bluuebunny/crossref_metadata_2025_split huggingface dataset:
The connection between dark matter, internal motions and configurational properties of triple galaxies
Authors: Kiseleva L. 
Published: July 2016

AbstractNumerical simulations of the dynamics of triplets of galaxies show that virial estimations of the individual masses of triplets are unreliable because of strong nonsteadiness of these groups and projection effects. However, the mass of a typical small galaxy group can be estimated statistically, from data on a whole homogeneous ensemble of groups such as, for example, Karachentsev’s Catalogue of compact galaxy triplets. The characteristic total mass of a triplet from this catalogue is 4 - 7 times greater than the visible mass when the standard mass-to-light ratio is assumed. This suggests the presence of some considerable amount of dark matter even in these compact triplets. In wide triplets of galaxies the amount of dark matter may be significantly larger. The presence of distributed dark matter makes motions of galaxies in triplets more stochastic. In this case the existence of long-lived hierarchical configurations (temporary binaries) in triple systems becomes much less probable than without dark matter. The analysis of internal motions of galaxies in triplets and their configurations may be interpreted as additional non-dynamical evidence of the presence of dark matter in galaxy triplets.
Deducing the orbit of the radio galaxy 3C 129
Authors: Nilsson K. , Valtonen M. , Zheng J.-Q. , Byrd G. , Korhonen H. , Andersen M. I. 
Published: July 2016

AbstractWe have obtained new optical spectra of the radio galaxy 3C 129 and the giant galaxy close to it. From these spectra we deduce a relative radial velocity of 710 km s−1 between the two galaxies. Using the orbit calculations of Byrd & Valtonen (1978) and the new observations we obtain a new value, 3.3 × 1014M⊙, for the mass of the system.
On the Formation of Small Groups of Galaxies at High Redshifts
Authors: Saslaw William C. 
Published: July 2016

AbstractCosmological many-body clustering agrees with the spatial and velocity distribution functions of galaxies at low redshifts, and it can be extended to high redshifts z ≈ 3 or more. The high redshift distribution functions are predicted to have a particular form. In the simplest case, there are no free parameters in this prediction, but the degree of clustering depends sensitively on Ω0. Current observations of small groups at high redshifts suggest that Ω0 = 0.3 ± 0.2 for Einstein-Friedmann cosmologies.
Merging galaxies in compact groups: analytical theory
Authors: Kontorovich Victor M. 
Published: July 2016

AbstractThe predominance of minor mergers, i.e. the non-locality of mergings, results in a mass function slope (“Shechter” index) intermediate between a power-law index of a spectrum with constant mass flux and that of constant flux of the number of massive galaxies. The index proves to be close to that of the faint end of the galaxy luminosity function.
Be Star Surveys in Open Clusters with Balmer-line Photometry
Authors: Capilla Gemma , Fabregat Juan , Baines Deborah 
Published: July 2016

AbstractWe present CCD Hα and Hβ photometry of young open clusters. We show that the comparison of the α and β photometric indices provides an efficient tool for identifying emission line stars. We report on the discovery of several new Be stars.The preliminary results of our survey are the following: i. the younger clusters (age < 10 Myr) are almost lacking of Be stars, ii. clusters in the age interval 10–30 Myr are rich in Be stars. Almost all of them are of spectral types earlier than B5, while late-type Be stars are scarce. These results point towards an evolutionary interpretation of the Be phenomenon, in the sense that Be stars are close to the end of their main sequence lifetime.
Discovery of New Be Stars in the Galactic Open Cluster NGC7128
Authors: Balog Z. , Vinkó J. , Fűrész G. , Alfaro E. J. , Delgado A. J. , Moitinho A. 
Published: July 2016

AbstractWe present medium resolution spectroscopy (λ/Δλ ≈ 7,000) covering 6500-6750 Å of three emission stars in the highly reddened young open cluster NGC7128. Two of them were previously unknown. The known Be star (V1814 Cyg) is an irregular variable; one of the newly discovered stars is an eclipsing binary (V1481 Cyg) (Jerzykiewicz et al., 1996.). Physical parameters of the cluster have been determined from new UBV and uvbyHβ photometric measurements.
Be Stars in the Magellanic Clouds
Authors: Keller Stefan C. , Bessell M.S. , DaCosta G.S. 
Published: July 2016

