bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new actinospore type Unicapsulactinomyxon (Myxozoa), infecting the marine polychaete,Diopatra neapolitana(Polychaeta: Onuphidae) in the Aveiro Estuary (Portugal)
Authors: RANGEL LUÍS F. , CECH GÁBOR , SZÉKELY CSABA , SANTOS MARIA J. 
Published: February 2011

SUMMARYThis work reports a new type of actinospore, Unicapsulactinomyxon, which exhibits a unique morphological characteristic in that it has a single and large polar capsule (9·3×4·1μm) (which possesses a longitudinally-folded polar filament) instead of the 3 polar capsules previously described for actinosporeans. The spore has a binucleated sporoplasm and 3 valves, each of which forms a long process. The spore has a total length of 241·3μm. This parasite develops in groups of 8 inside pansporocysts in the coelomic cavity of the polychaete host. Molecular investigations on the SSU rDNA show that the new actinospore type is most closely related toEnteromyxumspecies (81–84% similarity). A survey of actinospore infections of the marine polychaeteDiopatra neapolitanain 2007 and 2009, in the Aveiro Estuary (Portugal), showed an annual prevalence of 1·0% and 0·3%, respectively.
Exploring causal effects of combining work and intergenerational support on depressive symptoms among middle-aged women
Authors: OPREE SUZANNA J. , KALMIJN MATTHIJS 
Published: February 2011

ABSTRACTIn debates about ageing western societies it is often assumed that many middle-aged women struggle to combine paid employment and intergenerational support, and that the subsequent stress leads them to experience an increase in depressive symptoms. Cross-sectional studies have supported this notion, but the question remains whether combining work and intergenerational support actuallycausesan increase in depressive symptoms. In order to fill a gap in the literature, this study examines the proportion of middle-aged women combining paid work and support to an adult child and/or parent, and the extent to which combining these roles affects women's depressive symptoms over time. For this purpose, we make use of the Survey of Health, Ageing, and Retirement in Europe (SHARE) data set which includes longitudinal data collected on European women aged 50+. Descriptive analyses indicated that 14 per cent of middle-aged women combine the roles of employee, support provider to an adult child, and/or support provider to a parent. Results from semi-dynamic and full-dynamic regression analyses indicate that combining roles can take away some, of the positive mental health effects of fulfilling a role. These findings support the role combination stress hypothesis.
The formation of relativistic cosmic jets
Authors: Meier David L. 
Published: February 2011

AbstractI review current ideas on the launching, acceleration, collimation and propagation of relativistic jets and the influence of strong magnetic fields in the process. Recently, several important elements of the entire jet “engine” structure have been shown to play key roles in the production of an astrophysical jet. Depending on the type of system, these include the spin of the central black hole, the thermal and/or magnetic state of the accretion flow, the presence of a re-collimation point in the jet outflow far away from the central object, and the behavior of MHD shocks and kink instabilities in the final jet. While these physical processes probably are at work in all types of relativistic jets (and many even in more benign stellar outflows), I shall concentrate on ones produced by lower luminosity black hole sources, both in active galactic nuclei and in X-ray binaries. I also will discuss the connection between the theoretical concepts and the large body of observational data now available on these systems.
Relativistic jets at high energies
Authors: Levinson Amir 
Published: February 2011

AbstractA recent progress in the study of γ-ray jets is reviewed, with a focus on some theoretical interpretations of the VHE emission from M87, and possibly other misaligned blazars; the connection between the GeV breaks exhibited by bright LAT blazars and opacity sources in the broad line region; the consequences of the detection of GeV emission from GRBs to models of magnetic outflows; and the implications of the thermal emission observed is some GRBs to dissipation of the outflow bulk energy.
The optimal locations for shock acceleration in MHD jets
Authors: Polko Peter , Meier David L. , Markoff Sera 
Published: February 2011

AbstractJets can contribute to the spectra of X-ray binaries (XRBs) and active galactic nuclei (AGN) from the radio through the γ-ray bands; thus understanding their physics is key for interpreting the data. Recent VLBI observations suggest that jets begin to accelerate particles into power-law distributions at a point offset from the black hole by ~104rg, possibly via a collimation shock. Spectral fitting of simultaneous, broadband data from both XRBs and AGN in jet-dominated states corroborates this picture. From a magnetohydrodynamical (MHD) point of view, it is natural to associate the onset of particle acceleration with the final MHD critical point in the flow, the modified fast point (MFP), where causal contact with the upstream flow is broken. In this way a standing disruption like a shock can form, and this location might vary with the physical parameters of the jet. In order to study this issue, we have used the self-similar formalism of Vlahakis & Königl (2003, hereafter VK03) to simplify the MHD equations and to derive solutions that cross the critical points. We have found a new parameter space of solutions that cross the MFP at a finite height above the disc and are relativistic, spanning a range of Lorentz factors Γ ≤ 10 (Polko et al. 2010). We present these results, as well as preliminary work connecting the relativistic formalism to the non-relativistic conditions with gravity near the base of the jets.
On the reprocessing of gamma-rays produced by jets
Authors: Orellana M. , Pellizza L. J. , Romero G. E. 
Published: February 2011

