bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beobachtungen Kleiner Planeten. XIII
Authors: Börngen F. , Schmadel L. D. 
Published: July 2007

AbstractEs wird eine Übersicht gegeben über die im Jahr 1992 auf Tautenburger Schmidtplatten gefundenen Kleinen Planeten. Es wurden 518 Objekte beobachtet und für diese 2396 Positionen gerechnet. Es handelt sich um 408 Planetoiden mit provisorischer Bezeichnung, unter denen 274 neu vergebene Bezeichnungen sind, sowie um 110 numerierte Objekte. Für 172 Tautenburger Objekte wurden Bahnen aus einer Opposition gerechnet. Für 55 im Berichtszeitraum numerierte Planeten haben Tautenburger Positionen einen Beitrag geleistet. Acht Tautenburger Planetoiden wurden numeriert (Tab. 3). A summary is given about the Minor Planet survey performed in 1992 on Tautenburg Schmidt plates. 518 asteroids were observed and 2396 positions are calculated for them. These are 408 asteroids with provisional designations (274 of them have new designations) and 110 numbered objects. One‐opposition orbits have been computed for 172 Tautenburg asteroids. Tautenburg observations could give a contribution to 55 planets numbered in the period of this report. Eight Tautenburg asteroids have been numbered (Tab. 3).
Dynamics of dimensions in factor‐space cosmology
Authors: Bleyer U. , Rainer M. , Mohazzab M. 
Published: July 2007

AbstractFor multi‐dimensional cosmological models we investigate the dynamics of both, scales and dimensions. The classical equation of motions and the corresponding Wheeler‐de Witt equation are set up generally and the qualitative behaviour of the system is discussed for some specific model with 2 factor spaces: A space M1 with dynamical dimension, and a compact internal space M2 of constant dimension. With a natural choice of some contraint, there exist a solution where M1 expands as usual space while M2 is shrinking down to unobservable scales.
Schmidt plate survey towards the Galactic centre. 2. Stellar statistics in the direction of the Sagittarius‐Carina arm
Authors: Kharchenko N. , Schilbach E. 
Published: July 2007

AbstractA study of the structure and kinematics of the Galaxy from Tautenburg Schmidt plates taken towards the Galactic centre (l = 17.0°, b = +0.8°) is presented. Proper motions and B, V magnitudes were determined for about 36 500 stars up to the limiting magnitude V = 16m.8 in a field of 8.95 square degrees. Proper motion accuracy of about 3 mas/year has been obtained for stars brighter than V = 15m. The rms errors of stellar magnitudes and (B–V) colours is about 0.1 mag.The majority of field stars in the survey are main sequence stars and red giants of the disk. They belong to the Local or Sagittarius‐Carina arms, or they are located between these spiral arms. Comparing the modelled and observed distributions of magnitudes and colours, we specified the interstellar extinction determined in the preceding study of open clusters in this field.The luminosity function towards the Galactic centre was determined for stars with absolute magnitudes from ‐4m.35 to +9m. Kinematical and spatial distribution parameters up to 4 kpc from the Sun were obtained as a function of galactocentric distance.
Photometric survey near the main Galactic meridian: 2.2. Finding charts and photoelectric UBVR stellar magnitudes in 26 fields
Authors: Andruk V. , Kharchenko N. , Schilbach E. , Scholz R.‐D. 
Published: July 2007

AbstractFinding charts and photoelectric magnitudes of stars in the UBVR system in 26 fields of the MEGA programme are presented. This part of the photometric survey near the Main Galactic Meridian includes the fields with right ascentions 8h < α < 16h30m and declinations −2° < δ < 58°. Together with the finding charts of 2.5° × 2.5° the equatorial coordinates of the stars are given for epoch and equinox 1950. Photometric properties of the night sky at the Mount Terskol observatory near Mount Elbrus are derived from the photoelectric observations.
The irregular galaxy Cassiopeia 1 – a new member of the Local group
Authors: Tikhonov N. 
Published: July 2007