AbstractWe present the results of our studies of Be stars within the Magellanic Clouds. We have studied the Be population within four young populous clusters, NGC 330 in the SMC, NGC 1818, 2004 and 2100 in the LMC as well as the field population around NGC 2004. The Be fraction within each cluster is seen to peak towards the luminosity of the main sequence turnoff. The field, which exhibits a large spread of ages, has a Be fraction more uniformly distributed in luminosity. We interpret this difference as evidence for an evolutionary enhancement of the Be phenomenon that occurs towards the end of the main sequence lifetime.
The B[e] Star MWC 84 (CI Cam)
Authors: Jaschek Carlos , Andrillat Yvette 
Published: July 2016

The star MWC 84 (CI Cam) was first discovered to be an emission line object classified Bep (Merrill & Burwell, 1933), then classified as a symbiotic star and finally identified as the possible optical counterpart of the X-ray transient XTE J0421+560 (Wagner & Starrfield, 1998)We have observed MWC 84 at the Haute Provence Observatory (CNRS) with a resolution of about 1.3 Å in 1992 (wavelength regions Hα and near infrared), 1998 and 1999 (from 4080 to 8880 Å).
Rapid Variations of Discrete Absorption Components in the spectrum of P Cygni
Authors: Israelian G.L. 
Published: July 2016

AbstractThe morphology and variability of spectral lines in the P Cygni high-resolution and high signal-to-noise near-UV spectra have been studied in detail over a period of few days. It is found that several Balmer lines have profiles with a complicated structure. All those lines which are well developed, but still not saturated, show two absorption components. A striking profile variability is discovered on a time-scale of from 1 to 3 days. The most dominant part of rapid variations is the drift of absorption components. It appears that there are two different kinds of components: long lived (with a characteristic time-scale of 200 days) and short-lived (time-scale of few days). The DAC phenomenon in the P Cygni stellar wind is a problems that still remains unsolved.
The Nebula Surrounding the B[e] Supergiant R4
Authors: Pasquali A. , Nota A. , Langer N. , Schulte-Ladbeck R.E. , Clampin M. 
Published: July 2016

AbstractNew, NTT observations of the B[e] supergiant RMC4 in the Small Magellanic Cloud show that the star is embedded in a circumstellar nebula, whose velocity structure is typical of a bipolar outflow. The nebula is kinematically associated with RMC4 and expanding at 100 km/s on average. Its diameter as computed from the spatial extension of its spectral lines is of 8.6″ which corresponds to a linear size of 2.4 pc and gives a dynamical age of 12500 yr. The line ratio [NII]λ6584/[SII]λ6717 indicates that the nebula is nitrogen enriched as it is expected for ejected nebulae. This is the first bipolar outflow detected around a well-established B[e] supergiant which also belongs to a binary system. The nebular morphology and chemistry are consistent with the picture of a binary merger in which RMC4 was composed by a close pair and a third star (the observed companion). The close pair merged into a single star (the present B[e] supergiant) and produced a circumstellar nebula to be later shaped by the ensuing B star wind (cf. Langer & Heger 1998).
Probing the Small Scale Structures around Herbig Be Stars using Hα Spectropolarimetry
Authors: Oudmaijer René D. , Drew Janet E. , Busfield Graeme 
Published: July 2016

AbstractWe present spectropolarimetric observations across Hα of a sample of Herbig Be objects. Roughly half of the observed Herbig Be stars show polarization changes across Hα, implying immediately that their ionized, hence inner, envelopes are not spherically symmetric. This pattern, if confirmed by observations of a larger sample, could indicate that the non-detection rate is simply a consequence of sampling randomly-oriented circumstellar disks able to scatter starlight within a few stellar radii, with as implication that the massive Herbig Be stars are still surrounded by accretion disks. In addition, we present preliminary modelling which will assist interpreting the kinematic structure of the electron-scattering region.
Optical Variability of the Be Star o And during the Period 1975–1998: Rotational Modulation or Multimodal Pulsations?
Authors: Guerrero G. , Sareyan J.P. , Alvarez M. , Chauville J. , Ferro A. Arellano , Mathias P. , Pena J. , Garciá E. 
Published: July 2016

AbstractPhotometric observations of o And collected from 1994 to 1998 are presented. Neither multimodal pulsations nor rotational modulation seems able to explain completely the complex light curves, but a model based on the pulsations together with some type of magnetic activity could be applicable.
Mid-term Photometric Periodic Variations in Be Stars HR 1960 and HR 2968
Authors: Carrier F. , Burki G. 
Published: July 2016

