bluuebunny/crossref_metadata_2025 huggingface dataset:
The La Palma Data Archive
Authors: Benn Chris
Published: July 2016

The Observatorio del Roque de los Muchachos is perched atop a volcanic caldera on the island of La Palma in the Canary Islands, 400 km off the coast of North Africa. Three of the telescopes at the observatory are products of a collaboration between the UK, the Netherlands, Spain and the Republic of Ireland. They are the 1.0-m Jacobus Kapteyn Telescope, the 2.5-m Isaac Newton Telescope and the 4.2-m William Herschel Telescope (which saw first light in July 1987)1. The telescopes are computer controlled (running under ADAM software), and the observations are recorded primarily in electronic form. Recognising the success of astronomical-satellite data archives, such as that generated by the International Ultraviolet Explorer, a La Palma Data Archive has been established at the Royal Greenwich Observatory. The archive will be used by astronomers wishing to exploit data obtained by other observers, by engineers interested in the performance of telescope and instruments under varying conditions, and for monitoring the way in which the telescope is used.
A Proposal for Better Cooperation among Libraries of Astronomical Observatories
Authors: Dale Paul-Henri
Published: July 2016

The cooperation between libraries of astronomical Observatories remains clearly insufficient despite the numerous means of communication now available. The library of the Royal Observatory of Belgium therefore recommends the establishment of a “subgroup” of users (Libraries of Astronomical Observatories) within the already existing Dobis-Libis Users Group.
Administration of Libraries at Distant Sites and Remote Telescope Locations
Authors: Bouton Ellen , Gómez Maria Eugenia
Published: July 2016

Many librarians are responsible for libraries at outstations and/or remote telescope sites. Such sites may range in size from facilities with as many personnel as the central headquarters to remote observing stations where only a few people are present at any one time. Sites may be only a few kilometers away, or they may be half way around the world. In an informal evening discussion, concerned librarians discussed issues and problems created by such far-flung library systems.

Budgetary constraints are a primary problem in managing site libraries at most institutions. Staff and visiting scientists want duplicates at the sites of the books and journals they use regularly in their work, but with current prices it is often difficult to provide even the major astronomy journals for site as well as central libraries. Even when researchers are encouraged to do preparatory research before going to observe, some library materials may still be necessary. In the case of larger sites where people work on a permanent basis, larger collections will, of course, be needed. It is especially important at such sites to provide easy access for materials directly involved in preparation of observations, e.g. photographic sky atlases, reference catalogs of astronomical objects, etc. We discussed at length the problems of selection and acquisition of materials for remote libraries, including questions of purchasing and technical processing, binding, inventory, and bibliographic control.
The Exchange of “Lists of Duplicates” and its Importance for Astronomical Libraries
Authors: Gertner Barbara
Published: July 2016

Problems of an international exchange and especially of “Lists of Duplicates” which in my opinion are very important for small and not too rich libraries like our Library, are briefly discussed.
Library and Information Services in Chinese Astronomy
Authors: Yunfen Zhou
Published: July 2016

The development of the library science marks the progresses of science and culture in a country or a district. The study courses and results of a research institute are strongly reflected by its library and information work. The development of the astronomical research, the collection of astronomical observations, and the manufacture of astronomical instruments and equipments, etc., are all being made progress by library and information services to consult scientific foundation, to seek method, and to derive needed nourishment. The astronomical library and information service system is growing and expanding with continuously providing information to the astronomical study. In this paper I shall give some introductions about the Libraries and Information Divisions of astronomical observatories in our country.
Summary of a Survey of Astronomy Libraries
Authors: Vargha Magda , Mizser Attila
Published: July 2016

A questionnaire about astronomy libraries was distributed in June 1988. The returns from 54 libraries are summarised; they show a large range in size, scope and procedures. Many libraries are connected to networks that give access to bibliographic databases, but only a small number use local computers for cataloguing. Some comments on the returns are given.
Site Preservation at Palomar Observatory
Authors: Brucato Robert J.
Published: July 2016

Palomar Mountain was selected as the site of the 200-inch Hale Telescope in 1934. Since then, and especially over the past decade, the population growth of southern California has had a growing adverse impact on the observatory’s environment. In 1981, a very active program was initiated to work with the local governmental agencies to prevent further deterioration of the conditions as the area continues to become increasingly urbanized. The character and scope of the program are described in the paper, as well as more general observations relating to the site preservations process.
Software Tools for Engineering Dark Skies
Authors: Smith A. M. , Dilaura D. L.
Published: July 2016

Atmospheric scattering of outdoor nighttime electric illumination produces the principal component of background sky luminance that seriously affects ground-based optical astronomy. The sources for this scattering are Tight emitted skyward directly from luminaires, and light reflected off the ground and other illuminated objects. Careful illumination engineering can thus significantly reduce background sky luminance in two ways: 1) by providing outdoor electric lighting equipment that controls the directions in which light is emitted, and; 2) by proper design of outdoor lighting systems which make efficient use of the east amount of light. Recent developments in applied mathematics and computer software have produced computational tools that are being used to design lighting equipment and lighting systems. The software system for luminaire design significantly reduces the cost of this process by eliminating the need for extensive prototyping and provides for inexpensive experimentation with new designs. The system for outdoor lighting calculations permits the design of highly controlled lighting systems that eliminate glare and upward directed light while providing light appropriate for the visual task. These two software systems are described, along with examples of their use in areas that directly affect astronomical observations.
The Effect of Public Lighting on Sky Glow
Authors: Cunnen J.M.L
Published: July 2016

