bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic Field Decay in the Non-superfluid Regions of Neutron Star Cores
Authors: Muslimov A.G. , Van Horn H.M.
Published: July 2016

We consider a simple model for the evolution of a poloidal magnetic field initally trapped in a region containing normal npe matter within the outerliquid core of a neutron star. We have performed numerical computations for neutron stars with masses of 1.4, 1.6, and 1.7 M⊙ that undergo very rapid cooling due to the direct Urca process. Because the timescale for the magnetic field decay is directly proportional to T2, such a cooling history produces a rapid decline in the magnetic-field strength B, even for B as low as ∼ 1012 G. In particular, we show that an initially quasi-homogeneous magnetic field of strength B = 1012 G declines during the first ∼ 1 Myr.
Mount Stromlo PZT Results
Authors: Abraham H. J. M. , Boots J. N.
Published: July 2016

The results from about 28,000 star transits that were – observed with the Mount Stromlo PZT during the period 1959.5 to 1967.5 – are being Investigated. This material has given information about

(a)

the relative positions and proper motions of zenith stars, and

(b)

the apparent diurnal displacement of the vertical.
Effects of the Earth Tides on the Motion of the Earth
Authors: Mateo J.
Published: July 2016

This report shows as the earth tides produces variations of the local vertical, specially with respect to the solid crust. One set of horizontal pendulums recording at the same place of the Photo Zenith Tube, would be convenient to certify the variation of the vertical astronomically observed, because the ratio between the coefficients Y and A must remains almost constant. If an earth tides recorder is also available, then the numbers of Love and Shida, can also be known.
Rotation and Evolution of Be Stars
Authors: Hardorp Johannes , Strittmatter Peter A.
Published: July 2016

The evidence in favor of the hypothesis that Be stars owe their emission properties to material rotationally ejected from the equator is reviewed. The evolutionary state of Be Stars is then discussed with reference to evolutionary sequences of stellar models. It is concluded that (i) Be stars are not confined to the secondary contraction phase as previously proposed (ii) evolution probably proceeds with uniform rotation at least outside the initial convective core. Mechanisms for transporting angular momentum are briefly discussed.
Evolution of Rapidly Rotating B-Type Stars
Authors: Sackmann I. Juliana , Anand S.P.S.
Published: July 2016

It has become clear in recent years through the work of Collins (1963, 1965, 1966), Collins and Harrington (1966), Hardorp and Strittmatter (1968a, b) and Roxburgh and Strittmatter (1965) how seriously the spectrum of a star may be affected by rotation. However, before atmospheric models for rotating stars can be computed, the results of corresponding interior models have to be available. For polytropic configurations a great many rotating interior models have been constructed (Chandrasekhar, 1933; James, 1964; Stoeckly, 1965; Monaghan and Roxburgh, 1965; and Anand, 1968), but for rotating main-sequence stars few computations exist (Sweet and Roy, 1953; Roxburgh et al, 1965; Ostriker and Mark, 1968; Faulkner et al., 1968). In fact for B- and Be-type stars for which the most rapid rotation along the main sequence is observed, not a single interior model has yet been computed except in this conference reported by Kippenhahn and Thomas (1970). It is this gap that the present paper attempts to close.
On the Loss of Angular Momentum from Stars in the Pre-Main Sequence Phase
Authors: Okamoto Isao
Published: July 2016

The braking of stellar rotation in the wholly convective phase in the pre-main sequence is numerically discussed. The structure of stars in that phase is expressed by a rotating polytrope with an index of 1.5 and the Schatzman-type mechanism is used as the means of loss of angular momentum. The magnetic energy is assumed to change with evolution asH02/8π(R/R0)s, whereH0andR0are initial magnetic field and radius, andsis a free parameter. The changes of angular momentum, rotational velocity, etc. with contraction are calculated from the initial state, which is taken to be the state when the stars flared up to the Helmholtz-Kelvin contraction. It is shown that the exponentsmust be in the range from – 1 to – 3 so that the stars with adequate strength of the initial magnetic field may lose almost all of their angular momenta in a suitable rate if they are initially in the state of rotational instability.

Stellar rotation from the time of star formation to the main sequence stage is discussed. Also, the formation of the solar system and other planetary systems is discussed, with respect to the braking.
Rotating Stellar Atmospheres and the Energy Distribution of Altair
Authors: Jordahl Peter R.
Published: July 2016

Models of rotating stellar atmospheres have been constructed for masses appropriate to middle and late A stars, and some of the photometric properties of these models are discussed. A specific model for the rapidly rotating star Altair has been constructed matching the observed radius, luminosity, and projected rotational velocity. It is found that the energy distribution predicted for the model agrees well with that observed for Altair, after the latter has been corrected for line blanketing.
Fission and the Origin of Binary Stars
Authors: Ostriker Jeremiah P.
Published: July 2016

Brief reviews of the classical ‘angular momentum problem’ and the statistics of upper-main-sequence binaries are presented as background for the suggestion that the close, early-type, binaries are produced by fission of rapidly rotating protostars.

Next, theoretical sequences of contracting, rotating stars are described. Recent work demonstrates that the zero-viscosity, polytropic sequences, have essentially the same properties as the McLaurin sequence. Thus, fission is possible for centrally condensed stars. Observations of close early-type binaries are compared with theoretical predictions for the minimum angular momentum in binary systems of given total mass; the agreement is excellent.

