bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiwavelength studies of Markarian galaxies
Authors: Mickaelian A.M. , Abrahamyan H.V. , Paronyan G.M. , Harutyunyan G.S.
Published: October 2014

Markarian galaxies are the result of the First Byurakan Survey (FBS) conducted in 1965–1980 by B.E. Markarian et al. The sample consists of 1515 UV‐excess galaxies containing many active galaxies, both AGN and starburst (SB) galaxies that are interesting from the point of view of galaxy evolution and multiwavelength studies. Several catalogs of Markarian galaxies have been published; however, multiwavelength (MW) data were not provided and matched for more efficient investigations. Moreover, SDSS spectra now give possibility for better classification by activity types, and we have accomplished fine classification obtaining new types and subtypes for most of the objects. We have cross‐correlated the Markarian catalogue with all available large‐area MW catalogues at various wavelengths, from X‐ray to radio: ROSAT BSC and FSC, GALEX, APM, MAPS, USNO B1.0, GSC 2.3.2, SDSS, 2MASS PSC and ESC, WISE, AKARI‐IRC, IRAS PSC, FSC, and SSSC, AKARI‐FIS, GB6, NVSS, FIRST, SUMSS, WENSS, and 7C providing 35 photometric data‐points, as well as the Digitized FBS (DFBS, http://byurakan.phys.uniroma1.it/) and Hamburg Quasar Survey (HQS) low‐dispersion spectra. The Armenian Virtual Observatory (ArVO, http://www.aras.am/Arvo/arvo.htm) services have been used for crosscorrelations and extraction of DFBS spectra; MW SEDs have been built using the IVOA tools, and MW classification has been accomplished. Diagrams with MW flux ratios have been built to reveal objects with extreme characteristics. The classifications have been matched with these flux ratios. A MW catalog of Markarian galaxies has been compiled. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Re‐determining the parameters of the Galactic spiral density wave from data on masers with trigonometric parallaxes
Authors: Bajkova A.T. , Bobylev V.V.
Published: October 2014

The parameters of the Galactic spiral wave are re‐determined using a modified periodogram (spectral) analysis of the galactocentric radial velocities of 58 masers with known trigonometric parallaxes, proper motions, and line‐of‐site velocities. The masers span a wide range of galactocentric distances, 3 < R < 14 kpc, which, combined with a large scatter of position angles θ of these objects in the Galactic plane required an accurate account of logarithmic dependence of spiral‐wave perturbations on both the galactocentric distance and position angle. A periodic signal was detected corresponding to a spiral density wave with wavelength of λ = 2.4 ± 0.4 kpc, peak velocity of wave perturbations of fR = 7.5 ± 1.5 km s–1, phase of the Sun of χ⊙ = –160 ± 15°, and pitch angle of –5.5 ± 1°. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Eclipsing variables: Catalogue and classification
Authors: Avvakumova E.A. , Malkov O.Yu. , Kniazev A.Yu.
Published: October 2014

A new version of the Catalogue of Eclipsing Variables is presented. The catalogue contains parameters and morphological types of light curves for some 7200 stars. Spectral classification is also given when available. Recently published information about classification of 1352 systems is also included in the catalogue. Thus, the catalogue represents the largest list of eclipsing binaries classified from observations. The analysis of stellar parameter distributions of catalogued eclipsing systems has been performed, and an algorithm of eclipsing‐variable classification has been developed. Classification of some systems is troublesome or contradictory due to lack of modern observational data or their possible rare evolutionary class. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PAOLO: A Polarimeter Add‐On for the LRS Optics at a Nasmyth focus of the TNG
Authors: Covino S. , Molinari E. , Bruno P. , Cecconi M. , Conconi P. , D'Avanzo P. , di Fabrizio L. , Fugazza D. , Giarrusso M. , Giro E. , Leone F. , Lorenzi V. , Scuderi S.
Published: October 2014

We describe a new polarimetric facility available at the Istituto Nazionale di AstroFisica / Telescopio Nazionale Galileo at La Palma, Canary islands. This facility, PAOLO (Polarimetric Add‐On for the LRS Optics), is located at a Nasmyth focus of an alt‐az telescope and requires a specific modeling in order to remove the time‐ and pointing position‐dependent instrumental polarization. We also describe the opto‐mechanical structure of the instrument and its calibration and present early examples of applications. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability of the Kepler‐36 two‐planet system
Authors: Nagy I. , Ágas M.
Published: October 2014

In this paper we study the dynamics of the Kepler‐36 exoplanetary system. The two planets are engaged in the mean‐motion resonance of 6:7. The dynamical stability of this system has been studied by numerical methods using a Lie‐integrator and calculating the Lyapunov characteristic indicator (LCI) and maximum eccentricity (ME). We studied the stability of the system, the stability of another planet, and the stability of satellites belonging to the known planets. The possibility of trojans were also studied using the massless approximation. The tidal perturbations were neglected although they can become significant in some cases. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Symbiotic stars with spectral indication of bipolar ejection and stellar wind
Authors: Tomov N.A. , Tomova M.T. , Bisikalo D.V.
Published: October 2014