The principal reason that public lighting exists is that it fulfills the needs for: traffic safety, personal security, comfort and pleasantness, and environmental esthetics.
The Measure of Light Pollution and the Populations of Cities
Authors: Upgren Arthur R.
Published: July 2016

A program to measure the night sky brightness has been in progress for some years in order to calibrate the extent of the night sky brightness surrounding the Van Vleck Observatory. Both the central intensity and the areal extent of the brightest sky caused by campus and city were repeatedly measured in order to gauge the extent of the problem. For this purpose, portable visual photometers were designed which have remained stable and usable for nearly a decade. They are now useful for the measurement of the effects of increases in urban growth and of the more flexible attitude of the campus administration toward excess campus lighting. The inability to define city populations which realistically model and predict the measured sky brightness is the largest source of uncertainty. The observatory is in the Northeastern Corridor where the observed brightness is the sum of the illumination from a number of overlapping city sources. Present light pollution studies have not correctly defined the model for the population of an urban area. The two paradigmatic definitions now available for use are shown to be flawed for light pollution comparisons. An algorithm, unlike any in present use, must be sought which distinguishes between individual core cities within metropolitan areas.
Light Trespass
Authors: Tanner Albert A.
Published: July 2016

Light trespass is a real problem to astronomers, and, to some extent, to the general public. There is really no valid excuse for most of our existing light trespass. If we were all aware of the problems, we could rather easily implement solutions to cure the problems.
120 HZ Variations in Sky Brightness Over Vancouver, BC
Authors: Crabtree David , Westpfahl David , Richer Harvey
Published: July 2016

We have detected a component of sky brightness varying with a frequency of 120 Hertz during high speed photometric observations of 40 Eridani with the 30-cm telescope of the University of British Columbia. The observations were made in 1974, but only recently has their significance to the field of urban illumination been realized. The 120 Hertz component was detected by Fourier analysis of data sets of the star and of the sky alone. We confirmed that the 120 Hertz component was due to urban lighting by direct observation of a “standard source,” a lamp on the campus.
Side Effects of Space Debris on Astronomical Observation
Authors: Maley Paul D.
Published: July 2016

Astronomical research continues to use ground-based facilities as a principal means of gathering data. The optical light buckets which are trained each night on celestial sources have historically had to just contend with natural interference. Sunlight, moonlight, clouds, debris created by volcanic eruptions, atmospheric seeing, and aurora are examples of factors which modify the interception and analysis of energy radiated in the optical spectrum and received at the collector end. In the last 5 years the “unnatural” encounters with artificial earth satellites are making themselves more pronounced and have become the subject of this limited study.
SMM Coronagraph Observations of Particulate Contamination
Authors: St. Cyr O.C. , Warner T.
Published: July 2016

Some recent images taken by the white light coronagraph telescope aboard the Solar Maximum Mission (SMM) observatory show bright streaks that are apparently caused by particles associated with the spacecraft. In this report we describe these observations, and we analyze the times of their occurrence. We demonstrate that the sightings occur most often near SMM’s orbital dawn, and we speculate that thermal shock is the mechanism that produces the particles. Although these sightings have not seriously affected the coronagraph’s scientific operations, the unexpected passage of bright material through the field of view of sensitive spaceborne telescopes can lead to data loss or, in some cases, serious detector damage. The topic of space debris has become a significant concern for designers of both manned and unmanned orbiting platforms. The returned samples from the SMM spacecraft and the observations reported here provide a baseline of experience for future orbital platforms that plan long duration missions.
The Use of Meteor Radars in the Detection of Infalling Space Debris
Authors: Olsson-Steel D.I. , Elford W.G.
Published: July 2016

Radars of various configurations are used to detect the flux of meteors into the atmosphere, and therefore may be of use in characterizing the artificial meteors produced by small (100 microns - 1 cm) pieces of space debris upon re-entry. Both conventional and over-the-horizon radars are discussed here, and the ways in which they may be deployed in order to detect infalling space debris are outlined.
Interference with Astronomical Observations of OH Masers from the Soviet Union’s GLONASS Satellites
Authors: Galt John
Published: July 2016

Measurements at the 1612 MHz OH line are necessary to identify and study an important class of highly evolved stars whose properties cannot be determined by other means. Observing at this frequency over an 18 month period has been a frustrating experience in “sharing” a small portion of the 1610-1626.5 MHz frequency allocation on a secondary basis with the Aeronautical Radionavigation Service. Transmissions from the GLONASS satellite system are so powerful that they are received in the side lobes and back lobes of the radio telescope, no matter where in the sky it is pointing as long as one satellite is above the horizon. On most days about half the observations had to be discarded to prevent spurious satellite signals from masquerading as astronomical spectral lines.
Protection of Omniwavelength Radio Astronomy and Preventing Radio Pollution of Space
Authors: Doubinsky B. A.
Published: July 2016

