bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of primordial magnetic fields
Authors: Banerjee R.
Published: October 2014

Here we briefly summarise the main phases which determine the dynamical evolution of primordial magnetic fields in the early universe. On the one hand, strong fields undergo damping due to excitations of plasma fluctuations, and, on the other hand, weak magnetic fields will be strongly amplified by the small‐scale dynamo in a turbulent environment. We find that, under reasonable assumptions concerning the efficiency of a putative magnetogenesis era during cosmic phase transitions, surprisingly strong magnetic fields 10–13–10–11 G, on comparatively small scales 100 pc–10 kpc may survive to prior to structure formation. Additionally, any weak magnetic field will be exponentially amplified during the collapse of the first minihalos until they reach equipartition with the turbulent kinetic energy. Hence, we argue that it seems possible for cluster magnetic fields to be entirely of primordial origin. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling giant radio halos Doctoral Thesis Award Lecture 2012
Authors: Donnert J.M.F.
Published: October 2014

We review models for giant radio halos in clusters of galaxies, with a focus on numerical and theoretical work. After summarising the most important observations of these objects, we present an introduction to the theoretical aspects of hadronic models. We compare these models with observations using simulations and find severe problems for hadronic models. We give a short introduction to reacceleration models and show results from the first simulation of CRe reacceleration in cluster mergers. We find that in‐line with previous theoretical work, reacceleration models are able to elegantly explain main observables of giant radio halos. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cosmological simulations of galaxy formation: Successes and challenges in the era of supercomputers
Authors: Scannapieco C.
Published: October 2014

I use cosmological hydrodynamical simulations to study the formation and evolution of galaxies similar in mass to the Milky Way. First, I use a set of eight simulations where the haloes have a great variety of merger and formation histories, to investigate how similar or diverse these galaxies are at the present epoch, and how their final properties are related to the particular formation history of the galaxy. I find that rotationally‐supported disks are present in 7 of the 8 galaxies at z ∼ 2–3; however, only half of the galaxies have significant disks at z = 0. Both major mergers and the accretion of gas that is misaligned with the preexisting stellar disk contribute to the transfer of material from the disks to the spheroidal components, lowering the disk‐to‐total ratios during evolution. I also present and discuss recent results of the Aquila Project, which compares the predictions of 13 different numerical codes for the properties of a galaxy in a Λ cold dark matter universe. All simulations use a unique initial condition and are analysed in the exact same way, allowing a fair comparison of results. We find large code‐to‐code variations in stellar masses, star formation rates, galaxy sizes and morphologies. We also find that the way feedback is implemented is the main cause of the differences, although some differences might also result from the use of different numerical technique. Our results show that state‐of‐the‐art simulations cannot yet uniquely predict the properties of the baryonic component of a galaxy, even when the assembly history of its host halo is fully specified. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Large Hadron Collider and Dark Matter
Authors: Covi L.
Published: October 2014

We review shortly the scenarios of Weakly Interactive Massive Particle (WIMP) and Super‐Weakly Interacting Massive Particle (SuperWIMP) Dark Matter candidates and discuss the recent searches for Dark Matter candidates at the Large Hadron Collider (LHC). (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Long‐term photometry of three active red giants in close binary systems: V2253 Oph, IT Com and IS Vir
Authors: Oláh K. , Moór A. , Strassmeier K.G. , Borkovits T. , Granzer T.
Published: October 2014

We present and analyze long‐term optical photometric measurements of the three active stars V2253 Oph, IT Com and IS Vir. All three systems are single‐lined spectroscopic binaries with an early K giant as primary component but in different stages of orbital‐rotational synchronization. Our photometry is supplemented by 2MASS and WISE near‐IR and mid‐IR magnitudes and then used to obtain more accurate effective temperatures and extinctions. For V2253 Oph and IT Com, we found their spectral energy distributions consistent with pure photospheric emission. For IS Vir, we detect a marginal mid‐IR excess which hints towards a dust disk. The orbital and rotational planes of IT Com appear tobe coplanar, contrary to previous findings in the literature. We apply a multiple frequency analysis technique to determine photometric periods, and possibly changes of periods, ranging from days to decades. New rotational periods of 21.55±0.03 d, 65.1±0.3 d, and 23.50±0.04 d were determined for V2253 Oph, IT Com, and IS Vir, respectively. Splitting of these periods led to tentative detections of differential surface rotations of δP/P ≈ 0.02 for V2253 Oph and 0.07 for IT Com. Using a time‐frequency technique based on short‐term Fourier transforms we present evidence of cyclic light variations of length ≈ 10 yr for V2253 Oph and 5‐6 yr for IS Vir. A single flip‐flop event has been observed for IT Com of duration 2–3 yr. Its exchange of the dominant active longitude had happened close to a time of periastron passage, suggesting some response of the magnetic activity from the orbital dynamics. The 21.55‐d rotational modulation of V2253 Oph showed phase coherence also with the orbital period, which is 15 times longer than the rotational period, thus also indicating a tidal feedback with the stellar magnetic activity. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Peculiarity of stellar kinematics in the solar vicinity
Authors: Popova M.E.
Published: October 2014