AbstractA photometry in the V, R, I (Cousins) system has been performed for stars in the galaxy Cassiopeia 1. The resulting colour‐agnitude (CM) diagram of Cas 1 reveals the existence of blue stars and the absence of red ones. From an analysis of the CM diagram of the galaxy it is concluded that Av = 4.0 mag, and the distance modulus (m – M)o = 24.5 mag, corresponding to a distance of 790 kpc. The visual magnitude of the galaxy is V = 14m.62 (Mv = −13m.8) and the colour index (V – R) = 0.89 mag. From the distance determination the galaxy Cassiopeia 1 is a member of the Local group.
Nearby galaxies. IV. The global Hubble parameter and the dispersion of the Hubble relation
Authors: Schmidt K.‐H. , Karachentsev I. D. 
Published: July 2007

AbstractUsing a spherically symmetric model of the Virgo flow the global Hubble parameter has been estimated from the observed radial velocities and the photometrically measured distances of nearby galaxies. Adopting the observed recession velocity of the Virgo Cluster to about 1000 km s−1 and the infall velocity of the Local Group to 350 km s−1 the global Hubble constant results to 73 ± 10 km s−1 Mpc−1. This value corresponds with the distance of the Virgo Cluster of 18 ± 2 Mpc. The cosmic dispersion of the galaxies around the Hubble relation is of order of 35 km s−1.
Young stars in the disk of M82
Authors: Notni P. , Karachentsev I. , Makarova L. 
Published: July 2007

AbstractWe present CCD VIC photometry in a field 1.9 − 1.3 square arcmin and positioned about 3 arcmin north‐east of the centre of M82. More than 100 stars have been identified and measured above the photometric limits V = 23m.5, I = 22m. Most of the objects fainter than V ≈︁ 20m should be members of M82 as expected from the statistics of foreground stars.Starlike as well as 2–3 somewhat diffuse objects ‐ candidates of globular clusters ‐ preferentially occupy yellow colours in the colour‐magnitude diagram; extreme blue and red objects are missing. The colour‐magnitude diagram indicates continuing star formation in this part of the disk. The absence of blue stars is caused by reddening; no convincing explanation is found for the missing red supergiants. Young stars are distributed throughout the whole field, the youngest being concentrated in associations at the SW edge of the field.To cope with the very irregular background created by the galaxy' s main body and with the low contrast of many of the stars against this background, a modified photometric method is introduced in which the background is estimated using the intensities in a ring drawn very tightly around the star in the wings of the point spread function.
Fluxtube magnetic field measurements in a solar flare in comparison with non‐flare regions
Authors: Kostenko L. M. , Lozitskij V. G. 
Published: July 2007

AbstractMeasurements of the fluxtube field strength B and filling α in solar flares, active regions and faculae have been analyzed. To estimate the values of B, Stokes V peak separations of the Fe I 5247 Å and Fe I 5250 Å lines have been used. It was found that the value of B in an In‐flare (˜ 1.1 kG) was slightly smaller than that in faculae (˜ 1.3 kG) and a non‐flare active region (˜ 1.4kG). On the other hand, in a more power 2b‐flare the value of B was in the range from. 1.1 kG (the start of the flare) to 1.55kG. (during the peak). Thus the values of the field strength of flares somewhat differ from those both of faculae and active regions. The magnetic filling factor is approximately equal in flares (0.2‐0.40) and active regions (0.3) but several times larger as compared with faculae.
Diurnal variations of cosmic rays during a solar magnetic cycle
Authors: El‐Borie M. A. , Sabbah I. S. , Bishara A. A. 
Published: July 2007

AbstractWe have used data from five neutron monitor stations with primary rigidity (Rm) ranging from 16 GeV to 33 GeV to study the diurnal variations of cosmic rays over the period: 1965–1986 covering one 22‐year solar magnetic cycle. The heliosphere interplanetary magnetic field (IMF) and plasma hourly measurements taken near Earth orbit, by a variety of spacecraft, are also used to compare with the results of solar diurnal variation. The local time of maximum of solar diurnal diurnal variations displays a 22‐year cycle due to the solar polar magnetic field polarities. In general, the annual mean of solar diurnal amplitudes, magnitude of IMF and plasma parameters are found to show separte solar cycle variations. Moreover, during the declining period of the twenty and twenty‐ne solar cycles, large solar diurnal amplitudes are observed which associated with high values of solar wind speed, plasma temperature and interplanetary magnetic field magnitude B3.
Seasonal oscillations in length‐of‐day
Authors: Höpfner J. 
Published: July 2007

