bluuebunny/crossref_metadata_2025 huggingface dataset:
Note on the Multiplicity of dMe Stars
Authors: Lippincott Sarah Lee
Published: July 2016

There is much current interest in flare stars of the type dMe with particular concern as to their ages and mechanism responsible for flaring. Some fifty Me stars are on the Sproul Astrometric program. They have been discussed as flare stars or potential flare stars (Lippincott 1971). At least half are known to be members of binary or multiple systems. All are on the Sproul program to obtain accurate parallaxes and to analyze the long interval observations for non-linear proper motions indicating unseen companions. The astrometric results are discussed and statistics presented for the multiplicity among these nearby systems.
Kappa Pegasi—A Quadruple System of Possible Low Total Mass
Authors: Beardsley W. R. , King M. W.
Published: July 2016

Analyses of early Lick Obs. spectra and recent high dispersion Kitt Peak National Obs. spectra indicate that k Peg is a quadruple system having all four spectra visible under favorable conditions. Preliminary spectroscopic orbital elements are presented for the AB system, and for Bb. The Bab system has been found to be the previously known 5.97-day spectroscopic system. The total mass is found to be between 2 and 3 solar masses only. Thus the brightest of the four stars Ba(F5IV) —or possibly all four of the stars—must have an abnormally small mass for its luminosity. This system appears to be similar to several others which have apparent overluminous components. Such systems are of interest in regard to stellar evolution.
Recherche Sur L’existence Possible D’un Compagnon Astrometrique Dans Le Couple Visuel Ads 9476 — Aitken 14
Authors: Mourão R. R. De Freitas
Published: July 2016

Observations made during the 70 last years of the visual binary star Aitken 14 reveal systematic deviations in its motion, suggesting the existence of an astrometric companion.
Three Dimensional Stability of A Rectilinear Periodic Solution of the Three-Body Problem, for all Values of the Masses
Authors: Hénon M.
Published: July 2016

We consider a rectilinear periodic solution in which the central body collides alternately with each of the two other bodies. This solution is found to exist for all values of the three masses. Its stability with respect to three-dimensional perturbations is computed. Domains of stability and instability are delimited in a triangular mass diagram. Large domains of stability are found. This reinforces the conclusion that triple stars may have an “interplay” type of motion.
A New Trapezium System Associated with A Compact H II Region
Authors: Sharpless S. , Pipher J.L. , Savedoff M.P.
Published: July 2016

The region S106 = G 76.4 — 0.6 has been photographed in the 8000Å region with the Carnegie image converter attached to the 0.6m telescope at the Mees Observatory. This was done in connection with a larger program designed to assemble radio, infrared, and optical data on compact HII regions.

S106 has angular dimensions of 1’ by 3’ and has relatively high surface brightness. Its kinematic distance based on H109a observations (Reinfenstein, et al. 1970) is 2.3 kpc ± 3.0.

Several bright maxima are observed within the nebula at wavelengths of 12.6/x and 2.7 GHz. These are believed to be the result of thermal radiation from hot dust and free-free emission from ionized gas, respectively. At the nominal distance their linear sizes are of the order of 0.2 pc and they may be similar to the “cocoon” type objects discussed by various authors.
Multiple Stars as A Result of the Dynamical Evolution of Small Stellar Systems
Authors: Hayli Avram
Published: July 2016

Some double, triple or quadruple stars could be the final stage of the dynamical evolution of small galactic clusters. This evolution is nothing but a redistribution of the kinetic and mutual potential energy of the stars. It has two main effects: the escape of stars from the cluster and the formation of tight subsystems.
Mutiple Star Formation from N-Body System Decay
Authors: Harrington R. S.
Published: July 2016

The dynamical decays of random, unstable, negative-energy, n-body systems have been followed numerically, to investigate the statistics of stable decay products. From initial quadruple systems, about 20% of the products were stable triples while 30% resulted from initial quintuple systems. These numbers are consistent with the observed ratio of triples to binaries, especially for the higher-multiplicity initial systems.
A Bibliography of Astronomical Catalogues and the Organization of Stellar Designations
Authors: Collins M.J.
Published: July 2016

A comprehensive bibliography of astronomical catalogues for the period 1951-75 inclusive containing over 2000 items and including an index of designations has shown that there is an urgent need to control the use of designation notation. It is suggested that a small data base, similar to the one created for this bibliography could serve as a useful guide to the assignment and subsequent citation of catalogued objects. This in turn would help those compiling inverted files of stellar objects such as the Catalog of Stellar Identifications.
The Use of SI Units in Astronomy
Authors: Wilkins G. A.
Published: July 2016

The principal features of the International System of Units (SI) are briefly described and the advantages of its wider adoption in astronomy are discussed. The need for the continued use of a system of astronomical units for some purposes is recognised.
Data Distribution
Authors: Hauck B.
Published: July 2016

Before answering, or trying to answer, the question “how to distribute astronomical and astrophysical data”, it is necessary to reply briefly to the question “why distribute these data?” This question is not so trivial as it first appears and it even hides the basic problem.