Four out of a total of five symbiotic systems whose optical spectral lines contain satellite components indicating collimated ejection have an additional absorption of P Cyg type with different velocity. These systems are Z And, Hen 3‐1341, StHα 190, and BF Cyg. It is shown that the line profiles of every of these systems can be interpreted in the framework of a model of a collimated stellar wind from the hot compact component proposed initially to interpret the line profiles of Z And, observed during its last active phase after 2000. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The outbursts of the comet 29P/Schwassmann‐Wachmann 1: A new approach to the old problem
Authors: Gronkowski P.
Published: October 2014

As far as outbursts activity is concerned, the 29P/Schwassmann‐Wachmann 1 is the exceptional comet. This Centaur object shows quasi‐regular flares with periodicities of 50 days (Trigo‐Rodriguez et al. 2010). In the introductory part of the presented paper the most well‐known hypotheses which try to explain this cometary behaviour are reviewed. The second, actual part of this paper presents the new model for the outburst activity of this comet. The model is based on the idea of Ipatov (2012), according to which there are large cavities below a considerable fraction of the comet's surface containing material under high gas pressure. In favourite conditions the surface layers over the cavities are thrown away and the interior of these cavities is exposed. Consequently, an outburst of the comet's brightness may be observed. The main characteristics of an outburst of this comet, the brightness jump, is calculated. Numerical simulations were carried out for wide range of possible cometary parameters. The obtained results are in good agreement with the observations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
XMM‐Newton publication statistics
Authors: Ness J.‐U. , Parmar A.N. , Valencic L.A. , Smith R. , Loiseau N. , Salama A. , Ehle M. , Schartel N.
Published: October 2014

We assessed the scientific productivity of XMM‐Newton by examining XMM‐Newton publications and data usage statistics. We analyse 3272 refereed papers, published until the end of 2012, that directly use XMM‐Newton data. The SAO/NASA Astrophysics Data System (ADS) was used to provide additional information on each paper including the number of citations. For each paper, the XMM‐Newton observation identifiers and instruments used to provide the scientific results were determined. The identifiers were used to access the XMM‐Newton Science Archive (XSA) to provide detailed information on the observations themselves and on the original proposals. The information obtained from these sources was then combined to allow the scientific productivity of the mission to be assessed. Since around three years after the launch of XMM‐Newton there have been around 300 refereed papers per year that directly use XMM‐Newton data. After more than 13 years in operation, this rate shows no evidence that it is decreasing. Since 2002, around 100 scientists per year become lead authors for the first time on a refereed paper which directly uses XMM‐Newton data. Each refereed XMM‐Newton paper receives around four citations per year in the first few years with a long‐term citation rate of three citations per year, more than five years after publication. About half of the articles citing XMM‐Newton articles are not primarily X‐ray observational papers. The distribution of elapsed time between observations taken under the Guest Observer programme and first article peaks at 2 years with a possible second peak at 3.25 years. Observations taken under the Target of Opportunity programme are published significantly faster, after one year on average. The fraction of science time taken until the end of 2009 that has been used in at least one article is ∼90%. Most observations were used more than once, yielding on average a factor of two in usage on available observing time per year. About 20 % of all slew observations have been used in publications. The scientific productivity of XMM‐Newton measured by the publication rate, number of new authors and citation rate, remains extremely high with no evidence that it is decreasing after more than 13 years of operations.
The Subaru Telescope High Dispersion Spectrograph (HDS)
Authors: Aoki W.
Published: October 2014

The High Dispersion Spectrograph (HDS) is the échelle spectrograph for an open‐use instrument of the Subaru Telescope. The current status of the instrument is reviewed. The new image slicers that significantly improve the efficiency of observations with very high resolving power have been installed in the past three years. Brief overview of recent science results is given on studies of early generations of stars and extra‐solar planets. An upgrade plan and future prospects of this instrument are discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ESPRESSO: The next European exoplanet hunter
Authors: Pepe F. , Molaro P. , Cristiani S. , Rebolo R. , Santos N.C. , Dekker H. , Mégevand D. , Zerbi F.M. , Cabral A. , Di Marcantonio P. , Abreu M. , Affolter M. , Aliverti M. , Allende Prieto C. , Amate M. , Avila G. , Baldini V. , Bristow P. , Broeg C. , Cirami R. , Coelho J. , Conconi P. , Coretti I. , Cupani G. , D'Odorico V. , De Caprio V. , Delabre B. , Dorn R. , Figueira P. , Fragoso A. , Galeotta S. , Genolet L. , Gomes R. , González Hernández J.I. , Hughes I. , Iwert O. , Kerber F. , Landoni M. , Lizon J.‐L. , Lovis C. , Maire C. , Mannetta M. , Martins C. , Monteiro M. , Oliveira A. , Poretti E. , Rasilla J.L. , Riva M. , Santana Tschudi S. , Santos P. , Sosnowska D. , Sousa S. , Spanó P. , Tenegi F. , Toso G. , Vanzella E. , Viel M. , Zapatero Osorio M.R.
Published: October 2014