AbstractVariations of annual and semiannual oscillations in rotation parameters have been investigated on the basis of length‐f‐ay(LOD) as well as atmospheric‐ngular‐omemtum (AAM) series. These oscillations were determined using band‐ass filters. In order to show the character of variations of seaasonal oscillations, amplitudes, phases and periods were computed by a least‐quares adjustment with the method of modified harmonic analysis at quarterly intervals. In addition, the seasonal imbalances in LOD and AAM budgets were determined and analysed in a similar way. These discrepancies were corrected for tidally excited effects. The non‐tmospheric oscillations without the annual tide effect Sa and the semiannual tide effect Ssa have variable amplitudes between 0.02 and 0.10 msec.
Multi‐colour surface photometry of a sample of HI‐detected late type galaxies
Authors: Vennik J. , Richter G. M. , Thänert W. , Biering C. 
Published: July 2007

AbstractWe perform BV RI surface photometry of 27 late type spiral and dwarf galaxies. All but two galaxies are selected from the HI‐survey of Schneider et al. (1990). We derive integral photometric parameters and the radial light and colour profiles and compare them to those of several LSB and bright field galaxy samples. Our new data confirm the earlier suggestions that the ‘ Schneider's sample’ consists of two different types of galaxies, with probably different star formation histories. First, the nearby (v0 ⩽ 1600 km s‐ 1) galaxies are mostly true dwarfs with the mean absolute magnitude of MB = ‐ 14.9±1.5 and with disk scale lengthes smaller than 1 kpc. These dwarfs are reasonably blue with median B – V = 0.49 and contain a large amount of neutral gas. Second, the distant (v0 ⩾ 4500 km s‐ 1) galaxies are late type LSB galaxies with typical face‐on disk central surface brightnesses of about 23.3 B‐ mag arcsec‐ 2 and ‘ normal’ disk scale lengthes of 3.6±1.5 kpc. Observed LSB galaxies are significantly redder, with median B – V ⋍ 0.72, than are the typical field LSB galaxies. The observed LSB galaxies are rich in HI but the current star formation activity is probably low.
An alternative method of finding bifurcation points in pseudo‐barotropes
Authors: Caimmi R. 
Published: July 2007

AbstractStarting from the equations of hydrodynamics, which include both collisional and collisionless ideal fluids, the special case of pseudo‐arotropes with anisotropic pressure distribution along tangential or vertical direction (in respect to a “vertical” rotation axis) is considered. We find that vertical motions are equivalent to an imaginary rotation, and call “pseudo‐otation” the combination of rotation and real or imaginary peculiar circular motions. By use of a necessary condition for equilibrium, i.e. the coincidence of the boundary with an isopotential (gravitational + rotational centrifugal + real peculiar or imaginary peculiar centrifugal) surface, a new method of finding bifurcation points from axisymmetric to triaxial pseudo‐arotropic sequences – discussed in an earlier paper – is dealt with for the systems under discussion. A simple application to the special case where the isopycnic surfaces are spheroidal discloses that, on one hand, steadily pseudo‐otating, heterogeneous spheroids, cannot be equilibrium configurations and, on the other hand, the same results obtained by use of the virial technique hold when the current method can work. Then the coincidence of the boundary with an isopotential surface and the validity of the virial equations of the second order make two independent (necessary) conditions for equilibrium and both must be satisfied. Under the further assumptions of steady rotation and homeoidally or focaloidally striated distribution of matter, the configurations for which a bifurcation point must necessarily occurr, are determined. In the former alternative a connection is also established, between local (on the boundary) and global anisotropy of pressure distribution; in particular, it is found that local isotropy (on the boundary) involves global isotropy and vice versa. In both cases, the right amount of of anisotropy turns out to yield violation of a treshold for stability, ϵrot = −Erot/Epot ⩽ 0.14, conjectured by Ostriker and Peebles (1973). This result gives additional support to a conclusion established in an earlier paper: it seems more germane to speak about Ostriker‐eebles conjecture for stability in connection with visible bodies of galaxies, instead of Ostriker‐eebles criterion for stability in connection with self‐ravitating fluids.
On the emptiness of voids
Authors: Schmidt K.‐H. , Böhm P. , Elsässer H. 
Published: July 2007

AbstractThe observability of a galaxy population inside of voids is estimated by assuming a void population similar to the one of nearby field galaxies in density as well as in morphological mixture. Obviously an extension to apparent magnitudes beyond m = 22 for a complete sample of galaxies in a sufficient large field is needed to get reliable information on a void population.
Preliminary results on the study of the environment of a complete sample of Seyfert galaxies
Authors: Salvato M. , Rafanelli P. 
Published: July 2007