Radio pollution of space is connected with general ecological conditions resulting from world development. A practical aspect of the problem is related to the possibility of making radioastronomy observations of cosmic emissions and searching for signals from extraterrestrial civilizations over almost all of the entire radio spectrum. For this purpose, it was decided at WACR-79 to keep a quiet zone on the shielded side of the moon. Here we shall discuss the problem as it relates to an observatory in orbit. The vicinity of the L2 Lagrangian point of the earth-sun system is of particular interest as a location for such an observatory.
On the evolutionary status and instability mechanism of the Luminous Blue Variables (LBV)
Authors: Maeder André
Published: July 2016

Various evolutionary sequences leading to LBV are examined. The sequence O-Of-LBV-WR-SN is well supported by the models; some LBV with relatively lower luminosity may turn into OH/IR sources. The overall duration of the LBV phase depends mainly on the average mass loss rate; for <Ṁ> = 10−3M⊙y−1, it lasts about 104y.

Very massive stars undergo, when they reach logTeff= 3.9, strong departure from hydrostatic equilibrium due to supra-Eddington luminosities at some depth in the outer layers. This results in heavy mass loss, as the growth rate of the instability is very fast. We suggest that the amount of mass ejected in a shell episode is mainly determined by the mass of such a layer that its thermal adjustment timescale is within an order of magnitude of the stellar dynamical timescale. Simulations of B-light curves due to shell ejections by LBV are performed and some sensitive properties are identified.
Age of Luminous Blue Variable candidates from their stellar and nebular environment
Authors: Lortet M.-C.
Published: July 2016

The study of the context of LBV stars, that is close neighbourhood (companions) and spatial relationship to young objects such as cepheids. stellar associations, red supergiants. enriched OB supergiants. Hll regions. WR stars can provide useful clues on their true luminosity, their age thus eventually initial mass and evolutionary status.
Changes in the atmospheric structure of LBV’s during eruptions
Authors: Leitherer Claus , Abbott David C. , Schmutz Werner
Published: July 2016

Some LBV’s undergo brightness variations in the visual of about 1–2 magnitudes on time-scales of decades. These outbursts occur at approximately constant bolometric luminosity with the stellar radius and the temperature changing correspondingly. This subgroup of the LBV’s is generally called Hubble-Sandage variables or S Doradus stars and will be the focus of this talk. We present self-consistent radiation-hydrodynamic calculations to model the observations from minimum to maximum states.
Mass ejections from the G-type hypergiant HR 8752
Authors: Smoliński J. , Climenhaga J.L. , Fletcher J.M.
Published: July 2016

One of the most luminous stars in our Galaxy (Humphreys 1988) HR 8752 = HD 217476 (G0 Ia), is similar in some respects to Luminous Blue Variables. Studies by several authors (Sargent 1965; Smoliński 1971; Smoliński et al. 1977; Stickland and Harmer 1978; Lambert and Luck 1978; Lambert et al. 1981; Smoliński et al. 1986; Sheffer and Lambert 1987) have contributed to the understanding of activities in the atmosphere of this star, but its nature is still not well understood.
Circumstellar ejecta around LBV’s
Authors: Stahl O.
Published: July 2016

The properties of circumstellar shells around LBV’s are reviewed. Some LBV’s are surrounded by very extended nebulosities, similar to classical planetary nebulae, with AG Car as the prototype. The masses of these nebulae are of the order of a solar mass and their kinematic ages are about 104years. The origin of these nebula is still controversial, but they probably have been ejected in some major outburst in the past. It is then remarkable that the historical outburst of P Cyg has left no bright remnant. There is evidence for CNO processed matter in the ejecta. LBV’s with no detectable extended emission also commonly have nebular emission lines. Some of these nebulae are probably related to the resolved nebulae, but some certainly are very much smaller and have much higher densities.
Observational connections between LBV’s and other stars, with emphasis on Wolf-Rayet stars
Authors: Moffat A. F. J. , Drissen L. , Robert C.
Published: July 2016

We suggest that the LBV mechanism is an essential step to “force” massive stars (M(ZAMS) ≥ 40M⊙) to finally enter the Wolf-Rayet (W-R) domain in the Hertzsprung-Russel diagram (HRD). Just as massive supergiants showincreasingvariability as theyapproachthe Humphreys-Davidson (H-D)instability limit (horizontally in the HRD diagram), so the W-R stars showdecreasingvariability as theyrecede fromthe H-D limit (at first horizontally into the WNL domain, then, with their high mass loss rates, plunging irreversably downwards as ever hotter, smaller and fainter, strong-line W-R stars). Among the W-R stars, the luminous WNL subtypes (especially WN8) are the most variable, probably as a consequence of blob ejection in the wind. The underlying mechanism which triggers this ejection is possibly related to wind instabilities and may thus be quite different from the source of variability in luminous supergiants or LBV’s in quiescence, where photospheric effects dominate.
On the periodicity of Hubble-Sandage objects in M 31
Authors: Ivanov G. R.
Published: July 2016

The spectral and photometric characteristics of the Hubble-Sandage objects (HSO) are similar to those of the η Car and S Dor variables. They are actually referred to as S Dor-type in the General Catalogue of Variable Stars. Their light variations differ from star to star.

