bluuebunny/crossref_metadata_2025 huggingface dataset:
The CfA Seyfert Sample at 8.4 GHz
Authors: Kukula Marek J. , Pedlar Alan , Baum S. , O'Dea C. , Unger S.
Published: July 2016

Increasingly, the evidence from optical and infra–red wavebands suggests that the difference between Seyfert 1 and Seyfert 2 nuclei is due largely to orientation effects rather than intrinsic differences between the two classes, but the evidence from radio observations has been less clear–cut. We have observed the CfA Seyfert Sample at 8.4 GHz using the VLA in A– and C–configurations. At this frequency our A–array maps have a resolution of 0.25″ – much higher than those achieved in previous surveys – whilst the 3″ C–array beam is ideal for measuring the total radio flux of the active nucleus. The 1–sigma noise in both sets of observations was 70 μJy.
The Influence of Selection Effects on the Properties of BL Lacs
Authors: Marchã M.J.M. , Browne I.W.A.
Published: July 2016

The fact that the recognition of BL Lacs always requires optical confirmation, regardless of whether the objects were first selected in the radio, or X-ray frequencies means that deep surveys will miss some objects simply because the optical emission from the host galaxy outshines that of the BL Lac. In particular, the deeper the survey, the more difficult it will become to recognize low luminosity BL Lacs in the nuclei of luminous galaxies. This recognition effect will modify the intrinsic distribution of objects, and influence their statistical properties in general.
AGN as a Result of Evolution of Binary Gravimagnetic Rotators
Authors: Sil'chenko Olga K. , Lipunov Vladimir M.
Published: July 2016

Supermassive black holes in AGN can form directly as the results of collapse of supermassive magnetic and rotating stars (gravimagnetic rotators). In this case naturally we can consider the binary magnetic rotator systems as progenitors of active galactic nuclei. One of the most important consequence of this scenario is an existence of moving galactic nuclei, so called “nomadic” nuclei.
II. The Galaxy
Authors: Larsson-Leander G.
Published: July 2016

This section deals with a few remarks on stellar systems outside the Galaxy which were considered to be of importance in the interpretation of galactic observations.
III. The Magellanic Clouds
Authors: Thackeray A. D.
Published: July 2016

The Magellanic Clouds offer a unique opportunity to study fully resolved stellar systems at, optical and radio wave-lengths. Optically, with the largest southern telescopes available it is possible to reach absolute magnitudes + 1 to + 2 by direct photography and absolute magnitudes - 6 to - 4 spectroscopically. The greatest value of the Clouds to galactic research is the opportunity to calibrate the absolute magnitudes of luminous objects within the Galaxy. Uncertainty regarding location in depth within the Clouds adds a random error of about ± 0·13 m, i.e. considerably less than the uncertainty of the distance modulus of the Clouds themselves.
Short-term analyses of the variation of latitude
Authors: Cooklin G. , Read E. J. C. , Young A.
Published: July 2016

In an earlier paper on “The Future of the International Latitude Service”, Young reported a conclusion that short-term analyses of the variation of latitude could never be expected the produce accurate representations of the variation. Short term analyses may be needed either for the interpolation of results for immediate use, or for the investigation of the theoretical motion. In this paper we consider both these needs.
On the Problems of Selenodetic Photogrammetry
Authors: Arthur D. W. G.
Published: July 2016

As a technique for dealing with measurements on photographs, photogrammetry is distinguished by its emphasis on stereoscopic measurement and by its insistence on projection of the photographs as cones of perspective rays. In most photogrammetric operations the object is the construction of a three-dimensional model by intersections of these rays.
A Photographic Map of the Moon
Authors: Arthur D. W. G. , Whitaker E. A.
Published: July 2016

The cartography of the lunar surface can be split into two operations which can be carried on quite independently. The first, which is also the most laborious, is the interpretation of the lunar photographs into the symbolism of the map, with the addition of fine details from telescopic sketches. An example of this kind of work is contained in Johann Krieger'sMond Atlaswhich consists of photographic enlargements in which Krieger has sharpened up the detail to accord with his telescopic impressions. Krieger did not go on either to convert the photographic picture into the line symbolism of a map, or to place this picture on any definite map projection.
On Moon Volcanism
Authors: Bonev N.
Published: July 2016

The Moon craters grew out of Moon volcanism in the remote past. N. A. Kozyrev observed a volcanic eruption at the beginning of November 1958. In the remote past this activity was probably much more intense. The distribution of the craters over the eastern and the western halves of the Moon disk does not support the meteoritic hypothesis of the origin of the Moon craters. We ascertained this in 1955 and 1956 by means of some theorems from the field of continued probabilities bearing on the hemisphere and on the polygon†. The eastern hemisphere of the Moon is continually undergoing a meteoritic bombardment to an even greater degree than the western one, yet no adequate effect is to be observed. It is true that nowadays the orbital velocity of the Moon about the Earth is slow in respect to the annual motion of the Earth about the Sun. However, according to the theory of probability, the slight advantage of the eastern over the western hemisphere would certainly have become apparent after a sufficiently large number (say several hundreds of millions) of years.
Physical Nature of Different Zones of the Lunar Surface
Authors: Markov A. V.
Published: July 2016