AbstractThe results of the study of the environment of a complete sample of Seyfert galaxies taken from the CfA Redshift Survey (Davis et al. 1983; Huchra et al. 1983) are shown. In particular we compare the distribution of the positions of all galaxies located within five diameters from each Seyfert galaxy of our sample with the angalogous distribution observed in a control sample of normal galaxies taken from the Merged Catalogue of Galaxies (hereafter MERCG) (Kogoshvili 1986). This research is based on the analysis of the digitized images of the “Digitized Sky Survey” and on the on‐line catalogues APM (Automatic Plate Measuring System) and APS (Automated Plate Scanner).
X‐ray variability study of ROSAT sources
Authors: Voges W. , Boller T. 
Published: July 2007

AbstractThe Röntgensatellite ROSAT has been in orbit since June 1,1990. After a 6‐month all‐sky survey ˜ 6,500 pointed observations have been performed. In total more than 150,000 X‐ray sources have been detected. Among the various object classes observed are comets, stars, white dwarfs, cataclysmic variables, neutron stars, black hole candidates, supernova remnants, nearby galaxies, AGN, and clusters of galaxies. Many of these objects are known to be time variable sources. Various catalogues of sources found in the ROSAT All‐Sky Survey and in the pointed observations are used as the basis for studying the temporal behaviour of ROSAT sources. This paper deals with the description, production and content of the various ROSAT catalogues with particular emphasis on the usefulness for the study of source variability.
Ultrasoft narrow‐line Seyfert 1 galaxies and X‐ray surveys
Authors: Brandt N. , Boller T. 
Published: July 2007

AbstractWe describe how recent X‐ray surveys have led to advances in the understanding of ultrasoft narrow‐line Seyfert 1 galaxies. The number of known ultrasoft narrow‐line Seyfert 1s has increased greatly in recent years due to X‐ray surveys, and it is now possible to obtain high quality 0.1–10 keV spectral and variability measurements for a large number of these galaxies. We generalize some of the correlations between X‐ray properties and optical emission line properties, focusing on how the ROSAT band spectral slope appears to be directly connected to the Boroson & Green (1992) primary eigenvector. We discuss how ultrasoft narrow‐line Seyfert 1s may well have extremal values of a primary physical parameter, and we describe new projects that should further improve our understanding of these extreme representatives of Seyfert activity.
Faint galaxies and the X‐ray background
Authors: Almaini O. , Shanks T. , Gunn K. F. , Boyle B. J. , Georgantopoulos I. , Griffiths R. E. , Stewart G. C. , Blair A. J. 
Published: July 2007

AbstractWe summarise our recent work on the faint galaxy contribution to the cosmic X‐ray background (XRB). At bright X‐ray fluxes (in the ROSAT pass band), broad line QSOs dominate the X‐ray source population, but at fainter fluxes there is evidence for a significant contribution from emission‐line galaxies. Here we present statistical evidence that these galaxies can account for a large fraction of the XRB. We also demonstrate that these galaxies have significantly harder X‐ray spectra than QSOs in the ROSAT band. Finally we present preliminary findings from infra‐red spectroscopy on the nature of this X‐ray emitting galaxy population. We conclude that a hybrid explanation consisting of obscured/Type 2 AGN surrounded by starburst activity can explain the properties of these galaxies and perhaps the origin of the entire XRB.
The X‐ray evolution of clusters of galaxies
Authors: Jones L. R. , Scharf C. , Perlman E. , Ebeling H. , Horner D. , Wegner G. , Malkan M. , Mchardy I. 
Published: July 2007

AbstractThe WARPS survey currently contains 48 X‐ray selected clusters and groups of galaxies, detected serendipitously in ROSAT PSPC archival pointed observations. The survey includes the highest redshift X‐ray selected cluster known (z=0.8325). The redshift range is large enough for evolutionary effects to be studied within the sample. Here we describe the X‐ray luminosity function and Log(N)‐Log(S) results for the initial complete sample of 29 spectroscopically confirmed clusters. We find that the X‐ray luminosity function does not evolve at z∽0.5 for cluster luminosities of ∽1044 erg s−1, but that there is a hint of positive evolution at lower luminosities from the number of groups & clusters found in the faintest available X‐ray cluster sample (the UK deep survey).
New ROSAT PSPC all‐sky survey maps of the diffuse soft X‐ray background
Authors: Freyberg M. J. 
Published: July 2007