The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations; this instrument will be the next VLT high resolution spectrograph. The spectrograph will be installed at the Combined‐Coudé Laboratory of the VLT and linked to the four 8.2 m Unit Telescopes (UT) through four optical Coudé trains. ESPRESSO will combine efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve a gain of two magnitudes with respect to its predecessor HARPS, and to improve the instrumental radial‐velocity precision to reach the 10 cm s–1 level. It can be operated either with a single UT or with up to four UTs, enabling an additional gain in the latter mode. The incoherent combination of four telescopes and the extreme precision requirements called for many innovative design solutions while ensuring the technical heritage of the successful HARPS experience. ESPRESSO will allow to explore new frontiers in most domains of astro‐physics that require precision and sensitivity. The main scientific drivers are the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby G to M‐dwarfs and the analysis of the variability of fundamental physical constants. The project passed the final design review in May 2013 and entered the manufacturing phase. ESPRESSO will be installed at the Paranal Observatory in 2016 and its operation is planned to start by the end of the same year. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fundamental constants and high‐resolution spectroscopy
Authors: Bonifacio P. , Rahmani H. , Whitmore J.B. , Wendt M. , Centurion M. , Molaro P. , Srianand R. , Murphy M.T. , Petitjean P. , Agafonova I.I. , D'Odorico S. , Evans T.M. , Levshakov S.A. , Lopez S. , Martins C.J.A.P. , Reimers D. , Vladilo G.
Published: October 2014

Absorption‐line systems detected in high resolution quasar spectra can be used to compare the value of dimensionless fundamental constants such as the fine‐structure constant, α, and the proton‐to‐electron mass ratio, μ = mp/me, as measured in remote regions of the Universe to their value today on Earth. In recent years, some evidence has emerged of small temporal and also spatial variations in α on cosmological scales which may reach a fractional level of ≈ 10 ppm (parts per million). We are conducting a Large Programme of observations with the Very Large Telescope's Ultraviolet and Visual Echelle Spectrograph (UVES), and are obtaining high‐resolution (R ≈ 60000) and high signal‐to‐noise ratio (S/N ≈ 100) spectra calibrated specifically to study the variations of the fundamental constants. We here provide a general overview of the Large Programme and report on the first results for these two constants, discussed in detail in Molaro et al. (2013) and Rahmani et al. (2013). A stringent bound for Δα /α is obtained for the absorber at zabs = 1.6919 towards HE 2217‐2818. The absorption profile is complex with several very narrow features, and is modeled with 32 velocity components. The relative variation in α in this system is +1.3 ± 2.4stat ± 1.0sys ppm if Al II λ 1670 Å and three FeII transitions are used, and +1.1 ± 2.6stat ppm in a slightly different analysis with only FeII transitions used. This is one of the tightest bounds on α ‐variation from an individual absorber and reveals no evidence for variation in α at the 3‐ppm precision level (1σ confidence). The expectation at this sky position of the recently‐reported dipolar variation of α is (3.2–5.4) ± 1.7 ppm depending on dipole model used and this constraint of Δα /α at face value is not supporting this expectation but not inconsistent with it at the 3σ level. For the proton‐to‐electron mass ratio the analysis of the H2 absorption lines of the zabs ≈ 2.4018 damped Lyα system towards HE 0027–1836 provides Δμ /μ = (–7.6 ± 8.1stat ± 6.3sys) ppm which is also consistent with a null variation. The cross‐correlation analysis between individual exposures taken over three years and comparison with almost simultaneous asteroid observations revealed the presence of a possible wavelength dependent velocity drift as well as of inter‐order distortions which probably dominate the systematic error and are a significant obstacle to achieve more accurate measurements. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Constraints on variations of mp/me based on UVES observations of H2
Authors: Wendt M.
Published: October 2014

This article summarizes the latest results on the proton‐to‐electron mass ratio μ derived from H2 observations at high redshift in the light of possible variations of fundamental physical constants. The focus lies on UVES observations of the past years as enormous progress was achieved since the first positive results on Δμ /μ were published. With the better understanding of systematics, dedicated observation runs, and numerous approaches to improve wavelength calibration accuracy, all current findings are in reasonable good agreement with no variation and provide an upper limit of Δμ /μ < 1 × 10–5 for the redshift range of 2 < z < 3. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inverse Compton origin of pulsar γ ‐ray emission and the reconnection model of Crab Nebula flares
Authors: Lyutikov M.
Published: October 2014

There is growing evidence that the pulsar high‐energy emission is generated by the inverse Compton effect. The particles producing the Crab nebula flares, and possibly most of the Crab Nebula's high‐energy emission, are accelerated by reconnection events, and not by a shock according to the Fermi mechanism. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Review of the theory of pulsar‐wind nebulae
Authors: Bucciantini N.
Published: October 2014

Pulsar‐wind nebulae (PWNe) are ideal astro‐physical laboratories where high energy relativistic phenomena can be inves‐tigated. They are close, well resolved in our observations, and the knowledge derived in their study has a strong impact in many other fields, from AGNs to GRBs. Yet there are still unresolved issues, that prevent us from a full clear under‐standing of these objects. The lucky combination of high resolution X‐ray imaging and numerical codes to handle the outflow and dynamical properties of relativistic MHD, has opened a new avenue of investigation that has lead to inter‐esting progressed in the last years. Despite all of these, we do not understand yet how particles are accelerated, and the functioning of the pulsar wind and pulsar magnetosphere, that power PWNe. I will review what is now commonly known as the MHD paradigm, and in particular I will focus on various approaches that have been and are currently used to model these systems. For each I will highlight its advantages and limitations, and degree of applicability. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐energy pulsar models: Developments and new questions
Authors: Venter C. , Harding A.K.
Published: October 2014