At the present time a sufficiently objective analysis of the data on the nature of the lunar surface collected by Soviet as well as foreign astronomers [1] has been made. Therefore, it is timely to examine critically the question of the nature of the upper layer of the lunar crust, since it is specially important for the astronaut to know its structure to a depth of from 2 to 5 m.
Meteor-Slag Theory of the Lunar Surface
Authors: Sytinskaya N. N.
Published: July 2016

In my communication I am confronted with the task of applying the results of photometric, colorimetric and thermal investigations of the Moon for certain conclusions regarding the nature and origin of the outer layer of the lunar surface. The considerations which I am to share with you in the present chapters have already been published by me under the title “Meteoric-Slag Theory of the Lunar Surface”. This theory had to be developed and supplemented as results of new observations, measurements and theoretical calculations were obtained [2].
Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts
Authors: Stanyukovich K. P. , Bronshten V. A.
Published: July 2016

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.
Some Results Deduced from Simulation of Lunar Craters
Authors: Sabaneyev P. F.
Published: July 2016

It has been repeatedly noted that formations possessing all the attributes of lunar craters are produced in a layer of some loose materials, placed on a level and firm base, on dropping of a lump—made likewise of a loose substance—into such materials. The experiments demonstrate the possibility of obtaining in this way individual special features of separate craters, as well as their combinations, and of clarifying the origin of many enigmatic features of the Moon's relief.
Processes on the Lunar Surface
Authors: Gold T.
Published: July 2016

The coloration of the Moon in light and dark areas requires a remarkably specific interpretation and is therefore a good starting point for the discussion of processes on the lunar surface. It is generally true that the high ground is light and the low flat ground is dark. Generally the ray material ejected from craters both in the high and the low ground is light (there are a few exceptions). The light ray material is present only in association with craters judged youngest on all other evidence, and it must therefore be supposed that such ray material does not show on the surface for long, compared with the age of most features.
Radio Emission of the Moon, its Physical State, and the Nature of its Surface
Authors: Troitsky V. S.
Published: July 2016

Recently experimental data have been obtained on lunar radio emission which enable one to solve the problem as to which model of structure for its upper layer corresponds to reality: single layer (homogeneous structure of the covering) or a widely distributed two-layer-dust cover [1]. They also enable one to draw more definite conclusions as to the physical properties, thermal conditions, and structure of lunar material.
Observations of Radio Emission of the Moon at 2.3 cm by the Pulkovo Large Radio Telescope
Authors: Kaydanovsky N. L. , Ihsanova V. N. , Apushkinsky G. P. , Shivris O. N.
Published: July 2016

The measurement of the amplitude of variation of the brightness temperatureTaat the centre of the lunar disk enables, as is shown in [1], to evaluate the magnitude of the equivalent conductivity σ of the material of the lunar crust. The amplitude of variation of brightness temperatureTacan be determined with the aid of radio telescopes with high resolving power by direct measurements of the brightness temperatureTein the course of a lunation. Such measurements require that the area efficiency σ of the antenna and conditions of calibration of the receiving apparatus over the period of observations to be constant, and this is hard to ensure.Tacan also be determined by measuring the shift of the centre of gravity of radiationxu[2]†, resulting from the fact that the variable component of brightness temperature, in superimposing itself on the constant component, distorts the symmetry of the curves of equal light intensity (isophotes) relative to the central meridian, and shifts the point of maximum brightness away from the centre of the disk in the direction of the subsolar point, asTais a functionxu.
On X-ray radiation of the quiet Sun
Authors: Mandelshtam S. L.
Published: July 2016

The conditions of production of the solar X rays are briefly discussed. The comparison of the results of recent calculations and experimental measurements supports the assumption of a thermal origin of the X ray radiation. In the “tail” of the solar spectrum below 15 Å, the main contribution comes from the free-bound radiation of electrons and ions of carbon, nitrogen, oxygen and other elements.

The solar X ray radiation consist of a “quasi-stable” component, produced in undisturbed coronal regions and a “slowly varying” component generated in the active regions of the corona.
The interpretation of the Sun'S XUV radiation
Authors: Allen C. W.
Published: July 2016

This paper reviews our understanding of (a) the earth's ionosphere, and (b) the solar atmosphere, in relation to the recent observations of solar XUV.

The expected ionospheric characteristics are derived as directly as possible from the XUV observations and then compared with the well known E and F layer formation. Agreement does not come very naturally. There are indications of a high ionospheric recombination coefficient decreasing rather rapidly with height. It is found that radiations from the high ions have greater solar cycle variations than radiations from the low ions. This leads to some difficulty in explaining the constancy of the E to F critical frequency ratios. Both UV and X-rays appear to contribute to the E layer.

There are about 250 identified XUV solar emission lines from about 50 ions. The flux measurements for each line gives information on the number of corresponding ions in the solar atmosphere. Each radiation comes from a region with a well specified temperature selected from the whole available range 20000° to 2000000°K. This makes it possible to derive, (a) the amount of solar material in each temperature range, (b) the chemical abundances, and (c) the physical differences between normal solar atmosphere, centres of activity, and flares. The analysis is held up at the present moment until the problem of the dielectronic recombination coefficient is cleared. In due course a good distribution of matter with temperature should be available but the fitting of such results to chromospheric and coronal models provides many problems.
The Zeta/solar lines between 170 Å and 220 Å
Authors: Wilson R.
Published: July 2016

An important problem in solar physics is the identification of the intense system of spectral lines lying between 170 Å and 220 Å. These lines have also been observed in the high temperature plasma, Zeta, and also in a number of other sources. These sources are reviewed and the experimental evidence relating to the problem of identification is discussed.
On the determination of the solar chemical composition from a study of the ultraviolet resonance lines
Authors: Pottasch S. R.
Published: July 2016

On the assumption that the ultraviolet resonance lines are formed by collisional excitation followed by direct radiative transition of a quantum which eventually escapes from the atmosphere, it is shown how the chemical composition may be found. These assumptions are discussed, as is the accuracy of the determinations. The effects of non-radial inhomogeneities are also discussed. Finally the question of the determination of the hydrogen abundance is raised, for which purpose the solar radio observations are used.

