bluuebunny/crossref_metadata_2025_split huggingface dataset:
Galaxy Photometry in the Virgo Cluster. I.
Authors: Fritze K. 
Published: July 2007

AbstractIn a field of about 0.6 square degrees near the centre of the Virgo cluster of galaxies a photometry in B, V, and R has been performed by means of the microphotometer of the Zentralinstitut für Astrophysik. For 84 galaxies identified in this field magnitudes, diameters, and axis ratios has been determined.
Dwarf Galaxies in the M 81/82 Group. New Photometric Data
Authors: Börngen F. , Karachentseva V. E. , Schmidt R. , Richter G. M. , Thänert W. 
Published: July 2007

AbstractWe present a list of 39 dwarf galaxies of the M 81/82 group. Three different methods are applied to determine their apparent integral magnitude: digital processing, equidensitometry, and calculation according to the formulae of FISHER and TULLY. The plates used were obtained with the Tautenburg Schmidt telescope. For a distance of the group of 3.5 Mpc the absolute magnitudes of the dwarf galaxies investigated are ‐15m < M < ‐9m.
A New Light Curve Analysis of the Eclipsing Binary SX Aur
Authors: Giuricin G. , Mardirossian F. , Mezzetti M. 
Published: July 2007

AbstractUsing WOOD's (1972) model, we have analysed BONDARENKO's (1974) two‐colour photoelectric observations – till now unsolved – of the eclipsing binary SX Aur. Our photometric solutions turn out to be in substantial agreement with those derived by CHAMBLISS and LEUNG (1979); they confirm that SX Aur is a post‐mass exchange (case A) semi‐detached system.
On Equations of Motion for Cross Term Modified Gravitational Field Equations
Authors: Müller V. 
Published: July 2007

AbstractAs proposed by TREDER, possible consequences of a unitary field theory may be described phenomenologically by additional cross terms in EINSTEIN's equations. The violation of the weak principle of equivalence and potential observable effects are discussed in deriving hydrodynamic EIH equations. Conclusions on gravitational instabilities follow in the quasistatic approximation.
Photometric catalogue of Shakhbazian compact groups of galaxies. III.
Authors: Stoll D. , Tiersch H. , Oleak H. , Macgillivray H. T. 
Published: July 2007

AbstractThe third part of the photometric catalogue of Shakhbazian compact groups of galaxies contains optical and geometrical properties of another 24 groups (Shkh 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312). As in the first paper photometric data were obtained from the COSMOS/UKST catalogue of the Southern sky with δ ⩽ +2°30'. The survey of compact galaxy groups by Shakhbazian, Petrosian, Baier, and Tiersch is a basis for studying physical properties of such groups.
Confirmation of the Friedmann‐Lemaǐtre universe by the distribution of the larger absorbing clouds
Authors: Hoell J. , Liebscher D.‐E. , Priester W. 
Published: July 2007

AbstractA new theoretical approach is applied to the cloud model as an explanation for the Lyman α forest. It is based on the complete Friedmann equations including a Λ‐term. In the data sets of Lu et al. 1991 and Röser 1993 the lines are constrained by a lower limit (0.36 Å, 0.32 Å) of the intrinsic equivalent width. This makes them suitable for a cloud model analysis, supplementing the bubble wall models which also make use of the weaker lines. Both data sets can be represented satisfactorily by a Friedmann‐Lemaǐtre model with λ0 = 1.08 ± 0.02 and ω0 = 0.014 ± 0.006, although the regression formulae differ by an essential factor depending on the redshift. The age of the universe according to this model is 2.8.H0−1. It is not necessary to invoke any evolutionary effects in the number densities and in the physical parameters of the clouds.
The time‐delayed solar cycle luminosity modulation by sub‐surface magnetic flux tubes
Authors: Yoshimura Hirokazu 
Published: July 2007