AbstractSystems of two very different sizescales are known to produce very high-energy (VHE) radiation in their jets: AGNs and microquasars. The produced VHE photons (Eγ ~ 1 TeV) can be absorbed by the intense environmental soft photon fields, coming from the companion star (in high mass binaries) or from the accreting material (disk+corona in AGNs), as these are the dominant sources at energies around ~(mec2)2/Eγ. Energetic pairs are created by the photon-photon annihilation, and, depending on how efficient are the competing cooling channels, the absorption can lead to a reprocessing by Inverse Compton pair-cascade development. A self-consistent modeling of these systems as gamma-ray sources should then include, along with the emission and absorption processes, a thorough treatment of the pair cascades. We discuss here on this issue, focusing on our (preliminary) results of numerical simulations devoted to a study case similar to the high-mass microquasar candidate LS 5039.
Numerical theory of accretion flow and jet launching: A study on the galactic center
Authors: Dibi Salomé , Drappeau Samia , Markoff Sera , Fragile Chris 
Published: February 2011

AbstractWe obtained the first spectral predictions from a simulation of the Galactic Center to include radiative processes internally. We performed simulations with and without cooling, with and without spin, and for different initial configurations of the magnetic field, in order to test the effect on jet launching and inner accretion disk characteristics. By exploring parameter space, we will attempt to place new constraints on the controversial question about the presence or not of a jet from Sgr A*, as well as study jet launching in general. We have shown that, as expected, the spin of the BH affects the structure of the jet. The presence of cooling also strongly influences the inner structure of the accretion disk and therefore affects jet launching. These results show that radiative cooling is not negligible, as is usually assumed for the very underluminous supermassive BH, Sgr A*. On the contrary, the inclusion of cooling has a very visible influence on the accretion disk. Furthermore it creates an important difference in the resulting spectra.
Long-term simulations of extragalactic jets: cavities and feedback
Authors: Perucho Manel , Quilis Vicent , Martí José María 
Published: February 2011

AbstractWe present long-term numerical simulations of powerful extragalactic relativistic jets in two dimensions. The jets are injected in a realistic atmosphere with powers 1044, 1045 and 1046 erg/s, during tens of Myrs. After this time, the jet injection is switched off. We follow the evolution of the jets and associated shocks from 1 kpc to hundreds of kiloparsecs during more than 100 Myrs. The 1045 erg/s jet was simulated with leptonic and baryonic composition. Our results show that, for powerful jets, the main heating mechanisms are the driving shock-wave and mixing. We discuss the implications that these results have in the frame of cooling flows in clusters.
The far-infrared view of M87 as seen by the Herschel Space Observatory
Authors: Baes M. , Clemens M. , Xilouris E. M. , Fritz J. , Cotton W. D. , Davies J. I. , Bendo G. J. , Bianchi S. , Cortese L. , De Looze I. , Pohlen M. , Verstappen J. , Böhringer H. , Bomans D. J. , Boselli A. , Corbelli E. , Dariush A. , di Serego Alighieri S. , Fadda D. , Garcia-Appadoo D. A. , Gavazzi G. , Giovanardi C. , Grossi M. , Hughes T. M. , Hunt L. K. , Jones A. P. , Madden S. , Pierini D. , Sabatini S. , Smith M. W. L. , Vlahakis C. , Zibetti S. 
Published: February 2011

AbstractThe origin of the far-infrared emission from the nearby radio galaxy M87 remains a matter of debate. Some studies find evidence of a far-infrared excess due to thermal dust emission, whereas others propose that the far-infrared emission can be explained by synchrotron emission without the need for an additional dust emission component. We observed M87 with PACS and SPIRE as part of the Herschel Virgo Cluster Survey (HeViCS). We compare the new Herschel data with a synchrotron model based on infrared, submm and radio data to investigate the origin of the far-infrared emission. We find that both the integrated SED and the Herschel surface brightness maps are adequately explained by synchrotron emission. At odds with previous claims, we find no evidence of a diffuse dust component in M87.
An additional broad line region in 3C 390.3 associated with the jet
Authors: Nazarova L. S. , Bochkarev N. G. 
Published: February 2011