The results of this analysis are compared with other solar abundance determinations.
Silicon in the solar corona
Authors: Widing K. G. , Porter J. R.
Published: July 2016

Resonance lines of coronal ions of silicon are prominent in the spectral ranges 40–62 Å and 254–356 Å.

An unexpected feature of the soft X-ray spectrum is the weakness or absence of the resonance lines of iron in ionization stages XI through XV.

A second feature is the prominence of lines of the type (3d → 2p) relative to the resonance transitions (3p → 2s) in Li-like and Beryllium-like spectra. It is suggested that the upper levels (3d) are excited by quadrupole collisions from the ground 2s or 2s2levels.

The intensity of the soft X-ray lines relative to the resonance lines in the 300 Å region seems to be more consistent with temperatures well above one million degrees than with temperatures as low as 700000°K, but the data are not adequate for a precise comparison. The relative intensity of the line emission from the various stages of silicon ionization may be interpreted as indicating that the ionization of silicon peaks in stages IX and X.

The abundances of C, Mg, S, and Al relative to silicon do not seem to be greatly different from the chromospheric abundances reported by Pottasch or with the photospheric abundances.
Far ultra-violet radiation : stars, nebulae and interstellar matter
Authors: Seaton M. J.
Published: July 2016

The ultra-violet flux radiated by hot stars is found to be smaller than the value deduced from theory. The possible origins of this discrepancy are discussed : interstellar absorption, deviation from local thermodynamic equilibrium, molecular absorption, blanketting effect. Observations of planetary nebulae provide data about UV radiation from very hot stars.
Développements récents en spectroscopie des continus atomiques et des raies autoionisées
Authors: Kieffer Par Jean , Damany-Astoin Nicole
Published: July 2016

Bibliographical study of the principal experimental research of the last ten years on atomic and autoionization continua. We have restricted ourselves to the alkaline, alkaline-ferrous and rare gas groups. Moreover, with one exception, all the work cited is concerned with absorption spectra.

We indicate the connections with theory and give the most important of the theoretical references.
Comparison between model atmospheres and spectra from early-type stars
Authors: Avrett E. H. , Strom S. E.
Published: July 2016

To assist in the interpretation of ultraviolet continuum observations, we present observational features of a grid of non-grey model atmosphères in strict radiative equilibrium which have effective temperatures in the range 10000 °K to 20000 °K and surface gravities 103 and 104. For three models, we add the blended wings of the higher Balmer and Lyman hydrogen lines and include in an approximate way further effects of line blanketing in the ultraviolet. Finally, we present a preliminary calculation of the effect of departures from L. T. E. on the continuous flux.

To examine the validity of the models, we compare the predicted continuous flux and predicted line profiles with the corresponding observed quantities for Vega and Sirius.

We consider the question of discrepancies between theory and observations in the ultraviolet from the viewpoint of these new calculations, and find generally good agreement with recent observations made by T. Stecher.
Very high energy cosmic gamma rays
Authors: Libber M. , Milford S. N. , Spergel M. S.
Published: July 2016

Collisions of high energy cosmic rays with intergalactic gas produce various secondaries, including neutral pions that decay into high energy γ rays. The Landau-Milekhin hydrodynamical model for proton-proton collisions is used to calculate the pion production spectrum corresponding to cosmic γ rays of energy above 10 Gev. A source function for these high energy γ rays in space is found by combining the pion production and decay spectra with the primary cosmic ray proton flux. The resulting γ ray spectrum follows a different power law than spectra based upon the usual assumption of a line spectrum for the pions in the center of mass system of the colliding protons. The high energy γ ray intensity in space is calculated for a simple model universe. By comparison with previous estimates for the proton photoproduction process, it is found that proton-proton and proton-photon collisions appear to contribute about the same order of magnitude to the intergalactic γ ray intensity above ∼1016 eV.
A quantitative measurement of water-vapor in the atmosphere of Venus
Authors: Bottema Murk , Plummer William , Strong John
Published: July 2016

Water vapor in the atmosphere of Venus was discovered in November 1959 by observations made at 80000-ft. altitude with a manned balloon-telescope system. This result was confirmed and measured far more precisely in February 1964 with an automatic unmanned system. The method of observing Venus water-vapor absorption in the 1.13-μ band, and the interpretation of that absorption, are described.
Infrared emission lines from celestial sources
Authors: Gould Robert J.
Published: July 2016