The past few years have seen a major advance in observational knowledge of high‐energy (HE) pulsars. The Fermi Large Area Telescope (LAT) and AGILE have increased the number of known γ‐ray pulsars by an order of magnitude, its members being divided roughly equally among millisecond pulsars (MSPs), young radio‐loud pulsars, and young radio‐quiet pulsars. Many new and diverse emission characteristics are being measured, while radio and X‐ray follow‐up observations increase the pulsar detection rate and enrich our multiwavelength picture of these extreme sources. The wealth of new data has provided impetus for further development and improvement of existing theoretical pulsar models. Geometric light curve (LC) modelling has uncovered three broad classes into which HE pulsars fall: those where the radio profile leads, is aligned with, or lags the γ‐ray profile. For example, the original MSP and original black widow system are members of the second class, requiring co‐located emission regions and thereby breaking with traditional notions of radio emission origin. These models imply narrow accelerator gaps in the outer magnetosphere, indicating copious pair production even in MSP magnetospheres that were previously thought to be pair‐starved. The increased quality and variety of the LCs necessitate construction of ever more sophisticated models. We will review progress in global magnetosphere solutions which specify a finite conductivity on field lines above the stellar surface, filling the gap between the standard vacuum and force‐free (FF; plasma‐filled) models. The possibility of deriving phase‐resolved spectra for the brightest pulsars, coupled with the fact that the HE pulsar population is sizable enough to allow sampling of various pulsar geometries, will enable much more stringent testing of future radiation models. Reproduction of the observed phase‐resolved behavior of this disparate group will be one of the next frontiers in pulsar science, impacting on our understanding of particle acceleration, emission, and magnetosphere geometry. One may now also study evolutionary trends of the measured or inferred quantities, and probe pulsar visibility and population properties such as radiation beam sizes of different pulsar classes, as well as the distribution of spin‐down power, γ‐ray luminosity, conversion efficiency, spectral index, and cutoff energy across the population. Lastly, the recent detection of very‐high‐energy (VHE) pulsations from the Crab pulsar generated quite a few ideas to explain this emission, leading to an extension of standard models and possibly even a bridge between the physics of pulsars and pulsar wind nebulae (PWNe). (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A phase‐variable absorption feature in the X‐ray spectrum of the magnetar SGR 0418+5729
Authors: Tiengo A. , Esposito P. , Mereghetti S. , Turolla R. , Nobii L. , Gastaldello F. , Götz D. , Israel G.L. , Rea N. , Stella L. , Zane S. , Bignami G.F.
Published: October 2014

An absorption feature, the properties of which strongly depend on the pulse phase, has been recently discovered in the X‐ray spectrum of the soft gamma repeater SGR0418+5729. If interpreted as a proton cyclotron line, its energy implies a magnetic field ranging from 2× 1014 G to more than 1015 G, which confirms the magnetar interpretation for this source and provides us with the most direct measurement of the magnetic field intensity of an isolated neutron star. The lower value of the dipole field inferred from the timing parameters for SGR 0418+5729 (B = 6× 1012 G) requires that the high magnetic field responsible for the observed feature resides in a strong multi‐polar component located close to the neutron star surface, in agreement with the predictions of the magnetar model. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic field instabiities in neutron stars
Authors: Ciolfi R.
Published: October 2014

Magnetic fields represent a crucial aspect of the physics and astro‐physics of neutron stars. Despite its great relevance, the internal magnetic field configuration of neutron stars is very poorly constrained by the observations, and understanding its properties is a long‐standing theoretical challenge. The investigation on the subject is focused on the search for those magnetic field geometries which are stable on several Alfvèn timescales, thus constituting a viable description of neutron star interiors. Assessing the stability of a given magnetic field geometry is therefore an important part of this research. So far only simple configurations, such as the purely poloidal or purely toroidal ones, have been studied in detail in perturbation theory and, most recently, by means of nonlinear magnetohydrodynamic simulations. Here we review the basic results of the state‐of‐the‐art general relativistic nonlinear studies, discussing the present status of the field and its future directions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray observations and the search for Fermi ‐LAT γ‐ray pulsars
Authors: Saz Parkinson P. M. , Belfiore A. , Caraveo P. , De Luca A. , Marelli M.
Published: October 2014

The Large Area Telescope (LAT) on Fermi has detected ∼150 γ‐ray pulsars, about a third of which were discovered in blind searches of the γ‐ray data. Because the angular resolution of the LAT is relatively poor and blind searches for pulsars (especially millisecond pulsars, MSPs) are very sensitive to an error in the position, one must typically scan large numbers of locations. Identifying plausible X‐ray counterparts of a putative pulsar drastically reduces the number of trials, thus improving the sensitivity of pulsar blind searches with the LAT. I discuss our ongoing program of Swift, XMM‐Newton, and Chandra observations of LAT unassociated sources in the context of our blind searches for γ‐ray pulsars. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chandra imaging of gamma‐ray binaries
Authors: Kargaltsev O. , Rangelov B. , Hare J. , Pavlov G.G.
Published: October 2014