Finally, the existing theoretical objections to the fission hypothesis for the origin of binary stars are reviewed, and it is concluded that, although fission remains unproven, there are now no strong theoretical arguments against the process, and there is considerable observational support for its existence.
La mesure des étoiles doubles visuelles. (Exposé Introductif)
Authors: Couteau Paul
Published: July 2016

La découverte des étoiles doubles visuelles a été une des conséquences logiques du développement de l’astrométrie equatoriale. L’étude de ces objets est fonction du temps et de l’abondance des découvertes qui dépend, elle aussi, du temps. Il en résulte que nos connaissances dans ce domaine croissent en progression arithmétique, au lieu de suivre une progression géométrique comme la plupart des spécialités astrophysiques qui dépendent davantage de méthodes que du temps.
Twenty Years of Double-Star Interferometry and its Lessons
Authors: Finsen W. S.
Published: July 2016

If we may judge by the number of eulogistic review articles to which it gave rise, one of the main talking points among astronomers in the early nineteen-twenties was undoubtedly the application of the interferometer to optical astronomy. It was only natural that interest was focused mainly on the brilliant success of Michelson and Pease (1921) in measuring stellar diameters with the 20-ft beam interferometer on the 100-in Mount Wilson reflector. But almost equally exciting, to the double-star observer at least, was the success of Anderson (1920) and Merrill (1922) in resolving several very close double stars, notably Capella, also with the 100-in but with much simpler equipment. Perhaps the most courageous venture of all was the attempt made by Pease (1925) to measure the spectroscopic binary Mizar Aa as a visual double star with a separation of the order of only O’.’Ol. This he did by estimating the fringe visibility with the 20-ft beam oriented in four different position angles – a more exacting and tedious operation it would be difficult to imagine. However sceptical one may be regarding the reliability of so delicate a technique, Russell’s (1927) orbit based on these observations still has a place in our catalogues if only as a monument to a daring experiment.
Astrometric Application of the Photoelectric Scanning Technique
Authors: Franz Otto G.
Published: July 2016

A new photoelectric area scanner, designed primarily for observations of double stars, has been put into routine use at the Lowell Observatory. A description of the scanner and of the associated data acquisition system is given. The procedure of measuring the relative positions of double star components is described and the accuracy obtainable by this method is discussed.

This contribution and a subsequent one (p. 170) will appear jointly under the title ‘A Photoelectric Area Scanner for Astrometry and Photometry of Double Stars’ inLowell Observatory BulletinNo. 154. This work has been supported by National Science Foundation Grant GP-6983.
L’observation spectroscopique des couples visuels. (Exposé Introductif)
Authors: Dommanget J.
Published: July 2016

Le concours de diverses techniques d’observation a toujours été profitable au progrès des connaissances astronomiques.

Dans le cas des couples stellaires, l’observation visuelle et l’observation spectroscopique se complètent heureusement: chacune d’elles – lorsqu’elles sont possibles – conduit à la connaissance des éléments orbitaux, sauf que la première ne fournit pas l’échelle de l’orbite en unités astronomiques et laisse subsister une certaine indétermination, relative à la position du nœud ascendant, et que la seconde n’apporte aucune information sur la valeur de l’inclinaison et sur celle de l’angle de position de la ligne des nœuds.
The Measurement of Radial-Velocity Differences Between the Components of Close Visual Binary Systems
Authors: Batten A. H. , Fletcher J. M.
Published: July 2016

The value obtained for the difference in radial velocity between components of a visual binary that is unresolved on the spectrograph slit appears to depend, sometimes, on whether the measurement is made visually with a microscope or by means of an oscilloscopic setting device. This apparent dependence has been confirmed by measurement of artificially produced double-lined spectrograms, and disappears for line pairs separated by more than 1.5 or 2 times the half-widths of their components. The dependence arises from blending of the two line profiles. There is some evidence that the results obtained from visual measures are affected by the scale of the image being measured. For this reason, oscilloscope measures are probably to be preferred; although their errors are sometimes larger, they seem to be more consistent. Errors arising from this sort of blending are not sufficient to explain measures of relative radial velocity of the components of some visual binaries, that differ widely from the predictions made from the visual orbits.
Calcul des Erreurs Moyennes Affectant les Mesures D’Étoiles Doubles Visuelles
Authors: Dommanget J.
Published: July 2016

Au cours de recherches bibliographiques diverses, nous avons remarqué que bien des observateurs se sont servis et se servent encore de formules par trop approximatives pour calculer – lorsqu’ils le font – les erreurs moyennes affectant leurs mesures.

Nous croyons important et opportun de rappeler ici la formule correcte dont nous avons donné une démonstration à une autre occasion (1959).
Photometric Observations of Visual Double Stars by the Area Scanning Technique
Authors: Franz Otto G.
Published: July 2016

UBV magnitude differences in visual binaries are presented and their accuracy is discussed. Typical observed image profiles of double stars, including sample profiles of Antares, are shown.