Data acquisition in itself is a single or manifold technique, often very delicate, constituting in itself a whole field of research. The interpretation of data follows it and will not necessarily be made by the same people. Very often only one possible aspect will be examined. It is consequently absolutely necessary that the data should be disseminated as widely as possible in order that they are used to the utmost. If it is necessary to assure the dissemination of data, it is no less necessary to ascertain their conservation. I shall give here only one example: the observations which have permitted to obtain the light curve of the quasar 3C273.
A Master List of Non-Stellar Objects
Authors: DIXON ROBERT S.
Published: July 2016

It has been nearly 70 years since Dreyer completed his famous NGC and IC compendia of all the 13,000 non-stellar objects known in his time. Since then, the number of these objects known has increased by an order of magnitude, but this knowledge is scattered throughout the astronomical literature in such a way that it 1s nearly inaccessible from a practical standpoint to any individual.

The present work is an amalgamation of all known catalogs of non-stellar objects, in a uniform, easily readable form. It is Intended not only for astronomers, but also for scientists and engineers in other fields who have need for rapid access to this basic reference data. The types of objects included are galaxies (including both normal and all specialized types such as interacting, peculiar, dwarf, Seyfert, etc.), clusters of galaxies, nebulae of all kinds (planetary, reflection, emission, absorption, etc.), blue objects, groups of stars (open and globular clusters, associations, rings, chains, etc.), quasi-stellar objects, super-novae and others. The Information given for each object includes name, 1950.0 position, angular diameter in arcseconds, magnitude, description, and original reference. A portion of the work is shown in Figure 1. Approximately 185,000 listings appear in the full master 11st.
Stellar Data and Computing Facilities at the Pulkovo Observatory
Authors: Polojentsev D.D.
Published: July 2016

The Pulkovo Observatory computing laboratory began its activities in 1956. Originally it was equipped with card-punched machines. An essential work of processing astronomical data was carried out with the help of these machines ([1] and other).

With the development of the computing techniques in the USSR, the laboratory has been equipped with more modern computing devices. At present the Laboratory disposes of the third generation computer ES-1020 of the Ryad type, as well as the second generation computers Minsk-22 and Nairi-K.
Report of Discussions
Authors: Wilkins G. A.
Published: July 2016

This report summarises the discussions on the topics of the five invited papers, and on other matters of general interest that were raised by the contributed papers. The principal headings are: standards for datafiles; the influence of acquisition and processing techniques; the critical evaluation of data; the designation of astronomical objects; the distribution of data; survey of facilities; the future role of data centres; and recommendations on IAU activities.
Energy Balance and Structure Of Active Regions
Authors: Orrall Frank Q. , Kopp Roger A.
Published: July 2016

With the advent of radio and space astronomy it became necessary to extend the definition of a center of activity or active region (AR) originally proposed by L. d’Azambuja. At IAU Symposium 35, K.O. Klepenheuer (1968) defined an AR as “The totality of all observable phenomena preceding, accompanying and following the birth of sunspots, including radio-, X-, EUV-, and particle emission.” The recognition that there are other short-lived bipolar features with a distribution similar to that of active regions (ephemeral active regions) by Harveyet al. (1975) and their identification with coronal bright points by Golub et al. (1975) suggests that the definition will have to be extended further. Active regions manifest themselves in the photosphere as sunspots and faculae; in the chromosphere as the plage and its structures; in the corona as a coronal enhancement with a complex, often loop-like internal structure. (The termenhancementwas Introduced by Billings. The original termpermanent coronal condensation, introduced by Waldemeler, only referred to the very bright enhancements and was, moreover, often confused with hissporadic coronal condensations, a flareassodated phenomena. The termcoronal active regionhas, recently also been used for the coronal extension of the AR.) In keeping with the aims of this symposium the stress of this review will be on the chromosphere and corona. Active regions are especially Important as the site of most flare-associated phenomena. Here we shall be concerned with flares only as they affect the overall energy balance. Our concern is with the “quiet” active regions that cause the slowly varying components of solar activity and provide the ambiance within which solar flares occur.
Systematic errors in galaxy redshifts
Authors: Lewis B.M.
Published: July 2016

Environ 410 galaxies possèdent une estimation de leur vitesse de récession déduite à la fois des spectres optiques et des observations de la raie 21cm. La comparaison de ces observations est un moyen sensible de détecter les erreurs systématiques. A partir de l’énorme quantité de données expérimentales dont on dispose à ce jour, ce papier a pour but de vérifier le travail antérieur de Roberts, sur l’effet de décalage vers le rouge, et de tester les erreurs d’échelle et les erreurs corrélées au type, à la couleur, à l’inclinaison ou au degré de concentration central.
The 3 C 303 system
Authors: Kronberg Philipp P.
Published: July 2016

La combinaison des cartes radio en synthèse d’ouverture à haute résolution de 3C 303 et de plaques optiques montre que les principales composantes de la radio source peuvent être identifiées respectivement avec une galaxie de magnitude 17 et un objet de magnitude 22 possédant un excès d’U-V, la coincidence se faisant à mieux d’une seconde près. L’objet de magnitude 22 a un compagnon plus brillant de mv~20 et de décalage vers le rouge 1. 57. Les principales composantes radio sont seulement séparées de 17”. Ce système montre le meilleur cas (non prouvé à 100%) d’une association physique d’objets possédant des décalages vers le rouge différents.
Distances of nearby Groups and Clusters, and the Local Value of the Hubble Ratio
Authors: Vaucouleurs G. de
Published: July 2016

The correct approach to build up the extragalactic distance scale is to use all available primary (novae, cepheids, RR Lyrae) and secondary indicators (brightest stars, globular clusters, largest HII rings) to calibrate without arbitrary extrapolation all reliable tertiary indicators (magnitudes and diameters of galaxies), precisely corrected for all known effects of type, luminosity class, orientation, internal and galactic extinction and redshift. Such data are now available for over 1000 galaxies in the Second Reference Catalogue.

