bluuebunny/crossref_metadata_2025 huggingface dataset:
Early Results From the Cosmic Background Explorer (COBE)
Authors: Mather J. C. , Hauser M. G. , Bennett C. L. , Boggess N. W. , Cheng E. S. , Eplee R. E. , Freudenreich H. T. , Isaacman R. B. , Kelsall T. , Lisse C. M. , Moseley S. H. , Shafer R. A. , Silverberg R. F. , Spiesman W. J. , Toller G. N. , Weiland J. L. , Gulkis S. , Janssen M. , Lubin P. M. , Meyer S. S. , Weiss R. , Murdock T. L. , Smoot G. F. , Wilkinson D. T. , Wright E. L.
Published: July 2016

The Cosmic Background Explorer, launched November 18, 1989, has nearly completed its first full mapping of the sky with all three of its instruments: a Far Infrared Absolute Spectrophotometer (FIRAS) covering 0.1 to 10 mm, a set of Differential Microwave Radiometers (DMR) operating at 3.3, 5.7, and 9.6 mm, and a Diffuse Infrared Background Experiment (DIRBE) spanning 1 to 300 µm in ten bands. A preliminary map of the sky derived from DIRBE data is presented. Initial cosmological implications include: a limit on the Comptonization y parameter of 10−3, on the chemical potential μ parameter of 10−2, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy has the spectrum expected from a Doppler shift of a blackbody. There are no significant anisotropies in the microwave sky detected, other than from our own galaxy and a cosθ dipole anisotropy whose amplitude and direction agree with previous data. At shorter wavelengths, the sky spectrum and anisotropies are dominated by emission from ‘local’ sources of emission within our Galaxy and Solar System. Preliminary comparison of IRAS and DIRBE sky brightnesses toward the ecliptic poles shows the IRAS values to be significantly higher than found by DIRBE at 100 μm. We suggest the presence of gain and zero-point errors in the IRAS total brightness data. The spacecraft, instrument designs, and data reduction methods are described.
The Advanced X-Ray Astrophysics Facility
Authors: Weisskopf M.C.
Published: July 2016

The Advanced X-Ray Astrophysics Facility (AXAF) is a remarkable and unique scientific endeavor. It will be a space-based earth orbiting X-ray observatory, designed to address fundamental questions in astronomy and astrophysics. It is remarkable in that it represents enormous advances in observational capability. It is unique in that it will be the best means of obtaining high resolution, spectrally resolved X-ray images of astronomical objects for the rest of this century and beyond.
The X-Ray Timing Explorer
Authors: Bradt H. V. , Levine A. M. , Morgan E. H. , Remillard R. A. , Swank J. H. , Dingus B. L. , Holt S. S. , Jahoda K. M. , Rothschild R. E. , Gruber D. E. , Hink P. L. , Pelling R. M. , Jernigan J. G.
Published: July 2016

The capabilities of the X-ray Timing Explorer (XTE) are described with particular attention paid to current scientific problems it will address from galactic neutron star systems to active galactic nuclei. It features a low-background continuous 2-200 keV response with large apertures (a 0.63-m2 proportional counter array and a 0.16-m2 dual rocking NaI/CsI scintillation array). Rapid response (in hours) to temporal phenomena, e.g. transients, is obtained by virtue of a scanning all-sky monitor and rapid maneuverability. XTE will carry out detailed energy-resolved studies of phenomena close to neutron stars (e.g. QPO’s) because of its sub-millisecond timing (to 10 μs), its high telemetry rates (to 256 kb/s), and the high throughput of its data system (to ≳ 2 × 105 c s−1).
Far and Extreme Ultraviolet Astronomy with Orfeus
Authors: Krämer G. , Barnstedt J. , Eberhard N. , Grewing M. , Gringel W. , Haas C. , Kaelble A. , Kappelmann N. , Petrik J. , Appenzeller I. , Krautter J. , Mandel H. , Östreicher R. , Bowyer S. , Hurwitz M.
Published: July 2016

ORFEUS (Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer) is a 1 m normal incidence telescope for spectroscopic investigations of cosmic sources in the far and extreme ultraviolet spectral range. The instrument will be integrated into the freeflyer platform ASTRO-SPAS. ORFEUS-SPAS is scheduled with STS ENDEAVOUR in September 1992. We describe the telescope with its two spectrometers and their capabilities i.e. spectral range, resolution and overall sensitivity. The main classes of objects to be observed with the instrument are discussed and two examples of simulated spectra for the white dwarf HZ43 and an O9-star in the LMC are shown.
IRTS: Infrared Telescope in Space
Authors: Matsumoto Toshio
Published: July 2016

IRTS is a small cryogenically cooled telescope onboard the small space platform SFU (Space Flyer Unit). SFU will be launched with the new Japanese HII rocket on January 1994 and retrieved by the space shuttle.