We review the multiwavelength properties of the few known γ ‐ray binaries, focusing on extended emission recently resolved with Chandra. We discuss the implications of these findings for the nature of compact objects and for physical processes operating in these systems. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling statistical properties of the X‐ray emission from aged pulsar wind nebulae
Authors: Bandiera R.
Published: October 2014

The number of known pulsar wind nebulae (PWNe) has recently increased considerably, and the majority of them are now middle‐age objects. Recent studies have shown a clear correlation of both X‐ray luminosity and size with the PWN age, but fail in providing a thorough explanation of the observed trends. Here I propose a different approach to these effects, based on the hypothesis that the observed trends do not simply reproduce the evolution of a “typical” PWN, but are a combined effect of PWNe evolving under different ambient conditions, the leading parameter being the ambient medium density. Using a simple analytic approach, I show that most middle‐aged PWNe are more likely observable during the reverberation phase, and I succeed in reproducing trends consistent with those observed, provided that the evolution of the X‐ray emitting electrons remains adiabatic over the whole reverberation phase. As a direct consequence, I show that the X‐ray spectra of older PWNe should be harder, also consistent with observations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Long‐term X‐ray timing of the double pulsar PSR J0737–3039
Authors: Iacolina M. N. , Pellizzoni A. , Egron E.
Published: October 2014

The relativistic double neutron star binary PSR J0737–3039 is a truly unique system offering the diagnostics of two interacting radio pulsars in a short orbital period system. Clear evidences of orbital phase‐dependent interactions between the two neutron stars are seen both in radio and X‐rays observations. We present the timing analysis results of the PSRJ0737– 3039 observations performed in the context of the 2006 and 2011 XMM‐Newton Large programs providing ∼ 20000 X‐ray counts overall from the system. Despite only marginal orbital flux variability is detected, both pulsars of the system are clearly seen in X‐ray providing physical insights on the physics of the mutual interactions in their close environment. In particular, we discuss possible processes behind the peculiar X‐ray brightening of the “lazy pulsar” PSR B via energy transfer from the “power plant” PSR A. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetars: The strongest magnets in the Universe
Authors: Rea N.
Published: October 2014

Neutron stars provide a unique environment where we can test (at the same time) our understanding of matter with extreme density, temperature, and magnetic field. In particular, the properties of matter under the influence of magnetic fields and the role of electromagnetism in physical processes are key areas of research in physics. However, despite decades of research, our limited knowledge on the physics of strong magnetic fields is clear: we only need to note that the strongest steady magnetic field achieved in terrestrial laboratories is some millions Gauss, only thousands of times stronger than a common refrigerator magnet. In this general context, I will review here the state of the art of our research on the most magnetic objects in the Universe, a small sample of neutron stars called magnetars. The study of the strong high energy emission, and the flares from these strongly magnetised (∼1015 G) neutron stars is providing crucial information about the physics involved at these extremes conditions, resulting in many unexpected discoveries. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Beyond the 2nd Fermi Pulsar Catalog
Authors: Hou X. , Smith D.A. , Reposeur T. , Rousseau R.
Published: October 2014

Over thirteen times more γ‐ray pulsars have now been studied with the Large Area Telescope on NASA's Fermi satellite than the ten seen with the Compton Gamma‐Ray Observatory in the nineteen‐nineties. The large sample is diverse, allowing better understanding both of the pulsars themselves and of their roles in various cosmic processes. Here we explore the prospects for even more γ‐ray pulsars as Fermi enters the 2nd half of its nominal ten‐year mission. New pulsars will naturally tend to be fainter than the first ones discovered. Some of them will have unusual characteristics compared to the current population, which may help discriminate between models. We illustrate a vision of the future with a sample of six pulsars discovered after the 2nd Fermi Pulsar Catalog was written. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The CMC15, the last issue of the series “Carlsberg Meridian Catalogue, La Palma”
Authors: Muiños J.L. , Evans D. W.
Published: October 2014

CMC15 is the last of the series “Carlsberg Meridian Catalogue, La Palma” and comprises all the observations made between March 1999 and March 2011 with the Carlsberg Automatic Meridian Circle in El Roque de los Muchachos Observatory on the island of La Palma (Spain). The catalogues CMC12, CMC13, and CMC14 are superseded by this one. It contains more than 122 million observations of right ascension, declination, and magnitude of stars in the magnitude range of 9m < r′ < 17m and declination range of –40° < δ < +50°. The catalogue internal errors in astrometry are below 30 mas in both coordinates for stars brighter than r′ = 13, reaching 60 mas for r′ = 16. The internal magnitude error is below 0.020 mag for stars brighter than r′ = 13, and about 0.090 mag for r′ = 16. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectra of faint sources in crowded fields with FRODOSpec on the Liverpool Robotic Telescope
Authors: Shalyapin V. N. , Goicoechea L. J.
Published: October 2014