Revised distances to members of the Local Group from primary indicators and new estimates of distances to the nearest groups from primary and secondary indicators are used to calibrate the tertiary indicators via a new, composite luminosity index.

The distances derived from globular clusters for 3 galaxy clusters dominated by ellipticals (Vir I, For I, Hya I) with mean corrected velocities 1000 ≤ Vo ≤ 3650 km s-1 give a mean Hubble ratio  = 88 (1 ± 0.15) km s-1 Mpc-1. This value rests entirely on the calibration of the globular clusters luminosity function in the Galaxy as a gaussian of dispersion σ = 1.1 mag. and mean (⊕) = -6.55, with <(B-V)o > = 0.75, based on the adopted RR Lyrae zero point  (RR) = + 0.86 ± 0.15.

The distances derived from tertiary indicators to 19 field spirals and 28 nearby groups dominated by spirals with corrected velocities Vo < 1800 km s-1 give  = 82 (1 ± 0.15) km s-1 Mpc-1. This value rests on the relations between luminosity index and fully corrected absolute magnitudes or linear diameters of galaxies derived without extrapolation and calibrated in ~20 nearby galaxies by seven secondary indicators. The zero points were derived from the 3 primary indicators, including 15 galactic novae with  = -5.5 ± 0.15, and 13 cepheids in 8 galactic clusters with  (logPo = 0.8) = -2.92 ± 0.15 (for an adopted Hyades modulus of 3.16 ± 0.05).

The low values of Ho≃50 to 55 can be explained by an accumulation of complex systematic errors arising from a multiplicity of sources. These errors, all but one acting in the same sense, have been identified and evaluated; a full report will appear elsewhere.
Mass-to-light ratios of binary galaxies
Authors: Turner Edwin L.
Published: July 2016

Le rapport entre le rapport masse-luminosité pour les galaxies de type jeune et celui pour les galaxies de type tardif est égal à 2.0±0.5. La distribution des séparations spatiales r entre paires de galaxies est approximativement une loi en r-1/2. Il existe toute une variété de modèles dynamiques pour les systèmes de galaxies binaires. Cependant tous impliquent des rapports masse-luminosité pour les galaxies spirales largement supérieurs aux valeurs conventionnelles (courbe de rotation). L’interprétation la plus plausible des données sur les galaxies binaires implique que les galaxies spirales possèdent des halos contenant ~10 fois la masse du disque et ont des rapports masse totale -luminosité ~65 M⊙/L⊙ (Ho = 50 km s-1 Mpc-1).
Super-light motion in radio sources and its implications for the distance scale problem
Authors: Kellermann K. I. , Shaffer D. B.
Published: July 2016

Plusieurs radio sources comme 3C 345 et 3C 120 sont constituées de plusieurs composantes qui semblent se séparer avec une vitesse apparente de 5 ou 10 fois la vitesse de la lumière. Ce phénomène peut être interprété comme une preuve contre l’interprétation cosmologique du décalage vers le rouge. D’autres explications tirées de la physique et de la cosmologie conventionnelles sont abordées mais elles ne sont pas tout à fait satisfaisantes.
High redshift 21-cm lines
Authors: Roberts Morton S.
Published: July 2016

On résume l’ensemble des décalages vers le rouge dont on dispose à partir de la raie 21 cm. La plus grande valeur obtenue pour la raie HI en émission est z =0.0369, et z = 0.692 en absorption. Il y a un excellent accord avec les décalages vers le rouge mesurés optiquement (lorsqu’ils existent). Les deux techniques donnent la même valeur (en moyenne), et montrent que les décalages vers le rouge sont indépendants des longueurs d’onde dans un intervalle de longueur d’onde de ~5x105 et un intervalle en z de -0.0012 à +0.692. C’est une condition nécessaire, mais non suffisante pour interpréter les décalages vers le rouge par l’effet Doppler. Des limites sont fixées pour la variation possible de certaines constantes atomiques fondamentales en fonction de z, et si z est une mesure de la loi d’expansion de Hubble, en fonction du temps, jusqu’à des temps au moins égaux à 35% de l’âge de l’Univers.
Radio-quiet QSO’s in the region of Hercules cluster of galaxies
Authors: Hoag A. A. , Burbidge E. M. , Smith Harding E.
Published: July 2016

Nous présentons le début d’une recherche de QSO, calmes en radio, dans la région de l’amas d’Hercule.
Is there a Low Surface Brightness Universe?
Authors: Disney M.J.
Published: July 2016

I have been asked to review some of the arguments for and against the existence of a significant population of Hidden Galaxies, and to concentrate on the distant past and the possible future of this subject, leaving more recent observations to others. In particular I ask how should we correct for selection effects and how are we to resolve contradictory evidence?
Selection Effects at 21cm
Authors: Briggs F.H.
Published: July 2016

Surveys in the 21cm line of neutral hydrogen are testing the completeness of the catalogs of nearby galaxies. The remarkable observational fact is that the potential wells that confine gas to sufficient density that it can remain neutral in the face of ionizing radiation also provide sites for star formation, so that there are no known cases of neutral intergalactic clouds without associated star light.
The radial extent of the Fornax cluster Low Surface Brightness galaxy population
Authors: Davies J.I. , Kambas A. , Morshidi-Esslinger Z. , Smith R.
Published: July 2016