The peculiar velocities of nearby stars are studied. We determine the solar velocity components from the radial velocities and proper motions of stars and open clusters. We show that nearby stars are not very suitable for the determination of the solar motion components because of peculiarities in their velocity distribution. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recent revolutions and unsolved problems in the galaxy evolution paradigm
Authors: Sil'chenko O.K.
Published: October 2014

Due to the fast development of observational techniques, observations of high‐redshift galaxies and detailed studies of nearby galaxies bring surprises every week. Many quite unexpected discoveries have been made over the last years, which have changed our views about galaxy formation and evolution substantially. I review some of the most important and unexpected observational facts, which bring changes even to paradigms. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stochastization in gravitating systems
Authors: Ovod D.V. , Ossipkov L.P.
Published: October 2014

We discuss the effective stochastization time τe for gravitating systems in terms of the Krylov and GurzadyanSavvidi paradigm. The truncated Holtsmark distribution for a random force proposed by Rastorguev and Sementsov implies τe/τc α N0.20, where τc is the crossing time. We find in the case of the Petrovskaya distribution for a random force τe/τc α Nk, where k = 0.27–0.31, depending on the oblateness and rotation of the system, and τe/τc α N1/3/(ln N)1/2 when N » 1. The latter result agrees with those of Genkin (1969) and Gurzadyan & Kocharyan (2009) (k = 1/3). (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Four states of the recurrent symbiotic nova V407 Cyg
Authors: Esipov V.F. , Kolotilov E.A. , Komissarova G.V. , Shenavrin V.I. , Shugarov S.Yu. , Tarasova T.N. , Tatarnikov A.M. , Tatarnikova A.A.
Published: October 2014

We analyze the results of our spectroscopic and photometric monitoring of V407 Cyg in 1984–2009. We show that the hot component of V407 Cyg can be in four different states: a passive state (the system looks as an ordinary, non‐symbiotic Mira), a quiescent state (the system looks as a low‐excitation classical symbiotic star), a Z And‐type outburst, and an RS Oph‐type outburst. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Virtual Observatory for stellar astronomy
Authors: Malkov O. , Zolotukhin I.
Published: October 2014

The principal idea of the Virtual Observatory is to achieve real transparency for astronomical data, similar to transparency for all the world's documents in the World Wide Web. In the Virtual Observatory, all the world's astronomical data is available from one's desktop. All archives understand the same query language, can be accessed through a uniform interface, and diverse data can be analyzed with the same tools. In particular, facilities of the Virtual Observatory allow users to make a fast and correct analysis of objects from various surveys. It yields multi‐photometry data on registered objects and makes it possible to determine stellar parameters. Methods of astronomical data analysis as well as their application to various areas of stellar astronomy are discussed in this paper. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discovery and investigation of open star clusters in the Milky Way
Authors: Glushkova E.V.
Published: October 2014

During the recent decade, many investigators searched for new clusters using data from large surveys. In this paper, we review the results of these studies and discuss the methods used to derive physical parameters of open clusters. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New programs for determining the main parameters of open clusters
Authors: Popova M.E.
Published: October 2014

A set of computer programs for the determination of the main parameters of open clusters, such as color excess, distance, and age, is developed. The set consists of two units. The first unit is designed to search for open clusters in wide fields using JHKs‐photometry from various catalogs (2MASS, UKIDSS, VISTA) by identifying areas of high stellar density. The second unit determines the parameters of open clusters by fitting photometric diagrams. This is the unit described in the paper. Probable cluster members are identified by the proximity to the basic sequences on the J–(J — H) and Q–(J — H) diagrams. The color excess is determined by minimizing the deviations of Q values on the Q–(J — H) diagram. Ages and distance moduli are determined by comparing the color‐magnitude diagrams with theoretical isochrones. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of radio sources with the virtual observatory tools: Results and problems
Authors: Zhelenkova O.P.
Published: October 2014

Radio sources of the RCR catalogue, obtained from observational data of the “Cold” experiment, have been identified, almost completely, with optical objects. For this purpose, we used optical, infrared, and radio sky surveys as well as archive data from the VLA (NRAO) and the 6‐m telescope (SAO). According to spectroscopy and color index constraints, the identified sources are classified as galaxies and quasars; about 20 % of the sources remain unclassified because of being optically faint. We estimated radio luminosities of the sources and found that a majority (60%) of them belong to strong radio sources. Using ratios of FIRST and NVSS flux densities and angular sizes, we prepared a sample of steep spectrum compact sources. The existing infrastructure of the virtual observatory increases the effectiveness of astronomical studies like ours greatly. However, we still cannot consider the virtual observatory a completed project because it requires further development of services providing actualization of user data and better semantic compatibility of information. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
HARPS spectropolarimetry of Herbig Ae/Be stars
Authors: Hubrig S. , Ilyin I. , Schöller M. , Lo Curto G.
Published: October 2014