The IRTS telescope has an aperture of only 15 cm diameter, but is optimized to observe diffuse extended infrared sources. Four focal plane instruments are being developed under collaboration between Japan and the U.S.A. IRTS covers a wide wavelength range from near-infrared to submillimeter region, and has a capability for the spectroscopic measurement. Due to newly developed detectors, the sky will be surveyed with very high sensitivities. IRTS will provide valuable data on cosmology, galactic structure, cosmic dust, etc.
The Submillimeter Wave Astronomy Satellite
Authors: Melnick G.J.
Published: July 2016

The Submillimeter Wave Astronomy Satellite (SWAS) is a NASA Small-Explorer Class experiment whose objective is to study both the chemical composition and the thermal balance in dense (NH2 > 103 cm−3) molecular clouds and, by observing many clouds throughout our galaxy, relate these conditions to the processes of star formation. To conduct this study SWAS will be capable of carrying out both pointed and scanning observations simultaneously in the lines of four important species: (1) the H2O (110–101) 556.963 GHz ground-state ortho transition, (2) the O2 (3,3–1,2) 487.249 GHz transition, (3) the CI (3P1 – 3P0) 492.162 GHz ground-state fine structure transition, and (4) the 13CO (J = 5–4) 550.926 GHz rotational transition. These atoms and molecules are predicted to be among the most abundant within molecular clouds and, because they possess low-lying transitions with energy differences (ΔE/k) between 15 and 30K (temperatures typical of many molecular clouds), these species are believed to be dominant coolants of the gas as it collapses to form stars and planets. A large-scale survey in these lines is virtually impossible from any platform within the atmosphere due to telluric absorption.
VSOP, A Space VLBI Programme
Authors: Hirabayashi H.
Published: July 2016

VSOP, VLBI Space Observatory Programme, is an approved space VLBI programme of ISAS for the study of very compact radio sources with the synthesized aperture of 30,000 km diameter, by connecting an orbiting radio observatory with ground radiotelescopes. The VSOP satellite carrying 10 m antenna with 1.6, 5, and 22 GHz band receivers will be launched in early 1995 by M-V rocket of ISAS into an eccentric orbit with 20,000 km in apogee height. The tracking network will be formed for the satellite orbit determination, phase transfer and IF down-link. VSOP aims imaging capability with best resolution of 0.0001 arc second in 22 GHz band. Imaging of active galactic nuclei, star forming regions and stellar objects, and radioastrometry are main scientific targets.
VLBI with TDRSS
Authors: Linfield R. P.
Published: July 2016

VLBI observations using a satellite in earth orbit and ground antennas in Japan and Australia were conducted in 1986, 1987, and 1988. Sources were detected on space-ground baselines at both observing frequencies: 2.3 and 15 GHz. The coherence on space-ground baselines for 340 s was 90% at 2.3 GHz and 76% at 15 GHz. Brightness temperatures in the range 1–4×1012 K were measured for 10 sources at 2.3 GHz and 6 sources at 15 GHz.
The Planetenteleskop Mission
Authors: Neukum G.
Published: July 2016

The scientific focus of the Planetenteleskop project will be on time-variable solar system phenomena (planet-magnetosphere-satellite interactions, active processes of cometary nuclei, atmospheric circulation and dynamics), on time-invariant solar system phenomena (geochemical provinces on planetary and satellite surfaces, global characteristics of primitive bodies), on planetary environments of other stars, and on general astronomical and astrophysical applications. The proposed Planetenteleskop in elliptical 24 h earth orbit will combine near-simultaneous, high-resolution spectroscopic observations, diffraction-limited imaging quality, long integration times (< 10 h) and excellent target tracking accuracy (nominally 0.05 arc sec/10 h, up to 0.02 arc sec). The excellent tracking accuracy and stability on extended objects and features is provided by a novel real-time on-board image correlation scheme. The Planetenteleskop has been studied in prephase A and phase A by industry and the involved science community in Germany in cooperation with American colleagues.
Future Solar System Missions
Authors: Briggs Geoffrey A.
Published: July 2016

After a decade long hiatus in launches beyond Earth orbit, NASA’s planetary exploration program is again moving forward, beginning with the Magellan launch to Venus in May 1989 and the Galileo launch to Jupiter in October 1989. These spacecraft will reach their targets in August 1990 and December 1995, respectively. Both are missions of longstanding priority, Magellan to provide the first global high resolution mapping of the cloud-shrouded Venus surface, Galileo to make comprehensive measurements of the Jovian system in follow-up to the 1979/1980 Voyager flybys.

Beyond these two missions there are other already approved missions: the Mars Observer for launch in 1992, the Comet Rendezvous and Asteroid Flyby CRAF mission (Fig. 1) for launch in 1995, and the Cassini mission (Figs. 2 and 3) to Saturn and its moon Titan for launch in 1996. The very diversity of these five missions and their targets (Venus, the Jovian system, Mars, comet Kopff, asteroids Gaspra and Ida by Galileo, Hamburga by CRAF, and Maja by Cassini, and the Saturnian system, is indicative of the strategy being pursued in the program: one of deliberate breadth that seeks to explore all three main classes of solar system bodies (the terrestrial planets, the outer giants and their moons, and the primitive small bodies).
The Ulysses Mission in the High Latitude Heliosphere
Authors: Page D.E. , Marsden R.G. , Smith E.J. , Wenzel K.-P.
Published: July 2016

Ulysses, a joint ESA/NASA mission launched in October 1990, will be the first to explore the high latitude heliosphere. Launch will be from the Shuttle and a Jupiter gravity assist will be used to send the spacecraft first over the southern solar pole approximately three and one half years after launch and then over the northern solar pole one year later. Instruments will be carried to study the solar wind, the heliospheric magnetic field, energetic solar particles, galactic cosmic rays, solar X- rays, cosmic gamma rays cosmic dust and interstellar neutral helium. The radio signals used to track and transmit spacecraft data will be used also to sound the corona and to search for gravitational waves.
Launch Vehicles of the Future: Earth to Near-Earth Space
Authors: Keyworth G. A.
Published: July 2016

None of us thought, when this colloquium was scheduled, that the timing would enable it to become a celebration as well. The launch, after years of postponements, of the Hubble Space Telescope, has cast a galactic glow over the proceedings here this week. But at the same time, the frustrating delays caused by the collapse in 1986 and very slow regeneration of the U.S. space launch capabilities since then make this discussion of near-earth access very pointed.