In this paper we compare the radial distribution of Fornax cluster galaxies selected at different surface brightness values. The bright galaxy (RC3) sample surface brightness distribution peaks at a μBx = 21.5, the Low Surface Brightness (LSB) sample at μBx = 23.7 and the very Low Surface Brigthness (VLSB) sample at μBx = 25.7. The bright galaxy surface density decreases with an exponential scale length of α = 0.5°, the LSB galaxies with α = 1.3° and the VLSB galaxies with α = 2.0°. Thus the LSB and VLSB populations define a mass scale size some 2.5 and 4 times larger than the bright galaxies respectively. The contribution of the VLSB population to the total cluster luminosity is comparible to that of the brighter galaxies. If their mass to light ratios are significantly larger than than that of the bright galaxies they will dominate the mass and possibly account for the missing mass in clusters.
The Discovery of Red Low Surface Brightness Galaxies
Authors: O’Neil Karen
Published: July 2016

We have performed a digital survey for Low Surface Brightness (LSB) galaxies in the spiral-rich Cancer and Pegasus clusters as well as the low density regime defined by the Great Wall. A total of 127 galaxies were found with μB(0) > 22.0 mag arcsec‒2, 119 of which were previously unidentified.

Consistent with other surveys, we find a significant number of galaxies with μB(0) > 23.0 mag arcsec‒2 which suggests that the space density of galaxies as a function of μB(0) is not strongly peaked. To more rigorously test this hypothesis we compare the actual surface brightness distribution from our survey with that from two different types of Monte-Carlo based sky images and show that it is not possible to distinguish between the flat distribution and the Gaussian one as the proper description of the underlying surface brightness distribution for this survey beyond 24.0 mag arcsec−2.

The colors of the survey galaxies range continuously from very blue to the first discovery of very red LSB galaxies. It also includes a group of old galaxies which show evidence for recent star formation. This continuous range of colors clearly shows that LSB galaxies at the present epoch define a wide range of evolutionary states.
The Structure of the Superthin Spiral Galaxy UGC7321
Authors: Matthews L.D. , Gallagher J.S. , van Driel W.
Published: July 2016

UGC 7321 is an edge-on low surface brightness (LSB) spiral galaxy with a number of extraordinary properties. Its vertical scale height (~70 pc) is one of the smallest ever measured for a galaxy disk. Its disk also exhibits strong vertical and radial color gradients. UGC 7321 appears to be an extremely unevolved galaxy in both a dynamical and in a star-formation sense.
VLA HI Imaging of the Low Surface Brightness Dwarf Galaxy DDO 47
Authors: Walter F. , Brinks E.
Published: July 2016

We present high resolution VLA-observations of the nearby Low Surface Brightness Dwarf Galaxy DDO 47. This object shows many hole-like structures in its neutral interstellar medium. The majority of the detected H I-shells are found to be expanding. Their origin is therefore believed to be due to stellar winds of the most massive stars and their subsequent supernova (SN type II) explosions within regions of recent star formation (SF). Current SF in DDO 47 is predominantly present on the rims of the HI-shells suggesting propagating SF. At a projected distance of 20 kpc (adopting a distance to DDO 47 of 4 Mpc), a companion galaxy was detected at almost the same systemic velocity (DDO 47 B). A search for an optical identification suggests that CGCG 087-033 is the optical counterpart of the companion. A preliminary dynamical analysis based on DDO 47’s rotation curve yields that it is dark matter dominated (about 80% of its dynamical mass is in some non-visible form). A simple mass model suggests that DDO 47 is one of the ‘thickest’ dwarf galaxies studied so far.
Results from the Dwingeloo Obscured Galaxies Survey
Authors: Rivers A.J. , Henning P.A. , Kraan-Korteweg R.C. , Lahav O. , Burton W.B.
Published: July 2016

Approximately 25% of the extragalactic sky is obscured by dust in our own Milky Way galaxy. Diligent optical and infrared surveys are successful at detecting galaxies through moderate Galactic dust extinction, but in the most heavily obscured regions near the Galactic plane, only radio surveys are effective.

The Dwingeloo Obscured Galaxies Survey (DOGS) is a 21-cm blind survey out to 4000 km s−1 in the northern “Zone of Avoidance” (ZOA). The DOGS project is designed to reveal hidden dynamically important nearby galaxies and to help “fill in the blanks” in the local large scale structure.
Optical Diffuse Light in Clusters of Galaxies
Authors: Vílchez-Gímez Rosendo
Published: July 2016

I present here a review of the observed characteristics of the optical diffuse light in clusters, the possible sources of this light and some of the theories that try to explain the existence of big envelopes around the brightest cluster galaxies.
Chemical Constraints, Baryonic Mass and the Chemical Evolution of Low Surface Brightness Galaxies
Authors: Edmunds M.G.
Published: July 2016

A brief review of primordial helium and deuterium abundances suggests a baryonic mass density of ΩB ≈ 0.04 – 0.045 (for Ho = 70). This mass may be dominated by intergalactic gas in clusters and groups of galaxies. The observed low chemical abundances in evolved dwarf galaxies might suggest that outflow was the origin for such gas, and we make general suggestions for the interpretation of the data from the next generation of X-ray spectroscopic satellites. The effects of both outflow and inflow on the chemical evolution of galaxies is discussed, particularly in the context of low surface brightness galaxies, and we comment on their dust content.
Kinematic analysis of Sculptor Group galaxies
Authors: Schoenmakers R. H. M.
Published: July 2016

