bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractWe 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.
The Blue Stellar Objects of the First Byurakan Survey
Authors: Mickaelian A.M. 
Published: July 2016

AbstractThe 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

AbstractThe 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

AbstractWe 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

AbstractThe 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

AbstractWe 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

AbstractThe 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

AbstractAbout 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

AbstractIt 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

AbstractA 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.
Collisional evolution of asteroids
Authors: Farinella P. , Davis D.R. , Marzari F. , Vokrouhlický D. 
Published: July 2016

AbstractWe review the evidence for, and the modelling work devoted to, the substantial collisional evolution which has generated the current asteroid population and continually injects asteroid fragments into dynamicalroutesthrough which they can reach near-Earth space and sometimes hit our planet. The main obstacles to further progress in this research field are theoretical (mainly related to the physics of high-velocity impacts), but better observational data (in particular on the small-size end of the asteroid population) would help. However, in the last decade new insights have been obtained on specific important issues, such as the total mass of the asteroids at the time when the accretion process was stopped (only moderately larger than the current one), the “demography” of asteroid families (how many/how old they are and how they evolve) and the way meteorites and near-Earth asteroids are delivered/transported by a complex mixture of collisional and dynamical mechanisms.
Chemical and physical aging of comets
Authors: Meech K.J. 
Published: July 2016

AbstractAging effects for comet nuclei encompass both chemical and physical changes to the nucleus which may be manifested as a change in the level of and type of activity that the nucleus experiences. Recent observations have shown the importance of the amorphous to crystalline water ice phase transition in comet nuclei for controlling activity at large distances, and for altering the porosity and volatile distribution in the interior of comets. Evidence for secular changes in activity levels or differences between dynamical classes of comets which have spent different amounts of time in the inner solar system must be decoupled from expected primordial differences between comets. Long-term observational programs by several groups have demonstrated that the effects of aging are detectable. This paper will discuss the expected primordial comet differences, the expected physical and chemical effects of aging, the techniques for observing differences in activity levels, and will present summaries of results of several observing programs.
The possibility of capture of short-period comets on retrograde satellite orbits
Authors: Pittich E.M. , Solovaya N.A. 
Published: July 2016

AbstractThe possibility to capture a small body moving on a heliocentric stable orbit by Jupiter has been investigated. Initial conditions were taken from the 8th retrograde satellite of Jupiter where we changed the orbital velocity so that the fictitious body was now in a heliocentric stable orbit. Using the numerical integrate techniques, we found conditions at which the small body can be captured by Jupiter on a retrograde orbit. To change the stable heliocentric orbit of the body to a transfer orbit to Jupiter, we used the techniques of small orbital velocity variations.
A study of cometary eruptions through OH radio-lines
Authors: Silva A.M. , Miró R.D. 
Published: July 2016

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.
Motion of the near-nucleus shells of comet Hale-Bopp and rotation of its nucleus
Authors: Churyumov K.I. , Evtushevsky O.M. , Kravtsov F.I. 
Published: July 2016

Abstract270 images of the near-nucleus region of comet HB were obtained both in integral light (without filters) and using the narrow band interference IHW filters CO+C3C2, RC (red continuum). Prom the measurements of the expanding shells (arcs) the following result was obtained: the period of rotation of the comet nucleus is equal to 11.41±0.05 h; expansion velocities of the shells (arcs)vare in the limits of 0.61-1.99 kms−1, and accelerations of the shellsgin the limits from −18.3 × 10−3ms−2to 4.0 × 10−3ms−2.
Dust shells in the coma of C/1995 O1 (Hale-Bopp)
Authors: Paulech T. 
Published: July 2016

AbstractThe comet Hale-Bopp was continuously observed from September 1996 to April 1997. We used altogether 316 images of Hale-Bopp to analyse the evolution of dust shells system close to the nucleus. We performed measurements of relative distance of envelopes and velocity of its expansion. Evolution of the spiral arm revealed spin of the nucleus. We estimated the period of rotation to be 11.42 hours. With purpose to confront the real CCD images of dust éjecta and the measured ejection velocities a computer model of formation and expansion of the dust shells has been developed.
Distribution of long-period comets in perihelion distance
Authors: Klačka J. 
Published: July 2016

AbstractDistribution of long-period comets in perihelion distance is investigated. The relationN( &gt; q)=C qαseems to be a good approximation to the reality −N(&gt;q)is the number of long-period comets with perihelion distance greater than the valueq( in AU). The complete group of long-period comets is characterized by the valueα =4/3, however, also subsets are important.
Resonances and chaos in the asteroid belt
Authors: Šidlichovský M. 
Published: July 2016

AbstractThe present paper reviews the evolution of our understanding of the effect of resonances on the distribution of asteroids in the asteroid belt. The history of this problem goes back to the Kirkwood's discovery (1867) of the Kirkwood gaps located at resonances with Jupiter. We started to understand the mechanism of their origin only in last decades. It seems that only gravitational effects are sufficient for the depletion. It is now clear that the overlap of secular resonances inside the orbital resonance is the most effective mechanism leading to large chaos and variation of orbital elements. This results in the final removal of asteroids from the gaps by collisions with the inner planets. Chaos, however, does not always mean fast removal of the body. The question of the so called stable chaos will be discussed together with the offered explanations (the high order resonances and the so called three-body resonances). Recently it was shown that chaotic diffusion can play an important role for the 2/1 resonance where the aforementioned explanation for other gaps fails. Basic facts will be reviewed but we will not go into this problem as the importance of chaotic diffusion in dynamics of asteroids (and comets) will be the subject of invited lecture at this conference given by Morbidelli and Nesvorný.
Symmetric Multistep Methods Revisited: II. Numerical Experiments
Authors: Fukushima T. 
Published: July 2016