AbstractIn order to explore the mechanism of the solar cycle luminosity change observed by the Active Cavity Radiometer Irradiance Monitor (ACRIM) I experiment on board of the spacecraft Solar Maximum Mission, we examined running mean time profiles of the daily ACRIM data from the declining phase of solar cycle 21 to the rising phase of solar cycle 22. By comparing them with those of the daily sunspot number, integrated surface magnetic field flux, integrated He I 10830 Å line equivalent width data, and two kinds of data sets of the daily integrated Ca II K line index as indices of the surface magnetic activities, we found (i) that the running mean time profiles of the six independent data sets have several peaks and valleys in common in one solar cycle with time intervals on the order of a few hundreds of days, and (ii) that the peaks and valleys of the ACRIM data profiles followed the peaks and valleys of all the other five indices of the surface activities by 40 to 60 days. This time delay phenomenon suggests (i) that the luminosity modulation was not directly caused by dark and bright features of the surface magnetic activities that the other five indices represent, and (ii) that the missing sunspot radiative flux which was blocked by sub‐surface magnetic flux tubes of sunspots and sunspot groups should be re‐radiated 40 to 60 days after the surface emergence of the magnetic flux tubes. The concept of the time delay resolves the enigma of the missing sunspot radiative flux and the enigma of the ACRIM experiment that the luminosity dropped when a sunspot or a sunspot group appeared on the surface while the yearly mean of the luminosity decreased and increased along with the decrease and increase of the yearly sunspot number of the 11‐year solar cycle. A model of the mechanism to understand these phenomena is presented and its application to other stars is suggested.
prior to surface appearance of sunspot flux tubes and magneto‐thermal pulsation of the Sun
Authors: Yoshimura H. 
Published: July 2007

AbstractWe found an evidence that the luminosity of the Sun systematically decreased about 20 days before sunspot surface appearance by analysing time‐lag correlation of time derivatives of running mean time profiles of the data of the Active Cavity Radiometer Irradiance Monitor (ACRIM) I experiment on board of Solar Maximum Mission (SMM) and of the data of the daily sunspot number. This indicates that sunspot flux tube cooling and heat transport blocking by the flux tubes start to take place in the interior of the solar convection zone well before the sunspot surface appearance. From this finding and our previous finding that the luminosity of the Sun systematically increased and the blocked heat appeared on the surface about 50 days after the sunspot surface appearance, a new view of sunspot formation and dynamics and a new view of the luminosity modulation emerged. (i) Sunspots of a solar cycle are formed from clusters of flux tubes which can be seen in the running mean time profile of the sunspot number as a peak with duration on the order of 100 to 200 days. (ii) Heat flow is blocked by the cluster of sunspot flux tubes inside the convection zone to decrease the luminosity about 20 days before the surface emergence of the sunspot cluster. (iii) The blocked heat appears on the surface about 50 days after the surface emergence of the cluster of sunspot flux tubes to heat up the surface. This appears as a thermal pulse in the running mean time profile of the ACRIM dat in between the peaks of the sunspot running mean time profile. This process of heating the surface makes the temperature gradient less steep and weakens the buoyancy of sunspot flux tubes below the surface. (vi) The radiative cooling of the surface layer by the excess heat release steepens the temperature gradient so that the buoyancy of the sub‐surface magnetic flux tubes becomes stronger to cause the next surge of emergence of a cluster of sunspots and other magnetic activities, which creates a peak in the time profile of the sunspot number. We call this peak a magnetic pulse of the Sun and the coupled process of alternating pulsed appearance of heat and sunspots the magneto‐thermal pulsation of the Sun.
A spectrum of the veiled T Tauri star CY Tau
Authors: Stüwe J. A. , Schulz R. 
Published: July 2007

AbstractWe present a flux calibrated spectrum of the star listed as CY Tau in the “General Catalogue of Variable Stars 4th ed.” (Kopolov et al. 1987) in the spectral range 3700 Å ⩽ λ ⩽ 6400 Å with a resolution of ≈︁ 15 Å showing the Balmer‐Series from Hβ to H10 as well as the Call H (in blend with Hα) and K lines in emission. Apart from the emission. Apart from the emission lines the spectrum is composed of a continuum equivalent to that of an ordinary pre‐main sequence star (i.e. a “naked” T Tau) of spectral type M2 V with emission lines plus a “blue” veiling continuum that can be described as black body radiation of temperature Tbl ≈︁ 7000 K due to accretion onto a boundary layer at a rate of Macc ⪆ 2.8 10−8 M⊙ a−1.
Photographic photometry for stellar statistics with Tautenburg Schmidt telescope
Authors: Andruk V. , Kharchenko N. , Schilbach E. 
Published: July 2007