An analysis of the kinematics of the five major spiral galaxies in the Sculptor Group is presented. These galaxies are analyzed using the method of harmonic expansion of the velocity field as described in Schoenmakers, Franx and de Zeeuw (1997). Three different types of kinematic distortions were found: warps, lopsidedness and elongation. All the Sculptor galaxies show kinematic lopsidedness, two show signs of global elongation and two are kinematically warped. The detected kinematic distortions are well in excess of those typically found for isolated galaxies.
Dynamics of Galaxies in Compact Groups I
Authors: de Oliveira C. Mendes , Amram P.
Published: July 2016

We describe a long-term program based on Fabry-Perot Hα velocity field data of compact groups taken at the ESO and the CFH 3.6m telescopes. The main goals of our project are: 1) determine the evolutionary stages of the studied groups, 2) search for tidal dwarf galaxy candidates in interacting systems and 3) in combination with photometry available in the literature, determine the Tully-Fisher relation for the group galaxies. In this paper we summarize all the Hα Fabry-Perot data we have obtained to date and present a preliminary discussion of point 1).

The sample of 18 systems (with 64 galaxies) studied here contain groups at a variety of dynamical stages: from a false group that is in fact one single irregular galaxy with several star-forming blobs (e.g. HCG 18) to a group whose members are strongly interacting and possibly forming tidal dwarf galaxies (e.g. HCG 92) to a group in the final process of merging (e.g. HCG 31). A companion paper (Amram and Mendes de Oliveira, 2000) shows examples of galaxy velocity fields for groups in different dynamical stages.
Two color photometry of dwarf galaxies within 10 Mpc
Authors: Bremnes Torbjϕrn
Published: July 2016

Two-color CCD photometry of dwarf galaxies in and around the M81, M101 and CVnI groups is presented. These observations are part of a long term project aimed at obtaining surface photometry data of all known dwarf galaxies within 10 Mpc. The global photometric parameters derived will serve as the basis for a comparison between dwarf galaxies in different galactic environments.
Vorontsov-Velyaminov’ nests: what are they?
Authors: Zasov A. V. , Arkhipova V. P.
Published: July 2016

We give a short review of optical observations of the objects classified by Vorontsov-Vel’yaminov as “nests” of galaxies, describing their luminosity, color, structure and star formation properties. Some ideas on the nature of single dwarf “nests” are discussed.
Tracing interactions in HCGs through the H I
Authors: Verdes-Montenegro L. , Yun M. S. , Williams B. A. , Huchtmeier W. K. , Del Olmo A. , Perea J.
Published: July 2016

We present a global study of Hɪ spectral line mapping for 16 Hickson Compact Groups (HCGs) combining new and unpublished VLA data, plus the analysis of the Hɪ content of individual galaxies. Sixty percent of the groups show morphological and kinematical signs of perturbations (from multiple tidal features to concentration of the Hɪ in a single enveloping cloud) and sixty five of the resolved galaxies are found to be Hɪ deficient with respect to a sample of isolated galaxies. In total, 77% of the groups suffer interactions among all its members which provides strong evidence of their reality. We find that dynamical evolution does not always produce Hɪ deficiency, but when this deficiency is observed, it appears to correlate with a high group velocity dispersion and in some cases with the presence of a first-ranked elliptical. The X-ray data available for our sample are not sensitive enough for a comparison with the Hɪ mass; however this study does suggest a correlation between Hɪ deficiency and hot gas since velocity dispersions are known from the literature to correlate with X-ray luminosity.
Statistical Properties of the Mid and Far IR Emission in Mixed Morphology (E+S) Pairs of Galaxies
Authors: Toledo H. M. Hernández , Dultzin-Hacyan D. , Sulentic J. W.
Published: July 2016

We report the results of a detailed statistical analysis of the Mid and Far IR (MIR/FIR) emission properties in a mixed morphology (E+S) sample of galaxy pairs from the Karachentsev (1972) Catalogue. The sample is large and diverse enough (≃ 130 pairs) to permit discrimination of pairs by morphological types and interaction classes. It samples a large enough volume to enable a non-parametric estimate of a Far-Infrared Luminosity Function (FIRLF). We find average factors of 3 and 5 enhancement in FIR and 25μm luminosities of the late-type pair components relative to an isolated galaxy control sample from Karachentseva (1973) Catalogue. This is interpreted as the MIR/FIR signature of the link between interaction and star formation. Although the spirals in (E+S) pairs fail to show a trend towards higher FIR luminosity with decreasing companion separation, a high-order comparison that takes into account information on the interaction classes, morphological types and the HI content suggests that:

•

a clear correlation between the IR luminosities and interaction classes is present suggesting that a subsample of the (E+S) pairs is more closely related to recent events of star formation,

•

the ratio of present to past star formation (as measured by the IR luminosities scaled to LB luminosity), increases measurably along the sequence Sa-Sc in paired spirals,

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no Hɪ depletion in the star formation-enhanced spirals in mixed pairs is found, and

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the high mass (M ≥ 10 M⊙) star formation rate (SFR) in paired Sc spirals is higher than that of the isolated Sc’s by a factor ~ 2 – 3.
FIR Infrared Emission as Indicator of Interaction in Hickson Compact Groups
Authors: Merluzzi P. , Shaker A. A. , Longo G.
Published: July 2016

Due to their very high spatial density and relatively low velocity dispersion, Hickson’s compact groups of galaxies (hereafter HCGs, Hickson et al. 1989a, H89a) are ideal test grounds where to study the physics of galaxy interaction.

