio
Published: July 2016

It has been found difficult to explain both the absolute intensity and energy spectrum of the background component of cosmic X-rays in terms of a superposition of X-ray sources in distant galaxies [1] and of the inverse Compton collisions of metagalactic electrons with microwave photons [2]. Although the absolute intensity could be obtained by choosing suitable values of parameters which are not well known as yet, the gradual bending of the X-ray spectrum around 30 keV provides a critical test of theories. In this respect innerbremsstrahlung of intergalactic protons colliding with electrons is a candidate of background X-rays, since the X-ray spectrum is closely related to the proton spectrum and the latter usually bends in the non-relativistic region.
Possible initial evidence of extragalactic cosmic-ray protons and the age of extragalactic cosmic-ray sources
Authors: Stecker F. W.
Published: July 2016

We have compared the recent cosmic background γ-ray observations with spectra predicted by various possible cosmic interactions. We find that the observed isotropic γ-rays with energies > 1 MeV can best be explained as being due to the decay of π°-mesons produced in extra-galactic cosmic-ray collisions. This interpretation indicates that extragalactic cosmic-ray sources were more active (or prevalent) in the past and started to form at a redshift of ∼ 100 corresponding to 107–108 years after the ‘big-bang’.

For a present extragalactic gas density of 10−7–10−5 cm−3, the present extragalactic cosmic-ray flux is inferred to be 10−5–10−3 the galactic value.
Diffuse cosmic X-rays from non-thermal intergalactic bremsstrahlung
Authors: Silk Joseph
Published: July 2016

The diffuse X-ray background between 1 keV and 1 MeV is interpreted as non-thermal bremsstrahlung in the intergalactic medium. The observed break in the X-ray spectrum at ∼40 keV yields the heat input to the intergalactic medium, the break being produced by ionization losses of sub-cosmic rays. Proton bremsstrahlung is found not to yield as satisfactory an agreement with observations as electron bremsstrahlung: excessive heating tends to occur. Two alternative models of cosmic ray injection are discussed, one involving continuous injection by evolving sources out to a redshift of about 3, and the other model involving injection by a burst of cosmic rays at a redshift of order 10. The energy density of intergalactic electrons required to produce the observed X-rays is ∼ 10−4 eV/cm3. Assuming a high density (∼ 10−5 cm−3) intergalactic medium, the energy requirement for cosmic ray injection by normal galaxies is ∼ 1058–59ergs/galaxy in sub-cosmic rays. The temperature evolution of the intergalactic medium is discussed, and we find that a similar energy input is also required to explain the observed high degree of ionization (if 3C9 is at a cosmological distance).
X-ray emission from the solar wind
Authors: Boldt E. , Klimas A. , Sandri G.
Published: July 2016

Recent developments have made it possible to detect cosmic X-rays with energies as low as several hundred eV. Several measurements of the diffuse X-radiation in this range have been reported (Baxter et al., 1969; Bowyer et al., 1968; Henry et al., 1968). In this note we investigate the possibility that these observers have detected X-radiation emitted by the solar wind. We conclude that they probably have not. However, we also find that bremsstrahlung may be detectable from a region of the sky near the sun. If this measurement is possible, it would represent an important method for determining some characteristics of the solar wind away from the ecliptic plane of the solar system. Even though the mean free path for electron collisions is large compared with the astronomical unit, the collision frequency, electron density, and energy released per encounter are sufficient to yield detectable soft X-radiation for lines of sight close to the sun. We have estimated the expected X-ray intensity in the vicinity of the earth on the basis of two models of the solar wind flow pattern; in the first, the flow is radial in all directions away from the sun, and in the second, the flow is confined to a disc of uniform thickness near the ecliptic. In both cases, we neglect temperature gradients for the electrons and compute the total flux received from interplanetary plasma along the line of sight. Most of the received intensity comes from the segment of the line of sight which is nearest the sun. The results are insensitive with respect to the position of the boundary of the solar cavity. Accordingly, we neglect the boundary and consider an infinitely large solar cavity.
Mechanism for X-ray production in extars
Authors: Manley O. P. , Olbert S.
Published: July 2016

This presentation attempts to describe in very qualitative terms a theory of production of high energy radiation (soft and hard X-rays) in magnetoactive plasmas of astrophysical interest. Special emphasis has been placed on the application of our model to extars and in particular to Sco X-1. More rigorous arguments may be found elsewhere [1] and the interested reader is urged to consult that reference for more details.
Collective Plasma Phenomena and their Role in the Dynamics of the Interstellar Medium
Authors: Kadomtsev B. B. , Tsytovich V. N.
Published: July 2016