AbstractPhotometric properties of deep Tautenburg Schmidt plates in the UBV system over the whole field and over a wide range of stellar magnitudes are discussed. Different reduction models based on the calibration curve alone and with additional terms containing colour and plate coordinates are considered.With the filter‐emulsion combinations used the Johnson UBV system can be reproduced quite well by the Tautenburg telescope. The accuracy of photometric data can be improved if geometrical terms are taken into account. For deep plates with a significant effect of background nebulosity a supplementary term is to be included in the reduction model. The polynomial coefficients vary in dependence on spectral bands and individual properties of each plate.
Schmidt plate survey in the galactic centre direction. 1. Investigation of open clusters in the Sagittarius‐Carina spiral arm
Authors: Kharchenko N. , Schilbach E. 
Published: July 2007

AbstractA study of four open clusters on Tautenburg Schmidt plates in the direction to the Galactic Centre (l = 17.0°, b = +0.8°) is presented. In a field of 8.95 square degrees proper motions and B, V magnitudes were determined for about 36 500 stars up to the limiting magnitudes B = 17m.9, V = 16m.8. For stars brighter than B = 16m an accuracy of about 3 mas/year has been estimated for proper motions. The rms errors of stellar magnitudes and (B—V) colours is about 0.1 mag.There are two open clusters already known in this sky area: Trumpler 32 (C 1814‐133) and NGC 6611 (C 1816‐138). By the inspection of the plates two additional anonymous clusters were identified near the double star ADS 11285 or BD −14°5014 (C 1819‐146) and near the star BD −14°5016 (C 1820‐146). The cluster membership determination was carried out using information on spatial and proper motion distributions of stars in the field. The colour‐magnitude diagrams up to the limiting stellar magnitude were constructed. For each cluster interstellar extinction AV, diameters of the core and corona, ages and spatial velocity components (V, W) relative to the LSR in the Y, Z‐galactic directions were derived.The distances to the clusters were obtained to 1720 pc, 2260 pc, 2130 pc and 2130 pc for Trumpler 32, NGC 6611, C 1819‐146 and C 1820‐146, respectively. All clusters are situated in the Sagittarius‐Carina spiral arm. Their spatial location confirms the assumption that galactic spiral arms are close to logarithmic spirals with a characteristic angle of about 20 degrees.
Coherence between Seyfert galaxies and their surroundings
Authors: Mahtessian A. P. , Khachikian E. Ye. , Tiersch H. 
Published: July 2007

AbstractA sample of galaxy groups is investigated for the occurence of Seyfert objects within them. The velocity dispersion in groups with Seyfert galaxies is significantly larger than in groups without Seyfert galaxies. But there was not found any correlation between the galaxy density within the groups and the content of Seyfert galaxies.
Eléments Orbitaux Definitif de I'Etoile Double Visuelle ADS 5871 — STF1037
Authors: Scardia M. 
Published: July 2007

AbstractAus einer Gesamtheit von 315 Beobachtungen wurden die Bahnelemente des visuellen Doppelsternes ADS 5871 — STF 1037 wiederberechnet. Die nach der Methode von KOWALSKY erhalten vorläfigen Elemente wurden mit der Differenzenmethode von HELLERICH korrigiert und die dynamische Parallaxe und Gesamtmasse berechnet.
Density and Radial Velocity Strucutre of the Hydra I Cluster of Galaxies
Authors: Baier F. W. , Oleak H. 
Published: July 2007

AbstractThe investigation of the distributions of number densities, radial velocities and morphological types in the Hydra I cluster led us to the conclusion that this cluster possesses dominant substructures. This result is in agreement with former conclusions of different authors that substructures are a typical phenomenon for a high percentage of all clusters of galaxies. The galaxies inside the radius 60 from the cluster centre giv ea mean cluster redshift 3332±102 km/s and a velocity dispersion 679 ± 87 km/s.
Iterative and Direct Determinations of the Gravitational Potential of Axisymmetric Mass Distributions in Spherical Coordinates
Authors: Tschaepe R. 
Published: July 2007

