bluuebunny/crossref_metadata_2025_split huggingface dataset:
IC5063: A Merger with A Hidden Luminous Active Nucleus
Authors: Colina L. , Sparks W. , Macchetto F. 
Published: July 2016

Despite intense theoretical and observational effort during the past few years, two important questions in the field of active galaxies remain open and are the subject of vigorous debate.The first concerns the connection between the interaction/merger of galaxies and the generation of starburst and/or active nuclei. A large fraction of high luminosity radio galaxies (Baum et al. 1988), quasars (Hutchinga, 1987) and IRAS galaxies (Sanders et al. 1988), show the presence of a large companion or have a peculiar optical morphology which is offen interpreted as evidence of a recent merger or interaction. In Seyferts, there are also several examples of individual galaxies with clear evidence of interaction/merger (Colina et al. 1987; Fricke and Kollatschny, 1989; Macchetto et al. 1990). Also a significant fraction of low luminosity radio galaxies are associated with a system of two elliptical galaxies in interaction (Colina and Pérez-Fournon, 1990a,b).
A Classification of the Galaxy Groups
Authors: Anosova Joanna P. 
Published: July 2016

AbstractA statistical criterion has been proposed to reveal the random and physical clusterings among stars, galaxies and other objects. This criterion has been applied to the galaxy triples of the list by Karachentseva, Karaschentsev and Scherbanovsky, and the double galaxies of the list by Dahari where the primary components are the Seyfert galaxies. The confident physical, probable physical, probable optical and confident optical groups have been identified. The limit difference of radial velocities of components for the confident physical multiple galaxies has also been estimated.
A Survey of Young Stars in Taurus for Multiplicity
Authors: Leinert Ch. , Weitzel N. , Haas M. , Lenzen R. , Zinnecker H. , Christou J. , Ridgway S.T. , Jameson R. , Richichi A. 
Published: July 2016

AbstractWe surveyed all stars in Taurus (3h 45m < α < 4h 15m, 15° < δ < 35°) for multiplicity which are contained in the Herbig-Bell catalogue of young stars and have a 2 micron brightness of K ≤ 9.5 mag. This sample consists of 106 stellar systems (single or multiple), of which 43 are double or multiple according to the criteria of our survey, i.e. with separations of ≈0″.2 ≤ d ≤ 10″. Of these, 23 binaries are new detections found in this survey. The resulting degree of multiplicity, 43/106 = 41±6%, is higher than found for main-sequence stars. Provided that the period distribution is the same for young stars as on the main sequence, our result implies that the vast majority of stars are born in binary or multiple systems.
A Comparative Study of Lithium Abundances, Radial Velocities, and Emission Lines in Pre-Main Sequence Visual Binaries
Authors: Martín Eduardo L. , Rebolo Rafael , Magazzù Antonio 
Published: July 2016

AbstractHigh resolution (R ~ 20000) spectroscopic observations of visual pairs of T Tauri stars (TTS) in the spectral range 655-675 nm, and 385-405 nm for some systems, are reported. Good seeing allows us to resolve pairs with minimum angular separation of ~ 2″. The radial velocities, overall spectral properties and detection of the Li I line are used to decide whether the components of the binaries are likely to be gravitationally bounded. In this paper we present first results on a subset of our sample: 3 visual companions are not TTS, namely DL Tau/c, GG Tau/c(SW) and NTTS 45251+3016/c. The star GG Tau/c(S) is confirmed as a T Tauri star. The system UZ Tau is probably composed of at least 4 components. The star 1E0255.3+2018 (Fleming et al. 1989), previously thought to be single, is found to be a close visual binary. Finally, lithium abundances for the PMS components of 6 binaries are presented and their consistency with theoretical expectations is briefly discussed.
Duplicity Among Solar-Type Stars
Authors: Abt Helmut A. , Willmarth Daryl W. 
Published: July 2016

AbstractFrom a new study of 113 F8-G1 IV or V primaries in an apparent-magnitude limited sample, measured with a CCD for about 20 radial velocities of accuracy 0.2-0.5 km s−1 each, we collected data for 28 binary orbits and 39 visual systems. We again found a flat distribution (or slightly decreasing toward lower masses) of secondary masses, unlike the Salpeter distribution for B2-B5 stars. But we find that the different distributions for these field stars and for open clusters of various ages can all be explained by a capture mechanism of binary formation.
Searching for Optical Visual Double Stars
Authors: Sinachopoulos D. , Mouzourakis P. 
Published: July 2016