Our knowledge of the presence and the strength of magnetic fields in intermediate‐mass pre‐main‐sequence stars remains very poor. We present new magnetic field measurements in six Herbig Ae/Be stars observed with HARPS in spectropolarimetric mode. We downloaded from the European Southern Observatory (ESO) archive the publically available HARPS spectra for six Herbig Ae/Be stars. Wavelength shifts between right‐ and left‐hand side circularly polarised spectra were interpreted in terms of a longitudinal magnetic field 〈Bz〉, using the moment technique introduced by Mathys. The application of the moment technique to the HARPS spectra allowed us in addition to study the presence of the crossover effect and quadratic magnetic fields. Our search for longitudinal magnetic fields resulted in first detections of weak magnetic fields in the Herbig Ae/Be stars HD 58647 and HD 98922. Further, we confirm the previous tentative detection of a weak magnetic field in HD 104237 by Donati et al. and confirm the previous detection of a magnetic field in the Herbig Ae star HD 190073. Surprisingly, the measured longitudinal magnetic field of HD 190073, 〈Bz〉 = 91 ± 18 G at a significance level of 5σ is not in agreement with the measurement results of Alecian et al. (2013), 〈Bz〉 = –10 ± 20 G, who applied the LSD method to exactly the same data. No crossover effect was detected for any star in the sample. Only for HD 98922 the crossover effect was found tobe close to 3σ with a measured value of –4228 ± 1443 km s–1 G. A quadratic magnetic field of the order of 10 kG was detected in HD 98922, and of ∼3.5 kG in HD 104237. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A photometric study of the nova‐like variable TT Arietis with the MOST satellite
Authors: Vogt N. , Chené A.‐N. , Moffat A.F.J. , Matthews J.M. , Kuschnig R. , Guenther D.B. , Rowe J.F. , Rucinski S.M. , Sasselov D. , Weiss W.W.
Published: October 2014

Variability on all time scales between seconds and decades is typical for cataclysmic variables (CVs). One of the brightest and best studied CVs is TT Ari, a nova‐like variable which belongs to the VY Scl subclass, characterized by occasional low states in their light curves. It is also known as a permanent superhumper at high state, revealing “positive” (PS > P0) as well as “negative” (PS < P0) superhumps, where PS is the period of the superhump and P0 the orbital period. TT Ari was observed by the Canadian space telescope MOST for about 230 hours nearly continuously in 2007, with a time resolution of 48 seconds. Here we analyze these data, obtaining a dominant “negative” superhump signal with a period PS = 0.1331 days and a mean amplitude of 0.09 mag. Strong flickering with amplitudes up to 0.2 mag and peak‐to‐peak time scales of 15–20 minutes is superimposed on the periodic variations. We found no indications for significant quasi‐periodic oscillations with periods around 15 minutes, reported by other authors. We discuss the known superhump behaviour of TTAri during the last five decades and conclude that our period value is at the upper limit of all hitherto determined “negative” superhump periods of TTAri, before and after the MOST run. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics of clockwise and counterclockwise spiral galaxies
Authors: Hoehn C. , Shamir L.
Published: October 2014

We compared measurements of 126 501 spiral galaxies to test whether the photometry of galaxies that rotate clockwise is different from the photometry of galaxies that rotate counterclockwise for the purpose of testing whether there is a link between photometry and spin direction of galaxies. The rotation directionality of the galaxies was determined by converting the galaxy image to its radial intensity plot, and then the galaxies in each 30° RA sector were separated into clockwise and counterclockwise rotating galaxies. The mean and standard deviation of SDSS DR7 photometric attributes of clockwise and counterclockwise rotating galaxies were then compared. The results show no significant difference between galaxies that rotate clockwise and galaxies that rotate counterclockwise. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FIES: The high‐resolution Fiber‐fed Echelle Spectrograph at the Nordic Optical Telescope
Authors: Telting J.H. , Avila G. , Buchhave L. , Frandsen S. , Gandolfi D. , Lindberg B. , Stempels H.C. , the NOT staff  , Prins S.
Published: October 2014

FIES is a cross‐dispersed high‐resolution echelle spectrograph at the 2.56 m Nordic Optical Telescope (NOT), and was optimised for throughput and stability in 2006. The major 2006 upgrade involved the relocation of FIES to a stable environment and development of a fiber bundle that offers 3 different resolution modes, and made FIES an attractive tool for the user community of the NOT. Radial‐velocity stability is achieved through double‐chamber active temperature control. A dedicated data reduction tool, FIEStool, was developed. As a result of these upgrades, FIES is now one of the work‐horse instruments at the NOT. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Combining optical spectroscopy and interferometry
Authors: Kraus S.
Published: October 2014

Modern optical spectrographs and optical interferometers push the limits in the spectral and spatial regime, providing important new tools for the exploration of the Universe. In this contribution I outline the complementary nature of spectroscopic and interferometric observations and discuss different strategies for combining such data. Most remarkable, the latest generation of “spectro‐interferometric” instruments combine the milliarcsecond angular resolution achievable with interferometry with spectral capabilities, enabling direct constraints on the distribution, density, kinematics, and ionization structure of the gas component in protoplanetary disks. I will present some selected studies from the field of star‐ and planet formation and hot star research in order to illustrate these fundamentally new observational opportunities. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The sun‐as‐a‐star solar spectrum
Authors: Pevtsov A.A. , Bertello L. , Marble A.R.
Published: October 2014