AbstractWe suggest the existence of two BLRs in 3C 390.3 which have different locations. The BLR1 is located at a distance in accordance to the hydrogen line time lags of ≈20 days. This disk-like region emits predominantly low ionization lines. The BLR2 forms around the radio-jet and is located at the distance corresponding to time lags of ≈ 40-80 days. The BLR2 is responsible for most of the emission in UV lines. The Lα line partly forms in BLR2 (40-60%) and partly in BLR1.
Evidence for shock-shock interaction in the jet of CTA 102
Authors: Fromm C. M. , Perucho M. , Savolainen T. , Ros E. , Lobanov A. P. , Zensus J. A. , Lähteenmäki A. 
Published: February 2011

AbstractWe have found evidence for interaction between a standing and a traveling shock in the jet of the blazar CTA 102. Our result is based in the study of the spectral evolution of the turnover frequency-turnover flux density (νm, Sm) plane. The radio/mm light curves were taken during a major radio outburst in April 2006.
Evolution of the parsec-scale jet in 3C 345
Authors: Schinzel F. K. , Lobanov A. P. , Zensus J. A. , Taylor G. B. , Jorstad S. , Marscher A. 
Published: February 2011

AbstractThe 16m quasar 3C 345 is one of the best examples of an AGN showing structural and flux variability on parsec scales around a compact unresolved radio core. It has been observed from radio to γ-ray wavebands with a special focus on Very Long Baseline Interferometry (VLBI) observations in the range 1-100 GHz that cover a period of over 30 years. The complex pc-scale jet of 3C 345 exemplifies an archetypal “superluminal” jet with helical substructure. Existing VLBI observations of 3C 345 form an unprecedented database enabling a unique insight into the long-term evolution of the pc-scale radio emission. Here we present the latest results from our ongoing long-term VLBI monitoring of 3C 345, focusing on the morphological, kinematic, and spectral evolution of the pc-scale jet. Special attention will be given to the recent onset of a new period of high activity in the source that has been manifesting itself since 2008 from radio through γ-rays. Recent VLBI and high energy observations to study the relation between the radio emission and the production of high energy photons in 3C 345 are combined.
Suzaku studies of microquasars
Authors: Ueda Yoshihiro , Shidatsu Megumi 
Published: February 2011

AbstractWe report our recent results from multiwavelengths studies of microquasars, focusing on X-ray data of GX 339–4 and GRS 1915+105 obtained with Suzaku and other observatories. The broad band coverage and high energy resolution achieved with Suzaku (or a combination of Chandra/HETGS and RXTE) enable us to perform the most reliable spectral analysis both on iron-K features and continuum, and thus to best constrain the accretion disk structure of microquasars and its relation to the jet formation at various mass accretion rates.
Accretion-outflow connection in the outliers of the “universal” radio/X-ray correlation
Authors: Coriat M. , Corbel S. , Prat L. , Miller-Jones J. C. A. , Cseh D. , Tzioumis A. K. , Brocksopp C. , Rodriguez J. , Fender R. P. , Sivakoff G. R. 
Published: February 2011

AbstractIn recent years, numerous efforts have been devoted to unravel the connection between accretion flow and jets in accreting compact objects. Here we report new constraints on these issues, through the long term study of the radio and X-ray behaviour of the black hole candidate H 1743–322. This source is known to be one of the “outliers” of the universal radio/X-ray correlation, i.e. a group of stellar mass accreting black holes displaying fainter radio emission for a given X-ray luminosity, than expected from the correlation. In this work we find, at high X-ray luminosity in the hard state, a tight radio/X-ray correlation with an unusual steep slope of b = 1.38 ± 0.03. This correlation then breaks below ~5 × 10−3LEdd (M/10M⊙)−1 in X-rays and becomes shallower. When compared with radio/X-ray data from other black hole X-ray binaries, we see that the deviant points of H 1743–322 join the universal correlation and seem to follow it at low luminosity. Based on these results, we investigate several hypotheses that could explain both the b ~ 1.4 slope and the transition toward the universal correlation.
The pertinence of jet emitting discs in microquasars. Theory and comparison to observations
Authors: Petrucci Pierre-Olivier , Ferreira Jonathan , Henri Gilles , Malzac Julien , Foellmi Cedric 
Published: February 2011

AbstractJet Emitting Disc (JED) has dynamical properties quite different from both the standard and advection dominated discs. It also exhibits three different thermal equilibrium branches at a given radius: two stable (cold and hot) and one intermediate unstable. The hot solution has all the characteristics of the so-called “hot corona” generally invoked in XrB sytems in the Low/Hard states. We detail the energetics and radiative expectations of our model and show their good agreement with those observed in Cygnus X-1 in terms of jet power, jet velocity and spectral emission.
Conditions for jet formation in accreting neutron stars: the magnetic field decay
Authors: García Federico , Aguilera Deborah N. , Romero Gustavo E. 
Published: February 2011