Some possible strong astronomical emission lines in the infrared region are discussed. The line at 12.8 microns, which results from a transition between the fine structure components of the ground state of the ion Ne+, is thought to be emitted from galactic H II regions and also possibly from extended stellar envelopes. The line at 28 microns is emitted in the J = 2 to J = 0 rotational transition in the (para) hydrogen molecule, and could be emitted from interstellar H I regions and from collapsing protostars. Estimates of the expected intensities of these astronomical emission lines are given.
Observations of the galactic radio emission between 1.5 and 10 MHz from the Alouette Satellite
Authors: Hartz T. R.
Published: July 2016

Since September 29, 1962, a sweep-frequency receiver covering the range 0.5 to 12 MHz has been operating in a 1000 km height, 80.5° inclination orbit about the earth for about 5 hours a day on the average. Only a very small portion of the data has yet been analyzed, and from this the spectrum of the galactic radio emission between 1.5 and 5 MHz has been determined fairly reliably, but it has not been possible from these data to extend this up to 10 MHz with any accuracy. Although there is no provision for absolute gain calibration of the receiver in flight, the data are so consistent as to give confidence to the pre-flight calibration. The greatest uncertainty hinges on the effects of the ionization on the antenna impedances. To evaluate these, galactic noise measurements have been made under a variety of local electron densities and different magnetic field strengths : these values have then been extrapolated to zero electron density and the free space values obtained by this extrapolation procedure are taken as a measure of the galactic emission. At 2.3 MHz the brightest region of the galaxy is centred on the south galactic pole and has a temperature of about 1.8 × 107 °K. The lowest temperature, about 5.0 × 106 °K, at 2.3 MHz was found for the region centred on R. A. 9 hr., dec + 75°. At this same frequency the brightness temperature versus frequency curve has a elope of — 1.7; at 1.5 MHz the slope is — 1.3 and at 5.0 MHz the slope is — 2.2.
Antenna impedance in a plasma : problems relevant to radio astronomy measurements from space vehicles
Authors: Walsh D. , Haddock F. T.
Published: July 2016

A critical review is given of the theory and experimental observations of antenna impedance behaviour in a plasma, as related to radio astronomy. The emphasis is on electrically small antennas. Three simplified cases of plasma are considered, namely, cold plasma without magnetic field, cold plasma with magnetic field and warm plasma without magnetic field. Newly reduced experimental results are reported for the case of cold plasma without magnetic field, showing detailed agreement with theory in the neighbourhood of a cutoff in the propagation of the extraordinary magnetoionic wave.
Some measurements of aerial impedance in the ionosphere
Authors: Hugill J.
Published: July 2016

The admittance of a wire dipole of overall length 20 m was measured at a height of approximately 125 km in the night-time ionosphere. Measurements were obtained at 60 kHz and at a frequency swept over the range 1.4 MHz to 1.8 MHz so as to include the gyro frequency. The results are interpreted in terms of a theory due to Kaiser, and fair agreement is obtained. The electron density and collision frequency in the plasma surrounding the aerial are estimated.
Searches for Young Pulsars
Authors: Camilo Fernando
Published: July 2016

I review the results of radio and X-ray searches for pulsations from young neutron stars, emphasizing work accomplished in the last five years. I cover undirected searches, as well as directed searches of pulsar wind nebulae, EGRET γ-ray sources, and also the search for pulsations from “isolated neutron stars” and “central compact objects”.
Searching for Compact Objects in Supernova Remnants: Initial Results
Authors: Kaplan D. L. , Kulkarni S. R. , Frail D. A. , Gaensler B. M. , Slane P. O. , Gotthelf E. V.
Published: July 2016

Most astronomers now accept that stars more massive than about 9 M⊙ explode as supernovae and leave stellar remnants, either neutron stars or black holes. However, less than half of the SNRs within 5 kpc have identified central sources. Here, we discuss a systematic effort to search for compact central sources in the remaining 23 SNRs of this distance-limited sample. As the first part of this survey, we are able to state with some confidence that there are no associated central sources down to a level of one tenth of that of the Cas A central source, LX ≲ 1031 ergs s−1, in four SNRs (G093.3+6.9, G315.4−2.3, G084.2+0.8, and G127.1+0.5). We compare our limits with cooling curves for neutron stars and find that any putative neutron stars in these SNRs must be cooling faster than expected for traditional 1.35 M⊙ neutron stars.
A 20 cm Search for Pulsars in Globular Clusters with Arecibo and the GBT
Authors: Hessels J. W. T. , Ransom S. M. , Stairs I. H. , Kaspi V. M. , Freire P. C. C. , Backer D. C. , Lorimer D. R.
Published: July 2016

We are conducting deep searches for radio pulsations at L-band (∼ 20 cm) towards more than 30 globular clusters (GCs) using the 305 m Arecibo telescope in Puerto Rico and the 100 m Green Bank Telescope in West VirginiA. With roughly three quarters of our search data analyzed, we have discovered 12 new millisecond pulsars (MSPs), 11 of which are in binary systems, and at least three of which eclipse. We have timing solutions for several of these systems.
2D Relativistic MHD Simulations of PWNe: Preliminary Results
Authors: Amato Elena , Del Zanna Luca , Bucciantini Niccolò
Published: July 2016

We present preliminary results of 2D axisymmetric relativistic MHD simulations of PWNe, aimed at investigating whether structures such as the rings and jets revealed by high resolution X-ray imaging can be due to anisotropy of the outflow from the pulsar. We confirm that these features can qualitatively be explained when the energy flux is larger in the equatorial plane than along the spin axis. Detailed comparison between simulation results and observations is required to constrain the wind energy distribution upstream of the termination shock.
The Vela Pulsar, the Key?
Authors: Dodson Richard , Lewis Dion , Legge David , McCulloch Peter , Reynolds John , McConnell David , Deshpande Avinash
Published: July 2016