AbstractHighly flattened objects may appear in early stages as well as in late stages of stellar evolution. The calulation of their axisymmetric gravitational potential in spherical coordinates requires a lot of computer time. In this paper we compare iterative solutions of the Poisson differential equation with direct evaluations of the Poisson integral with respect to accuracy and time consumption. further, we derived a fast direct method which is superior in computer time to the discussed methods whereas its accuracy remains nearly unchanged.
Beobachtungen Kleiner Planeten. III
Authors: BÖrngen F. , Kirsch K. 
Published: July 2007

AbstractEs wird eine Übersicht über die im Jahr 1982 auf Tautenburger Schmidtaufnahmen gefundenen Kleinen Planeten gegeben. Es wurden 229 Objekte entdeckt und für sie 643 Positionen gerechnet. Für zehn, 1982 numerierte Planeten haben Tautenburger Beobachtungen einen Beitrag geleistet. Der von uns entdeckte Planet (2424) erhielt den Namen Tautenburg.
Luminosity Profiles of 6 Dwarf Galaxies in the M 81/82 Group
Authors: Karachentseva V. E. , Schmidt R. , Richter G. M. 
Published: July 2007

AbstractThe main photometric parameters of six very low surface brightness dwarf galaxies of the M81 group are obtained. For the first time the luminosity profiles of extreme dwarfs outside the local group are given. The profiles are much more consistent to the exponential law than to the r1/4 law. No significant differences in profile between irregulars and sphericals could be found.
A Catalogue of Extremely Young, Massive and Compact Infrared Objects (Mitteilungen der Universitäts‐Sternwarte zu Jena Nr. 165)
Authors: Henning Th. , Friedemann C. , Gürtler J. , Dorschner J. 
Published: July 2007

AbstractAusgehend vom Becklin‐Neugebauer‐Objekt in der Orion‐Molekülwolke I als Prototyp wird anhand zahlreicher Beobachtungsmerkmale eine Klasse von kompakten Infrarotquellen abgegrenzt, von denen man annehmen kann, daß sie junge massereiche von optisch dicken Staubhüllen umgebene Sterne sind. Ein Katalog gibt für 34 Objekte ausführliche Informationen, u. a. über Infrarot‐ und Radiospektren, das Vorhandensein von Masern und Ausströmungserscheinungen.
Photometric and Spectroscopic Study of the Variable Star ET And
Authors: Gerth E. , Scholz G. , Panov K. P. 
Published: July 2007

AbstractSpectroscopic and photometric observations of the variable ET And were carried out in the years 1981/82. In addition to the known periodical variation of the radial velocities of 48.308 days produced by a companion and the photometric period of 1.61883 days probaly resulting from the rotation of the star some other periodical variations exist. The radial velocities vary further with a period of 0.1989 days and the photometric data with the half of this value, i.e. with 0.0994 days. The minima of the light coincide with the extrema of the radial velocity. The radial velocity curve deviates somewhat from a pure harmonic, more precisely, the values increase more rapidly than they decrease. The same behaviour also appears for the corresponding part in the light curve.
Scale Factor of Isotropic Homogeneous Universe
Authors: Popic R. V. 
Published: July 2007

AbstractFour fundamental expressions of isotropic homogeneous universe lead to the scale factor equations. Their solution is achieved by developing the factor as a power series of time, establishing the recursion relations among its coefficients, performing the summation of this power series and obtaining the scale factor as a function of time in a closed form. This one should be used in comparison to observational data with different cosmological models, generally present within this formalism.
Pre‐main sequence stellar activity
Authors: Belvedere G. 
Published: July 2007

AbstractModels of stellar activity based on the α–ω dynamo have recently been proposed by BELVEDERE et al. (1980c, 1981b) for main sequence and giant late type stars.In the present work we extend the theoretical analysis to the pre‐main sequence fully convective phase of stellar evolution. As a measure of magnetic activity we assume the intensity of the toroidal magnetic field Bt. The results show that Bt decreases with the increasing effective temperature along the evolutionary track of a star of given mass. It is stressed the crucial dependence of the intensity of the magnetic field on the rotation rate.Comparison with the observations of pre‐main sequence stellar activity in the very young galactic cluster NGC 2264 is briefly discussed.
Secondary α‐effect in the nearly symmetric dynamo
Authors: Cupal I. 
Published: July 2007