The Sun is the only star for which individual surface features can be observed directly. For other stars, the properties of starspots, stellar rotation, stellar flares, etc, are derived indirectly via variation of star‐integrated spectral line profiles or their luminosity measurements. Solar disk‐integrated and disk‐resolved observations allow for investigations of the contribution of individual solar disk features to sun‐as‐a‐star spectra. Here, we provide a brief overview of three sun‐as‐a‐star programs, currently in operation, and describe recent improvements in observations and data reduction for the Integrated Sunlight Spectrometer (ISS), one of three instruments comprising the Synoptic Optical Long‐term Investigations of the Sun (SOLIS) system. Next, we discuss studies employing sun‐as‐a‐star observations (including Ca II K line as proxy for total unsigned magnetic flux and 2800 MHz radio flux) as well as the effects of flares on solar disk‐integrated spectra. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐resolution absorption spectroscopy of the circumgalactic medium of the Milky Way
Authors: Richter P. , Fox Aj. , Ben Bekhti N. , Murphy M. T. , Bomans D. , Frank S.
Published: October 2014

In this article we discuss the importance of high‐resolution absorption spectroscopy for our understanding of the distribution and physical nature of the gaseous circumgalactic medium (CGM) that surrounds the Milky Way. Observational and theoretical studies indicate a high complexity of the gas kinematics and an extreme multi‐phase nature of the CGM in low‐redshift galaxies. High‐precision absorption‐line measurements of the Milky Way's gas environment thus are essential to explore fundamental parameters of circumgalactic gas in the local Universe, such as mass, chemical composition, and spatial distribution. We shortly review important characteristics of the Milky Way's CGM and discuss recent results from our multi‐wavelength observations of the Magellanic Stream. Finally, we discuss the potential of studying the warm‐hot phase of the Milky Way's CGM by searching for extremely weak [Fe X] λ 6374.5 Å and [Fe XIV] λ 5302.9 Å absorption in optical QSO spectra. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plasma‐producing gaps in the global structure of the pulsar force‐free magnetosphere
Authors: Petrova S.A.
Published: October 2014

The pulsar high‐energy emission is usually associated with the magnetospheric gaps which are traditionally considered within the framework of the vacuum dipole model of the magnetosphere. Actually, the presence of an abundant plasma should modify the magnetospheric structure, and the context of a force‐free magnetosphere where the electromagnetic forces are balanced over most part of the volume is more appropriate. The gaps included into the structure of the force‐free magnetosphere should play an important role in sustaining and closing the pulsar current circuit. Here we examine the vacuum polar gap adjustment to the stationary force‐free magnetosphere in the presence of a closing current sheet. Our simplified model incorporates the regimes of the force‐free and vacuum monopole with the transition region amidst, where the bulk of pair plasma is formed and the poloidal force‐free current is closed. The analysis of the force and energy balance in the transition region shows that the current sheet cannot be regarded as infinitesimal and the closing process may be dissipation‐free. The implications of our results for the pulsar emission are outlined. In particular, the interpretation of a peculiar radio–X‐ray correlation in the pulsar PSR B0943+10 is suggested. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The stability of strong waves and its implications for pulsar wind shocks
Authors: Mochol I. , Kirk J. G.
Published: October 2014

Strong waves can mediate a shock transition between a pulsar wind and its surroundings, playing the role of an extended precursor, in which the energy is effectively transferred from fields to non‐thermal particles. The damping of such precursors results in an essentially unmagnetized shock near the equator. In this context, we discuss the stability of strong waves and its implications for the properties of shocks. Those with stable precursors can exist in the winds of most of isolated pulsars, but the precursors may be unstable if the external pressure in the nebula is high, as in Vela‐like pulsars. Pulsar wind shocks in eccentric binary systems, such as B1259–63, can acquire precursors only at certain orbital phases, and this process should be accompanied by enhanced synchro‐Compton and inverse Compton emission from the precursor. The same scenario may be at work in the binary HESS J0632+057. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Unifying neutron stars getting to GUNS
Authors: Igoshev A.P. , Popov S.B. , Turolla R.
Published: October 2014