Of all pulsars known, Vela has been one of the most productive in terms in understanding pulsars and their characteristics. We present the latest results derived from Australian telescopes. These include a more accurate pulsar distance, a more precise pulsar local space velocity, a new model of spin-up at a glitch, and the association of a radio nebula with the X-ray pulsar wind nebula.
Chandra Study of the Central Object Associated with the Supernova Remnant MSH 11–62
Authors: Harrus Ilana , Bernstein Joseph P. , Slane Patrick O. , Gaensler Bryan , Hughes John P. , Moffett David , Dodson Richard
Published: July 2016

We present results from our analysis of Chandra data on the supernova remnant MSH 11–62 (also known as G291.0−0.1). Our previous ASCA analysis showed that MSH 11–62 is most likely a composite remnant whose strong non-thermal emission is powered by a compact object, most probably a pulsar. The present analysis confirms in a spectacular fashion the earlier detection of a compact source. The Chandra data reveal a small region with a hard non-thermal spectrum located at the tip of the central radio emission seen in data taken at the Australia Telescope Compact Array (ATCA). This source is likely the young rapidly rotating neutron star powering the synchrotron nebula in MSH 11–62. Compared to other young rotation-powered pulsars the Chandra specrum of MSH 11–62 implies an energy loss rate of Ė ∼ 5 × 1036 ergs s−1.
On the Nature of Magnetars
Authors: Istomin Ya. N.
Published: July 2016

The electromagnetic fields of magnetodipole radiation can penetrate to the conducting matter of a neutron star crust and create there electric currents and tangential magnetic fields of high magnitude. The solution obtained here has the form of surface magnetic field discontinuities propagating through the crust to the core. This model explains the phenomena of magnetars — Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars.
Imprints of Neutron Stars in the Interstellar Medium
Authors: Reynoso Estela M. , Johnston Simon , Green Anne J. , Goss W. M. , Dubner Gloria M. , Giacani Elsa B.
Published: July 2016

We have carried out an H I survey towards X-ray central compact objects (CCOs) inside supernova remnants (SNRs), which shows that many of them are placed within local H I minimA. The nature of these minima is not clear, but the most likely explanation is that the CCOs have evacuated the neighboring gas. This survey also allowed us to detect a weak, diffuse radio nebula inside the SNR G266.2−1.2, probably created by the winds of its associated CCO.
Modeling the Atmosphere of RX J1856.5−3754
Authors: Walter Frederick M. , Pons Jose A.
Published: July 2016

The nearby compact object RX J1856.5−3754 may be a paradigm for the vast majority of neutron stars. Its spectral energy distribution lacks any non-thermal continuua or lines. Study of the thermal surface has provided insights into the surface and interior properties of neutron stars. We report on attempts to model the spectrum. Non-magnetic heavy metal atmospheres reproduce the overall spectral energy distribution, but not the lack of absorption lines.
Nuclear Pasta Structure in Hot Neutron Stars
Authors: Watanabe Gentaro , Sato Katsuhiko , Yasuoka Kenji , Ebisuzaki Toshikazu
Published: July 2016

The structure of cold and hot dense matter at subnuclear densities is investigated by quantum molecular dynamics simulations. The phase diagrams obtained show that the density of the phase boundaries between the different nuclear structures decreases with increasing temperature due to the thermal expansion of the nuclear matter region.
Observing Single Pulses Over a Broad Frequency Range
Authors: Karastergiou A. , Johnston S. , Kramer M. , Bhat N. D. R. , Gupta Y.
Published: July 2016

We have obtained simultaneous observations of single pulses from the bright pulsars B0329+54 and B1133+16 at two frequencies in full polarization and a total of four frequencies in total power only. Here is a summary of our fantastic results!
High-frequency Turnover in Pulsar Spectra
Authors: Kijak J. , Maron O.
Published: July 2016

Spectra of several pulsars with turnover at unusually high frequencies ∼ 1 GHz are presented. These are relatively young pulsars with DM typically larger than for pulsars showing a low-frequency turnover.
MRT Observations of the MSP J0437–4715 at 150 MHz
Authors: Issur Nalini H. , Deshpande Avinash A.
Published: July 2016

We report some results based on 150 MHz observations of the millisecond pulsar J0437–4715 carried out using the Mauritius Radio Telescope (MRT). For the single pulse properties we also consider 327 MHz data from the Ooty Radio Telescope.
Pulse Emission Mechanisms
Authors: Melrose Don
Published: July 2016

High-energy and radio emission mechanisms for pulsars are reviewed. The source region for high energy emission remains uncertain. Two preferred radio emission mechanism are identified. Some difficulties may be resolved by appealing to nonstationary pair creation distributed widely in height.
Orthogonal Mode Polarization of Pulsar Radio Emission
Authors: Luo Q. , Melrose D. B.
Published: July 2016

We discuss a model for polarization of pulsar radio emission, based on the assumption that waves propagate in two elliptically polarized natural modes. Some results from numerical simulation of single pulses are discussed with emphasis on circular polarization, microstructures and single pulse statistics.
A Model for Non-thermal Optical Emission from Radio Pulsars
Authors: Petrova S. A.
Published: July 2016