This contribution will appear jointly with the earlier one (p. 20) inLowell Obs. Bull., No. 154. The work has been supported by NSF Grant GP-6983.
Summary
Authors: Sahade Jorge
Published: July 2016

According to the program, I am supposed to summarize what has been discussed during the three previous days’ sessions. But actually no summary is necessary as we have heard and discussed at length three excellent, extremely well presented survey papers. So, if you will allow me, I will just make a few comments that are suggested by some statements and some questions posed during the conference. Circumstances have prevented me from bringing special material for the talk, so I am just going to speak from memory.
The Astrographic Catalogue as a Source of Old Epoch Places
Authors: Wood Harley
Published: July 2016

At the General Assembly of the I. A. U. in Prague in 1967 I became involved in a discussion on the merit of using stars with positions taken from the Astrographic Catalogue as reference stars in finding positions of faint members of the solar system. The answer was that little choice exists if the positions are being found from photographs of small field taken with large telescopes.
Secular Perspective Acceleration
Authors: van de Kamp Peter
Published: July 2016

The secular perspective acceleration in the proper motion of a star is directly proportional to the parallax p, proper motion μ, and radial velocity V (van de Kamp, 1967):

The largest effect is known is for Bernard’s star, for which

The predicted perspective acceleration is:
The Physical Distortion of Schmidt Plates
Authors: Herget Paul
Published: July 2016

One characteristic of Schmidt telescopes is that the focal surface is spherical. This causes a flat photographic plate to be buckled and under strain while it is in the plate holder. In the early days of the space program, it was proposed to use Schmidt telescopes for the calibration of tracking stations because they were photographically fast. The writer opposed this proposal because they are not of high astrometric quality, for the reason indicated above.
A Suspected Supernova in A.D. 1181
Authors: Stephenson F.R.
Published: July 2016

The new star which appeared in Cassiopeia in A.D. 1181 attracted considerable attention in the Far East. It was visible for about six months, and its position was carefully recorded by the Chinese and Japanese astronomers. Their observational evidence favours the identification of the star as a supernova of type I. It is proposed that the radio source 3C 58 is the remnant of the new star.
Observed and Theoretical Values of the Nutations
Authors: Vicente R.O.
Published: July 2016

We are here concerned with the nutations that appear in the motion of the Earth because of the existence of the external forces due to the Sun and Moon, that is, the forced nutations.

We can consider the nutations divided in two groups from the point of view of their values and the precision attained by astronomical observations. The first group comprises the nutations that have values greater than 1″ and in this group we have the nutation of period 18.6 yr called the principal nutation and the value of this nutation in obliquity is called the constant of nutation. The second group comprises the nutations with values smaller than 1″ and corresponds to the great majority of all other nutations.
Precession-Nutations and Tidal Potential
Authors: Melchior P.
Published: July 2016

We have previously established (Melchior and Georis, 1968) the equations connecting the development of precession-nutation with the tesseral part of the tidal potential. These equations are:

where

ωiAirespectively represent the frequencies and amplitudes of the tidal waves, ω the Earth’s rotation velocity,
Treatment of Close Approaches in the Numerical Integration of the Gravitational Problem of N Bodies
Authors: Bettis D. G. , Szebehely V.
Published: July 2016

One of the main difficulties encountered in the numerical integration of the gravitational n-body problem is associated with close approaches. The singularities of the differential equations of motion result in losses of accuracy and in considerable increase in computer time when any of the distances between the participating bodies decreases below a certain value. This value is larger than the distance when tidal effects become important, consequently, numerical problems are encountered before the physical picture is changed. Elimination of these singularities by transformations is known as the process of regularization. This paper discusses such transformations and describes in considerable detail the numerical approaches to more accurate and faster integration. The basic ideas of smoothing and regularization are explained and applications are given.
Integration Methods where Force is Obtained from the Smoothed Gravitational Field
Authors: Hohl Frank
Published: July 2016

Many problems in stellar dynamics involve phenomena occurring in inhomogeneous systems in which the interaction between the particles is fully described by a self-consistent field operating in phase space. Because the particles interact by means of the long-range Coulomb force, each particle is under the simultaneous influence of a large number of other particles. Therefore, stellar systems will respond to any perturbation in a collective manner, and a study of such systems is concerned essentially with the N-body problem.
Changes with Height of Longitudinal Magnetic Field in Active Regions
Authors: Gopasyuk S.I.
Published: July 2016

Results of a study of longitudinal magnetic fields in active regions are presented. The observed magnetic field strength increases with height in the photosphere. The maximum of the magnetic field intensity coincides with the level where the central parts of λ5324,2 Å FeI and λ5269,5 FeI line profiles are formed. On the Hβ formation level the observed magnetic field intensity is smaller as compared with the potential one calculated on the basis of the observed field in FeI λ5253, 5Å line. The difference between the observed magnetic field and potential one is explained in terms of transverse electric currents. The current value can mount to 3×1011 A.
The Formation of a Moat Around a Sunspot as Observed on Longitudinal–Field Magnetograms (?)
Authors: Ermakova L.V.
Published: July 2016

In this paper the dynamics of the photospheric magnetic field near the sunspot of the active region McMath 15508 is considered on the basis of longitudinal magnetic field B11 magnetograms. The magnetograms were obtained at the panoramic magnetograph of the Sayan Observatory. The time taken to obtain one magnetogram was 5 min. The spatial resolution was 1.8“ × 3.6“. In the active region McMath 15508 a new bipolar spot group formed westward of the existing sunspot group on September 1; the next day the main sunspots had penumbras, and on September 3 the new sunspot group reached a maximum area and began decaying thereafter.
Relation Between the Longitudinal Field and the Radial Velocity in Sunspots
Authors: Pevtsov A. A.
Published: July 2016