As we know, the sheer momentum of the U.S. Space Shuttle Program has dominated our perceptions of space launch for a decade and a half. It reached its peak in the early 1980s when our national policy placed nearly total reliance on the Shuttle as our means of access to space. It was a policy doomed to fail, for obvious and not-so-obvious reasons.
Comments
Authors: Hoyle Fred
Published: July 2016

The word 'origin' is one of the most widely used in science. Yet it seems to me to be always used either improperly or ineffectively. Ineffective uses have a derivative quality about them. As an example, suppose we ask: What was the 'origin' of the magnetic field of the Sun? The best answer I suppose is that the magnetic field of the Sun was formed by the compression of a magnetic field that was present already in the gases of the molecular cloud in which the Sun and Solar System were formed some 4.5 X 109 years ago. But what then was the 'origin' of the field in the molecular cloud? It was present already in the gases from which our galaxy was formed, one might suggest. A further displacement then takes us to the manner of 'origin' of t he entire universe, so that no ultimate explanation has really been given. The problem has only been displaced along a chain until it passes into a mental fog through which some claim to see clearly but through which others, including myself, do not see at all.
SIXA: The Solid State Spectrometer Array Onboard Spectrum-X-Gamma
Authors: Vilhu O. , Sipilä H. , Kämäräinen V.J. , Taylor I. , Laegsgaard E. , Leppelmeier G. , Schnopper H.W.
Published: July 2016

The SPECTRUM - X-GAMMA mission is being developed by the Space Research Institute (IKI), USSR, together with many other countries and is scheduled for launch in 1993 ( Sunyaev,1990; Schnopper,1990). Mission objectives include broad and narrow band imaging spectroscopy over a wide range of energies from the EUV through gamma rays, with an emphasis on studying galactic and extragalactic X-ray sources. The Danish Space Research Institute (DSRI) and IKI will provide two thin-foil X-ray telescopes (SODART), each with an aperture of 60 cm and focal length of 8 m. They are designed to have a half-power width of less than 2 arc minutes and will have collecting areas of 1700, 1200 and 100 cm2 at 1, 8 and 20 keV, respectively. Images and polarization will be recorded by position-sensitive proportional counters. Moderate resolution spectroscopy will be done by the segmented solid state detector SIXA (Silicon X-ray Array), designed and to be constructed by a consortium in Finland, Denmark and USSR. Finland will have the main responsibility in financing and delivering the detector. The Institute of Electromechanics in Moscow will provide its passive cooling system (110 K). The detector will consist of 19 segments (Si(Li)), each with a diameter of about 8 mm. The spectral resolution of 160 eV (at 6 keV), combined with the large collecting area, provide good opportunities for time-resolved iron line spectroscopy ( 6-8 keV). The potential observing program includes stellar coronae, cataclysmic variables and X-ray binaries, accretion discs and coronae of neutron stars and black hole candidates, supernova-remnants, active galactic nuclei, clusters of galaxies and the diffuse cosmic X-ray background. We demonstrate the instrument’s power through some astrophysical simulations.
The All-Sky Extragalactic X-Ray Foreground
Authors: Boldt Elihu
Published: July 2016

Observations of galaxies in the IR and optical (Lynden-Bell et al. 1989) suggest that the 600 km/s peculiar velocity of the LG (Local Group of galaxies) arises mainly from a foreground of anisotropically distributed mass within z = 0.013 (i.e., HR < 4000 km/s). Since the X-ray luminosity of bright extragalactic X-ray sources provides a good mass measure of the radiating objects involved and can be observed relatively free of galactic obscuration effects, such sources are likely candidates for serving as reliable tracers of the total underlying mass (i.e., dark as well as visible) responsible for the acceleration of the LG. In this connection, we note that the local gravitational dipole implied by the fifty X-ray brightest clusters of galaxies at z > 0.013 considered by Lahav et al. (1989) is relatively small compared with that inferred from the only three clusters at lower redshifts. Since the local space density of AGN (Active Galactic Nuclei) is about two orders of magnitude greater than rich clusters, however, such compact sources have the potential of providing a vastly improved statistical sample for tracing mass in the low-redshift region of particular interest. Furthermore, recent dipole analysis of the X-ray flux from bright AGN observed with HEAO-1 A2 indicates that they are indeed strong tracers of this matter (Miyaji and Boldt 1990). The implications of this for the very pronounced large-scale foreground anisotropies to be measured via low-redshift AGN resolved in more sensitive all-sky surveys are explored.
The Astro Mission
Authors: Gull T.R.
Published: July 2016