Interpretation of the non-thermal optical emission of pulsars as a spontaneous synchrotron re-emission of the secondary particles involved in the process of resonant absorption of pulsar radio emission is suggested. Our model can explain the non-thermal high-energy luminosities and spectra of both young and middle-aged pulsars. Moreover, it implies a physical link between the radio and higher-energy emission of pulsars.
New Pulsars Coincident with Unidentified Gamma-Ray Sources
Authors: Roberts Mallory , Ransom Scott , Hessels Jason , Livingstone Margaret , Tam Cindy , Kaspi Victoria , Crawford Fronefield
Published: July 2016

We present the results of radio searches for pulsars within unidentified EGRET source error boxes. Using the Parkes multibeam system, we have surveyed 56 sources at Galactic latitudes |b| > 5° which do not appear to be associated with blazars. This population has been suggested to be distributed like the local star forming region known as the Gould Belt, the Galactic Halo, and/or the millisecond pulsars. We have discovered several new pulsars in this survey, including three new binary systems.
Results of Russian-Japanese Precise Timing of PSR B1937+21
Authors: Ilyasov Yu. P. , Imae M. , Hanado Y. , Oreshko V. V. , Potapov V. A. , Rodin A. E. , Sekido M.
Published: July 2016

Results of joint Russian-Japanese timing observations of the millisecond pulsar B1937+21 are presented. RMS of the post-fit residuals of the combined data is 1.8 μs. Secular change of dispersion measure with rate of −0.0012 ± 0.0003 pc cm−3 per year has been observed.
The Radio Pulsar J0205+6449 in the SNR 3C 58
Authors: Malofeev V. M. , Malov I. F. , Malov O. I. , Glushak A. P.
Published: July 2016

Pulsed radio emission has been detected from the X-ray pulsar J0205+6449 in the SNR 3C 58 at 111 and 88 MHz on radio telescopes of the Pushchino Radio Astronomy Observatory. The dispersion measure DM = 141 pc cm−3 has been confirmed. The synchrotron mechanism is proposed for the radio and X-ray emission to explain the lower X-ray and radio luminosities of this pulsar compared to the Crab pulsar.
An Accretion Column Model for the Accreting Pulsar Hercules X-1
Authors: Leahy D. A.
Published: July 2016

A model is developed here to reproduce the pulse shape of Her X-1. The 35-day cycle of pulse shape changes during the 35-day Her X-1 cycle “High – Low – Short High – Low” is caused by varying obscuration of the emission region by the accretion disk. The observed sequence of pulse shape changes imply a pencil beam from the near pole and a fan beam from the far pole. Using a newly developed code for modeling accretion column emission, including accurate treatment of gravitational light-bending effects, the observed pulse shape of Her X-1 is modeled here.
Periodicities of Radio Flares in RS CVn and Algol Binaries
Authors: T. Richards Mercedes , B. Waltman Elizabeth , D. Ghigo Frank , St. P. Richards Donald
Published: July 2016

Periodicities of radio flaring activity from the Algol systems β Per and δ Lib and the RS CVn systems V711 Tau and UX Ari were determined from a continuous 5-year survey. The radio continuum fluxes at 2.3 GHz and 8.3 GHz were monitored with the NRAO—Green Bank Interferometer for 2096 days from 1995 January to 2000 October. The maximum detected flare strengths at 8.3 GHz were 1.17 Jy for β Per, 0.034 Jy for δ Lib, 1.44 Jy for V711 Tau, and 0.82 Jy for UX Ari. Power Spectrum Analysis and Phase Dispersion Minimization were used to determine the periodicity of flaring activity in each binary. The strongest periodicities found were 48.9 days for β Per, 120.7 days for V711 Tau, and 141.4 days for UX Ari. No significant periodicities were found for δ Lib. The continuous survey has demonstrated that there are active and quiescent flaring cycles in V711 Tau and β Per.
X-ray Emission from Single Stars
Authors: M. M. Schmitt J. H.
Published: July 2016

During the last two decades a new field in stellar astrophysics emerged: Stellar X-ray astronomy. With the advent of soft X-ray imagery X-ray emission was found from many thousands of solar-like stars. I will summarize the most important X-ray properties of cool stars and how they compare to the Sun.
X-rays from M-type Giants—Signs of Late Stellar Activity?
Authors: Hünsch Matthias , Konstantinova-Antova Renada , M. M. Schmitt Jürgen H. , Schröder Klaus-Peter , Kolev Dimitar , de Medeiros Jose-Renan , Lèbre Agnes , Udry Stephane
Published: July 2016

We present recent X-ray and optical observations of five M-type giants which were detected as strong X-ray sources. One of these stars, HR 5512, shows short-term variations in both X-ray flux as well as in the shape of the Hα and Ca ii H+K lines, and it rotates much faster than M-type giants usually do. No indication of binarity has been found for this star. We propose that the X-ray emission of HR 5512 is related to a large degree of stellar activity. For two other stars (15 Tri, HR 7547) radial velocity observations seem to indicate spectroscopic binarity.
The Structure and Dynamics of the Outer Atmosphere of ∊ Eri
Authors: Sim S. A. , Jordan C.
Published: July 2016