We describe some new aspects of the observed relationship between the longitudinal magnetic field (Blong) and the Doppler velocity (VD) and propose an explanation of the effect in terms of a two-component penumbra model.
The Small-Scale Photospheric Magnetic Field as an Indicator of the Dynamo
Authors: Petrovay K. , Szakály G.
Published: July 2016

The presently widely accepted view that the solar dynamo operates near the base of the convective zone makes it difficult to relate the magnetic fields observed in the solar atmosphere to the fields in the dynamo layer. The large amount of observational data concerning photospheric magnetic fields could in principle be used to impose constraints on dynamo theory, but in order to infer these constraints the above mentioned “missing link” between the dynamo and surface fields should be found. This paper proposes such a link by modeling the passive vertical transport of thin magnetic flux tubes through the convective zone.
Spectrometer-Based Magnetographs
Authors: Jones Harrison P.
Published: July 2016

The techniques and instrumentation for inferring magnetic fields using a spectrometer or spectrograph rather than a narrowband filter are reviewed. With array detectors and/or Fourier transform spectroscopy, the polarimetric data is acquired over the relevant spectral range strictly simultaneously with no possibility of spatial misregistration. Several recent examples of spectrometer-based magnetographs are discussed and compared, and new observations from the NASA/NSO Spectromagnetograph of magnetic flux, velocity field, continuum intensity, equivalent width, and line depth in active regions and the whole sun are shown.
Asymmetric Stokes Q, U and V Line Profiles Observed in Sunspots
Authors: Almeida J. Sánchez , Lites B.W.
Published: July 2016

We present a systematic description of the asymmetric shapes the Stokes line profiles exhibit in sunspots. These asymmetries seem to be caused by gradients of both magnetic field and velocity in the photospheres of sunspots.
High Angular Resolution Stokes V Spectra in Penumbrae
Authors: Almeida J. Sánchez , Pillet V. Martínez , Bueno J. Trujillo , Lites B.W.
Published: July 2016

Stokes I and V profiles of Fel 630.1 nm and Fel 630.2 nm observed in a sunspot with an angular resolution ≥0.5” are analyzed. We find asymmetric V-profiles whose shapes are in agreement with previous determinations having lower angular resolution (~5”). We also find a correlation between penumbral small scale variations of continuum intensity and velocity. Although it involves smaller velocities, such correlation resembles that existing in the quiet sun as a consequence of convection.
Rapid Variations in Intergranular Space
Authors: Nesis A. , Hanslmeier A. , Hammer R. , Komm R. , Mattig W. , Staiger J.
Published: July 2016

Spectrograms of high spatial resolution taken every 15s reveal rapid variations of the continuum intensity and line width. Variations of the latter seem to be related to Doppler velocity gradients.
Hard X-Ray Imaging Observations by Yohkoh of the 15 November, 1991 Flare
Authors: Sakao Taro
Published: July 2016

We present hard X-ray imaging observations by Yohkoh of the 15 November, 1991 flare. The pre-impulsive and the impulsive phase observations are summarized as follows: (1) Hard X-ray sources in the precursor (or pre–impulsive) phase appear in a much wider area compared with the impulsive phase sources and they show clear evolution just before the onset of the impulsive phase. This suggests that some global re-structuring of coronal magnetic fields led to the impulsive energy release. (2) In the impulsive phase, at the peaks of the individual spikes of the time profile, the bulk of the hard X-ray emission (above 20 keV) originates from the footpoints of the flaring loop. At the valleys between the spikes, X-rays below 30 keV are emitted from near the loop top, while higher energy ones (above 30 keV) are still emitted from the footpoints. Such behavior of hard X-ray sources can be explained by the partial precipitation model.
The Reversed Polarity Structures of Chromospheric Magnetic Fields in Active Regions
Authors: Li Wei , Ai Guoxiang , Zhang Hongqi , Chen Jimin
Published: July 2016

The reversed polarity structures of chromospheric magnetic fields are magnetic gulfs and islands of opposite polarity relative to the underlying photospheric fields. In this paper data were analyzed from the Solar Magnetic Field Telescope of the Huairou Solar Observing Station (HSOS) in Beijing. From more than 300 pairs of photospheric magnetograms (in FeIλ5324.19 Å) and relevant chromospheric magnetograms (in Hβλ4861.34 Å), the reality of the reversed polarity structures is demonstrated. According to an analysis of the fine structures of the magnetic fields in the two layers of active regions, we found that there are probably four different types.
Observational Evidence for Magnetic Reconnection in Solar Flares
Authors: Henoux J.C. , Demoulin P. , Mandrini C.H. , Rovira M.G.
Published: July 2016

From studies of the magnetic topology of flaring active regions, the separator - a region were magnetic reconnection can take place - appears to be magnetically connected to places of intense chromospheric flare brightening. This suggests that magnetic reconnection occurs in the separator region in solar flares. Observational support for magnetic reconnection releasing the energy stored in field align currents systems is presented.
Some Characteristics of the Development and Emissions of May 13, 1981 Flare Related to the Flare Model
Authors: Krivsky Ladislav
Published: July 2016