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.
Models of comets with strongly variable nongravitational effects
Authors: Królikowska M. , Sitarski G. , Szutowicz S. 
Published: July 2016

AbstractThe nongravitational motion of five “erratic” short-period comets is studied on the basis of published astrometric observations. We present the precession models which successfully link all the observed apparitions of the comets: 21P/Giacobini-Zinner, 31P/Schwassmann-Wachmann 2, 32P/Comas Solá, 37P/Forbes, and 43P/Wolf-Harrington. We used the Sekanina's forced precession model of the rotating cometary nucleus to include the nongravitational terms into equations of the comet's motion. Values of six basic parameters (four connected with the rotating comet nucleus and two describing the precession of spin-axis of the nucleus) have been determined along the orbital elements from positional observations of the comets. The solutions were derived with additional assumptions which introduce instantaneous changes of modulus of reactive force,Aand of maximum of cometary activity with respect to perihelion time. The present precession models impose some contraints on sizes and rotational periods of cometary nuclei. According to our solutions the nucleus of 21P/Giacobini-Zinner with oblateness along the spin-axis of about 0.32 (equatorial to polar radius of 1.46) is the most oblate among five investigated comets.
Magnetic Equilibria and Instabilities
Authors: Sakurai Takashi 
Published: July 2016

AbstractSolar flares are understood as a process of explosive liberation of magnetic energy, coming after a slow phase of energy build-up. The slow evolution of magnetic equilibria may end up with (a) the termination of an equilibrium sequence, or (b) an instability. The distinction between the two can be made by drawing schematic potential curves. Case (a) has been extensively studied in two-dimensional models. The appearance of multiple solutions, or disappearance of a solution takes place as the system evolves away from the current-free configuration. Case (b) can be discussed in terms of ideal MHD or resistive MHD instabilities. A possible route to explosive energy release is suggested by combining these two cases.
Advances in Densitometry
Authors: Hambleton J. 
Published: July 2016

Firstly I should like to apologise for Mr. Loebl’s inability to come here today. Because of illness, he has been asked to rest and since he and I are working together on the same problems, he has asked me to present this paper.It must be obvious to all concerned in the evaluation of photographic images, that microdensitometry has rapidly changed with the advance in technology. Improvements have taken place over the years in the use and refinement of double beam recording instruments. Present trends indicate that little further can be done regarding optical resolution and diffraction limited systems can now be built. The quantitative evaluation of images based on a line integral has not changed in principle for many years. A scanning spot of the requisite size is passed across, for example, a spectral line, and the densitometric profile line gives the information required, either by its height or its area.
Automated Spectrophotometry
Authors: Thompson G. I. 
Published: July 2016

Starting from a digitized and calibrated stellar spectrum—what can we most usefully do with it?Traditionally a spectrum consists of two parts, a continuum and some lines. These have been variously defined in the past, so perhaps another definition may be allowed. Over large ranges the two components can be distinguished quite sharply in the spatial frequency plane. The continuum contains only low frequencies, whereas in the line the information is contained in the high frequencies. In the word “continuum” is included the instrumental absorption functions, emulsion sensitivity, wide interstellar and atmospheric bands, and even the wide wings of very strong lines. From the word “lines”, on the other hand, the strongest lines are excluded; these may contain intermediate spatial frequencies in their core regions. They are relatively infrequent and so may be treated as special cases.
Polarization of Infrared Objects
Authors: Kruszewski A. , Smak J. 
Published: July 2016

We know several infrared objects showing large intrinsic polarization (FORBES 1967, APPENZELLER and O’DELL 1967, KRUSZEWSKI 1968, SERKOWSKI 1969, SHAWL 1969, SHAWL and ZELLNER 1970, KRUSZEWSKI 1971, DYCK, FORBES and SHAWL 1971).In the following discussion I shall speak about the broad category of infrared stars which consists of reddest and coolest giants (M8 or later) and supergiants (M5 or later). This restriction is made because the yellow supergiants seem to have different polarization properties and these properties most likely extend to supergiants as late as M 2 or even M 4. Also it is not clear if normal red variables can be treated together with infrared objects.
A Photometric Search for Circumstellar Shell Variability and Pre-Main Sequence Delta Scuti Variables
Authors: Breger M. , Hardorp J. 
Published: July 2016

AbstractA light variability study in NGC 2264 shows that about 25 % of the pre-main sequence A and F stars show irregular short-period variability and/or brightness changes since 1953. There exists a good correlation between this variability and (other) shell indicators. The scatter in the pre-main sequence band in the color-magnitude diagram can be partially explained by shells and an age spread between 1 and 3 × 106 years is indicated. W 90, a star below the main sequence, has brightened by half a magnitude to V = 12.5 since 1953. The corresponding color variation suggests a ratio of total to selective extinction of about 9.
RW Arietis; an RR Lyrae Variable Star in an Eclipsing System
Authors: Wisniewski W. Z. 
Published: July 2016

AbstractRW Arietis was observed photoelectrically in the UBV-system during fall and winter 1966 with the 70 cm telescope at the Lunar and Planetary Laboratory Catalina station, University of Arizona, Tucson, on 19 nights. Peculiar variations of the usually stable RRc light curve observed on three nights can be interpreted as a superposition of the RR Lyrae type variation and an eclipsing type variation.