We present results from our study of the active dwarf ∊ Eri (K2 V) based on ultraviolet spectra recorded with the Space Telescope Imaging Spectrograph and the Far Ultraviolet Spectroscopic Explorer. A combination of simple theoretical arguments and observational constraints derived from measured line fluxes are used to deduce new information about the structure of the upper transition region/corona. The area filling factor of emitting material is determined in the upper atmosphere as a function of temperature. This provides new constraints on how the magnetic field might spread out in the atmosphere of an active main sequence star. Measured emission line widths are used, together with a new semi-empirical model of the atmosphere, to place limits on the energy fluxes carried by MHD waves. These are compared with estimates of the energy input required to support the combined radiative/conductive losses in the upper atmosphere. It is shown that, in principle, waves which propagate at the Alfvén speed could provide sufficient energy to heat the corona.
Variability in a Large Sample of Sun-Like Stars
Authors: C. Fekel Francis , W. Henry Gregory , L. Baliunas Sallie , A. Donahue Robert
Published: July 2016

We summarize photometric, spectrophotometric, and spectroscopic results for a sample of nearly 350 nearby late-F to early-K dwarfs and subgiants of various ages. The sun's position in this stellar sample is examined.
Magnetic Activity at Very Low Masses
Authors: Basri Gibor
Published: July 2016

The characteristics of stars of very low mass are reviewed with emphasis on signatures of and consequences of magnetic activity.
Search for Low-Amplitude Stellar Motions in NGC 752
Authors: Barden Samuel C. , Pilachowski Catherine A. , Deliyannis Constantine , Mathieu Robert , Meibom Soeren , Harmer Dianne
Published: July 2016

We report preliminary results of a radial velocity study of the old open cluster NGC 752 using an ensemble mean approach with Hydra multi-fiber spectroscopy on the 3.5-m WIYN telescope. The goal is to detect the higher amplitude extra-solar planetary systems and brown dwarf binaries that might reside in the cluster. The oscillation modes of mid-F stars at the redward edge of the instability strip can also be observed. The observation of NGC 752 is the first step in an ongoing study of a variety of clusters with different ages and metallicities.
Evolution of the Solar Magnetic Activity over Time and Effects on Planetary Atmospheres
Authors: Guinan Edward F. , Ribas Ignasi
Published: July 2016

We report on the results of a multi-wavelength program (X-rays to the near IR) of solar analogs with ages covering ∼0.1—9 Gyr. The chief science goals are to study the solar magnetic dynamo and to determine the radiative and magnetic properties of the Sun during its evolution across the main sequence. The present paper focuses on the latter goal, which has the ultimate purpose of constructing spectral irradiance tables to be used to study and model planetary atmospheres. The results obtained thus far indicate that the young Sun was extremely active, with large flares, massive winds, and high-energy emissions up to 1000 times stronger than presently. The strong radiation and particle emissions inferred should have had major influences on the photochemistry and photo-ionization of paleo-planetary atmospheres and also played an important role in the development of primitive life in the Solar System. Some recent results of the effects of the young Sun's enhanced radiation and particle emissions on the early Solar System planets are discussed.
Emerging Flux and the Heating of Coronal Loops
Authors: Schmieder B. , Démoulin P. , Rust D.M. , Georgoulis M.K. , Bernasconi P.N.
Published: July 2016

Observations of various instruments on board Yohkoh, SOHO, and TRACE complement high-resolution observations of the balloon-borne Flare Genesis Experiment, obtained on January 25, 2000. A subset of the TRACE loops are located in the vicinity of the SXT loops in the NOAA emerging active region 8844, but never coincide with them. We find that coronal loops appeared 6 ± 2 hr after the first detection of emerging magnetic flux. The loops evolved rapidly when the active region entered its impulsive flux emergence phase. In the low chromosphere, flux emergence was reflected in intense Ellerman bomb activity. Besides chromosphere, we find that Ellerman bombs may also heat the transition region, by contributing to the moss emission. Areas prolific in Ellerman bombs show moss ∼ 100% brighter than areas without Ellerman bombs. Only the strongest Ellerman bombs can heat their surroundings to coronal temperatures. In the corona, we find a spatio-temporal anti-correlation between the soft X-ray (SXT) and the extreme ultraviolet (TRACE) loops: First, the SXT loops preceded the appearance of the TRACE loops by 30 — 40 min. Second, the TRACE loops had different shapes and different footpoints compared to the SXT loops. The SXT and TRACE loops are probably formed independently.
FIP Effect and FIP-Dependent Bias in the Solar Corona
Authors: Dwivedi B.N. , Mohan A. , Landi E.
Published: July 2016

Using EUV spectra of an active region observed off the solar disk by the SOHO/SUMER spectrograph on the SOHO spacecraft, we investigate the dependence of the FIP effect on the height above the photosphere, and its relation to plasma magnetic structures present in the field of view. We also investigate the possibility of the FIP bias in the low-FIP elements to be FIP-dependent, so that different abundance anomalies must be found even within the low-FIP class of elements, which can provide important constraints on the FIP effect models.
Origin and Acceleration of Fast and Slow Solar Wind
Authors: Poletto Giannina
Published: July 2016