Proton flare of May 13, 1981 with various emissions and with registration of loop shaped flare in hard X-ray range above new created flare channel in Hα and Hβ is related with flare loop-model published earlier at IAU Symp. No. 35 in 1967.
Analyses of Vector Magnetograms
Authors: Wang Jingxiu
Published: July 2016

(1) Current techniques may now permit an acceptable resolution of the 180 degree ambiguity in determining the direction of transverse fields. (2) The non-potentiality of active regions can be described by parameters of angular shear, source field, line-of-sight current, force-free factor and force-free current. A 2-dimensional description of angular shear is necessary, and an alternative, FFT method of calculating the line-of-sight current seems recommendable. (3) For a sampling region, the degree of non-potentiality quantified by all the parameters shows great enhancement right before a 1M flare, and reduces somehow during the flare. (4) A highly intermittent distribution of force-free factor with fully mixed signs is obtained, consistent with a theoretical approach.
The Role of Filament Currents in a Flare Active Region
Authors: Aoao Xu , Guiping Wu , Yuhua Tang , Zhibo Jiang
Published: July 2016

The two-ribbon flare of May 13, 1981 is one of the most notable flares during solar cycle 21. There are rich observational data of this flare. We study carefully the characteristics about the evolution and motion of the filament related with the flare as well as the relationship between these characteristics and the development of the flare. The results indicate that the increase of the filament current plays an important role in the occurrence and development of the flare.
A Synthesized Method for Solving the 180° Ambiguity of Solar Transverse Magnetic Field
Authors: Huaning Wang , Yuanzhang Lin
Published: July 2016

The 180° ambiguity of the transverse magnetic field measured by a heliomagnetograph is an intrinsic problem due to the linear polarization in Zeeman effect(Harvey, 1969). Thus we have to make use of some criteria for calibrating the transverse magnetic fields in vector magnetograms. Up to now, a few criteria have been suggested by some solar physicists (Harvey, 1969; Krall et al., 1982; Sakurai et al., 1985; Aly, 1989; Wu and Ai, 1990; Canfield et al., 1991. The existing criteria could be classified as observational criteria and mathematical criteria. The former is based on the observation facts, such as the fibrils and the filaments in solar filtergrams, and the latter is derived from the mathematical model of solar magnetic field, such as divergence equation (∆. B = 0), potential field model and force-free field model. These criteria, however, are not applicable to all solar active regions, especially to those with complicated magnetic fields. For this reason, we suggest a synthesized method for calibrating the transverse magnetic fields in solar vector magnetograms.
Structure of Emerging Flux Regions
Authors: Chou Dean-Yi
Published: July 2016

We review the present status of our understanding of the structure and dynamics of emerging flux regions which form the first stage of active regions. We review the observations of the emerging flux regions, and discuss their structure, dynamics, and physical conditions derived from these observations. We also discuss implications about magnetic fields below the surface.
On Recurrent Solar Activity
Authors: Gaizauskas V.
Published: July 2016

Recurrent solar activity on a time-scale of the Sun’s rotation rate has for a long time been attributed to quasi-periodic disturbances in the solar interior. The following brief survey discusses recent attempts to come to grips with the Sun’s episodic activity.
Sunspot Seismology: The Interaction of Solar p-Modes with a Sunspot
Authors: Thomas John H.
Published: July 2016

Progress in sunspot seismology is briefly reviewed. New observations of the absorption of p-modes by a sunspot (Bogdan, Brown, Lites, and Thomas 1993) show that the absorption coefficient (averaged over frequency and azimuthal order) increases with horizontal wavenumber to a maximum near k = 0.9 Mm−1 and then decreases monotonically to zero at about k = 1.5 Mm−1. The absorption along individual p-mode ridges shows a sinusoidal-like modulation, which may be an important feature for comparison with theory. Results for the quiet Sun show no net absorption, but do show apparent emission along p1 over the same range of k where the sunspot shows its greatest absorption. This behavior, and the overall decrease in absorption at higher wavenumbers, can be explained as an effect of the decreasing lifetime of p-modes with increasing wavenumber k (increasing mode degree l).
Imaging Spectroscopy of Flows in Active Regions
Authors: Mein P. , Mein N.
Published: July 2016

We use imaging spectroscopy from the MSDP of the VTT telescope in Tenerife (collaboration Paris-Meudon Observatory and Kiepenheuer Institut) to analyse Doppler velocities of arch filaments in Hα and NαD1. The geometry of the magnetic loops is deduced from perspective effects with a simple dynamical model. Velocities are correlated in both lines.