The aim of the present paper is to discuss a possible periodicity in HSOs in M 31. We used phtometry from Hubble(1929), Sharov(1973, 1981), Rosino and Bianchini(1973), and added some observations taken during 1980-87. The latter were obtained with the 2-m Ritchey-Chretien-Coude and 0.5-m Schmidt telescopes of the Bulgarian National Astronomical Observatory – Rozhen.
High-resolution emission line profiles in blue luminous stars
Authors: Bandiera Rino , Focardi Paola , Altamore Aldo , Rossi Corinne , Stahl Otmar
Published: July 2016

Emission lines are often observed in high luminosity stars and provide evidence of the presence of extended stellar envelopes. Ha is the most frequently observed across the H-R diagram, but lines of Hel or Fell are also found in emission in these stars. They could be used as diagnostics of the structure of their outer atmospheres and winds. High resolution (1/dl ~ 105) high S/N profiles of Ha and Hel 5876 in the galactic LBVs η Car, AG and HR Car, and in the LMC star S22 have been obtained with the ESO CAT-CES during 1984-87, and are described in Figs.1-5. We find that these stars show a large variety of profiles with narrow and broad emissions, wide or multiple blue-shifted absorptions. The profiles are largely variable. Once, a kind of inverse P Cyg profile was observed in HR Car (Fig.4). These results indicate the presence of large scale phenomena and high velocity fields which are dramatically variable in time. Continuous HIRES monitoring of these stars is urgently needed.
NLTE analysis of R84
Authors: Schmutz W. , Leitherer C. , Torres-Dodgen A.V. , Vogel M. , Conti P.S. , Hamann W.-R. , Wessolowski U.
Published: July 2016

The LMC star R84 (-HDE 269227 -BR 18) belongs to the group of Ofpe/WN stars believed to be closely related to the Luminous Blue Variables. Support for such a relation comes from the spectral resemblance of these stars to AG Car during visual minimum, and from the observed outburst of the Ofpe/WN star R127.

The spectral analysis of R84 presented here is based on model calculations with the NLTE comoving-frame code described by Wessolowski et al. (1988) and references therein. The helium model atom was represented by 28 levels and hydrogen by 9 levels. The free model parameters were varied until the observed line profiles and the absolutely calibrated and dereddened continuum flux were reproduced. The comparison of the theoretical continuum flux distribution with the observed one yields a reddening of EB-V=0.1.
High-dispersion spectroscopy of the B[e] supergiant S 111
Authors: Stahl O. , Smolinski J. , Wolf B. , Zickgraf F.-J.
Published: July 2016

We studied the luminous emission-line star S 111 in the LMC with high-dispersion spectroscopy and classified it as a new member of the class of B[e] sup ergi ants.
Blobs in the winds of Wolf-Rayet stars
Authors: Robert C. , Drissen L. , Moffat A. F. J.
Published: July 2016

Concentrations of material have been observed to propagate in the winds of many W-R stars. These are short-lived, stochastic features of unknown origin.
The Interacting PAIR MKN 305/306
Authors: Dietrich Matthias
Published: July 2016

Direct images and spectra at different slit positions of the interacting system Mkn 305/306 are discussed. Both galaxies show starburst properties due to tidal interaction. The morphology and velocity structure of Mkn 306 reveals the strongest warp of a stellar disk so far known.
A Study of the Compact Group of Galaxies Shahbazian 4
Authors: Lynds C. R. , Khachikian E. Ye. , Amirkhanian A. S.
Published: July 2016

For the members of the compact group of galaxies Shahbazian 4 the radial velocities are defined. The velocity dispersion is 440 km s−1. Moreover the appparent and absolute magnitudes of galaxies in the V band as well as the mass-to-luminosity ratio are obtained. The latter is approximately 220 M⊙/L⊙. The “crossing time” for the group Shahbazian 4 is equal to 4.7 × 107 years. It is one of the densest group of galaxies with n ~ 104 galaxies Mpc−3.
The Environments of Markarian Galaxies
Authors: MacKenty John W. , McLean Brian , Simpson Caroline
Published: July 2016

The extensively studied Markarian sample of 1500 ultraviolet excess galaxies contains many Seyfert, starburst, and peculiar galaxies. Using the 20 minute V plates obtained for the construction of the Hubble Space Telescope Guide Star Catalog, we have investigated the morphologies of the Markarian galaxies and the environments in which they are located. This paper reports on the relationship between the types of nuclear activity and the morphologies and environments of the Markarian galaxies.
The Ringed X-Galaxy NGC 7020
Authors: Buta Ronald
Published: July 2016