The Astro Mission, an attached payload dedicated to astronomy, is now scheduled to fly May 9, 1990 in the shuttle Columbia. Four instruments make up the complement. Broad Band X-Ray Telescope (BBXRT, Peter Serlemitsos, Principal Investigator GSFC) utilizes the Two Axis Pointing System (TAPS). The three ultraviolet instruments are Hopkins Ultraviolet Telescope (HUT, Arthur Davidson, JHU), Ultraviolet Imaging Telescope (UIT, Ted Steccher, GSFC) and Wisconsin Ultraviolet Photopolarimeter Experiment (WUPPE, Art Code, UWI). The instruments are co-aligned in the Spacelabs Instrument Pointing System (IPS). Five of the seven astronauts are professional astronomers. Mission Specialists Mike Lounge, Jeff Hoffman, and Robert Parker, and Payload Specialists Samuel Durrance and Ron Parise. During the planned ten-day mission, over 290 shuttle manoeuvres will enable approximately 1000 individual instrument observations of 230 separate astronomical objects. The Astro mission is designed for multiple flights.
An Observatory for Mapping the Far UV Diffuse Galactic Emission Line Background
Authors: Roesler F.L. , Harlander J. , Reynolds R.J.
Published: July 2016

A new instrumental concept for interference spectroscopy called Spatial Heterodyne Spectroscopy (SHS) is described. This instrument as currently demonstrated could provide important information on the structure, excitation, and dynamics of the ≃ 105 K component of the interstellar medium by providing velocity-resolved (20 km s−1) maps of the faint FUV emission line background over a hemisphere of the sky within a 5-6 year observation period. We are currently studying concepts expected to reduce this time by at least an order of magnitude.

In the SHS technique, an all-reflection dispersive interferometer produces a Fourier transform of the spectrum as two-dimensional spatial frequencies on an imaging detector. The system does not require scanning, and measures its own internal alignment state. Although the system suffers the conventional Fourier transform multiplex disadvantage associated with the photon noise in the background FUV continuum, we estimate that for a broad-band survey Spatial Heterodyne Spectroscopy as currently demonstrated can provide 4-5 fold gains over practical grating spectrometers of similar dimensions and spatial and spectral resolution. Field widened methods currently being studied promise additional gains of two orders of magnitude.
Cryogenic Testing of Optics for ISOCAM
Authors: Davies John K.
Published: July 2016

The ROE ISOCAM optical test facility is described. The results of testing of lenses shows good agreement with theory and remarkable consistency.
Edison: A Second Generation Infrared Space Observatory
Authors: Thronson H.A. , Hawarden T.G. , Mountain C.M. , Davies J.K. , Lee T.J. , Longair M.
Published: July 2016

EDISON is a large-aperture telescope under study for the second generation of infrared space observatories, whether in orbit or on the moon. The optics equilibrate via radiative cooling to temperatures between 40 and 80 K, depending upon, for example, telescope structure and location. At these temperatures, telescope emission is below that of the astronomical background at all wavelengths shortward of 20-40 μm. The detector components can be cooled via mechanical refrigerators now in an advanced stage of development. A mixture of radiative and mechanical cooling means that there is no natural limit to EDISON’s lifetime. In addition, the upper stage rocket fairing can be almost filled with light-collecting optics and alternative low-emissivity optical designs, such as off-axis systems, can be easily engineered. We are presently evaluating a design for a 2.5 m observatory to be launched in collaboration with European astronomers as part of the NASA Explorer program. In this presentation, we describe possible spectroscopic and spectrophotometric studies of very faint infrared sources that will require large-aperture space telescopes working at the celestial background limit.
Merits of Space VLBI Missions for Geodynamics
Authors: Adam Jozsef , Mueller Ivan I.
Published: July 2016

Two dedicated space VLBI projects are currently in preparation to launch one or more VLBI radio telescopes in orbit between 1993-1996. One in the Soviet Union called RADIOASTRON is already an approved and funded mission. The second one is a Japanese orbiting VLBI mission called VSOP. There is a Western European mission with NASA participation in Phase A Study at ESA called QUASAT. Although this project was not approved by ESA at the end of 1988, it might still be taken into consideration during the next decade. In the meantime in 1986 a successful demonstration of space VLBI was made at the first attempt using the NASA TDRSS satellite.
Science Observations with the IUE Using the One Gyro Mode
Authors: Imhoff C. , Pitts R. , Arquilla R. , Shrader C. , Perez M. , Webb J.
Published: July 2016

The International Ultraviolet Explorer (IUE) is a geosynchronous orbiting telescope launched by the National Aeronautics and Space Administration (NASA) on January 26, 1978, and operated jointly by NASA and the European Space Agency. The science instrument consists of two spectrographs which span the wavelength range of 1150 to 3200 Å and offer two dispersions with resolutions of 6 Å and 0.2 Å. The spacecraft’s attitude control system originally included an inertial reference package containing 6 gyroscopes for 3-axis stabilization. The science instrument includes a prime and redundant Field Error Sensor (FES) camera for target aquisition and offset guiding. Since launch, 4 of the 6 gyroscopes have failed. The current attitude control system utilizes the remaining 2 gyros and a Fine Sun Sensor (FSS) for 3-axis stabilization. When the next gyro fails, a new attitude control system will be uplinked which will rely on the remaining gyro and the FSS for general 3-axis stabilzation. In addition to the FSS, the FES cameras will be required to assist in maintaining fine attitude control during target aquisition. This has required thoroughly determining the characteristics of the FES cameras and the spectrograph aperture plate as well as devising new target acquisition procedures. The results of this work are presented.
Jupiter Radio Bursts and Particle Acceleration
Authors: Desch Michael D.
Published: July 2016

Particle acceleration processes are important in understanding many of the Jovian radio and plasma wave emissions. However, except for the high-energy electrons that generate synchrotron emission following inward diffusion from the outer magnetosphere, acceleration processes in Jupiter’s magnetosphere and between Jupiter and Io are poorly understood. We discuss very recent observations from the Ulysses spacecraft of two new Jovian radio and plasma wave emissions in which particle acceleration processes are important and have been addressed directly by complementary investigations. First, radio bursts known as quasi-periodic bursts have been observed in close association with a population of highly energetic electrons. Second, a population of much lower energy (keV range) electrons on auroral field lines can be shown to be responsible for the first observation of a Jovian plasma wave emission known as auroral hiss.