Tidal shocks induced by galaxy interaction are expected to trigger rapid bursts of star formation in the circumnuclear region of galaxies. The increases in density and temperature caused locally by such shocks produce an enhancement in both the total FIR luminosity and in the ratio between the FIR fluxes at 60 and 100 μm. These enhancements have been actually observed in the circumnuclear regions of both interacting and ”putative” merging galaxies and should therefore be found also in all galactic environments where the frequency of interaction is higher than in the field. However, while interactions are more frequent among HCGs members than in the field (e.g. Hickson 1994, Shaker et al. 1999), there are conflicting arguments on whether HCGs present or do not present a FIR excess. As stressed by many authors, the critical point is the IRAS data resolution which prevents to map the spatial distribution of the FIR emission. We investigate the FIR properties of a selected sample of HCGs by sing the new high spatial resolution data from Allam et al. 1996 (A96). In particular, we address the problem whether or not there is any FIR enhancement in the compact groups and the reasons of that. This is a short presentation of the analysis performed and of the results obtained (Merluzzi et al. 1999).
Models of the Cartwheel Galaxy
Authors: Bosma A.
Published: July 2016

I will briefly describe ongoing work on numerical simulations intended to reproduce the Cartwheel galaxy, a prototype ring galaxy located in a compact group of galaxies.
Dynamical explorations of nuclear structures in barred galaxies
Authors: Anosova J. , Benedict G. F.
Published: July 2016

We construct models of a galaxy in order to provide a possible identification of the dynamical processes that lead to the formation of structure observed in galactic nuclei. We assume that the center of our model contains a very massive double black hole, surrounded by relatively low-mass particles - star clusters, gas, and dust complexes. Our previous work (Anosova et al. 1994, 1995) snowed that the dynamical evolution of such a model produces many structures similar to those observed in the nuclei of galaxies, including rings and various types of flows and jets. In such models the ’gravitational slingshot’ effect frequently occurs.

We consider a number of such models with different initial parameters. Comparison of our models with the observed structure of NGC 4314 shows good agreement at one stage of the evolution for certain combinations of initial parameters. The model predicts the velocity field observed in NGC 4314.
Presence and Absence of Outer Rings in Barred Galaxies
Authors: Rautiainen P. , Salo H.
Published: July 2016

Many barred spiral galaxies have an outer ring (R) or a pseudoring (R') in their outer disk. R. Buta (e.g. Buta 1995) has developed a detailed classification for different types of outer rings. Two main families of outer rings are recognized. In R1 family the major axis of the ring is perpendicular to the bar and the spiral arms wind 180° before meeting the other arm. In R2 family the major axis of the ring is parallel to the bar and the spiral arms wind 270°.

The outer rings are usually considered to be related to the outer Lindblad resonance (OLR) of a rotating stellar bar. The ring shapes correspond to families of closed orbits in the vicinity of this resonance (e.g. Contopoulos & Grosbøl 1989), and also the sizes of the outer rings relative to the bar component fit to this suggestion. Furthermore, test-particle simulations which use analytical bar potentials can produce different types of outer rings near the OLR (Schwarz 1981; Byrd et al. 1994). We have obtained similar results when we modelled ringed galaxy IC 4214 by constructing the gravitational potential from near-IR observations (Buta et al. 1999; Salo et al. 1999).
Dark Matter in the Milky Way
Authors: Flynn Chris
Published: July 2016

A major uncertainty in studying small groups of galaxies is the total masses of the individual galaxies themselves. I discuss here recent measurements of the mass of the Milky Way disk and new constraints on possible constituents of the putative dark halo.
Abundances of Be Stars in Very Young Open Clusters
Authors: Marco A. , Bernabeu G. , Torrejón J.M. , Rodes J.J. , Fabregat J.
Published: July 2016

We present here standard uvbyβ CCD photometry for five open clusters of the Galaxy in order to determine abundances of Be stars, as a function of age.
BCD Classification of Stars with the B[e] Phenomenon
Authors: Cidale L. , Zorec J. , Morrell N.
Published: July 2016

Stars in different evolutionary stages and/or environments can show the B[e] phenomenon. In order to establish possible relations between the stellar evolutionary stage and the presence of this phenomenon, the fundamental parameters of these stars need to be determined, as in most cases they are unknown. With this aim we undertook systematic low resolution spectroscopic observations of stars with the B[e] phenomenon. Preliminary determinations of fundamental parameters based on the BCD (Barbier-Chalonge-Divan Paris spectrophotometric system) analysis are reported in this paper.
Modelling of Spherical Extended Atmospheres: Some New Results
Authors: Vázquez Andrea C.
Published: July 2016

Assuming an extended spherical atmospheric model we analyze the continuum and line behaviors considering 3 different temperature laws and different density distributions. We show that - for the continuum intensity distribution - at some physical conditions, a limb brightening profile appears.
Interferometry and Stellar Magnetism
Authors: Chesneau O. , Rousselet-Perraut K. , Vakili F.
Published: July 2016

The classical detection of magnetic fields in Be stars remains a challenge due to the sensitivity threshold and geometrical cancelation of the field effects. We propose to study the Zeeman effect using Spectro-Polarimetric INterferometry (SPIN) which consists of the simultaneous use of polarimetry and very high angular resolution provided by long baseline interferometers. As monitoring of the instrumental polarisation is mandatory in order to calibrate interferometric observations in any case, the polarised signal is a natural by-product of interferometers. This method will be tested on the GI2T interferometer thanks to its high spectral resolution and its polarimetric capabilities.
A UV Spectrophotometric Technique for Measuring Temperatures of CS Structures over B Stars
Authors: Smith Myron A.
Published: July 2016

Do optical/UV variations of spectra of Be stars arise from pulsations or structures hanging over them? There is a need for a temperature-sensitive discriminator for circumstellar structures above Be stars to determine whether their UV flux variations are due to occulting structures or photospheric pulsations.