The First Symposium on cosmical gas dynamics clearly demonstrated that magnetic fields play an essential role in the dynamics of the interstellar matter. The Symposium emphasized that the behavior of interstellar gas should be described not by traditional gas dynamics but with the help of magneto-gas dynamics. As we now realize this was only the first step, since in plasmas a very broad range of phenomena can occur which are coupled not with large-scale magneto-gas dynamic motions but rather with more subtle collective plasma motions. To describe properly the dynamics of an ensemble of charged particles we should use not only average characteristics such as density, pressure and mean velocity, but also more detailed features of the particle distribution function.
Supernovae and the Interstellar Medium
Authors: Woltjer L.
Published: July 2016

The nature of the supernova event is still poorly understood. A variety of models has been proposed and the interpretation of the observations remains ambiguous. About all that is certain is that in the supernova event much of the matter is ejected at speeds of typically 10 000 km sec−1 and that about 1049 erg of visible light is emitted. The amount of matter ejected and the bolometric correction to be applied to the optical radiation are very uncertain. The discovery of a pulsar in two supernova remnants (Crab Nebula and Vela X) suggests that frequently a neutron star or other condensed object results following the outburst.
Discussion following the Reports by Salpeter and Woltjer
Authors: Davis L.
Published: July 2016

During the second half of this Discussion van de Hulst commented on the overall flow of energy in the interstellar medium. That part of the Discussion has been transferred to the Final Discussion (p. 362). The rest has been rearranged into the form presented here.
Interstellar Grains and Spiral Structure
Authors: Mayo Greenberg J.
Published: July 2016

The problem of the interstellar grains is in many ways still unsettled. The theories of the formation, growth, and destruction of the grains have undergone a number of modifications because of the very significant increase in our understanding of the dynamical processes in our Galaxy. I will emphasize here how the density wave theory of the origin of the spiral structure may lead to a new broad concept in dust formation and its generic relationship with star formation. The basic physical processes are not changed but rather the framework in which we consider them.
Appendix. Molecular Hydrogen in the Interstellar Gas
Authors: Salpeter E. E.
Published: July 2016

There are two levels of interest in the abundance of molecular hydrogen in the interstellar gas. (i) Even a low abundance can enhance the cooling rate at a few hundred K. (ii) Densities comparable with or larger than those of atomic hydrogen could affect the dynamics in the galactic disk, if widespread, or at least affect star formation, if restricted to isolated large clouds.
Spiral Arm Patches in Sc and SBc Galaxies
Authors: Pronik I. , Chuvaev K.
Published: July 2016

Multicolor observations of galaxies are being carried out at the prime focus of the 2.6-m Schajn telescope using an image intensifier and 6–9 color filters. The effective wavelengths of the bandpasses used are approximately 3600, 3730, 4400, 4680, 5090, 5280, 6090, 6600 and 7400 Å. The filters for 3730, 5090 and 6600 Å are centered on emission lines.
On the Mass-to-Light Ratios for Double Galaxies
Authors: Dickens R. J. , Peach J. V.
Published: July 2016

Statistical mass-to-light ratios are found for spiral and irregular galaxies, and E and S0 galaxies, using 57 multiple systems including 43 pairs. The results are consistent with those of the earlier study by Page. Preliminary conclusions point out the great uncertainties in such mass-to-light ratios due to inaccurate magnitudes and relative radial velocities. The derived masses are relatively insensitive to the choice of the distribution function of projected separations.
The Absorption-Line QSOs
Authors: Lynds C. R.
Published: July 2016

Many features of the distribution of emission and absorption line redshifts of QSO spectra and of the distribution of the differences between emission and absorption line redshifts may be due to observational selection. However, it seems significant that all six of the absorption line objects of largest redshift have multiple absorption systems. Observations seem to favor more strongly the hypothesis that the multiple absorption line systems are due to clouds associated with the QSO rather than in the intervening space. The multiple absorption line systems of the QSOs PKS 0237–23, Ton 1530 and 4C 05.34 are discussed. The persistence of the Lyman-α absorption feature and identification of multiple-absorption line systems strongly suggests that unidentified absorption lines shortward of the Lyman-α emission also arise from the Lyman-α transition.
Spectral Energy Distributions of Nuclei of Peculiar Galaxies
Authors: Oke J. B.
Published: July 2016