We check the performance of the FRODOSpec integral‐field spectrograph for observations of faint sources in crowded fields. Although the standard processing pipeline L2 yields too noisy fibre spectra, we present a new processing software (L2LENS) that gives rise to accurate spectra for the two images of the gravitationally lensed quasar Q0957+561. Among other things, this L2LENS reduction tool accounts for the presence of cosmic‐ray events, scattered‐light backgrounds, blended sources, and chromatic source displacements due to differential atmospheric refraction. Our non‐standard reduction of Q0957+561 data shows the ability of FRODOSpec to provide useful information on a wide variety of targets, and thus, the big potential of integral‐field spectrographs on current and future robotic telescopes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discussing the physical meaning of the absorption feature at 2.1 keV in 4U 1538–52
Authors: Rodes‐Roca J. J. , Torrejón J. M. , Martínez‐Nuñez S. , Giménez‐García A. , Bernabéu G.
Published: October 2014

High resolution X‐ray spectroscopy is a powerful tool for studying the nature of the matter surrounding the neutron star in X‐ray binaries and its interaction between the stellar wind and the compact object. In particular, absorption features in their spectra could reveal the presence of atmospheres of the neutron star or their magnetic field strength. Here we present an investigation of the absorption feature at 2.1 keV in the X‐ray spectrum of the high mass X‐ray binary 4U 1538–52 based on our previous analysis of the XMM‐Newton data. We study various possible origins and discuss the different physical scenarios in order to explain this feature. A likely interpretation is that the feature is associated with atomic transitions in an O/Ne neutron star atmosphere or of hydrogen and helium like Fe or Si ions formed in the stellar wind of the donor. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of a transiting planet candidate in Trumpler 37: An astro‐physical false positive eclipsing spectroscopic binary star *
Authors: Errmann R. , Torres G. , Schmidt T.O.B. , Seeliger M. , Howard A.W. , Maciejewski G. , Neuhäuser R. , Meibom S. , Kellerer A. , Dimitrov D.P. , Dincel B. , Marka C. , Mugrauer M. , Ginski Ch. , Adam Ch. , Raetz St. , Schmidt J.G. , Hohle M.M. , Berndt A. , Kitze M. , Trepl L. , Moualla M. , Eisenbeiß T. , Fiedler S. , Dathe A. , Graefe Ch. , Pawellek N. , Schreyer K. , Kjurkchieva D.P. , Radeva V.S. , Yotov V. , Chen W.P. , Hu S.C.‐L. , Wu Z.‐Y. , Zhou X. , Pribulla T. , Budaj J. , Vaňko M. , Kundra E. , Hambälek Ľ. , Krushevska V. , Bukowiecki Ł. , Nowak G. , Marschall L. , Terada H. , Tomono D. , Fernandez M. , Sota A. , Takahashi H. , Oasa Y. , Briceño C. , Chini R. , Broeg C.H.
Published: October 2014

We report our investigation of the first transiting planet candidate from the YETI project in the young (∼4 Myr old) open cluster Trumpler 37. The transit‐like signal detected in the lightcurve of F8V star 2M21385603+5711345 repeats every 1.364894 + 0.000015 days, and has a depth of 54.5 + 0.8 mmag in R. Membership in the cluster is supported by its mean radial velocity and location in the color‐magnitude diagram, while the Li diagnostic and proper motion are inconclusive in this regard. Follow‐up photometric monitoring and adaptive optics imaging allow us to rule out many possible blend scenarios, but our radial‐velocity measurements show it to be an eclipsing single‐lined spectroscopic binary with a late‐type (mid‐M) stellar companion, rather than one of planetary nature. The estimated mass of the companion is 0.15–0.44 M⊙. The search for planets around very young stars such as those targeted by the YETI survey remains of critical importance to understand the early stages of planet formation and evolution. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hydrodynamical study of multiple‐shell planetary nebulae
Authors: Schönberner D. , Jacob R. , Lehmann H. , Hildebrandt G. , Steffen M. , Zwanzig A. , Sandin C. , Corradi R.L.M.
Published: October 2014