AbstractThe Be stars HR 1960 and HR 2968 have been monitored from 1978 to 1998 in Geneva photometry and from November 1989 to March 1993 by the Hipparcos satellite. A spectroscopic survey of these stars started in September 1998. Both stars show luminosity variations with a period of 395 d and 371 d for HR 1960 and HR 2968 respectively.
The Multiperiodicity of μ Cen (B2 IVe)
Authors: Baade D. , Rivinius Th. , Štefl S. 
Published: July 2016

AbstractWe re-discuss the reality of the four periods near 0.5 d and reject the claim (Balona et al., these proceedings) that μ Cen exhibits a single ∼0.66-d period caused by co-rotating clouds. The alleged 0.66-d period is not genuine but results from the simultaneous proximity of this value to the beat period between the true 0.28- and 0.5-d periods as well as to a 2-c/d alias of the 0.28-d period.
Phase Variation and NRP Modes in Southern Be Stars
Authors: Janot-Pacheco E. , Leister N.V. , de Souza A.D. , Jankov S. , Hubert A.M. , Floquet M. 
Published: July 2016

Abstractζ Ophiuchi and η Centauri are hot, rapidly rotating, southern Be stars showing multi-mode nonradial pulsations (nrp). We use high resolution, high signal-to-noise ratio spectroscopic observations of these objects to test the Telting and Schrijvers’ method (TS) of mode degree l and azimuthal order | m | estimation. In this method, these quantum numbers are calculated from the blue-to-red phase difference of the corresponding main frequency and its first harmonic, respectively. The phase differences were obtained withe the help of the Clean and Cleanest algorithms. Quantum numbers calculated with TS are compatible with those obtained with the Fourier Doppler method within the estimated errors. In the absence of other tools, the TS method can thus be used to estimate l and | m | with reasonably accuracy.
Short-term Periodicity in the Pole-on Be Star υ Cyg
Authors: Floquet M. , Neiner C. , Hubert A.M. , Janot-Pacheco E. , Leister N.V. 
Published: July 2016

AbstractThe pole-on Be star υ Cyg (HD 202904) displayed with Hipparcos photometry a strong long-lived outburst between 1989 and 1993. High S/N spectroscopic observations were obtained in August-September 1998. The photospheric λ6678 line is strongly perturbed by variable outer V and R emission components and is itself highly variable.All the studied quantities (profiles, EW, radial velocity of the line centroid, V and R emission components, V/R ratio) are dominated by ν = 1.5 c/d frequency. The first harmonic (ν = 3.0 c/d) is also detected in the central part of the profile. In the nrp frame, this pair of frequencies corresponds to a low degree sectorial g-mode l = |m| = 2. Moreover mid-term variations are superimposed to short ones.
Mapping the Non-Radial Pulsations
Authors: Berdyugina S.V. , Korhonen H. , Schrijvers C. , Telting J.H. 
Published: July 2016

AbstractWe apply the surface imaging technique to high-resolution spectra of the rapidly rotating β Cep-type star ω1 Sco. Assuming only temperature fluctuations due to pulsations, we obtain a map of the surface corotating with the dominant pulsation mode. Prom the map we identify the dominant mode and find traces of a second pulsation mode. We conclude that the traditional surface imaging technique can be successfully used for mapping stellar non-radial pulsations.
Spectral and Light Variability of Be Star 60 Cygni
Authors: Koubský P. , Harmanec P. , Huber A.M. , Floquet M. , Kubát J. , Ballereau D. , Božić H. , Chauville J. , Holmgren D. , Yang S. , Cao H. , Eenens P. , Huang L. , Percy J.R. 
Published: July 2016

AbstractThe analysis of high S/N spectra and photometric data of 60 Cyg shows that: (1) Pronounced long-term variations in spectra are accompanied with light variations. (2) The medium-term variations of RV could indicate that 60 Cyg is a spectroscopic binary. (3) Two independent structures dominate the rapid variability of both spectrum and light of the star.
Light Curves of Be Stairs due to Orbiting Arcs of Matter or Prominence-Like Structures
Authors: Zorec J. , Frémat Y. , Hubert A.M. 
Published: July 2016

AbstractAn alternative explanation to the light variations of some Be stars observed during their Be ⇌ Be-shell phase changes is proposed in terms of orbiting or passing clouds. Discrete ejections of matter and/or the presence of orbiting clouds suggest that the circumstellar envelopes of these Be stars may be clumpy.
Spectrophotometric and Photometric Behaviours of Be Stars: the Circumstellar Envelope Formation Mechanisms
Authors: Zorec J. , Hubert A.M. , Moujtahid A. 
Published: July 2016