Studies of galaxies during the last seventy years have turned up a large array of peculiar objects. Vigorous work on these was rare until a few years ago when quasars were discovered. It then became clear that an understanding of quasars might come from an understanding of the less-extreme peculiar galaxies. It was further clear that even the physical processes occurring in nuclei of peculiar galaxies were far from easy to understand.
The Relation Between the Optical and Centrimetric Polarized Emission in BL Lac and Other QSOs
Authors: Kinman T. D.
Published: July 2016

The polarized optical and centimetric fluxes from BL Lac have their maxima at position angles which are roughly orthogonal. A similar tendency is found in other QSOs. If these fluxes are of synchrotron radiation then the magnetic fields associated with the optical and centimetric radiation are likely to be highly inclined with respect to each other. The implications of this are discussed.
Can the Optical Fluctuations of 3C 273 be Random?
Authors: Terrell James , Olsen Kenneth H.
Published: July 2016

The fluctuations in optical brightness of the quasi-stellar object 3C 273 have been investigated to determine whether the suggested periodicity of ∼ 10 yr is supported by the observational data extending over 80 yr. New methods of obtaining information from the power spectrum have been used, and moments and trends have also been investigated. No statistically-supportable evidence has been found in the power spectrum for such a non-random variation. The moments and trends are consistent with random fluctuations. If the observed fluctuations are of shot-noise character, due to random outbursts of light, the individual pulses must occur at the rate of 15 ± 5 per year and have an average effective length of 3.2 ± 1 yr. These conclusions were verified by computer-generation and power-spectrum analysis of such random signals. Thus any periodic variation in the brightness of 3C 273, if present, is completely obscured by random fluctuations. The power spectrum, moments, and trend are all consistent with random but long-lasting outbursts of light.
Radio Emission from Compact Objects
Authors: Kellermann K. I.
Published: July 2016

Compact radio stars are associated with both galaxies and quasi-stellar objects; and there appears to be no way to distinguish between the radio galaxies and the quasi-stellar radio sources from their radio properties alone.

The compact radio sources are opaque at the longer radio wavelengths and have spectra that are either peaked or complex. They have a complex brightness distribution and often contain components less than 0.001 arc sec in size.

Many of the compact sources show large intensity variations and in NGC 1275 there is evidence for a change in the angular size during one year.
Attempts to Detect Neutral Hydrogen in Compact Objects
Authors: Dent William A.
Published: July 2016

An attempt was made to detect the redshifted Hi line in absorption in the quasi-stellar sources 3C 273 and 1510 - 08 and in the N-galaxies 3C 120 and 3C 371. The Seyfert galaxies NGC 1068 and NGC 1275 were also searched for Hi in absorption as well as in emission. Although no lines were detected, it was possible to place upper limits on the column density of Hi in all these objects, as well as upper limits on the mass of Hi in the Seyfert galaxies observed.
The Velocity-Distance Relation and the Hubble Constant for Nearby Groups of Galaxies
Authors: de Vaucouleurs G.
Published: July 2016

The distances of about 100 nearby groups, clouds and clusters of galaxies (δ < 52 Mpc) have been derived from the apparent magnitudes and diameters of the 3 to 5 major members. The linearity of the distance scale was verified for δ < 40 Mpc by comparison with luminosity classifications and diameters of ring structures. The velocity-distance relation of these groups is apparently non-linear for δ < 30 Mpc. The velocity/distance ratio increases from H ≃ 50 to 150 km s−1 Mpc−1 when δ increases from δ ≃ 5 to δ ≃ 25 Mpc. Such local departures from linearity are predicted in condensed regions of an inhomogeneous ‘big bang’ hierarchical model obeying the universal density-radius relation. The galactic apex varies with the apparent magnitude of galaxies used for reference in a manner generally consistent with a model of the Local Supercluster in differential rotation and expansion. The best-fit rotation-expansion constants are ω1R1 = 400 ± 50 km s−1, ε1R1 = 1250 ± 50 km s−1, ż = −250 ± 50 km s−1. The velocity-magnitude relation corrected for solar motion is linear with slope 0.2 in 9 < m < 14, confirming that apart from local departures reflecting the supercluster kinematics the underlying Hubble flow is linear and isotropic. If the distance modulus of the Virgo Cluster is (m - M)0 = 30.5 ± 0.2 the Hubble constant derived from the survey of groups is H0 = (100 ± 10) km s−1 Mpc−1.
General Review of Cosmological Theories
Authors: Hoyle F.
Published: July 2016

Quantum effects in the early stages of some cosmological models are considered. Interactions between particles can be expressed in terms of the Dirac delta function, and the implications of the existence of both positive and negative frequencies in the Fourier expansion of this function are discussed.