Further results are expected from simultaneous observations with other instruments (SVST of La Palma and Huairou magnetograph).
Unsteady Wave-Packets in the Random Ensembles of Magnetic Flux Tubes: Acoustic Halos
Authors: Ryutova Margarita , Priest Eric
Published: July 2016

The propagation of unsteady acoustic wave-packets in a randomly magnetized solar atmosphere is accompanied by specific morphological effects which include the spreading of the energy absorption region over scales much larger than the size of the initial energy source. One of the manifestations of these effects can be acoustic halos. The regions of an efficient energy input and their localization crucially depend on the distribution of magnetic structures in space and over their physical parameters which makes the present study useful for diagnostic goals.
Chaos and Turbulence in Solar Wind
Authors: Buti B.
Published: July 2016

Large amplitude waves as well as turbulence has been observed in the interplanetary medium. This turbulence is not understood to the extent that one would like to. By means of techniques of nonlinear dynamical systems, attempts are being made to properly understand the turbulence in the solar wind, which is essentially a nonuniform streaming plasma consisting of hydrogen and a fraction of helium. We demonstrate that the observed large amplitude waves can generate solitary waves, which in turn, because of some propagating solar disturbance, can produce chaos in the medium. The chaotic fields thus generated can lead to anomalously large plasma heating and acceleration.

Unlike the solitary waves in uniform plasmas, in nonuniform plasmas we get accelerated solitary waves, which lead to electromagnetic as well as electrostatic (e.g. ion acoustic) radiations. The latter can be a very efficient source of plasma heating.
Observability of Coronal Heating Processes
Authors: Venkatakrishnan P.
Published: July 2016

The mechanisms that could possibly heat the corona are briefly reviewed with emphasis on their observability. Observing enhanced wave flux at footpoints of active regions would confirm wave heating. Observation of nonthermal electrons in tiny coronal events (nanoflares) would confirm dissipation of current sheets. Presence of large scale flows in coronal arcades would underline the importance of turbulent resistivity for coronal heating. A comparison of Hel absorption in quiet and active regions demonstrates the difficulty of interpreting data that connect chromospheric dynamics with coronal heating. Finally, the implications of the search for observations of coronal heating processes are mentioned.
Dependence of the North-South Component of IMF on the Solar Wind Acceleration
Authors: Felix Pereira B. , Girish T.E.
Published: July 2016

The monthly probability of occurrence of southward component of IMF estimated independent of the sector polarity observed near earth is found to change with the magnitude of solar wind velocity. The above analysis is done for each month during two years around sunspot minima and maxima in cycle 21. The results will be interpreted in terms of association of southward Bz events with solar wind flows of distinct solar origin such as low and high speed solar wind.
A Bimodal Model of the Solar Wind Speed
Authors: Coles W.A.
Published: July 2016

Until the ULYSSES spacecraft reached high latitude, the only means for measuring the solar wind velocity in the polar regions was from radio scattering observations (IPS), and these remain the only way to measure the velocity near the sun. However, IPS, like many remote sensing observations, is a “line-of-sight” integrated measurement. This integration is particularly troublesome when the line-of-sight passes through a fast stream but that stream does not occupy the entire scattering region. Observations from the HELIOS spacecraft have shown that the solar wind has a bimodal character which becomes more pronounced near the sun. Recent observations from ULYSSES have confirmed that this structure is clear at high latitudes even at relatively large solar distances. We have developed a method of separating the fast and slow contributions to an IPS observation which takes advantage of this bimodal structure. In this paper I will describe the technique and its application to IPS observations made using the receiving antennas of the EISCAT incoherent backscatter radar observatory in northern Scandinavia.
Solar Mass Ejections and Coronal Holes
Authors: Bhatnagar Arvind
Published: July 2016

In this paper we present observations of two types of solar mass ejections, which seem to be associated with the location of coronal holes. In the first type, a filament eruption was observed near a coronal hole, which gave rise to a strong interplanetary scintillations, as detected by IPS observations. In the second type, several large scale soft X-ray ‘blow-outs’ were observed in the YOHKOH SXT X-ray movies, in all the cases they erupted from or near the boundary of coronal holes and over the magnetic neutral line. It is proposed that the open magnetic field configuration of the coronal hole provides, the necessary field structure for reconnection to take place, which in turn is responsible for filament eruption, from relatively lower heights. While, in the case of X-ray ‘blow-outs’, the reconnection takes place at a greater height, resulting in high temperature soft X-ray emission visible as X-ray ‘blow-outs’.
Spectroscopic Diagnostics for N III Ion
Authors: Dwivedi B.N. , Mohan Anita , Gupta A.K.
Published: July 2016

Spectroscopic diagnostics for the N III ion have been studied using an atomic model comprising of the first eleven energy levels. We have taken account of the various populating and depopulating mechanisms to solve the detailed balance equations to determine the level populations as a function of electron density and temperature. We then studied the line emissivity ratios as tools for density and temperature diagnostics. Density-sensitive and temperature-sensitive line emissivity ratios have been presented and their diagnostic applications to the solar atmosphere have been discussed with the help of available observations.
Spectroscopic and Variability Surveys for AGN in the Groth Survey Strip
Authors: Sarajedini Vicki
Published: July 2016

Preliminary results are presented for a spectroscopic survey of the Groth Survey Strip (GSS), a 30 by 3 arcminute region of the sky imaged with HST, for which several hundred galaxy spectra have been obtained as part of the DEEP project (http://deep.ucolick.org). At least 6 broad-line AGNs (primarily Seyfert 1s) have been detected as well as several narrow-line Seyfert 2 candidates. The seyfert galaxies detected in our survey have integrated absolute magnitudes extending to MB ~-17.5, probing fainter magnitudes and higher redshifts than existing optical spectroscopic surveys. We also discuss a variablity study of the GSS using the original HST images from 1994 and new images obtained in 2001. The high resolution obtained with HST allows us to isolate and measure variable galactic nuclei too faint to be detected from the ground, reaching nuclear magnitudes of MB~-16 in galaxies to z~0.8. The combination of these techniques provide a powerful probe of the population of low-luminosity AGNs at moderate redshifts.
AGNs in Shakhbazian Compact Groups
Authors: Amirkhanian A.S. , Egikian A.G. , Tiersch H. , Stoll D.
Published: July 2016