We present the result of a study on the expansion properties and internal kinematics of round/elliptical planetary nebulae of the Milky Way disk, the halo, and of the globular cluster M 15. The purpose of this study is to considerably enlarge the small sample of nebulae with precisely determined expansion properties (Schönberner et al. 2005b). To this aim, we selected a representative sample of objects with different evolutionary stages and metallicities and conducted highresolution ´echelle spectroscopy. In most cases we succeeded in detecting the weak signals from the outer nebular shell which are attached to the main line emission from the bright nebular rim. Next to the measurement of the motion of the rim gas by decomposition of the main line components into Gaussians, we were able to measure separately, for most objects for the first time, the gas velocity immediately behind the leading shock of the shell, i.e. the post‐shock velocity. We more than doubled the number of objects for which the velocities of both rim and shell are known and confirm that the overall expansion of planetary nebulae is accelerating with time. There are, however, differences between the expansion behaviour of the shell and the rim: The post‐shock velocity is starting at values as low as around 20 km s–1 for the youngest nebulae, just above the AGB wind velocity of ∼ 10–15 km s–1, and is reaching values of about 40 km s–1 for the nebulae around hotter central stars. Contrarily, the rim matter is at first decelerated below the typical AGB‐wind velocity and remains at about 5–10 km s–1 for a while until finally a typical flow velocity of up to 30 km s–1 is reached. This observed distinct velocity evolution of both rim and shell is explained by radiation‐hydrodynamics simulations, at least qualitatively: It is due to the ever changing stellar radiation field and wind‐wind interaction together with the varying density profile ahead of the leading shock during the progress of evolution. The wind‐wind interaction works on the rim dynamics while the radiation field and upstream density gradient is responsible for the shell dynamics. Because of these time‐dependent boundary conditions, a planetary nebula will never evolve into a simple self‐similar expansion. Also the metal‐poor objects behave as theory predicts: The post‐shock velocities are higher and the rim flow velocities are equal or even lower compared to disk objects at similar evolutionary stage. The old nebula around low‐luminosity central stars contained in our sample expand still fast and are dominated by reionisation. We detected, for the first time, in some objects an asymmetric expansion behaviour: The relative expansions between rim and shell appear to be different for the receding and approaching parts of the nebular envelope. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TASTE IV: Refining ephemeris and orbital parameters for HAT‐P‐20b and WASP‐1b
Authors: Granata V. , Nascimbeni V. , Piotto G. , Bedin L. R. , Borsato L. , Cunial A. , Damasso M. , Malavolta L.
Published: October 2014

We present four new light curves of the transiting exoplanets WASP‐1b and HAT‐P‐20b, observed within the TASTE (The Asiago Search for Transit timing variations of Exoplanets) project. We re‐analyzed light curves from the literature in a homogeneous way, calculating a refined ephemeris and orbital‐physical parameters for both objects. WASP‐1b does not show any significant Transit Timing Variation signal at the 120 s level. As for HAT‐P‐20b, we detected a deviation from our re‐estimated linear ephemeris that could be ascribed to the presence of a perturber or, more probably, to a previously unnoticed high level of stellar activity. The rotational period of HAT‐P‐20 A that we obtained from archival data (Prot ≃ 14.5 d), combined with its optical variability and strong emission of Ca ii H & K lines, is consistent with a young stellar age (<1 Gyr) and support the hypothesis that stellar activity may be responsible of the measured deviations of the transit times. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Seven years photometry of the W UMa‐type eclipsing binary V2612 Oph
Authors: Özdarcan O. , Taş G.
Published: October 2014

We present the first long‐term Johnson UBVR observations and comprehensive photometric analysis of the W UMa‐type eclipsing binary V2612 Oph. Observations in the time interval between 2003 and 2009 enabled us to reveal the seasonal and long‐term variations of the light curve. Hence, we found that the mean brightness level of the light curve shows a variation with a period of 6.7 years. Maximum and minimum brightness levels of the light curve exhibit a variation from year to year which we attribute to a solar‐like activity. The O – C variation of eclipse timings of the system shows a decreasing parabolic trend and reveals a period decrease at a rate of P = 6.27×10‐7 day yr‐1 with an additional low‐amplitude sinusoidal variation that has a similar period as the long‐term brightness variations. Our light curve analysis shows that the system is a W‐subtype W UMa eclipsing binary. We calculated masses and radii of the primary and secondary components as M1 = 1.28 M⊙, M2 = 0.37 M⊙ and R1 = 1.31 R⊙, R2 = 0.75 R⊙, respectively. The derived absolute photometric parameters allow us to calculate a distance of 140 pc, which confirms that the system is a foreground star in the sky field of the Galactic open cluster NGC 6633. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamical evolution of two associated galactic bars
Authors: Garzón F. , López‐Corredoira M.
Published: October 2014

We study the dynamical interactions of mass systems in equilibrium under their own gravity that mutually exert and ex‐perience gravitational forces. The method we employ is to model the dynamical evolution of two isolated bars, hosted within the same galactic system, under their mutual gravitational interaction. In this study, we present an analytical treatment of the secular evolution of two bars that oscillate with respect to one another. Two cases of interaction, with and without geometrical deformation, are discussed. In the latter case, the bars are described as modified Jacobi ellipsoids. These triaxial systems are formed by a rotating fluid mass in gravitational equilibrium with its own rotational velocity and the gravitational field of the other bar. The governing equation for the variation of their relative angular separation is then numerically integrated, which also provides the time evolution of the geometrical parameters of the bodies. The case of rigid, non‐deformable, bars produces in some cases an oscillatory motion in the bodies similar to that of a harmonic oscillator. For the other case, a deformable rotating body that can be represented by a modified Jacobi ellipsoid under the influence of an exterior massive body will change its rotational velocity to escape from the attracting body, just as if the gravitational torque exerted by the exterior body were of opposite sign. Instead, the exchange of angular momentum will cause the Jacobian body to modify its geometry by enlarging its long axis, located in the plane of rotation, thus decreasing its axial ratios. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Relationship between low and high frequencies in the δ Scuti star KIC 9764965
Authors: Rostopchina A. , Breger M.
Published: October 2014