The southern S0+ galaxy NGC 7020 presents an unusual morphology: it includes a very regular outer ring which is completely detached and which envelops an inner ring/lens zone with a hexagon surrounding an X shape (Figures 1a and 1b). The outer ring has a high contrast compared to those usually observed in barred galaxies, yet NGC 7020 is not obviously barred. The morphology of this galaxy poses an interesting puzzle in that the hexagonal/X zone is not a typical type of feature to find in the interior of such a regular ring. Instead, the zone bears a striking resemblance to the edge-on galaxy IC 4767, recently studied by Whitmore and Bell (1988 = WB88) and dubbed by them as the “X-galaxy” because its inner regions appear to be crossed by two distinct enhancements lined at ±22° with respect to the major axis. The observation of a similar phenomenon in NGC 7020 is interesting because of the suggestion by WB88 that “X” structures could be related to accretion of matter associated with a merger or tidal encounter between an SO and a small satellite galaxy. If this interpretation is correct for NGC 7020, then it has important implications for the nature of the outer ring. An alternative interpretation is that the inner hexagonal/X zone is a region where resonant periodic orbits in a weak bi-symmetric potential perturbation are influencing the morphology more strongly than might be expected. In this paper, I give a brief summary of a more extensive paper (Buta 1990c = B90c) and a few other details concerning this interesting galaxy.
Observations of Multiple Nucleus Galaxies
Authors: Kollatschny W.
Published: July 2016

Disturbed Galaxies with two nuclei display the final state of the interaction process of two galaxies (Kollatschny et al., 1986; Fricke and Kollatschny, 1989). A few of these double nucleus galaxies contain Seyfert nuclei.
Interacting Nuclei in Distant Galaxies
Authors: Zheng Wei , Grandi Steven A.
Published: July 2016

The interaction of galaxies not only occurs in galactic scales, but also may be linked to the binary cores in active galactic galaxies. The presence of a binary in the center of galaxies was suggested by Begelman, Blandford and Rees (1980). Gaskell (1983) suggests that supermassive binaries may account for the observed structure of emission line profiles such as double peaks displaced by a significant velocity difference. Collin-Souffrin, et al. (1986) argue that line emission may be formed in the outer part of an accretion disk. The resultant profile, as expected from rotational motion, would be very broad and often possess a double-horn shape. However, the emission line profiles in most active galactic nuclei do not share such a resemblance, and there are only two reported cases, 3C390.3 (Pérez et al. 1987) and Arp102B (Chen, Halpern and Filippenko 1989), in which the broad Balmer line profile may be of such a shape. Therefore, the assumption for accretion disk is to be verified with care.
Fir Statistics of Paired Galaxies
Authors: Sulentic Jack W.
Published: July 2016

Much progress has been made in understanding the effects of interaction on galaxies (see reviews in this volume by Heckman and Kennicutt). Evidence for enhanced emission from galaxies in pairs first emerged in the radio (Sulentic 1976) and optical (Larson and Tinsley 1978) domains. Results in the FIR lagged behind until the advent of the IRAS satellite. The last five years have seen numerous FIR studies of optical and IR selected samples of interacting galaxies (e.g., Cutri and McAlary 1985; Joseph and Wright 1985; Kennicutt et al. 1987; Haynes and Herter 1988). Despite all of this work, there are still contradictory ideas about the level and, even, the reality of an FIR enhancement in interacting galaxies. Much of the confusion originates in differences between the galaxy samples that were studied (i.e., optical morphology and redshift coverage). We report on a study of the FIR detection properties for a large sample of interacting galaxies and a matching control sample. We focus on the distance independent detection fraction (DF) statistics of the sample. The results prove useful in interpreting the previously published work. A clarification of the phenomenology provides valuable clues about the physics of the FIR enhancement in galaxies.
Star Formation in Infrared Bright and Infrared Faint Starburst Interacting Galaxies
Authors: Lamb Susan A. , Bushouse Howard A. , Towns John W.
Published: July 2016

Short wavelength IUE spectra of Arp 248b and UGC 8315N are combined with optical spectra and interpreted using a combination of spectrum synthesis and spectral diagnostics to place constraints on the massive star populations of the central regions of these galaxies and to deduce information about the star formation histories in the last 108 years. We find that both galaxies have substantial fractions of their optical light coming from massive stars and that Arp 248b may be dominated in the UV by WR stars. The UV spectra are dominated by radiation from evolved massive stars and we place an age on the burst in Arp 248b of a few tens of millions of years.
On a Connection between Supernova Occurrence and Tidal Interaction in Early Type Galaxies
Authors: Kochhar R.K.
Published: July 2016

There are three types of supernovae: two subtypes SNIa and lb; and SNII. Late type galaxies produce all types of SN, whereas early types (E, SO, and non-Magellanic irregulars 10) have hosted only SNIa. The recently identified SNIb, like SNII, have massive stars as their progenitors.

Reviving Oemler & Tinsley’s (1979) suggestion that SNIa also come from short-lived stars, we have asserted that they need not occur in all early-type galaxies. SNIa occur only in those galaxies that have access to gas and can form stars in their main body. (SN in nuclear regions are a different matter altogether). In this model, SNIa are not associated with typical stellar population of E/SOs but with regions of localized star formation. Note that data on SNIa from spirals is already consistent with this model (see Kochhar 1989 for references and details).
Radio Emission in Peculiar Galaxies
Authors: de Mello Rabaça Dulia F. , Abraham Zulema
Published: July 2016

During the last decades a number of surveys of peculiar galaxies have been carried out and accurate positions become available. Since peculiarities are a possible evidence of radio emission (Wright, 1974; Sulentic, 1976; Stocke et al.,1978), we have selected a sample of 24 peculiar galaxies with optical jet-like features or extensions in different optical catalogues, mainly the Catalogue of Southern Peculiar Galaxies and Associations (Arp and Madore, 1987) and the ESO/Uppsala Survey of the ESO(B) Atlas (Lauberts, 1982) for observation at the radiocontinuum frequency of 22 GHz. The sample is listed in the Table.
The Kinematics and Morphology of NGC 520: One, Two, or Three Galaxies?
Authors: Stanford S.A. , Balcells M.
Published: July 2016