The results of CCD spectroscopic observations of Shakhbazian compact groups of galaxies (SHCGs) with the 1.54-m (La Silla, Chile), 2.2-m (Calar Alto, Spain) and 2.6-m (Byurakan) telescopes are presented. According to these preliminary data, about 10% of member galaxies in SHCGs are emission-line galaxies (ELGs) including the broad-line AGNs (of classical Seyfert 1 type) and the narrow-emission-line galaxies.

A research program has been developed in the University of Potsdam, Potsdam Astrophysikalisches Institut in cooperation with other observatories (particularly with Byurakan Astrophysical Observatory) to perform photometric and spectroscopic investigations of galaxies in the SHCGs. Within the framework of this program the redshift (radial velocity) measurements have been carried out for more than 200 galaxies in 36 SHCGs. The MIDAS software package was used for processing and interpreting of the galaxy spectra. Most of these redshifts were measured for the first time. 180 member galaxies (90%) in these groups have absorption spectra typical of E and SO galaxies. Twenty galaxies (10%) turn out to be ELGs. They are in the range 0.02 ≤ z ≤ 0.17, i.e., the SHCGs lie in approximately the same redshift space as Abell clusters. These compact groups contain predominantly elliptical and lenticular galaxies (del Olmo 1988; Amirkhanian 1989) like the cores of rich, regular, centrally condensed clusters of galaxies. The fraction of spirals falls in the densest matter concentrations. On the other hand, it is a well-established fact that in the local universe the active objects tend to avoid the cores of dense clusters of galaxies (e.g. Green and Yee 1984). That is why the discovery of an emission-line population with broad-line AGNs in SHCGs (Tiersch et al. 1999) was unexpected. As shown by Dressier, Thompson and Shectman (1985) in their sample of 1268 galaxies in the feilds of 14 rich clusters the ELGs comprise 31% of the field galaxies but only 7% of the cluster galaxies. Similarly, according to their statistics AGNs make up 5% of the field sample, but only 1% of the cluster sample. They note that the difference in the distribution of morphological types can only partially explain this effect. Obviously, some sort of environmental influence is present.
A Morphological Optical Survey of Nearby AGN
Authors: Boschetti C.S. , Ciroi S. , Funes J. , Omizzolo A. , Rafanelli P. , Richter G.M. , Rifatto A. , Vennik J.
Published: July 2016

We present preliminary results of an optical survey of a spectroscopically selected sample of nearby AGNs (z < 0.1). The aim of the program that we are currently carrying out is to demonstrate that the activity phenomenon is strongly related to galaxy interactions. In detail, we want to study the morphology of our sample of galaxies in order to reveal the presence of features like bars, rings, double nuclei, isophotal distortions and tidal tails, most of which are not detectable on the POSS plates. The work is based on the analysis of broad band B, V and R images, the study of their photometric parameters and the results of the application of a Laplacian adaptive filter, able to enhance hidden and faint structures.
Byurakan Surveys: Density of Bright AGN
Authors: Erastova L.K.
Published: July 2016

It is clear now that morphological criteria don’t divide galaxies from QSOs. Many galaxies are stellar-like objects and, conversely, quasars have host galaxies of various luminosities. For instance, two objects - SBS 1120+586A and SBS 1123+598 - absolutely do not differ from stars on the charts of the POSS and were classified as BSO-type. But they turned out to be galaxies with moderate luminosities (Markarian et al. 1988). Erastova (2000) produced a list of stellar-like galaxies from the SBS. Out of 339 KUV objects, 107 (31.6%) are emission-line galaxies of various luminosities (Darling & Wegner 1996). A considerable number of active galaxies appear among CSO - Case stellar objects. Conversely, objects having extended images on low-dispersion spectral plates turned out to be QSOs. SBS 1520+530 is a gravitationally lensed QSO with z=1.855 and on our low-dispersion plates appears as a galaxy (Chavushyan et al., 1997).
The Blue Stellar Objects of the First Byurakan Survey
Authors: Mickaelian A.M.
Published: July 2016

The Second part of the FBS is devoted to the discovery and study of blue stellar objects. It was carried out in an area of 4009 deg2 and identified 1103 objects: hot subdwarfs and white dwarfs, cataclysmic variables, QSOs and Seyfert galaxies, etc. The discovery of new bright QSOs led to a re-evaluation of their surface density (0.012 deg−2). Several interesting cataclysmic variables have been discovered as well.
Dubious Deductions from AGN Survey Data
Authors: Antonucci Robert
Published: July 2016