The variety of the observational appearance of young isolated neutron stars must find an explanation in the framework of some unifying approach. Nowadays it is believed that such scenario must include magnetic field decay, the possibility of magnetic field emergence on a time scale of ≲104–105 yr, significant contribution of non‐dipolar fields, and appropriate initial parameter distributions. We present our results on the initial spin period distribution, and suggest that inconsistencies between distributions derived by different methods for samples with different average ages can uncover field decay or/and emerging field. We describe a new method to probe the magnetic field decay in normal pulsars. The method is a modified pulsar current approach, where we study pulsar flow along the line of increasing characteristic age for constant field. Our calculations, performed with this method, can be fitted with an exponential decay for ages in the range of 8×104– 3.5×105 yr with a time scale of ∼5×105 yr. We discuss several issues related to the unifying scenario. At first, we note that the dichotomy, among local thermally emitting neutron stars, between normal pulsars and the Magnificent Seven remains unexplained. Then we discuss the role of high‐mass X‐ray binaries in the unification of neutron star evolution. We note, that such systems allow to check evolutionary effects on a time scale longer than what can be probed with normal pulsars alone. We conclude with a brief discussion of the importance of discovering old neutron stars accreting from the interstellar medium. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
NuSTAR results and future plans for magnetar and rotation‐powered pulsar observations
Authors: An H. , Kaspi V.M. , Archibald R. , Bachetti M. , Bhalerao V. , Bellm E. C. , Beloborodov A. M. , Boggs S. E. , Chakrabarty D. , Christensen F. E. , Craig W. W. , Dufour F. , Forster K. , Gotthelf E. V. , Grefenstette B. W. , Hailey C. J. , Harrison F. A. , Hascoët R. , Kitaguchi T. , Kouveliotou Ch. , Madsen K. K. , Mori K. , Pivovaroff M. J. , Rana V. R. , Stern D. , Tendulkar S. , Tomsick J. A. , Vogel J. K. , Zhang W. W. , the NuSTAR Team
Published: October 2014

The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing hard X‐ray mission in orbit and operates in the 3–79 keV range. NuSTAR's sensitivity is roughly two orders of magnitude better than previous missions in this energy band thanks to its superb angular resolution. Since its launch in 2012 June, NuSTAR has performed excellently and observed many interesting sources including four magnetars, two rotation‐powered pulsars and the cataclysmic variable AE Aquarii. NuSTAR also discovered 3.76‐s pulsations from the transient source SGR J1745–29 recently found by Swift very close to the Galactic center, clearly identifying the source as a transient magnetar. For magnetar 1E 1841–045, we show that the spectrum is well fit by an absorbed blackbody plus broken power‐law model with a hard power‐law photon index of ∼ 1.3. This is consistent with previous results by INTEGRAL and RXTE. We also find an interesting double‐peaked pulse profile in the 25–35 keV band. For AE Aquarii, we show that the spectrum can be described by a multi‐temperature thermal model or a thermal plus non‐thermal model; a multi‐temperature thermal model without a non‐thermal component cannot be ruled out. Furthermore, we do not see a spiky pulse profile in the hard X‐ray band, as previously reported based on Suzaku observations. For other magnetars and rotation‐powered pulsars observed with NuSTAR, data analysis results will be soon available. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A classification scheme for magnetars
Authors: Göğüs E.
Published: October 2014

We investigate cumulative burst occurrence trends of five soft gamma repeaters (SGRs) and introduce an indicative mea‐sure for the duration of their outburst phases. We find a clear distinction between the durations of the active episodes of persistent and transient magnetars: The outburst episodes of the persistent sources are significantly longer (≲100 days) than those of transient sources (≲10 days). We also investigate burst‐induced changes in the radiative behavior of transient sources and suggest a mechanism for the constant flux trend seen in the early phases of the outburst of SGRs with low burst rates. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The properties of the progenitor, neutron star, and pulsar wind in the supernova remnant Kes 75
Authors: Gelfand J. D. , Slane P. O. , Temim T.
Published: October 2014

By studying composite supernova remnants (SNRs), remnants which contain a pulsar wind nebula (PWN), it is possible to estimate physical properties of the progenitor explosion, central neutron star, and its pulsar wind that are difficult to measure directly. This is best done by fitting the dynamical and broadband spectral properties of a PWN with an evolutionary model for a PWN inside an SNR. We apply such a model to the composite SNR Kes 75, whose associated pulsar PSR J1846‐0258 is thought to have an extremely strong surface magnetic field. If ∼3 M⊙ of mass was ejected in the supernova, our model suggests a normal or slightly subenergetic supernova in a low density environment. Additionally, for the measured pre‐outburst braking index of p = 2.65, our model prefers an age of ∼430 years and an initial spin period P0 ∼ 0.2 s. Lastly, the magnetization of the pulsar wind and energy spectrum of particles injected at the termination shock are similar to those observed from other PWNe powered by less magnetized neutron stars. While further study is needed to verify these results, they are nominally inconsistent with strong neutron star magnetic fields resulting from very fast initial rotation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transmission profile of the Dutch Open Telescope Hα Lyot filter
Authors: Koza J. , Hammerschlag R. H. , Rybák J. , Gömöry P. , Kučera A. , Schwartz P.
Published: October 2014

Accurate knowledge of the spectral transmission profile of a Lyot filter is important, in particular in comparing observations with simulated data. The paper summarizes available facts about the transmission profile of the Dutch Open Telescope (DOT) Hα Lyot filter pointing to a discrepancy between sidelobe‐free Gaussian‐like profile measured spectroscopically and signatures of possible leakage of parasitic continuum light in DOT Hα images. We compute wing‐to‐center intensity ratios resulting from convolutions of Gaussian and square of the sinc function with the Hα atlas profile and compare them with the ratios derived from observations of the quiet Sun chromosphere at disk center. We interpret discrepancies between the anticipated and observed ratios and the sharp limb visible in the DOT Hα image as an indication of possible leakage of parasitic continuum light. A method suggested here can be applied also to indirect testing of transmission profiles of other Lyot filters. We suggest two theoretical transmission profiles of the DOT Hα Lyot filter which should be considered as the best available approximations. Conclusive answer can only be given by spectroscopic re‐measurement of the filter. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determining the nature of orbits in a three‐dimensional galaxy model hosting a BL Lacertae object
Authors: Zotos E. E.
Published: October 2014