AbstractWe study a sample of 123 wide visual double stars for which astrophysical parameters are at least partly available from uvby Hβ photometry. All of these have components brighter than 10 mags and a component angular separation between 10 and 20 arcseconds.We find that at least one third of them are optical; for relative proper motion (RPM) pairs this fraction is 60% or even more. These results are in fair agreement with the predictions we formulated in an earlier paper on the basis of a statistical criterion.
An Impression from Programmes Performed at ESO about the Interest of European Astronomers in Visual Double and Multiple Star Research
Authors: Van Dessel E.L. 
Published: July 2016

AbstractThe European Southern Observatory gives opportunity to the European astronomical community to use a large variety of instruments. In this paper we try to make an assessment about the proposals that show an interest in visual binary and multiple star research. The material is based on projects proposed and performed in the last 3 years. Main streams of research are: speckle measurements, radial velocities, photometry (completion of catalogues), and astrometric positions.
Survey for Duplicity Frequencies: Status and Prospects
Authors: Couteau Paul 
Published: July 2016

I.We recall the main surveys: J. Herschel (1826), W. Struve (1825), A.W. Burnham and G.W. Hough (1880), R.G. Aitken and W.J. Hussey (1910), R. Jonckeere and T.E. Espin (1910), W.H. van den Bos (1925), R.A. Rossiter (1950). Presently the classical surveys are continuing with P. Muller, W.D. Heintz, and P. Couteau. The interferometric survey with large telescopes is carried out at CHARA.II.The results of old surveys, up to 1950, amount to 700 known orbits out of more than 35000 found binaries. The new surveys since 1965, both visual and interferometric, had checked 4000 new binaries giving already about 30 orbits. The periods are shorter and shorter: the mean period is 200 years for Struve (1825) binaries, 75 years for Aitken’s (1910), 25 years for Couteau and Muller’s (1970), and 7 years for CHARA’s. The number of known orbits increases exponentially with time.III.The “classical” surveys will have to be performed again within fifty years with refractors.The interferometric and aperture syntheses surveys will be able to observe every binary, even those in contact with each other. With HIPPARCOS’ results, astronomers will dispose of a complete set of data for new theories of stellar evolution.
A Study of the Motion of the Nearby Red Dwarf Lalande 21185
Authors: Shakht Natalia A. 
Published: July 2016

AbstractA series of photographic observations spanning the interval 1962 – 1991 have been examined in a study of Lalande 21185, suspected to be a double or multiple object. The observed value of secular acceleration corresponds to the radial velocity of this star. The perturbations in proper motion with suspected period of 8 years have not been confirmed.
A Study of ADS 5983 (δ Geminorum)
Authors: Shakht Natalia A. , Kiyaeva Olga V. 
Published: July 2016

AbstractRegular photographic observations of ADS 5983 (δ Gem) with the Pulkovo 26-in refractor have been made since 1972. The series of observations over the time interval 1972-1990 are considered. New orbital elements of the binary are obtained by the AMP–method. Some wave with a period about 5 years in the orbital motion of this star is found.
The Analysis of HST Fine Guidance Sensor Transfer Functions
Authors: Lattanzi M.G. , Bucciarelli B. , Holfeltz S.T. , Taff L.G. 
Published: July 2016