The peculiar galaxy NGC 520 (Arp 157) is often interpreted as an interacting pair of galaxies. The identification of the two bulges and overall morphology of the two galaxies has long been a puzzle which we attempt to solve in this paper. New longslit optical spectroscopy and near-infrared images of NGC 520 are presented. These data suggest that the northwest peak is the bulge of one of two galaxies in the system. The other larger bulge is clearly evident in the K band image in the middle of the dust lane. The stellar radial velocity profile in the central 10” of the larger bulge is consistent with counterrotation seen in the molecular gas component. This kinematic subsystem could be the remains of a merged gas-rich irregular.
Galaxy Interactions and Strength of Nuclear Activity
Authors: Simkin S. M.
Published: July 2016

Almost a decade ago, the morphological similarities between patterns seen in Seyfert galaxies and those produced by gravitational forcing led to the suggestion that Seyfert activity might be fueled by material inflow induced by either a central bar or a perturbing companion (Simkin, Su, and Schwarz, 1980). More recent theoretical calculations suggest that such a feeding mechanism may involve a central bar-like, structure even if initially induced by the tidal effects of a companion galaxy (Noguchi, 1988a,b).
Nuclear and Extended Infrared Emission in Paired and Isolated Galaxies
Authors: Cutri Roc M.
Published: July 2016

The empirical connection between gravitational and collisional interactions among galaxies and enhanced activity has been well-documented. However, the physical mechanisms which are responsible for triggering the various forms of activity have not been determined. We present the preliminary results of a study of the nuclear and integrated infrared properties of galaxies chosen from the Catalog of Isolated Pairs of Galaxies in the Northern Hemisphere (Karachentsev 1972; hereafter CPG) and the Catalog of Isolated Galaxies (Karachentseva 1973; hereafter KI). Observations of these large, unbiased samples of paired and isolated galaxies are analyzed with the hope of identifying which aspects of galaxy encounters are most closely coupled to the presence of activity.
Radio Structures in QSO-Galaxy Pairs
Authors: Akujor Chidi E.
Published: July 2016

It is now generally agreed that if quasars and nearby low redshift galaxies are associated, then there should be luminous connections between them. However, most of the observational evidence being presented is in the optical domain, whereas such evidence should also exist at radio frequencies. We are, therefore, investigating some QSO—Galaxy pairs at radio frequencies to search for luminous connections and other structural peculiarities. Radio maps of some of these sources are presented.
A Tentative Explanation of Cosmological Red Shift
Authors: Chang T. , Torr D. G.
Published: July 2016

In this paper we suggest a possible alternative explanation of cosmological red shift. We consider that there exists a background field in the universe, and that light (the photon) has an extremely weak interaction with this background, and as result, experiences an energy loss. By analogy with damped oscillations, we introduce a dumping term with the first derivative with respect to time in the wave equation. The solution yields a linearly reduced freguency of the light with travel distance. The purpose of this exercise is to demonstrate how a simple alternative interpretation of the Hubble relation can be generated.
A Simulation Survey of Galaxy Interactions
Authors: Byrd G. , Keel W. , Howard S.
Published: July 2016

Many carefully selected samples of interacting galaxies have been observed expensively in attempts to clarify whether interaction produces activity in galaxies. Because the sample members represent a wide range of encounter parameters and times, one can then study whether there are correlations between observable encounter features and, for example, Seyfert activity. On the other hand, in theoretical studies, simulations typically deal with either time-consuming detailed modelling of single galaxy pairs or tracing a few model encounters over time. We are extending the observational survey approach by combining it with a simulation survey.
Dynamical Theory of Dense Groups of Galaxies
Authors: Mamon Gary A.
Published: July 2016

It is well known that galaxies associate in groups and clusters. Perhaps 40% of all galaxies are found in groups of 4 to 20 galaxies (e.g., Tully 1987). Although most groups appear to be so loose that the galaxy interactions within them ought to be insignificant, the apparently densest groups, known as compact groups appear so dense when seen in projection onto the plane of the sky that their members often overlap. These groups thus appear as dense as the cores of rich clusters. The most popular catalog of compact groups, compiled by Hickson (1982), includes isolation among its selection critera. Therefore, in comparison with the cores of rich clusters, Hickson’s compact groups (hereafter, HCGs) appear to be the densest isolated regions in the Universe (in galaxies per unit volume), and thus provide in principle a clean laboratory for studying the competition of very strong gravitational interactions. The $64,000 question here is then: Are compact groups really bound systems as dense as they appear? If dense groups indeed exist, then one expects that each of the dynamical processes leading to the interaction of their member galaxies should be greatly enhanced. This leads us to the questions: How stable are dense groups? How do they form? And the related question, fascinating to any theorist: What dynamical processes predominate in dense groups of galaxies?. If HCGs are not bound dense systems, but instead ID chance alignments (Mamon 1986, 1987; Walke & Mamon 1989) or 3D transient cores (Rose 1979) within larger looser systems of galaxies, then the relevant question is: How frequent are chance configurations within loose groups? In this review, I will answer these last four questions after comparing in some detail the methods used and the results obtained in the different studies of dense groups, while in the accompanying contribution, I will attempt to reconcile the recent observations of galaxy interactions in HCGs with a negative answer to the first question.
Collisional Removal of Hi from the Inner Disks of Virgo Cluster Galaxies
Authors: Valluri Monica , Jog Chanda J.
Published: July 2016