A three‐dimensional dynamical model for a galaxy hosting a BL Lacertae object is constructed. The model consists of a logarithmic potential representing an elliptical host galaxy with a bulge of radius cb and a dense massive nucleus. Using numerical experiments, we try to distinguish between regular and chaotic motion in both 2D and 3D system. In particular, we investigate how the basic parameters of our model, such as the mass of the nucleus, the internal perturbation and the flattening parameters influence the amount and the degree of chaos. Interesting correlations are presented for both 2D and 3D dynamical models. Our numerical results are explained and supported using elementary theoretical arguments and analytical calculations. Of particular interest is the local integral of motion which have been found to exist in the vicinity of stable periodic points. The obtained numerical outcomes of the present research are linked and also compared with several data derived from observations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenized Hertzsprung‐Russell diagram for the open cluster NGC 188
Authors: Malyuto V. , Zubarev S. , Shvelidze T.
Published: October 2014

We considered some selected published stellar catalogues with B – V and V values for the open cluster NGC 188 and estimated the errors from data comparisons. The results are used to homogenize the data by averaging with weights inversely proportional to the errors squared. A recent calibration by Casagrande et al. (2010) of B – V versus effective temperatures for F, G, and K dwarfs and subgiants is used to produce the homogenized effective temperatures for the cluster stars. A homogenized Hertzsprung‐Russell diagram (relationship between the effective temperatures and the absolute magnitudes) is presented and analysed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wide‐Field Plate Archive of the University Observatory Jena
Authors: Poghosyan A.V. , Pfau W. , Tsvetkova K.P. , Mugrauer M. , Tsvetkov M.K. , Hambaryan V.V. , Neuhäuser R. , Kalaglarsky D.G.
Published: October 2014

We present the archive of the wide‐field plate observations obtained at the University Observatory Jena, which is stored at the Astrophysical Institute of the Friedrich Schiller University Jena. The archive contains plates taken in the period February 1963 to December 1982 with the 60/90/180‐cm Schmidt telescope of the university observatory. A computer‐readable version of the plate metadata catalogue (for 1257 plates), the logbooks, as well as the digitized Schmidt plates in low and high resolution are now accessible to the astronomical community.This paper describes the properties of the archive, as well as the processing procedure of all plates in detail. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Speckle observations with PISCO in Merate: XIII. Astrometric measurements of visual binaries in 2012, and new orbits for ADS 10786 BC, 12144, 12515, 16314 and 16539
Authors: Prieur J.‐L. , Scardia M. , Pansecchi L. , Argyle R.W. , Zanutta A. , Aristidi E.
Published: October 2014

We present relative astrometric measurements of visual binaries, made in 2012 with the speckle camera PISCO at the 102‐cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our observing list contains orbital couples as well as binaries whose motion is still uncertain. We obtained 355 new measurements of 344 visual binary stars, with angular separations in the range 0′.14–6′.9, and an average accuracy of 0.′02. The mean error on the position angles is 0°.5. Most of the position angles were determined without the usual 180° ambiguity with the application of triple‐correlation techniques and/or by inspection of the long integration files. We also present new revised orbits for ADS 10786 BC, 12144, 12515, 16314, and 16539, partly derived from PISCO observations. The corresponding estimated values for the masses of those systems are compatible with the spectral types. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observational dynamics of low‐mass stellar systems
Authors: Frank M. J.
Published: October 2014

The last fifteen years have seen the discovery of new types of low‐mass stellar systems that bridge the gap between the once well‐separated regimes of galaxies and of star clusters. Whether such objects are considered galaxies depends also on the definition of the term “galaxy”, and several possible criteria are based on their internal dynamics (e.g. the common concept that galaxies contain dark matter). Moreover, studying the internal dynamics of low‐mass stellar systems may also help understand their origin and evolutionary history. The focus of this paper is on two classes of stellar systems at the interface between star clusters and dwarf galaxies: ultra‐compact dwarf galaxies (UCDs) and diffuse Galactic globular clusters (GCs). A review of our current knowledge on the properties of UCDs is provided and dynamical considerations applying to diffuse GCs are introduced. In the following, recent observational results on the internal dynamics of individual UCDs and diffuse Galactic globular clusters are presented. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cosmic wave‐particle interactions: Astrophysical magnetic turbulence and high‐energy particles
Authors: Tautz R.C.
Published: October 2014

Understanding the origin and the properties of energetic charged particles has been an important problems of both plasma astro‐physics and astroparticle physics. Here, an introduction is given about the complicated interaction processes between cosmic rays and turbulent electromagnetic fields. First, the formation of turbulent electromagnetic fields due to plasma instabilities is discussed. Second, the microphysics of particle scattering due to such turbulent fields is explained and a comparison with measurements in the Solar wind is shown. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positive and negative feedback by AGN jets in high‐redshift galaxies
Authors: Gaibler V.
Published: October 2014