To address this question, we acquired far-UV (SWP camera) echellograms covering λλ1150–2100 from the IUE final archive. For selected B stars we have selected suitably exposed spectra observed within a short timespan, typically 1–3 days. We summed all the valid net fluxes within each of 60 echelle orders and placed them into an order vs. time array. We identify those times corresponding to high and low fluxes over several reference orders and form the quantity 1 - Fmin(λ)/Fmax(λ), for all echelle orders. The result is a low-resolution spectrum sensitive to absorptions at certain wavelengths, either strong lines such as Lyman α and several UV resonance lines or aggregates of metallic lines. All these are potentially sensitive to temperature variations.
Non-radial Pulsation Modeling of μ Centauri
Authors: Rivinius Th.
Published: July 2016

It is shown that the line profile variability (lpv) of μ Cen can be modeled as non-radial pulsations (nrp). The use of the most recent available modeling technique for the nrp and carefully computed stellar observables (intrinsic line profile and flux) are, however, mandatory to take full advantage of present high-quality data.
Tracing the Transient Periods in the Be Star 28 ω CMa
Authors: Štefl S. , Budovičová A. , Baade D. , Kaufer A. , Rivinius T. , Stahl O. , Wolf B.
Published: July 2016

Spectra of the Be star 28 CMa obtained with the HEROS echelle spectrograph in 1996 and 1997 were used to check the presence of transient periods in commonly measured scalar parameters of absorption and emission lines. Transient periods can be convincingly detected in modes of higher absorption and single peak emission lines of the Balmer series as well as in the V/R ratio of Fell lines. Consequences for the frequency analyses of datasets containing radial velocities derived from different ions are discussed. The significant differences in amplitudes of radial velocities of different ions and in individual seasons were confirmed and a mean ephemeris derived.
Line Profile Variability in the Be Star α Eridani
Authors: Leister N. V. , Janot-Pacheco E. , Leyton Z. J. , Hubert A. M. , Floquet M.
Published: July 2016

We present an analysis of line profile variability of the Be star α Eri (Achernar). Spectra of He I λ667.8nm were collected at Brazilian Laboratório Nacional de Astrofísica (LNA) during 10 observing runs covering 27 nights in 6 years. The presence of a 1.26 days period reported previously is confirmed and we report also the detection of other periods (0.73 and 0.53 days) and a possible 12.5 days modulation. A transient high-velocity absorption component with RV = −500 km/s, higher than −υsini (−220 km/s) has appeared at the end of 1993, near the presumed maximum of the Hα emission phase.
Trans-Photospheric Wave Leakage in Be Stars
Authors: Townsend Rich
Published: July 2016

The phenomenon of trans-photospheric wave leakage in stars undergoing non-radial pulsation is investigated, with an emphasis on its significance for Be stars. It is demonstrated that a symmetry breaking in line-profile variability may be used as a diagnostic for such wave leakage in these stars.
Physical Requirements for Flares in Stars
Authors: Haisch Bernhard
Published: July 2016

A wide range of stellar analogs of solar X-ray flares has been observed. During the maximum of the solar activity cycle, one or two Mclass flares peaking at Lx ~ 1026 erg s−1 in the GOES 1−8 Å passband take place on average every day on the Sun. Such run-of-the-mill events have been measured by ASCA on our nearest neighbor, Proxima Centauri, a dM5.5e flare star (Haisch, Antunes & Schmitt 1995). At the other extreme, RS CVn systems and T Tauri stars have been observed to flare with peak luminosities of Lx ~ ×1032 ergs s−1 (Haisch & Schmitt 1996 and references therein). Current wisdom has it that this wide range of flares spanning at least six order of magnitude (and another factor of 10–100 if one counts even lower level solar flares) on the young T Tauri stars, main sequence G, K and M stars, and in evolved RS CVn subgiants and giants can all be understood as versions of solar flares originating ultimately in a convectively-driven magnetic dynamo. There is evidence pointing to two distinct types of dynamo perhaps even in the Sun (Durney, Young and Roxburgh 1993): the α − ω dynamo generated in a rather thin boundary layer near — in some interpretations just below — the interface between a star’s radiative core and convective envelope; and a turbulent distributed dynamo operative more or less throughout a convection zone. But what is one to make of the evidence for flares on Be stars (Smith, Robinson and Corbet 1998) where there is no subsurface convection to drive a dynamo? (Convective envelopes are thought to begin among the late-A spectral type stars, and steadily deepen for cooler stars.) This paper does not attempt to provide an answer, but it does attempt to outline the characteristics and requirements of magnetically-powered flaring.
Be Phenomena in Young Early-type Stars: Various Forms of Interaction between the Star and the Circumstellar Gaseous Envelope
Authors: Pogodin M.
Published: July 2016