AbstractA mechanism to create circumstellar envelopes in Be stars is proposed. The mechanism assumes a mass-loaded wind produced by ablated discrete stellar ejecta. The discrete mass ejections are suggested by the long-term spectrophotometric behaviours of Be stars and by their short and long-lived light outbursts discovered recently.
Shell Lines in Be Disks
Authors: Hanuschik R. W. 
Published: July 2016

AbstractShell lines have high diagnostic potential for the kinematical conditions in Be disks. We present here results from our long-term spectroscopic monitoring campaign of Fe II shell lines. We demonstrate that most of them are likely to arise in Keplerian disks being hydrostatically supported. There is furthermore one class of shell lines (dubbed NOACs) which does not fit into this simple scheme.
The Circumstellar Structure of the Be Shell Star ϕ Per
Authors: Hummel W. , Štefl S. , Rivinius Th. 
Published: July 2016

AbstractWe present phase resolved spectra of the Be binary ϕ Per. It is shown that orbital phase variations of the He I line profiles are due to a sector emission region in the circumprimary disk facing the secondary. The increasing asymmetry of Fe II emission lines indicates a density inhomogeneity in the circumprimary disk that developed after 1996.
Multiwavelength Monitoring of the Be/X-ray Binary XPersei - Evidence for Multiple Disk Structures
Authors: Roche P. , Tarasov A.E. , Lyuty V.M. , Clark J.S. , Larionov V. 
Published: July 2016

AbstractWe present optical photometry and high resolution optical spectra of the Be star X Persei/HD 24534, the counterpart to the X-ray pulsar 4U0352+30, obtained over the past ~10 years. These spectra show a variety of behaviour, ending with the onset of a strong V/R cycle. Observations of the He 16678 line suggest several episodes of discrete disc forming. This data forms part of a major long-term multiwavelength monitoring programme (UBVRIJHKL photometry plus optical and UV spectroscopy).
An MHD Model of Be Stars with Disks
Authors: Dudorov A. E. , Pudritz R. E. 
Published: July 2016

AbstractAn investigation of the formation and evolution of Be stars show that these stars could have dipolar fossil magnetic fields. This magnetic field should constrain the circumstellar magnetic disk and influence its dynamical features. For studying these effects we refine the alphamodel of accretion disks of Shakura and Sunyaev by incorporating into this model the evolution of large-scale magnetic fields. In the frame of our model we can investigate the rotational history of the star with the disk and the ionization and thermal properties of disks. We show in particular that in the magnetopause region a current sheet can form that can generate X-ray radiation.
Highly-Eccentric Be/X-ray Binaries: Evolution, Wind Rose Effect, Accretor-Propeller Luminosity Gap
Authors: Raguzova Natalya V. , Lipunov Vladimir M. 
Published: July 2016

AbstractThe influence of the spatial distribution of stellar wind velocities (Wind Rose effect) on the X-ray light curve of highly eccentric binaries is examined using the properties of Be disk-fed outflow. It is shown that a phase shift of the maximum X-ray luminosity is always present in the X-ray light curves. The observed X-ray light curves of some transient binaries are analysed using the developed model. We show that the Be/X-ray transients A0538–66, X0331+53 are likely to undergo transitions from the accreting neutron star regime to the propelling one. The example of evolutionary track which can lead to a formation of the Be/X-ray binary is presented. We conclude that synchronization is a very important process for Be star evolution in binary systems and calculate the critical orbital period for existence of a Be/X-ray binary.
The Evolutionary Evidence for Be/Black Hole Binaries
Authors: Raguzova Natalya V. , Lipunov Vladimir M. 
Published: July 2016

AbstractUsing a Monte Carlo simulation of the modern scenario of the evolution of binary systems (the “Scenario Machine”), we calculate the number of binary black holes with Be stars and their expected observational properties. So far, only two possible candidates for Be/BH binaries have been proposed among the observable sources, the superluminal source GRS 1915+105 in the Galaxy and RX J0117.6–7330 in the SMC. We obtained an evolutionary track that can lead to the formation of such systems. The modern evolutionary scenario predicts the existence of binary black holes on eccentric orbits around Be stars and such systems may be discovered in the near future.
The Evolutionary Evidence for Most Be Stars Being Paired with Hot White Dwarfs
Authors: Raguzova Natalya V. 
Published: July 2016

AbstractUsing the “Scenario Machine” we study the number and physical properties of binary Be stars with white dwarfs taking into account cooling of the compact object and discuss the formation of such systems. According to our calculations the number of binary systems containing a Be star paired with a white dwarf in our galaxy is very large − 46% of all Be stars formed as a result of binary evolution must have a white dwarf as companion. These white dwarfs should be very hot with a surface temperature lying in the range from 30,000 to 60,000 K.
NLTE Model Atmospheres of Irradiated Stars in B Binaries
Authors: Kubát Jiří 
Published: July 2016