Simulations of feedback by jets from active galactic nuclei (AGN) in the past mostly focused on the interaction at large scales as the circumgalactic medium or intra‐cluster medium for clusters of galaxies. Only in recent years, simulations have included the interaction of jets with a highly inhomogeneous medium as required by a multi‐phase interstellar medium (ISM). At the same time, feedback by AGN has become a common component for cosmological simulations of galaxy evolution to form massive galaxies compatible with observations. I will present some of our recent results and will put them into further context of other feedback simulations and how the opposing effects of positive and negative feedback by jets might be understood in terms of different properties of the ISM. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Jets from young stars and brown dwarfs
Authors: Whelan E. T.
Published: October 2014

The protostellar outflow mechanism operates for a significant fraction of the pre‐main sequence phase of a solar mass star and is thought to have a key role in star and perhaps even planet formation. This energetic mechanism manifests itself in several different forms and on many scales. Thus outflow activity can be probed in numerous different regimes from radio to X‐ray wavelengths. Recent discoveries have shown that it is not only solar mass stars that launch outflows during their formation but also the sub‐stellar brown dwarfs. In this article what is currently known about jets from young stars is summarised, including an outline of why it is important to study jets. The second part of this article is dedicated to jets from young brown dwarfs. While only a small number of brown dwarf outflows have been investigated to date, interesting properties have been observed. Here observations of brown dwarf outflows are described and what is currently known of their properties compared to low mass protostellar outflows. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The dispersal of protoplanetary discs
Authors: Ercolano B.
Published: October 2014

Protoplanetary discs are a natural consequence of the star formation process and as such are ubiquitous around low‐mass stars. They are fundamental to planet formation as they hold the reservoir of material from which planets form. Their evolution and final dispersal and the timescales that regulate these process are therefore of particular interest. In this contribution I will review the observational evidence for the dispersal of discs being dominated by two timescales and for the final dispersal to occur quickly and from the inside out. I will discuss the current theoretical models, including X‐ray photoevaporation, showing that the latter provides a natural explanation to the observed behaviour and review supporting and contrasting evidence. I will finally introduce a new mechanism based on the interaction between planet formation and photoevaporation that may explain a particular class of transition discs with large inner holes and high accretion rates that are problematic for photoevaporation models and planet formation models alone. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Methods in Molecular Biology, Vol. 1111: Artificial Riboswitches: Methods and Protocols. Edited by Atsushi Ogawa.
Authors: Comeau Marc‐André , Lafontaine Daniel
Published: October 2014

Springer, 2014, X+289 pp., hardcover, € 117.69.—ISBN 978‐1‐62703‐754‐9
Intentional right atrial exit for microcatheter infusion of pericardial carbon dioxide or iodinated contrast to facilitate sub‐xiphoid access
Authors: Rogers Toby , Ratnayaka Kanishka , Schenke William H. , Faranesh Anthony Z. , Mazal Jonathan R. , O'Neill William W. , Greenbaum Adam B. , Lederman Robert J.
Published: October 2014

Objectives: We test the safety of transatrial pericardial access using small catheters, infusion of carbon dioxide (CO2) or iodinated contrast to facilitate sub‐xiphoid access, and catheter withdrawal under full anticoagulation. Background: Sub‐xiphoid pericardial access is required for electrophysiological and structural heart interventions. If present, an effusion protects the heart from needle injury by separating the myocardium from the pericardium. However, if the pericardium is ‘dry' then there is a significant risk of right ventricle or coronary artery laceration caused by the heart beating against the needle tip. Intentional right atrial exit is an alternative pericardial access route, through which contrast media could be infused to separate pericardial layers. Methods: Transatrial pericardial access was obtained in a total of 30 Yorkshire swine using 4Fr or 2.8Fr catheters. In 16 animals, transatrial catheters were withdrawn under anticoagulation and MRI was performed to monitor for pericardial hemorrhage. In 14 animals, iodinated contrast or CO2 was infused before sub‐xiphoid access was obtained. Results: Small effusions (mean 18.5 ml) were observed after 4Fr (1.3 mm outer‐diameter) but not after 2.8Fr (0.9 mm outer‐diameter) transatrial catheter withdrawal despite full anticoagulation (mean activated clotting time 383 sec), with no hemodynamic compromise. Pericardial CO2 resorbed spontaneously within 15 min. Conclusions: Intentional transatrial exit into the pericardium using small catheters is safe and permits infusion of CO2 or iodinated contrast to separate pericardial layers and facilitate sub‐xiphoid access. This reduces the risk of right ventricular or coronary artery laceration. 2.8Fr transatrial catheter withdrawal does not cause any pericardial hemorrhage, even under full anticoagulation. © 2014 Wiley Periodicals, Inc.
Characteristics of secundum atrial septal defects not percutaneously closed
Authors: Ohno Naoki , Chaturvedi Rajiv , Lee Kyong‐Jin , Benson Lee
Published: October 2014

Objectives

We sought to review our single center experience with secundum atrial septal defect (ASD) device closure, evaluating the incidence and morphological characteristics where percutaneous closure was thought inappropriate.