AbstractNew maps of the soft X‐ray background (SXRB) using data from the ROSAT PSPC All‐Sky Survey have been constructed in 7 energy bands and with 12′ spatial resolution. Statistics of the intensity maps and of the exposure map are presented. Modeling of the 1/4 keV and of 3/4 keV data yields apparently conflicting results. However, besides the different data sets involved in the fits also different distances and regions may have been sampled with different properties (lower halo, upper halo of the Galaxy). Also model imperfections (e.g., temperature variations, non‐equilibrium) could explain some differences. An outlook is given to improved spectral binning of reprocessed (so‐called RASS2) survey data.
The XMM Serendipitous Survey
Authors: Watson M. G. 
Published: July 2007

AbstractThis paper provides an overview of the capabilities of the XMM Observatory and summarises the scope and potential of the XMM serendipitous survey. The role of the Survey Science Centre (SSC) in the XMM project is outlined, and a description is given of the SSC's plans for a follow‐up and identification programme which aims to ensure that the scientific potential of the serendipitous content of XMM fields can be fully exploited by the astronomical community.
Disila‐Okoumal: A Silicon Analogue of the Ambergris Odorant Okoumal
Authors: Büttner Matthias W. , Burschka Christian , Junold Konstantin , Kraft Philip , Tacke Reinhold 
Published: July 2007

AbstractTwo‐fold sila‐substitution (C/Si exchange) in the saturated ring of the tetrahydronaphthalene skeleton of the ambery odorant okoumal (5) provides disila‐okoumal (6). The okoumal isomers 5 a–d were synthesized from 1‐(5,5,8,8‐tetramethyl‐5,6,7,8‐tetrahydro‐2‐naphthyl)ethanone (7), and the silicon analogues 6 a–d were synthesized from 1‐(5,5,8,8‐tetramethyl‐5,8‐disila‐5,6,7,8‐tetrahydro‐2‐naphthyl)ethanone (8). Detailed olfactory properties of 5 a–d and 6 a–d are reported, together with the respective threshold values. All enantiomers of okoumal and disila‐okoumal exhibit typical ambery odor notes with woody facets, as is characteristic of okoumal and karanal, but a stereocenter at the 2‐position was found to be of utmost importance for the odor thresholds; the lowest value of 0.31 ng per L air was measured for the 2R‐configured silicon compounds 6 a and 6 c.
Lateral wall protein content mediates alterations in cochlear outer hair cell mechanics before and after hearing onset
Authors: Jensen‐Smith Heather , Hallworth Richard 
Published: July 2007

AbstractSpecialized outer hair cells (OHCs) housed within the mammalian cochlea exhibit active, nonlinear, mechanical responses to auditory stimulation termed electromotility. The extraordinary frequency resolution capacity of the cochlea requires an exquisitely equilibrated mechanical system of sensory and supporting cells. OHC electromotile length change, stiffness, and force generation are responsible for a 100‐fold increase in hearing sensitivity by augmenting vibrational input to non‐motile sensory inner hair cells. Characterization of OHC mechanics is crucial for understanding and ultimately preventing permanent functional deficits due to overstimulation or as a consequence of various cochlear pathologies. The OHCs' major structural assembly is a highly‐specialized lateral wall. The lateral wall consists of three structures; a plasma membrane highly‐enriched with the motor‐protein prestin, an actin‐spectrin cortical lattice, and one or more layers of subsurface cisternae. Technical difficulties in independently manipulating each lateral wall constituent have constrained previous attempts to analyze the determinants of OHCs' mechanical properties. Temporal separations in the accumulation of each lateral wall constituent during postnatal development permit associations between lateral wall structure and OHC mechanics. We compared developing and adult gerbil OHC axial stiffness using calibrated glass fibers. Alterations in each lateral wall component and OHC stiffness were correlated as a function of age. Reduced F‐actin labeling was correlated with reduced OHC stiffness before hearing onset. Prestin incorporation into the PM was correlated with increased OHC stiffness at hearing onset. Our data indicate lateral wall F‐actin and prestin are the primary determinants of OHC mechanical properties before and after hearing onset, respectively. Cell Motil. Cytoskeleton 2007. © 2007 Wiley‐Liss, Inc.