Subject headings: acceleration of particles — planets and satellites: individual (Jupiter) — radio continuum: solar system
Microwave Burst Timescales and Solar Flare Acceleration Processes
Authors: Krüger A. , Kliem B. , Hildebrandt J. , Zaitsev V. V.
Published: July 2016

The occurrence of quite different timescales in solar microwave bursts is considered and possible ways of their physical interpretation are discussed. An interesting feature is the existence of hierarchic time structures, an example of which is provided by the solar event of 1991 March 23.

Plasma parameter sets to be invoked for the interpretation of timescales are estimated on the base of different models such as the collisionless conduction front model, the twisted magnetic loop model, the coalescence model, and the electric circuit model. With emphasis on the interpretation of burst fine structures with timescales of a few seconds the coalescence model has been favored. On the other hand, the simultaneous occurrence of a large range of different timescales appears well suited to be described by the circuit model.

Subject headings: acceleration of particles — Sun: flares — Sun: radio radiation
Microwave Type III-RS Bursts
Authors: Sawant Hanumant S. , Fernandes Francisco C. R. , Neri José Ângelo C. F.
Published: July 2016

A decimetric (1600 ± 100 MHz), high-sensitivity digital spectroscope has been put into regular operation at São José dos Campos, Brazil, since 1991 March. The dynamic spectra are recorded on 35 mm film while 20 frequencies each separated by 10 MHz are digitized with time resolution of 100 ms. So far, about 350 groups of solar bursts have been observed by this system. These have been classified as microwave type and decimetric reverse slope (RS) type III bursts. Here, we report statistical investigations of the properties of the 44 moderately strong groups of decimetric type III-RS bursts. The average total duration of these bursts is ~0.7 s, the drift rate varied between ~400 and 3000 MHz s−1 , and average decay time is ~120 ms. These observed drifts and timescales suggest that decimetric type III-RS bursts are generated by beam plasma interaction at second harmonic in the inhomogeneous chromosphere, and that the acceleration region is located at a density level of ≤109 cm−3 .

Subject heading: Sun: radio radiation
Another Clue About Particle Acceleration in Impulsive Hard X-Ray/Microwave Bursts
Authors: Batchelor David
Published: July 2016

In a sample of impulsive bursts with rise times less than 30 s, a correlation between burst rise times and the frequency of maximum microwave emission has been found. The implications for source structure and dynamics are discussed in this paper. Previously evidence was found that such bursts are caused by some propagating disturbance such as a shock wave or thermal conduction front. Combining that evidence with the microwave and hard X-ray spectral information suggests that the most rapid bursts are emitted from the most compact and intensely magnetized sources. The most rapid bursts also exhibited the hardest X-ray spectra, as published previously. These facts are important clues to understanding the physical process responsible for impulsive bursts. A model for the bursts is suggested, based on the observations and inferences described.

Subject headings: acceleration of particles — Sun: radio radiation — X-rays: bursts
Evidence for Particle Acceleration in a Magnetized White Dwarf from Radio and Gamma-Ray Observations
Authors: Jager O. C. De
Published: July 2016

The DQ Her-type magnetic cataclysmic variable AE Aqr contains the most rapidly spinning white dwarf ( P = 33 s) in a close binary and can be considered as the “millisecond pulsar” equivalent of white dwarfs. It shows flare-like UV emission on timescales of an hour during which strong QPO activity is seen, as well as flare-like radio synchrotron emission on similar timescales up to frequencies of at least 250 GHz. It is one of the most efficient converters of accretion power to MeV electrons of all X-ray binaries, LMXB, and cataclysmic variables. TeV emission was also reported by two independent groups with a periodic and burst-like behavior similar to that seen in optical. The detection of a period derivative near 10−13 s/s in optical implies that the white dwarf is spinning down at a rate of ~6 × 1033 ergs s−1 which is at least an order of magnitude larger than the quiescent accretion luminosity and a few times larger than the typical UV flare luminosities. This spindown energy is not seen as disk luminosity, and the conditions appear to be favorable for the release of relativistic particles in a pulsar-type mechanism to explain the radio synchrotron emission in magnetic reconnection events, and the acceleration of particles to TeV energies in double layers if conditions are favorable.

Subject headings: acceleration of particles — binaries: close — stars: flare — stars: individual (AE Aquarii) — white dwarfs
Model Images of Radio Halos Around Supernova Remnants
Authors: Reynolds Stephen P.
Published: July 2016

I present model calculations of profiles and two-dimensional images of the radio synchrotron emission of young supernova remnants, concentrating on observable effects of relativistic electrons diffusing upstream of the shock wave. If the preshock electron scattering mean free path is sufficiently long, observable synchrotron halos outside the bulk of the radio emission can potentially result; their absence can constrain the mean free path from above. If scattering is primarily due, as expected, to Alfvén waves with amplitude δB, the halo is expected to extend a distance of order rg c(δB/B)−2 /vs beyond the shock, where rg is the gyroradius of the electrons emitting at the observed frequency, B is the upstream magnetic field strength, vs is the shock velocity, and the amplitude δB refers to waves with wavelength comparable to rg , of order 1013 cm for typical supernova-remnant parameters. However, the detailed geometry of the halo varies with the assumptions about particle acceleration in the shock wave. I present an atlas of model profiles and images as a function of preshock diffusion length, of aspect angle between the magnetic field and the line of sight, and of other relevant parameters.