Material and methods

All children assessed as unsuitable for transcatheter device closure were reviewed. Data collected included: demographics, defect morphology by echocardiogrphy or at cardiac catheterization and defect size focusing on the reasons for procedural deferral.

Results

Between January 2002 and December 2010, 639 children underwent closure of an isolated secundum ASD: 82 children (13%) where referred directly to surgery, 43 (6%) were thought unsuitable for device closure at the time of catheterization and underwent subsequent surgery and the remaining 514 (81%) underwent successful device closure including 2 on a second attempt. The reasons for pursuing a surgical closure (n = 124, mean age = 5.7 years; range: 0.6–17.4 years; defect diameter/body weight = 1.39) included: the need for a device thought too large for implantation versus the child's size (n = 51), defects with deficient rim(s) (n = 48), multiple defects (n = 7), defects sized >36 mm (n = 2), malposition (n = 2), ECG changes (n = 3), aneurysmal IAS (n = 2), sinus venosus (n = 2), or others (n = 7).

Conclusion

The reasons for deferring transcatheter device closure of a secundum ASD are diverse, not only isolated rim deficiencies but the requirements of large implants, malposition, arrhythmias, and lack of hemodynamic need are influential components in clinical decision making. © 2014 Wiley Periodicals, Inc.
A giant cystic pheochromocytoma mimicking liver abscess an unusual presentation – a case report
Authors: Sarveswaran Venugopal , Kumar Surees , Kumar Amit , Vamseedharan Muthukumar
Published: October 2014

Key Clinical Message

Giant cystic pheochromocytoma is a rare neuroendocrine tumor. The possibility of cystic pheochromocytoma should be considered for any peri‐adrenal mass even in absence of characteristic symptoms and negative biochemical analysis. The key in the management of a case of cystic pheochromocytoma is the preoperative suspicion and the intraoperative crisis management.
Increased eculizumab requirements during pregnancy in a patient with paroxysmal nocturnal hemoglobinuria: case report and review of the literature
Authors: Patriquin Christopher , Leber Brian ,   Canadian PNH Network
Published: October 2014

Key Clinical Message

Paroxysmal nocturnal hemoglobinuria (PNH) results from reduced complement regulatory proteins on hematopoietic cells, predisposing patients to intravascular hemolysis, thrombophilia, and cytopenias. Women diagnosed in pregnancy can experience significant maternofetal complications. Trials of eculizumab in PNH excluded pregnant women. Here, we report the first Canadian patient taken through pregnancy on eculizumab.
Guest‐Responsive Function of a Dynamic Metal–Organic Framework with a π Lewis Acidic Pore Surface
Authors: Joarder Biplab , Mukherjee Soumya , Chaudhari Abhijeet K. , Desai Aamod V. , Manna Biplab , Ghosh Sujit K.
Published: October 2014

A 3D dynamic coordination framework with an electron‐deficient pore surface has been synthesized by using ZnII (having a variable coordination number) and a predesigned flexible π‐electron‐deficient core‐based ligand, exhibiting chemical separations based on pore surface functionalization (π Lewis acidic pore surfaces and open metal sites) and framework flexibility, giving rise to a unique smart guest‐responsive material.
Phosphatidylcholine‐Coated Iron Oxide Nanomicelles for In Vivo Prolonged Circulation Time with an Antibiofouling Protein Corona
Authors: Groult Hugo , Ruiz‐Cabello Jesús , Lechuga‐Vieco Ana Victoria , Mateo Jesús , Benito Marina , Bilbao Izaskun , Martínez‐Alcázar María Paz , Lopez Juan. Antonio , Vázquez Jesús , Herranz Fernando F.
Published: October 2014

We report the synthesis of micellar phosphatidylcholine‐coated superparamagnetic iron oxide nanoparticles as a new long circulation contrast agents for magnetic resonance imaging. Oleic acid‐coated Fe3O4 nanoparticles were first prepared through thermal degradation and then encapsulated into small clusters with a phosphatidylcholine coating to obtain hydrophilic nanomicelles. A thorough characterization confirmed the chemical nature of the coating and the excellent colloidal stability of these nanomicelles in aqueous media. Magnetization and relaxivity properties proved their suitability as magnetic resonance imaging (MRI) contrast agent and in vitro cell viability data showed low toxicity. Vascular lifetime and elimination kinetics in the liver were assessed by blood relaxometry and by in vivo MRI in rats and compared with “control” particles prepared with a polyethylene glycol derivative. These micellar particles had a lifetime in blood of more than 10 h, much longer than the control nanoparticles (≈2 h), which is remarkable considering that the coating molecule is a small biocompatible zwitterionic phospholipid. The protein corona was characterized after incubation with rat serum at different times by high‐throughput proteomics, showing a higher proportion of bound apolipoproteins and other dysopsonins for the phosphatidylcholine particles. The antibiofouling properties of this corona and its resistance to the adsorption of proteins corroborate the observed enhanced stability and prolonged systemic circulation.