AbstractAn attempt has been made to examine the role of the secondary α‐effect in the nearly symmetric dynamo. The tensor form of the effect has been found and it is concluded that this effect only plays a role under special assumption of the disturbance velocity field. The secondary alfa effect can amplify the generation of the azimuthal field from the poloidal field in the α2‐dynamo rather than in the αω‐dynamo.
Bestimmung absoluter Eigenbewegungen in einem KSZ‐Feld mit zwei Astrographen
Authors: Dick W. R. 
Published: July 2007

AbstractIn the field No. 153 of the KSZ program relative proper motions of 144 stars up to 15m.0 are presented as well as parameters for the reduction to absolute with reference to 6 galaxies. The external error of one proper motion is 0.014″/y. It is shown that in a small field the statistical method for the estimation of the magnitude error is not able to give significant results due to the variance of the proper motion. It is concluded that in practice the long focus and the wide angle astrographs of the Main Observatory of the Ukrainian Academy of Science in Kiev can be combined for the derivation of proper motions.
Eine neue Methode zur Bestimmung der statistischen Zählverluste bei Photonenzählern
Authors: Hildebrandt G. , Lange D. 
Published: July 2007

AbstractA simple method for the determination of statistical pulse losses of photon counting photometer in dependence on the pulse intensity was deveoloped. The slowly decereasin brightness of the clear sky in the dusk serves a light source. With the help of neutral filter one gets two different pulse rates for two intensities. From a series of such measurements with different intensities one can derive the correction in dependence on pulse density in form of a power sequence.
A constraint on the past star formation rate from the kinematics of nearby stars
Authors: Meusinger H. 
Published: July 2007

AbstractThe age dependence of the velocity dispersions σv(τ) of the nearby stars is considered under distinct assumptions on the history of the star formation rate. The velocity distributions N¦U¦, N¦V¦, N¦W¦ are derived from this by means of the diffusion theory using the standard case by WIELEN AND FUCHS (1983a) and are compared with the observed distributions of a kinematically unbiased sample of nearby stars. The best agreement is found for a nearly constant star formation rate.
On the influence of density and temperature fluctuations on the formation of spectral lines in stellar atmospheres
Authors: Stahlberg J. 
Published: July 2007

AbstractEs wird eine Methode zur Berücksichtigung von Temperatur und Druckschwankungen, die durch das Geschwindigkeitsfeld bedingt sein sollen, angegeben. Um das so beeinflußte Linienprofil zu erhalten, werden die Größen einer statischen Atmosphäre durch gemittelt und fluktuierende Anteile ersetzt. Die auftretenden Korrelationen werden über bekannte Gleichungen der Hydrodynamik berechnet Es resultiert, daß in gewöhnlichen Sternatmosphären, in denen nur kleine Werte des Dichte‐ und Druckgradienten sowie der mittleren stochastischen Geschwindigkeit vorkommen, die optischen Linienprofile nur schwach durch diese Effekte beeinflußt werden.
An analytic model for phase transitions in the early Universe
Authors: Diósi L. , Lukács B. , Keszthelyi B. , Paál G. 
Published: July 2007

AbstractA simplified model of the very early Universe is presented for studying the effects of the GUT phase transition on the cosmic evolution and vice versa. An exact description of a strongly first order phase transition is given. Both inflationary and non‐inflationray solutions are obtained. The cosmological scale factor and the temperature are determined and graphically depicted. The self‐consistency of our simplifying assumptions needed to get analytic solutions are checked. Contrary to expectations spread in the literature, the strongly first order character of the phase transition in itself is found to be insufficient to solve the monopol problem inherent in most GUT cosmologies.
Search for dwarf galaxies in the IC 342 complex of galaxies
Authors: Börngen F. , Karachentseva V. E. 
Published: July 2007

AbstractA survey of dwarf galaxies was carried out in the inner part of the IC 342 complex of galaxies, which is a subgroup of the M81 group, in an area of about 42 sq. degrees by means of Tautenburg 52‐in. Schmidt plates. Fifteen new dwarf candidates and four extended “cloudy” objects of very low surface brightness not yet classified were discovered. Coordinates, linear dimensions as well as remarks on the nature of the cloudy objects are given. A deeper analysis with 6‐meter plates is planned to study a part of the new objects more exactly.