The participants in this meeting are almost all carrying out the hard work of making many different types of AGN surveys. Since it’s so much easier to criticize other people’s work than to do actual work myself, I’ll just present some demurs regarding recent papers drawing conclusions from various AGN survey data. In particular I’ll mention some questionable interpretations of surveys of Seyfert 2 near-UV polarization; interpreting the results of searches for polarized broad H-alpha lines in Seyfert 2s; testing the beam model for radio galaxies and quasars; testing the unification of Seyfert spectral types with a torus; and finally testing the energy sources for ULIRGs, especially those with LINER optical spectra. Only the polarized broad H-α results are examined in detail here.
The Nature of the Faint Far-Infrared Extragalactic Source Population: Optical/NIR and Radio Follow-up Observations of ISOPHOT Deep-Field Sources using the Keck, Subaru, and VLA Telescopes
Authors: Kakazu Yuko , Sanders D. B. , Joseph R. D. , Cowie L. L. , Murayama T. , Taniguchi Y. , Veilleux S. , Yun M. S. , Kawara K. , Sofue Y. , Sato Y. , Okuda H. , Wakamatsu K. , Matsumoto T. , Matsuhara H.
Published: July 2016

We report on optical and near-infrared (NIR) follow-up spectroscopy of faint far-infrared (FIR) sources found in our deep FIR survey by Kawara et al.
New Results from the REX Survey
Authors: Caccianiga A. , Marchā M. J. M. , Maccacaro T. , Wolter A. , Della Ceca R. , Gioia I. M.
Published: July 2016

The REX survey is an ongoing project aimed at the selection of new samples of QSOs and BL Lac objects. Spectroscopic identification of the ~1600 sources in the survey is in progress reaching, so far, about 40% of complete identification level. In this paper, the most recent results derived from the REX survey are briefly summarized.
The orientation of the Seyfert Nucleus in Mrk 348
Authors: Antón Sónia , Thean Andrew , Browne Ian , Pedlar Alan
Published: July 2016

We present new data on Mrk348: 5 GHz data with MERLIN and infrared data with ISO. The radio properties of Mrk 348 are unusual among Seyfert galaxies, and we discuss the orientation of the AGN axis with respect to the line of sight.
Energy Density and Radiation Losses in Giant Radio Galaxies
Authors: Jamrozy Marek , Machalski Jerzy
Published: July 2016

The volumes, equipartition energy density, and radiation losses due to the synchrotron and inverse Compton interactions as a function of redshift and projected linear size of Giant radio galaxies are discussed. The new results are based on data from three samples: 1) Ishwara-Chandra & Saikia (1999), 2) Schoenmakers (Ph.D. Thesis, 1999), and 3) Machalski, Jamrozy & Zola (2001).
Photometric Study of Radio Galaxies in the RATAN-600 “Cold” Survey
Authors: Verkhodanov O. V. , Parijskij Yu. N. , Soboleva N. S. , Kopylov A. I. , Temirova A. V. , Zhelenkova O. P. , Goss W. M.
Published: July 2016

About 100 steep-spectrum radio sources from the RATAN-600 RC catalog were mapped by the VLA and identified with optical objects down to 24m–25m in the R band using the 6-m telescope. An updated list of calibrators with known redshifts of the same class of RGs was compiled to evaluate the accuracy of photometric redshift estimates. BVRI photometry for 60 RC objects was performed with the 6-m telescope, and by standard model fitting we have estimated color redshifts and ages of the stellar populations of the host gE galaxies. The mean redshift of FR II RGs from the RC list turned out to be ≈1. Several objects were found in which active star formation began in the first billion years after the Big Bang.
The Formation and Feeding of Massive Black Holes in the Early Universe
Authors: Duschl Wolfgang J. , Strittmatter Peter A.
Published: July 2016

It is still an open question whether the super-massive black holes thought to be present in quasars are of primordial nature, or whether there is a viable way of forming them in the very short time scale (less than a billion years) permitted by the observational data. In this contribution, we present a way in which a galaxy-galaxy merger can provide not only the “fuel” for quasar activity, but can also build a super-massive black hole, i.e., “the engine”, in the first place.
Rapid Variations in the Broad Hβ Profile of the Radio Galaxy 3C 390.3: Possible Evidence for Turbulence in the Accretion Disk
Authors: Asatrian N. S. , Khachikian E.Ye. , Notni P.
Published: July 2016

We report on implications for the geometrical and kinematic parameters of BLR gas on the basis of short timescale variability in the broad Hβ profile.

Data on rapid variations have been obtained at the 6-m telescope of the SAO (Asatrian, Khachikian & Notni, 1999). To search for variations in the profile shape, difference spectra (first minus second epoch) were examined. We believe that the structure of the underlying stellar continuum and the atmospheric features do not affect the Hβ difference profiles of 3C 390.3 significantly.

Variations occurred simultaneously on the blue and red sides of Hβ on a timescale of ~ 1.452 hours and take the form of three narrow, positive and negative small bumps drifting across the line profile in the difference spectrum. The positions of the bumps are −2300, +4700 (negative) and −3700 kms2212;1 (positive).
Proper elements for Earth-crossers
Authors: Milani A. , Gronchi G.F.
Published: July 2016

A generalization of the averaging principle for planet-crossing orbits is given, together with an algorithm computing the solutions of the corresponding averaged equations. This allows us to define proper frequencies and proper elements for planet-crossing objects with arbitrary semimajor axis, eccentricity and inclination, in the approximation neglecting the eccentricities and the inclinations of the planetary orbits.