AbstractWe present an overview of the ST ScI calibration program and the reduction, smoothing, and analysis capabilities we have developed to deal with Transfer Functions. The Transfer Function (TF) is the name for the fringe visibility curve produced by the Koesters prism interferometer in the Fine Guidance Sensors (FGSs). The TF for a single, point, monochromatic source becomes modified — in different ways — when we observe a real source with a typical stellar energy spectrum, a finite disc, or a double system. Thus, we have constructed an in depth calibration program and designed and developed a comprehensive set of TF analysis algorithms. The ST ScI calibration program includes the acquisition of reference TFs at 19 different places in the astrometer FGS (there are field–dependent aberrations beyond the well–publicized spherical aberration of the primary mirror). In addition, for Cycle 2, both stars with finite angular diameters and minor planets will be observed. The software to implement our correlation–based analysis techniques has been extensively tested on artificial binary stars created by combining real TFs and re-introducing photon noise. A wide variety of synthetic binaries — with separations from 10 to 135 milli-arcseconds and magnitude differences from 0 to 4.2 mag — were used so that we can objectively and quantitatively characterize the capability of both the software and the instrument to resolve close pairs and to detect faint companions. Separations to a few milli-arcseconds, position angles to , and magnitude differences to are attainable for primaries brighter than V = 13 mag and Δm < 3 mag. The software is being incorporated into IRAF/STSDAS at the ST ScI.
Raw Data from HIPPARCOS Double and Multiple Stars
Authors: Bernacca P.L. , Donati F. , Mignard F. 
Published: July 2016

AbstractThe HIPPARCOS Input Catalogue comprises about 118,000 entries of which 16,000 are flagged as related to double or multiple stars. Data analysis begins by fitting Fourier model signals to the observations: the intensity coefficients and the phases at several locations on the spatial modulator are estimated and a first rough recognition of possibly unknown non-single stars is performed. After calibration corrections, a normal point is produced at every transit of a star across the field of view of the telescope and the improved parameters are stored for extensive multiplicity testing and relative astrometry when enough scans are accumulated.
HIPPARCOS First Results in the Double Star Photometry
Authors: Mignard F. , Falin J.L. , Froeschlé M. 
Published: July 2016

AbstractIn addition to its astrometric capabilities the HIPPARCOS main detector proves to be a good phototometer. The main features of the photometric reduction applied to double stars are outlined. We show how it is possible to discriminate single stars from multiple stars from the photometric signal. Results presented are based on about 16000 stars recognized as non-single, of which 8000 were not known to be double in the HIPPARCOS Input Catalogue. Magnitudes for multiple systems as a whole are derived with a precision usually better than 0.005 mag while the magnitude of each component is recovered up to magnitude difference of 3 mag, but with less accuracy and precision.
First Double Star Observations in the HIPPARCOS Tycho Project
Authors: Halbwachs Jean–Louis 
Published: July 2016

AbstractThe Tycho project will provide positions and (B, V) magnitudes for about 1 million stars, and will be complete for stars brighter than magnitude (B + V)/2 = 10.5. The components of double stars will obtain individual measurements when the separations are wider than 3″.
The Potential of Long–Baseline Optical Interferometry of Binary Stars
Authors: McAlister H.A. 
Published: July 2016

AbstractInterferometric arrays possessing sub-milliarcsecond resolution are either about to be fully scientifically productive, as in the case of the Sydney University Stellar Interferometer, or are under various stages of planning and development. The 1990’s will thus witness a hundred–fold gain in resolution over speckle interferometry at the largest telescopes and 5,000 times the resolution of classical direct imaging. Where speckle interferometry can now resolve binary stars with periods of 1 to 2 years, interferometric arrays with baselines of hundreds of meters will resolve binaries with periods of a few hours. Arrays will resolve the majority of the known spectroscopic binaries, providing a substantial increase in the quantity and quality of stellar mass determinations. Surveys for new binaries among the field stars and other restricted samples will be accomplished with unprecedented completeness. The remarkable enhancement in resolution we are about to witness from facilities like SUSI and our own proposed CHARA Array will quite literally revolutionize the field of double and multiple star research.
Binary Orbits from Interferometric Data
Authors: Hummel C.A. , Armstrong J.T. 
Published: July 2016

Using the variable baseline of the Mark III Optical Interferometer (Shao et al. 1988) with lengths ranging from 3 to 31.5 m, we measured the fringe visibility of stars in three 25 nm bandpass filters, at wavelengths between 800 nm and 450 nm. This setup gives fringe spacings ranging from 55 mas to 3 mas.255 stars brighter than fifth magnitude and north of –10° declination were selected from the Batten et al. (1989) catalog of spectroscopic binaries. We compiled values for the orbital axes from the McAlister & Hartkopf (1988) catalog. If unknown (in the majority of cases), they were estimated from the masses predicted from the spectral types, the periods (if known), and the distances to the binaries. Priority was given to the binaries with orbital axes between 3 mas and 40 mas. Observational procedures and the calibration of the data are described by Armstrong et al. (1992). Statistical and calibration uncertainties are in the range of 1% (red channel) to 10% (blue channel).
Photoelectric Photometry — The First Fifty Years
Authors: Hearnshaw J.B. 
Published: July 2016