In addition to the well established global HI-deficiency seen in Virgo cluster spirals, many of them are found to be HI-deficient in their inner disks. We show that collisions between galaxies in a cluster can lead to the preferential removal of HI from these galaxies. This follows directly from the application of the Spitzer-Baade collisional gas removal mechanism to galaxies consisting of stars and a two-component ISM of HI and H2, with HI having the largest filling factor. This can account for both the observed Hl-deficiency in the inner disks of these galaxies as well as their normal H2 contents. The frequency of galaxy collisions in the Virgo cluster is shown to be large enough to make collisional gas removal a viable mechanism.
A Two-Dimensional Near—Infrared Speckle Imaging Survey of T Tauri Stars in Taurus and Ophiuchus
Authors: Ghez A. , Neugebauer G. , Matthews K.
Published: July 2016

We present the results of a magnitude limited (K≤8.5 mag) multiplicity survey of T Tauri stars in the two nearest star forming regions, Taurus-Auriga and Ophiuchus-Scorpius (D = 150 pc), observable from the northern hemisphere. Each of the 70 stars in the sample was imaged at 2.2 μm using two-dimensional speckle interferometry resulting in a survey sensitive to binary stars with separations ranging from 0.″09 to about 2″.5.

The frequency of double stars with separation in this range is 46±8%. A division between the classical T Tauri stars and the weak-lined T Tauri stars shows no distinction. Furthermore, no difference is observed between the binary frequencies in the two star forming regions although the clouds have very different properties.

Given the limited angular separation range that this survey is sensitive to, both the spectroscopic and wide binaries will be missed. The rate at which binaries are detected suggests that most, if not all, T Tauri stars have companions.
The Murky Depths of the Main Sequence: Nearby Speckled Dwarfs and Elusive Brown Beasts
Authors: Henry Todd J. , McCarthy Donald W.
Published: July 2016

Using infrared speckle imaging techniques, we have completed a comprehensive survey of all northern (δ ≥ −25°) M dwarfs within 8 parsecs for low mass companions. Of the 74 targets searched, six new companions were found. Included in the final census are four objects orbiting their primaries at sub-arcsecond separations which have masses near 80 Jupiters, making them viable brown dwarf candidates. Three of these — LHS 1047B, GL 623B and G 208-44B — are the faintest red objects for which masses have been determined and represent the limit of our current knowledge about the faint end of the mass-luminosity relation.

The complete sample includes 99 members, and under further analysis reveals fundamental facts about the red dwarf population that were unknown until the present study: 1) 30-40 % of M dwarf primaries have companions, 2) more companions are found orbiting 1-10 AU from the primary than in any other decade interval, and 3) there are 50% fewer red dwarfs known in the more distant half of the survey volume, presumably because the parallax and proper motion surveys are incomplete.

In addition, we find that the infrared luminosity function (LF) is fiat or rising toward the end of the main sequence, while the visible LF may be flat, and we illustrate that the determination of an accurate LF is critically sensitive to the resolution of binaries. A better description of the stellar population, the mass function, is found to be undoubtedly rising to the stellar/substellar break. Finally, we have developed a much-needed mass-luminosity relation for stars of mass 1.2 to 0.08 M⊙, and using these relations find that the M dwarfs contribute ~0.2 M⊙/pc3 to the galactic mass.
The Short-Period Binary Frequency Among Low-Mass Pre-Main Sequence Stars
Authors: Mathieu Robert D.
Published: July 2016

The pre-main sequence (PMS) binary frequency is a fundamental datum in the study of binary formation. It reflects on numerous basic issues, such as:

• The formation process. Binary stars are the primary branch of the star-formation process, and thus their frequency is an essential challenge to star-formation theories. (Indeed, the infrequency of single-star formation is likely as significant as the binary frequency.)

• The epoch of binary formation. Assessing whether the binary population exists in total by the pre-main sequence phase sets an upper limit on the binary formation timescale.

• Early period evolution. The frequency distribution as a function of period of PMS binaries, when compared to the distribution at the zero-age main sequence, can shed light on early orbital evolution.