Subject headings: radiation mechanisms: miscellaneous — shock waves — supernova remnants
Acceleration Processes for Gamma-Ray Bursts
Authors: Mitrofanov Igor G.
Published: July 2016

Is it shown that for those astronomical models of cosmic gamma-ray bursts (GRBs) which are associated with galactic neutron stars (NSs), the initial energy of the outburst could be converted to gamma-rays through processes of particle acceleration. The main emission mechanisms are considered for two basic alternatives, when particles are accelerated either by radiative pressure or by an electric field.

Subject headings: acceleration of particles — gamma rays: bursts — radiation mechanisms: nonthermal
Cosmic-Ray Transport and Acceleration
Authors: Schlickeiser Reinhard
Published: July 2016

We review the transport and acceleration of cosmic rays concentrating on the origin of galactic cosmic rays. Quasi-linear theory for the acceleration rates and propagation parameters of charged test particles combined with the plasma wave viewpoint of modeling weak cosmic electromagnetic turbulence provides a qualitatively and quantitatively correct description of key observations. Incorporating finite frequency effects, dispersion, and damping of the plasma waves are essential in overcoming classical discrepancies with observations as the Kfit - Kql discrepancy of solar particle events. We show that the diffusion-convection transport equation in its general form contains spatial convection and diffusion terms as well as momentum convection and diffusion terms. In particular, the latter momentum diffusion term plays a decisive role in the acceleration of cosmic rays at super-Alfvénic supernova shock fronts, and in the acceleration of ultra-high-energy cosmic rays by distributed acceleration in our own galaxy.

Subject headings: acceleration of particles — convection — cosmic rays — diffusion — shock waves
Relativistic Particle Transport in Hot Accretion Disks
Authors: Becker Peter A. , Kafatos Menas , Maisack Michael
Published: July 2016

Accretion disks around rapidly rotating black holes provide one of the few plausible models for the production of intense radiation in AGNs above energies of several hundred MeV. The rapid rotation of the hole increases the binding energy per nucleon in the last stable orbit relative to the Schwarzschild case, and naturally leads to ion temperatures in the range 1012 -1013 K for sub-Eddington accretion rates. The protons in the hot inner region of a steady, two-temperature disk form a reservoir of energy that is sufficient to power the observed EGRET outbursts if the black hole mass is 1010M⊙ . Moreover, the accretion timescale for the inner region is comparable to the observed transient timescale of ~1 week. Hence EGRET outbursts may be driven by instabilities in hot, two-temperature disks around supermassive black holes. In this paper we discuss turbulent (stochastic) acceleration in hot disks as a possible source of GeV particles and radiation. We constrain the model by assuming the turbulence is powered by a collective instability that drains energy from the hot protons. We also provide some ideas concerning new, high-energy Penrose processes that produce GeV emission be directly tapping the rotational energy of Kerr black holes.

Subject headings: acceleration of particles — accretion, accretion disks — galaxies: nuclei — quasars: individual (3C 279) — radiation mechanisms: nonthermal
Effect of Advected Fields on Accretion Disk Dynamos
Authors: Mangalam Arun V. , Subramanian K.
Published: July 2016

We present calculations of favored dynamo modes when advection of ambient magnetic fields onto accretion disks is important. These models are relevant for compact binary systems and young stellar objects and can be extended to active galactic nuclei (AGNs). The dynamo equation, including the standard α-effect, is modified to take into account advected magnetic fields. Vacuum boundary conditions are assumed outside the disk and the dynamo number switches sign across the equatorial plane. For the local steady state problem, critical dynamo numbers for various modes are obtained analytically. Our motivation is to investigate whether the dominant dynamo generation of quadrupolar magnetic fields and accretion of dipolar magnetic fields is likely to lead to particle acceleration in the form of jets. The results shown here are for a particular choice of boundary conditions and geometry of the advected field. Besides examining other choices, we shall calculate growth rates for different modes, and the influence of the initial seed field configuration on the evolution of the magnetic fields in subsequent work.

Subject headings: acceleration of particles — accretion, accretion disks — binaries: close — galaxies: nuclei — MHD — stars: pre-main-sequence
STARBASE: A Network of Fully Autonomous Telescopes for Hands-on Science Education
Authors: Gelderman Richard , Barnaby David , Carini Michael , Hackney Karen , Hackney Richard , McGruder Charles , Scott Roger
Published: July 2016

Students Training for Achievement in Research Based on Analytical Space-science Experiences (STARBASE) is being established to provide exciting hands-on research opportunities for students. STAR-BASE is a network of networks, consisting of dedicated hardware, universities, professional astronomers, teachers, and students all working together in scientific investigations. Funded through the NASA Office of Space Science, the STARBASE network is working to bring major science research projects to motivated students all over the globe.
RTLinux Driven Hungarian Automated Telescope for All Sky Monitoring
Authors: Bakos Gáspár Á.
Published: July 2016