Two years of Kepler spacecraft data of the δ Sct/γ Dor star KIC 9764965 revealed 67 statistically significant frequencies from 0.45 to 59.17 c d–1 (0.005 to 0.685 mHz). The 19 low frequencies do not show equidistant period spacing predicted for gravity modes of successive radial order. We note a favored frequency spacing of 2.053 c d–1 that appears in both the low‐frequency (gravity mode) region and high‐frequency (pressure mode) regions. The value of this frequency spacing also occurs as a dominant low frequency and in a high‐frequency triplet. A peak at exactly twice the value of the 2.053 cd–1 mode is shown not to be a Fourier harmonic of the low‐frequency peak due to a different amplitude variability. This behavior is also seen in other δ Sct stars. The test for resonant mode coupling between low and high frequencies could not be carried out due to the small amplitudes of the peaks, making it difficult to separate the parent and child modes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A joint model for repeated events of different types and multiple longitudinal outcomes with application to a follow‐up study of patients after kidney transplant
Authors: Musoro Jammbe Z. , Geskus Ronald B. , Zwinderman Aeilko H.
Published: October 2014

This paper presents an extension of the joint modeling strategy for the case of multiple longitudinal outcomes and repeated infections of different types over time, motivated by postkidney transplantation data. Our model comprises two parts linked by shared latent terms. On the one hand is a multivariate mixed linear model with random effects, where a low‐rank thin‐plate spline function is incorporated to collect the nonlinear behavior of the different profiles over time. On the other hand is an infection‐specific Cox model, where the dependence between different types of infections and the related times of infection is through a random effect associated with each infection type to catch thewithindependence and a shared frailty parameter to capture the dependencebetweeninfection types. We implemented the parameterization used in joint models which uses the fitted longitudinal measurements as time‐dependent covariates in a relative risk model. Our proposed model was implemented in OpenBUGS using the MCMC approach.
Delphi survey to identify topics to be addressed at the initial follow-up consultation after oesophageal cancer surgery
Authors: Jacobs M , Henselmans I , Macefield R C , Blencowe N S , Smets E M A , de Haes J C J M , Sprangers M A G , Blazeby J M , van Berge Henegouwen M I
Published: October 2014

Background

There is no consensus among patients and healthcare professionals (HCPs) on the topics that need to be addressed after oesophageal cancer surgery. The aim of this study was to identify these topics, using a two-round Delphi survey.

Methods

In round 1, patients and HCPs (surgeons, dieticians, nurses) were invited to rate the importance of 49 topics. The proportion of panellists that considered a topic to be of low, moderate or high importance was then calculated for each of these two groups. Based on these proportions and the i.q.r., topics were categorized as: ‘consensus to be included’, ‘consensus to be excluded’ and ‘no consensus’. Only topics in the first category were included in the second round. In round 2, panellists were provided with individual and group feedback. To be included in the final list, topics had to meet criteria for consensus and stability.

Results

There were 108 patients and 77 HCPs in the round 2 analyses. In general, patients and HCPs considered the same topics important. The final list included 23 topics and revealed that it was most important to address: cancer removed/lymph nodes, the new oesophagus, eating and drinking, surgery, alarming new complaints and the recovery period.

Conclusion

The study provides surgeons with a list of topics selected by patients and HCPs that may be addressed systematically at the initial follow-up consultation after oesophageal cancer surgery.
Induction of cortical plasticity for reciprocal muscles by paired associative stimulation
Authors: Suzuki Makoto , Kirimoto Hikari , Sugawara Kazuhiro , Watanabe Makoto , Shimizu Shinobu , Ishizaka Ikuyo , Yamada Sumio , Matsunaga Atsuhiko , Fukuda Michinari , Onishi Hideaki
Published: October 2014

Background

Paired associative stimulation (PAS) is widely used to induce plasticity in the human motor cortex. Although reciprocal inhibition of antagonist muscles plays a fundamental role in human movements, change in cortical circuits for reciprocal muscles by PAS is unknown.

Methods

We investigated change in cortical plasticity for reciprocal muscles during PAS. PAS consisted of 200 pairs of peripheral electric stimulation of the right median nerve at the wrist at a frequency of 0.25 Hz followed by transcranial magnetic stimulation of the left M1 at the midpoint between the center of gravities of the flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles. Measures of motor cortical excitability included resting motor threshold (RMT), GABAA‐mediated short‐interval intracortical inhibition (SICI), and GABAB‐mediated long‐interval intracortical inhibition (LICI).

Results

Motor evoked potential amplitude‐conditioned LICI for the FCR muscle was significantly decreased after PAS (P = 0.020), whereas that for the ECR muscle was significantly increased (P = 0.033). Changes in RMT and SICI for the FCR and ECR muscles were not significantly different before and after PAS. Corticospinal excitability for both reciprocal muscles was increased during PAS, but GABAB‐mediated cortical inhibitory functions for the agonist and antagonist muscles were reciprocally altered after PAS.

Conclusion

These results implied that the cortical excitability for reciprocal muscles including GABAB‐ergic inhibitory systems within human M1 could be differently altered by PAS.