AbstractModel atmospheres of B stars irradiated by their companion are calculated using our model atmosphere computer code under the assumption of hydrostatic, radiative, and statistical equilibrium (NLTE). The external source of radiation (a hot white dwarf) is able to change the temperature structure of the outer atmospheric layers of B stars significantly. The changes of the temperature structure cause changes in the profiles of some lines, especially in those of hydrogen.
The X-ray Outbursts of Be/X-ray Transients
Authors: Negueruela Ignacio , Okazaki Atsuo T. 
Published: July 2016

AbstractWe present a new scenario for the behaviour of Be/X-ray binaries based on long-term multiwavelength monitoring and the decretion disc model. The circumstellar discs of the primaries are truncated because of the tidal and resonant effect of the neutron star. The geometry of the systems and the value of viscosity determine the presence or absence of Type I X-ray outbursts. The interaction of a strongly disturbed disc with the neutron star originates Type II X-ray and optical outbursts.
Substantial Disc Loss in the Be/X-ray Binary System A0535+26
Authors: Haigh N.J. , Coe M.J. , Steele I.A. , Fabregat J. 
Published: July 2016

AbstractInfrared JHK photometry from October 1998 revealed a remarkable change in the Be/X-ray binary system A0535+26, manifesting itself as a dramatic reduction in emission from the circumstellar disc. Optical and IR spectra presented here have confirmed this disc-loss in greater detail showing radically reduced Hydrogen and Helium line emission, to a degree never before seen in this system, and only rarely in a handful of Be/X-ray binaries. Optical spectroscopy has revealed the re-appearance of a small, stable inner disc, and IR spectra/photometry show the eventual regrowth of a robust circumstellar disc resembling the pre-disc-loss state.
The Parkes Multibeam Pulsar Survey
Authors: Camilo F. , Lyne A. G. , Manchester R. N. , Bell J. F. , Kaspi V. M. , D’Amico N. , McKay N. P. F. , Crawford F. , Stairs I. H. , Morris D. J. , Sheppard D. C. , Possenti A. 
Published: July 2016

AbstractThe Parkes multibeam pulsar survey uses a 13-element receiver operating at a wavelength of 20 cm to survey the inner Galactic plane with remarkable sensitivity. To date we have collected and analyzed data from 45% of the survey region (|b| &lt; 5°; 260° &lt;l&lt; 50°), and have discovered 440 pulsars, in addition to re-detecting 190 previously known ones. Most of the newly discovered pulsars are at great distances, as inferred from a median dispersion measure (DM) of 400 cm−3pc.
A VLA Survey for Radio Pulsars in the Galactic Center
Authors: Lazio T. Joseph W. , Cordes James M. 
Published: July 2016

AbstractA radio pulsar in the Galactic center will suffer 350secondsof pulse broadening. An imaging search for compact sources is far less desensitized by angular broadening than a periodicity search is affected by pulse broadening. We have conducted an imaging survey of the GC using the VLA and have detected approximately 200 sources. Six compact, steep-spectrum sources have been identified; additional compact sources with no spectral information have also been identified. Additional observations are in progress.
High Precision Timing of PSR J0437–4715
Authors: Britton M. C. , van Straten W. , Bailes M. , Toscano M. , Manchester R. N. 
Published: July 2016

AbstractSystematic effects currently dominate the timing residuals of the pulsar PSR J0437–4715. These systematics arise from transformations that occur during the propagation and detection of radio waves. The transformation properties of polarized radiation are related to the Lorentz group, and such effects may be represented using Lorentz transformations. These effects may be removed using the techniques of polarimetric self-calibration. Alternatively, an invariant profile may be formed from the polarimetric analogue of the Lorentz invariantI2–Q2–U2–V2and used for pulsar timing. Observations of PSR J0437–4715 are presented that show the consistency between these two techniques.
Millisecond Pulsars in 47 Tucanae
Authors: Freire Paulo C. , Camilo Fernando , Lorimer Duncan R. , Lyne Andrew G. , Manchester Richard N. 
Published: July 2016

AbstractRecent observations of the globular cluster 47 Tuc, made with the Parkes telescope at a wavelength of 20 cm, have resulted in the discovery of nine new millisecond pulsars (MSPs), all in binary systems. The number of timing solutions available has risen from two to 14. These results will make possible a more detailed study of the cluster dynamics.