Massive variability searches initiated the design of HAT (Hungarian Automated Telescope), an autonomous observatory. HAT consists of a horseshoe mount similar to the one used in the Automated All Sky Survey (ASAS, Pojmański 1997), a clamshell dome with various utilities, a telephoto lens and a CCD. Expensive hardware elements have been substituted by software running under Realtime Linux: a multitask operating system which can handle processes in real time. A virtual observer – modeled as a finite state machine – is responsible for managing the observatory. The modular structure allows of running virtually any kind of observing program for small telescopes. We describe technical aspects, as well as present test results carried out by HAT1 (Budapest).
ACE FlexGrid Telescope Flexure and Pointing Software
Authors: Mack Peter , Stein John , Han Wonyong
Published: July 2016

We describe ACE FlexGrid, a telescope flexure and pointing model based on an empirical grid of reference points. This software is valid for all types of telescopes and is especially suited to robotic telescopes which repeatedly observe the same object.
RIBOTS: An Automatic Telescope System for Gamma-Ray Burst Follow-Up Observations
Authors: Urata Yuji , Kawai Nobuyuki , Yoshida Atsumasa , Kohama Mitsuhiro , Kawabata Tetsuya , Ayani Kazuya
Published: July 2016

We are constructing a fully automatic observation system named RIBOTS (RIken-Bisei Optical Transient Seeker). We aim to detect optical flashes and early afterglows of Gamma-ray bursts (GRB) with RIBOTS. We are constructing RIBOTS with a small telescope because a quick pointing to the burst is essential for our purpose. RIBOTS is linked to the GRB alert system provided by the HETE-2 satellite.
The Moscow Long-Term Program of Cepheid Radial Velocities
Authors: Samus Nikolai , Gorynya Natalia
Published: July 2016

A correlation spectrometer has been used for 15 years by Moscow observers for different programs at several small telescopes and has proven itself to be very effective. Here we present some of the results in the field of Cepheid studies acquired with the spectrometer.
Spectroscopic Detection of an Extraordinary Flaring-Event on DF Tau
Authors: Li J.Z. , Chen W.P. , Ip W.H.
Published: July 2016

An accretion intrigued flare-like brightening of DF Tau has been recorded spectroscopically, during which spectacular spectral changes took place. We inferred the possible formation of a transient envelope during the process of this episodic mass accretion of DF Tau.
The Ongoing Search for Variables in Young Clusters: Up-to-Date Results and Perspectives
Authors: Pigulski A. , Kopacki G. , Kołaczkowski Z. , Jerzykiewicz M.
Published: July 2016

The goals, results and perspectives of the ongoing search for variables in open clusters and associations of the northern hemisphere, carried out at the Białków Observatory of the Wrocław University, are presented.
An Education Program Using Tera-Byte NEA Observation Data
Authors: Asami A. , Asher D.J. , Hashimoto T. , Isobe S. , Nishiyama S. , Ohshima Y. , Terazono J. , Urata T. , Yoshikawa M.
Published: July 2016

There are three wide-field telescopes at the Bisei Spaceguard Center operated by the Japan Spaceguard Association. These telescopes are dedicated to detect near-earth asteroids and produce several tera-byte data per month. Since these data contain many main-belt asteroids, we will use them for an education program that will allow school pupils and the general public to find new main-belt asteroids. We are now developing a new software for its purpose.
The Humps of KBO’s Size Distribution
Authors: Chen Cheng-Pin , Jiang Ing-Guey
Published: July 2016

We study the possible humps or deviation from the single-power law for the size distribution of the Kuiper Belt Objects (KBOs). Both the current observational data and theoretical simulations show evidence of such humps. We conclude that this is an imprint of the depletion of the outer Solar System in the Kuiper Belt region.
Observation of Comet C/1999 S4 (LINEAR)
Authors: Lin C.Y. , Ip W.H.
Published: July 2016

Comet C/1999 S4 (LINEAR) with a maximum magnitude of 6 mag was the brightest comet in 2000. The 24” telescope on NCU campus was used to observe its coma behavior in June and July of 2000 as it approached perihelion. The observations were carried out using the comet filters designed by the European Space Agency for the ground-based observational program of Comet Wirtanen (target comet of the Rosetta mission). Comet C/1999 S4 (LINEAR) ended up disrupting into many small fragments near perihelion. We are in the process of analyzing the time variations of the cometary dust coma and dust tail to examine the physical condition prior to the destruction of the nucleus of this intriguing comet. An image processing method will be developed to trace small-scale structures in the dust tail.
The Automated Telescope of Novosibirsk State University
Authors: Nesterenko A. , Nikulin M. , Vyprentsev D. , Zaytsev A. , Nesterenko I. , Prosvetov V. , Tsukanov V. , Valishev A.
Published: July 2016

The current status of the 30 cm automated telescope project at Novosibirsk State University (NSU) observatory with Internet access is presented.
Observational Results with the 1 Meter Telescope at Yunnan Observatory During 1990-2000
Authors: Chen P.S. , Zhang W.Y.
Published: July 2016

The specification and instruments for the 1-m telescope at Yunnan Observatory of China are briefly described in this paper. Scientific results observed during 1990-2000 are also summarized.
Spatial Structure of Star Clusters by the 2MASS Database
Authors: Chen J.W. , Chen W.P.
Published: July 2016

We present some results of a pilot program to study star clusters with the Two-Micron All-Sky Survey (2MASS) observations. While 2MASS cannot resolve the cores or detect much of the main sequence of globular clusters, the homogeneity and large angular coverages make the database suitable to study young star clusters. We show that member stars are centrally concentrated in open clusters, with a density distribution markedly shallower than that for globular clusters. In NGC2506 (age 3 Gyr) giant stars appear to occupy a smaller region than main sequence stars—a natural consequence of mass segregation.
Topological Pumping in the Lower Overshoot Layer
Authors: Petrovay Kristóf
Published: July 2016