AbstractThis historical review covers the first fifty years of the electrical measurement of starlight, which saw its beginnings in August 1892 when William Monck used a Minchin photovoltaic cell on his refractor in Dublin. The work of Stebbins using photoconductive cells from 1907 and of Guthnick, Stebbins and others using photoelectric cells from 1912 is also discussed. The advances brought about by thermionic amplification and the red-sensitive Cs-O-Ag photocathode in the early 1930s by respectively Whitford and Hall enabled new astrophysical problems to be tackled. Although many observers attempted photoelectric photometry, relatively few were successful during the 1920s and ‘30s. It was not until the introduction of the 1P21 photomultiplier tube that astronomers had a reliable and sensitive detector for photometric observations.
Atmospheric Intensity Scintillation of Stars on Milli- and Microsecond Time Scales
Authors: Dravins D. , Lindegren L. , Mezey E. 
Published: July 2016

AbstractStellar intensity scintillation on short and very short time scales (≃ 100 ms - 100 ns) was studied using an optical telescope on La Palma (Canary Islands). Photon counting detectors and real-time signal processing equipment were used to study atmospheric scintillation as function of telescope aperture size, degree of apodization, for single and double apertures, in different optical colors, at different zenith distances, times of night, and seasons of year. The statistics of temporal intensity variations can be adequately described by log-normal distributions, varying with time. The scintillation timescale (≃10 ms) decreases for smaller telescope apertures until ≃5 cm, where the atmospheric ‘shadow bands’ apparently are resolved. Some astrophysical sources may undergo very rapid intrinsic fluctuations. To detect such phenomena through the turbulent atmosphere requires optimized observing strategies.
Photometric and Spectrophotometric Data Required for the SUSI Programme
Authors: Shobbrook R.R. 
Published: July 2016

The Sydney University Stellar Interferometer, SUSI, a modern version of a Michelson stellar interferometer, will be capable of measuring the angular diameters of stars down to V ≈ 8.0, for all spectral types. The resolution of the 640 m baseline — <0.1 milliarcsec at optical wavelengths — includes reasonable sample sizes of all spectral types and luminosity classes to this magnitude limit.The angular diameter data require complementary photometric, spectrophotometric and also spectroscopic data for the determination of fundamental parameters of single and multiple stars. This paper discusses the accuracy required of these data for some of the main problems to be tackled by SUSI. A selection of the programmes planned for this unique instrument is listed below, where the need for complementary data is also indicated.• The measurement of the changes of angular diameters of Cepheids and other pulsating stars such as Mira variables. Comparison with the linear changes determined from radial velocity curves will enable their distances and luminosities to be determined by an essentially geometric method.• The measurement of the angular sizes of the orbits and of one or both components of spectroscopic binary stars. This effectively makes them ‘visual’ binaries so that the orbital inclination, i, may be determined. When these data are combined with the velocity curve solutions which include (mass)sin3i and (semi – majoraxis)sin i, we may determine masses and linear radii of one or both components and also the distances to the systems. Also, the light curve of an eclipsing binary provides information on the ellipticities and radii of the components and on the eccentricity of the orbit — information which may be used to aid the analysis of the SUSI data. In addition, the determination of the light curve (some bright systems have not been observed for up to one or two decades) is the quickest method of finding the current phase of its orbit.• The establishment of the total-flux-based temperature scale of all spectral types and luminosity classes from O to M. This requires accurate photometry and spectrophotometry over as wide a wavelength range as possible; it therefore also requires observations from space observatories, as was also necessary for the analysis using the Narrabri intensity interferometer data (Code et al., 1976).• The measurement of diameters of stars with shells or extended atmospheres, such as Be and Wolf Rayet stars, at different wavelengths — in particular, in the emission lines.
Transformations and Modern Technology
Authors: Tinbergen Jaap 
Published: July 2016