Before the advent of the Solar and Heliospheric Observatory (SOHO, launched in 1995), we had little information on how coronal plasma gets accelerated to the high speed measured in situ. The Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO, acquiring UV data over the first few solar radii, a region unexplored in this spectral range, allowed us to build a profile of the outflow plasma speed vs. heliocentric distance, based on empirical constraints. Still, much has to be learnt about the behavior of solar wind in the extended corona. In the following, after briefly reviewing the general properties of the solar wind, I'll focus on controversial issues — like the identification of the sources of fast and slow wind, and the acceleration of fast vs. slow wind streams — and I'll illustrate recent contributions to the solution of these problems.
Winds from Cool Stars
Authors: Dupree A. K.
Published: July 2016

Recent spectroscopic results from the far ultraviolet and X-ray region coupled with infrared observations demonstrate that winds from luminous stars can be warm (300000K) and fast (speeds of several hundred km s—1) linking the hot solar wind to the cool, massive winds of luminous M-type supergiant stars. Hot coronal material (T ∼107 K) appears to be confined near the star, and not expanding in the wind. These new spectra enable a comprehensive picture to be constructed of the presence and character of winds in cool stars.
Conference Summary
Authors: Binney James
Published: July 2016

The competition between CDM and MOND to account for the ‘missing mass’ phenomenon is asymmetric. MOND has clearly demonstrated that a characteristic acceleration a0 underlies the data and understanding what gives rise to a0 is an important task. the reason for MOND's success may lie in either the details of galaxy formation, or an advance in fundamental physics that reduces to MOND in a suitable limit. CDM has enjoyed great success on large scales. the theory cannot be definitively tested on small scales until galaxy formation has been understood because baryons either are, or possibly have been, dominant in all small-scale objects. MOND's predictive power is seriously undermined by its isolation from the rest of physics. in view of this isolation, the way forward is probably to treat CDM as an established theory to be used alongside relativity and electromagnetism in efforts to understand the formation and evolution of galaxies.
What is the Evidence for Dark Matter?
Authors: Sellwood J. A.
Published: July 2016

Newtonian mechanics indicates that galaxies and galaxy clusters are much more massive than we would have guessed from their luminosities, with the discrepancy being generally attributed to dark matter halos. An alternative hypothesis is that accelerations in very weak gravitational fields are larger than predicted by Newton's laws, and there is no need for dark matter. Even though we do not currently have a satisfactory theory associated with this rival hypothesis, we can ask whether any observational tests could rule it out or prefer it over the dark matter hypothesis. Current evidence suggests that neither hypothesis enjoys a decisive advantage over the other. If dark matter turns out to be the correct interpretation however, then theories of galaxy formation face some quite severe fine-tuning problems.
Inner Structure of Dark Matter Halos
Authors: Fukushige Toshiyuki , Kawai Atsushi , Makino Junichiro
Published: July 2016

We investigate the structure of the dark matter halo formed in the cold dark matter scenarios by N-body simulations with parallel treecode on GRAPE cluster systems (Fukushige, Kawai, Makino 2003). We simulated 8 halos with the mass of 4.4 × 1014M⊙ to 1.6 × 1015M⊙ in the SCDM and LCDM model using up to 30 million particles. With the resolution of our simulations, the density profile is reliable down to 0.2 percent of the virial radius. Our results show that the slope of inner cusp within 1 percent virial radius is shallower than −1.5, and the radius where the shallowing starts exhibits run-to-run variation, which means the innermost profile is not universal.
Determining the Properties of Galaxy 2237+0305 using Gravitational Lensing
Authors: Trott Cathryn , Webster Rachel
Published: July 2016

We have studied the mass distribution in the lensing galaxy 2237+0305 using constraints from both gravitational lensing and photometric and spectroscopic observations. We find that with sufficient dynamical information we can constrain the mass-to-light ratio of the luminous components and determine the dynamical contribution of the disk. in addition, future observations should allow us to place constraints on the shape of the dark matter halo and its inner slope.
MEGA: Microlensing Exploration of the Galaxy and Andromeda
Authors: Alves David R. , Baltz Edward , Crotts Arlin , Bergier Alex , Cseresnjes Patrick , Gersch Alan
Published: July 2016

Microlensing surveys have ruled out that the dark halos of the Milky Way and M31 are composed entirely of massive compact halo objects (MACHOs) for a wide range of MACHO masses. We have tried using the Subaru telescope to improve the limit on Moon-mass MACHOs, which is the lowest decade in MACHO mass that can be probed by microlensing. Unfortunately, only a half-night of Subaru data was obtained and this is not enough; at least 2 nights of data are required. the current limit is based on nearly 6 years of observations with smaller telescopes.
Lighting up the dark and dim in the Andromeda Galaxy
Authors: Kerins Eamonn
Published: July 2016

I discuss current and future applications of pixel lensing: the microlensing of unresolved stars. Pixel lensing is the tool of choice for studying the MACHO dark matter content of external galaxies like Andromeda (M31), and is at the heart of an ambitious new proposal to undertake a census of low-mass stars and brown dwarfs in the M31 bulge.
On Planetary-Mass Compact Objects as Dark Matter
Authors: Zackrisson Erik , Persson Carina , Bergvall Nils
Published: July 2016

We assess to what extent the claimed signature of planetarymass compact objects in the long-term optical light curves of quasars really can be explained by the dark matter populations allowed in the currently favoured ΩM = 0.3, ΩΛ = 0.7 cosmology. Revised upper limits on the cosmological density of planetary-mass compact objects inferred from the statistics of quasar light curves and the equivalent widths of quasar emission lines are also presented.