Problems associated with topological pumping in the lower overshoot layer suggest a strongly turbulent and strongly differentially rotating upper radiative zone as the seat of the dynamo and as flux reservoir.
Magnetic Tubes in Overshooting Compressible Convection
Authors: Jennings R. L. , Brandenburg A. , Nordlund Å. , Stein R. F. , Tuominen I.
Published: July 2016

A magnetic tube is introduced into turbulent compressible penetrative convection. After being strongly advected, most of the magnetic flux is stored in the overshoot region. With rotation there are meridional travelling waves.
Waves of Solar Activity
Authors: Proctor M.R.E. , Spiegel E.A.
Published: July 2016

We develop a theory of the sunspot cycle predicated on the assumption that the observed bands of activity are packets of dynamo waves. An approximate equation is proposed to describe the dynamics of these packets, using standard ideas from bifurcation theory. We show that in a certain limit the system can be described in terms of a slowly-evolving solitary wave, and that periodic behavior, like that of the observed butterfly diagram, can easily be found. Generalizations of the theory are discussed.
Non-steady Global Magnetic Fields in Kinematic Theory
Authors: van Geffen J.H.G.M. , Hoyng P. , Zwaan C.
Published: July 2016

The dynamo equation for the mean field ⟨B⟩ contains a random forcing term of unknown magnitude, which is therefore always omitted. The influence of this term is potentially large. To evaluate its effect, we employ ensemble averaging. If an ensemble average is used, there is no random forcing term in the dynamo equation. The effect of fluctuations is that the ensemble members get out of phase, so that ⟨B⟩→0. The damping time of ⟨B⟩ can be found by requiring that the mean energy ⟨BB⟩ remains finite. The eigenvalues к of the dynamo equation then all have negative real parts.Imк determines the period, and −Reк/Imк the relative period stability of the dynamo. We have developed a code to solve the equation for ⟨BB⟩ in a spherical shell (the convection zone), assuming axisymmetry. We report our first results, which do not yet include differential rotation. Using spherically symmetric boundary conditions, we reproduce the well known α2-dynamo, whose behaviour is known analytically. For instance, for an α2-dynamo located in a shell with inner boundary at R/2, we find that ⟨BB⟩ remains finite for R2γ/β=1.48, where β represents turbulent diffusion and γ turbulent vorticity. Taking α = ¼(βγ)½ — a factor of four below maximum helicity — implies that we have a dynamo number Cα ≡ Rα/β = 0.30. Using this value we find a damping time of 6 × 10−2R2/β for ⟨B⟩, which is a measure for the coherence time of B in a single ensemble member. This result implies that the large-scale field of this particular α2-dynamo reorganizes its structure completely on a time scale of only about one year (for solar values of R and β), and it shows the enormous influence of random forcing in general.
Evolution of Large and Small Scale Magnetic Fields in the Sun
Authors: Fox Peter A. , Theobald Michael L. , Sofia Sabatino
Published: July 2016

This paper will discuss issues relating to the detailed numerical simulation of solar magnetic fields, those on the small scale which are directly observable on the surface, and those on larger scales whose properties must be deduced indirectly from phenomena such as the sunspot cycle. Results of simulations using the ADISM technique will be presented to demonstrate the importance of the treatment of Alfvén waves, the boundary conditions, and the statistical evolution of small scale convection with magnetic fields. To study the large scale fields and their time dependence, the magnetic resistivity plays an important role; its use will be discussed in the paper.
A Topological Model of the Solar Magnetic Field Reversals
Authors: Benevolenskaya E.E.
Published: July 2016

The phenomenon of a three-fold reversal of the solar polar magnetic field in both hemispheres has not been observed during the last 115 years. Such three-fold reversals took place in the southern hemisphere alone in the even cycles Nos 12 (1885.8), 14 (1908.4) and in the northern hemisphere alone in solar cycles Nos 16 (1928.5), 18 (1949.0), 20 (1970.6). The single reversal took place in the odd cycles, the only exception is the solar cycle No 19 (Fig. 1).

There are periods of 1.7-2.5 years in the variation of background magnetic fields (Makarov et al., 1985). It determines the quasi-period of the high-frequency component and corresponds to a time interval between the zones of alternating polarity of the magnetic field. This enables us to show topologically that single and three-fold polarity reversals of the solar magnetic fields can result from interaction of two types of magnetic fields: a low-frequency component with period of the order of 20 years and a high frequency component with period of order of 1.7-2.5 years (Benevolenskaya and Makarov, 1990).
Solar Rotation over Solar Cycle 21
Authors: Ribes Elisabeth , Vince Istvan , Mein Pierre , Ferreira Eduardo Neto
Published: July 2016

Having measured the rotation rate of sunspots through solar cycle 21, from 1977 to 1983, we have found that the mean differential rotation averaged over this seven year record is similar to the grand average differential rotation determined by Howard et al. (1984) over the period 1921-1982. However, the rotation rate does change from year to year. These changes are evidenced by a steepening or a flattening of the mean differential rotation profile, as well as significant changes in the equatorial rate. The presence of a time-dependent pattern of azimuthal rolls inferred from the meridional circulation pattern of the sunspots offers a qualitative explanation of the observed rotation rates. The amplitude of the changes is almost one order of magnitude larger than that of the torsional oscillations found by Howard and LaBonte (1981).