AbstractTransformations are a central issue in making a global network do more than simple monitoring of low-amplitude variability. I explore the approach of observing at a much narrower instrumental bandwidth than is required for the scientific problem; such an approach would have the following advantages:•transformations can be handled in standard fashion at the instrumental level; at the scientific level, they can be avoided entirely,•users have almost complete freedom in specifying the shape of the scientific passbands, hence comparison of observational data with stellar atmosphere models can be maximally effective,•standard star observations can be used repeatedly, for programmes running concurrently in different scientific photometric systems,•an observer can use existing standard-star observations to create his own specially-tailored photometric system from scratch,•all-sky homogeneity of the instrumental system can be tested against space photometry such as that provided by HIPPARCOS; this will benefit other scientific systems synthesized from the same instrumental system.Key components in the hardware will be array detectors with low readout noise and a calibration lamp system designed specifically for this application. A data base provides the link between the observations (in the instrumental system) and the results (with scientific passbands defined by the end user).
CCD Time-Series Photometry of Faint Astronomical Sources
Authors: Howell Steve B. 
Published: July 2016

AbstractUsing CCDs to obtain time-series light curve information is an increasing area of interest in astronomy. For brighter, high signal-to-noise sources, the data collection and reduction procedures are very robust and easy to use. However, for fainter, low signal-to-noise objects we must resort to new methods. These include the use of optimum data extraction techniques, a fuller understanding of the CCD itself, and a more complete error model. This paper will provide a brief introduction to CCD time-series photometry and then explore the above new methods in relation to real observational situations.
Faint Photometry with the HST Wide Field Camera
Authors: Hughes S.M.G. 
Published: July 2016

AbstractA series of 40 HST WFC exposures in v (F555W) and i (F785LP) have been obtained of two fields in M81, in order to search for Cepheid variables. This has provided an ideal opportunity to compare how the photometry programs DoPHOT and DAOPHOT cope with undersampled images, and present our ‘best solution’ to the problem of reducing WFC photometry for faint stars in crowded fields.
Supernova Rates
Authors: Van Den Bergh Sidney 
Published: July 2016

Extragalactic supernova rates are reviewed. The main uncertainties in calculated rates are due to (1) the influence of the (still poorly known) luminosity function of supernova of a given type on “control times”, to (2) uncertain corrections for possible inclination - dependent bias in supernova discovery probabilities, and (3) interstellar absorption. The total supernova rate in late-type galaxies is found to be ∼ 2(H0/75)2 supernovae (SNe) per century per 1010LB(ʘ) This is consistent with the rate of 3 SNe per century that is derived from the historical data on Galactic supernovae. It is, however, a source of some concern that none of the three Galactic SNe expected to have occurred during the last century was actually observed!The expansion velocities of SNe Ia are found to correlate strongly with parent galaxy Hubble type. This relation is in the sense that low expansion velocities are only observed for those SNe Ia that occur in early-type galaxies. This suggests that V(exp) correlates with the ages of SNe Ia progenitors. It is speculated that the progenitors of a few SNe Ia with high V(exp) values in E and S0 galaxies were formed during recent starbursts.SNe Ia rates appear to be enhanced in post-starburst galaxies. It is suggested that supernova rates might be quite high in the recently discovered population of faint blue galaxies at intermediate redshifts.
Observations of Spectroscopic Binaries at Ultraviolet and Red Wavelengths
Authors: Fekel Francis C. 
Published: July 2016

AbstractRecent advances in detector technology as well as the launching of the International Ultraviolet Explorer (IUE) satellite have opened new spectral regions for extensive spectroscopic observation. A program to determine the feasibility of radial velocity measurement for binaries whose secondaries are of earlier spectral type has been initiated with the IUE satellite. It is expected that velocities with uncertainties as small as 2-5 km s−1 may be obtained for some stars. This observing program includes tau Per and other composite spectrum binaries as well as several early-type binaries.For the past five years, a Reticon solid-state photodiode array detector has been used at the coudé focus of the 2.7 m McDonald Observatory reflector to obtain radial velocities of spectroscopic as well as short-period visual binaries. The high quantum efficiency, red sensitivity, and stability of this detector system permit velocities of high accuracy to be determined and previously unseen spectroscopic components to be detected.