New results of high-resolution spectroscopy of four pre-main sequence Ae/Be stars are presented. An analysis of parameters of lines originating in different regions of the circumstellar (CS) envelope (Hα, Hβ, He I 5876, DNal) allows to reconstruct a picture of the interaction between the star and the CS environment which can be displayed in different forms. At least two separate processes seem to impact the structural and kinematical properties of the envelope: the stellar wind from the stellar surface and the matter infall onto the star from the CS media. A possible relation between these two phenomena is discussed in the framework of different models. Some similarity between observational phenomena in Herbig Ae/Be and classical Be stars is noted in spite of their difference in evolutionary status.
Short-lived and Long-lived Outbursts in B and Be Stars from Hipparcos Photometry and Modelling
Authors: Hubert A. M. , Floquet M. , Zorec J.
Published: July 2016

The number of Be stars which showed short- and long-lived outbursts during the Hipparcos photometric survey, previously reported in Hubert and Floquet (1998), have been increased by examination of light curves of fainter objects. Long-lived outbursts have been modelled as being due to an ejected layer/slab which becomes gradually diluted.
Short-Term Wind and Photospheric Activity in Be Stars Deduced from Campaigns with the IUE Spacecraft
Authors: Peters Geraldine J. , Gies Douglas R.
Published: July 2016

From 1985–96 twelve multiwavelength campaigns on 15 Be stars were carried through using data from the IUE spacecraft to study the phenomenon of short-term spectroscopic and photometric variability. Highlights from recent work on this database are presented here. Three classes of variability have been identified: 1) The FUV flux and wind strength are correlated, 2) The FUV flux varies cyclically but wind variability if present does not correlate with the flux, and 3) The wind strength cyclically varies but does not correlate with light variations. For Class 1 the period is usually less than the star’s expected rotational period, but for Classes 2 & 3, the period is sometimes close to Prot. We have employed a cross-correlation technique to extract information on the nature of the line profile variability (lpv). Evidence for nonradial pulsations (NRP) in low-order modes is found for objects in Classes 1 & 2, the light variations appear to be caused by a modulation of the star's photospheric temperature, and the hot crest of the NRP wave is in front when the star is bright. For Class 1 stars the wind is enhanced over the hot crest. The mass loss in Class 3 may originate from a localized active region on the star and the importance of NRP in these stars remains unknown.
Polarimetry as a Diagnostic of Circumstellar Envelopes
Authors: Bjorkman Karen S.
Published: July 2016

Polarimetric observations of stars can provide useful diagnostics of the geometry and physical conditions of the circumstellar envelope. This paper reviews the application of polarimetric techniques to hot stars (with particular emphasis on Be stars) and the status of polarization observations, and discusses some recent developments that improve our ability to make and to interpret such observations. Polarization measurements, bolstered by the increasing availability of new instruments on larger telescopes, continue to improve toward both higher signal-to-noise ratio and higher spectral resolution. Because of this we can begin to address specific questions of the physics of the circumstellar envelopes, since polarization provides a means to separate the effects of the photosphere from those of the envelope. New theoretical and analytic approaches are improving our ability to interpret spectropolarimetric data. We now are able to determine characteristics such as disk opening angle, density, and temperature. Furthermore, polarimetric observations in new wavelength regimes (e.g. ultraviolet and infrared) are opening new avenues to investigate circumstellar disks. The combination of spectropolarimetry with other kinds of data, such as spectroscopy, photometry, and interferometry, shows promise for providing stringent tests for theoretical models of the circumstellar envelopes of Be stars.
Line Profile Modeling of Disks
Authors: Hummel W.
Published: July 2016

In this talk I give a short overview of models for spectral lines in Be stars disks which I think are quite instructive. I then examine the arguments for my own model assumptions and discuss selected topics concerning radiative line transfer calculations in three dimensions. We show that symmetric Hα emission lines of Be stars can be understood in terms of Keplerian disks. It is also demonstrated that one-armed global disk oscillations provide the best available solution to understand the long-term V/R variations in Be star emission lines.
On the Fe II Dielectronic Recombination in Stellar Envelopes
Authors: Cruzado Alicia , Ringuelet Adela E.
Published: July 2016

We are interested in the atomic processes taking place in the envelopes of early type stars; the first part of our project consists of an investigation of the dielectronic recombination (DR) of metals. In earlier papers, we have studied the DR of Mg II and its contribution to the IR continuum; now, we are interested in accomplishing similar results analysing the Fe II atom.
Be Envelope Properties Determined from Fe II Emission Lines
Authors: Chauville J. , Ballereau D. , Cidale L. , Morrell N. , Friedjung M. , Zorec J.
Published: July 2016

Applying the SAC (self absorption curve) method to χ Oph (HD 148184) we conclude that Fell emission lines are optically thick. We estimate the excitation temperature of the permitted Fe II line formation region and the dimensions of this region. We conclude that this region may possibly have a non-uniform density structure.
Semi-empirical Model of the Star V923 Aquilae
Authors: Arias M. L. , Cidale L. S. , Ringuelet A. E.
Published: July 2016

V923 Aquilae (HD 183656) is a Be star which shows emission in Hα, cyclic V/R variations and variations in the near infrared region. This star displays a shell spectrum recognized by Harper(1937) and Bidelman (1950) who both remarked the presence of shell H lines, strong Fe II lines and variable radial velocity. Koubský et al. (1989) proposed V923 Aquilae to be a spectroscopy binary with an orbital period of 214.756 days and a semi-amplitude of 6.2 km/s. Iliev et al. (1994) found a correlation between the changes of the Balmer progression and the asymmetries of the Balmer lines with the orbital phase, considering the period calculated by Koubský.