• The interaction of binaries with disks. The formation and consequent dynamical evolution of a binary with semi-major axis less than typical disk radii must substantially modify disk structures and accretion flows. Thus the binary frequency might differ between PMS stars with and without associated disks.
Pre-Main Sequence Binaries: The ESO Imaging Survey
Authors: Zinnecker H. , Brandner W. , Reipurth B.
Published: July 2016

We have observed a complete sample of southern Hα emission line pre-main sequence (PMS) stars associated with the nearby dark clouds Chamaeleon and Ophiuchus in an effort to detect binary companions. We have used the high resolution CCD camera SUSI (0.13″ /pixel) at the ESO 3.5m New Technology Telescope (NTT). The observations were carried out in the Gunn z filter (0.95μ). As a result, we have discovered 28 companions out of 160 objects surveyed in the range of angular separation 0″.5 – 10″. We present histograms of semi-major axes and of brightness ratios of these PMS binaries. Taking small incompleteness corrections into account, the frequency of PMS binaries with semi-major axes in the range 100-1500 AU is 20%, while it is only 15% in same range for solar-type Main Sequence (MS) stars. Extrapolation yields a total PMS binary frequency of 70%. Evolutionary and environmental implications are briefly discussed.
Duplicity Among Young Stars in Chamaeleon
Authors: Chen Wen Ping , Graham J.A.
Published: July 2016

We present infrared imaging results of young stars in Cha I and II clouds that show either extended structure or a nearby neighboring star. Both regions appear to show high incidence rates of pairs. After excluding possible background stars, as judged from their brightness, color, or the local stellar surface number density, a frequency of 10% is deduced for binaries in Cha I with separations 2-5″, which is comparable to that in Taurus and to that of main sequence field stars.
Dusty Disks in the Multiple Systems UZ Tau and GG Tau
Authors: Simon M. , Guilloteau S.
Published: July 2016

Interferometric observations of the 2.6 mm dust thermal emission around the T Tauri triple system UZ Tau show that most of it is equally divided between UZ Tau W (the close binary) and UZ Tau E. The emission is at least partially optically thick at 2.6 mm which implies an origin in disks of size ~ 13 AU and mass ~ 0.024 M⊙. The 2.6 mm emission of the GG Tau system, a hierarchical quadruple, is partially resolved. Strong emission extended over ~ 3″ × 5″ is associated with the close binary GG Tau. Weak emission is detected at GG Tau/c, also a close binary. Evidently extensive dusty disks can survive in the environment of close binaries for at least ~ 105 y, and their structure can vary markedly from system to system.
Spectroscopic Studies of Multiple Stars and Speckle Binaries: How to observe ad infinitum
Authors: Fekel Francis C.
Published: July 2016

Over the past 16 years at the McDonald Observatory and the Kitt Peak National Observatory, I have obtained high-dispersion spectroscopic observations of roughly 3 dozen multiple systems and 7 speckle or astrometric binaries. The current status of this obviously long-term project is discussed. Although some systems have periods of about 50 to 85 years, most have periods in the range of 1 to 20 years. Thus, many now have been observed for at least one cycle and preliminary spectroscopic orbital elements have been determined. For a number of the systems fundamental data such as the distance to the system, as well as the individual spectral types, absolute magnitudes, and masses can be obtained if accurate visual/speckle orbital elements also are known. These elements and the derived fundamental parameters may be used as constraints on multiple-star formation theory.
Spectroscopic Studies of Binary and Multiple Star Systems
Authors: Griffin R.F.
Published: July 2016

There can be few subjects that benefit more than binary stars do from complementary approaches. Consider their orbits, for an initial example. By ‘visual’ methods — by which I mean all methods of obtaining angular resolution on the sky, including the modern techniques of optical interferometry — one can determine an orbit, but with the scale known in terms of angular measure only. By spectroscopic (radial-velocity) methods one obtains the linear scale of the orbit, but with those techniques the inclination to the line of sight is indeterminate. In order to find the complete characteristics of the orbit in three dimensions — as is essential in order to find those most important data, the masses of the component stars — one needs to utilize both methods. It is, accordingly, clearly of great value to have a meeting like this that is object-oriented rather than technique-oriented; it is a long time since there was a meeting specifically devoted to binary stars, and especially in view of the great advances that have taken place in observational techniques of all sorts in recent years it is more than timely that we should have this meeting now. We are certainly very grateful to Dr. McAlister and his colleagues for arranging it and holding it at this beautiful venue.
Ultra-High Accuracy Masses of Eclipsing Binary Stars
Authors: Lacy Claud H.
Published: July 2016

New observational spectroscopic methods have made it possible to obtain radial velocities of eclipsing binary star components with unprecedented accuracy. Most of the improvement in accuracy is due to two techniques: (1) The use of optical fibers to scramble the spatial distribution of stellar brightness at the input end of the spectrometer, and to allow the spectrometer to be located off the telescope where its temperature and position can be stabilized. (2) The simultaneous exposure of the comparison emission-tube light through a separate fiber or pair of fibers adjacent to the stellar fiber continuously during the stellar exposure. Any changes in the response of the spectrometer during the exposure then affect the stellar and adjacent comparison spectra in almost exactly the same way.
Adaptation of Docobo’s Method for the Calculation of Orbits of Spectroscopic-Interferometric Binaries with Mixed Data
Authors: Docobo J.A. , Ling J.F. , Prieto C.
Published: July 2016

Based on Docobo’s method for the calculation of orbits of visual binaries, an algorithm is presented for the calculation of short-period orbits when observational data comprise radial velocities and polar coordinates. The method is applied to some examples.
Calculation of Perturbations in the Stellar Three-Body Problem
Authors: Docobo J.A. , Prieto C. , Ling J.F.
Published: July 2016

The method of perturbations of Deprit has been applied to the stellar three-body problem. The calculation, developed previously by the authors in other articles, is here systematicized for easy use and applied to various triple systems.