AbstractAccreting neutron stars can produce jets only if they are weakly magnetized (B ~ 108 G). On the other hand, neutron stars are compact objects born with strong surface magnetic fields (B ~ 1012 G). In this work we study the conditions for jet formation in a binary system formed by a neutron star and a massive donor star once the magnetic field has decayed due to accretion. We solve the induction equation for the magnetic field diffusion in a realistic neutron star crust and discuss the possibility of jet launching in systems like the recently detected Supergiant Fast X-ray Transients.
A leptonic/hadronic jet model for the low-mass microquasar XTE J1118+480
Authors: Vila Gabriela S. , Romero Gustavo E. 
Published: February 2011

AbstractWe present a one–zone jet model that fits the data from simultaneous broadband radio-to-X-rays observations of XTE J1118+480. We calculate the radiative contribution to the non-thermal spectrum of both relativistic electrons and protons, as well as that from secondary muons, charged pions and electron-positron pairs produced at high-energy hadronic interactions. The distributions in energy of all the particle species are obtained taking into account the energy losses, injection, decay and escape from the emission region. We also include absorption effects on the emission spectrum due to photon-photon annihilation. Finally, we discuss the detectability of XTE J1118+480 at high energies with the present instruments according to the predictions of our model for the gamma-ray band.
Spectral evolution of the galactic microquasars XTE J1550-564 and GRO J1655-40 during outbursts
Authors: Lutovinov Alexander A. , Tsygankov Sergei S. , Arefiev Vadim A. , Revnivtsev Mikhail G. 
Published: February 2011

AbstractWe present results of a broadband spectroscopy of the galactic microquasars and black hole candidates XTE J1550-564 and GRO J1655-40, performed with the INTEGRAL and RXTE observatories during strong outbursts in 2003 and 2005, respectively. The spectral parameters evolution was traced during brightening and fading phases of each outburst to search a possible hysteresis and transitions from state to state. We estimated a size and optical depth of different regions around XTE J1550-564, like a hot plasma zone and optically thick accretion disk. Upper limits to the annihilation 511 keV line emission were obtained for both sources using data of the SPI spectrometer onboard the INTEGRAL observatory.
Evidence of an irradiated accretion disc in XTE J1818–245
Authors: Heras J. A. Zurita , Chaty S. , Bel M. Cadolle , Prat L. 
Published: February 2011

AbstractThe X-ray transient source XTE J1818–245 went through an outburst in 2005 that was observed during a multi-wavelength campaign from radio to soft γ-rays. We performed new optical observations with the ESO/NTT telescope at La Silla. The broad-band spectral energy distribution revealed that the outer parts of the accretion disc had to be irradiated by its inner parts to explain the optical emission.
Large-scale radio nebula around the Ultra-Luminous X-ray Source IC 342 X-1
Authors: Cseh Dávid , Lang Cornelia , Corbel Stéphane , Kaaret Philip , Grisé Fabien 
Published: February 2011

AbstractWe present discovery of a radio nebula associated with the ultraluminous X-ray source (ULX) IC 342 X-1 using the Very Large Array (VLA). Taking the surrounding nebula as a calorimeter, one can constrain the intrinsic power of the ULX source. We compare the obtained power that is needed to supply the radio nebula with the W50 nebula powered by the microquasar SS433 and with other ULXs. We find that the power required is at least two orders of magnitude greater than that needed to power radio emission from the W50 nebula associated with the microquasar SS433. In addition, we report the detection of a compact radio core at the location of the X-ray source.
Gamma Ray Bursts: basic facts and ideas
Authors: Ghisellini Gabriele 
Published: February 2011

AbstractThe recent years witnessed a dramatic improvement in our knowledge of the phenomenology and physics of Gamma Ray Bursts (GRBs). However, our “pillars of knowledge” remain a few, while many aspects remain obscure and not understood. There is no general agreement on the radiation mechanism of the prompt emission, nor on the process able to convert the bulk motion of the fireball into random energy of the emitting leptons. The afterglow phase can now be studied at very early phases, showing an unforeseen phenomenology, still to be understood. In this context, the detection of ~GeV emission from ~10% of GRBs, made possible by the Fermi satellite, can hopefully shed light on some controversial issues.
Gamma Ray Bursts Spectral–Energy correlations: recent results
Authors: Ghirlanda Giancarlo 
Published: February 2011

AbstractThe correlations between the rest frame peak of the νFν spectrum of GRBs (Epeak) and their isotropic energy (Eiso) or luminosity (Liso) could have several implications for the understanding of the GRB prompt emission. These correlations are presently founded on the time–averaged spectral properties of a sample of 95 bursts, with measured redshifts, collected by different instruments in the last 13 years (pre–Fermi). One still open issue is wether these correlations have a physical origin or are due to instrumental selection effects. By studying 10 long and 14 short GRBs detected by Fermi we find that a strong time–resolved correlation between Epeak and the luminosity Liso is present within individual GRBs and that it is consistent with the time–integrated correlation. This result is a direct proof of the existence in both short and long GRBs of a similar physical link between the hardness and the luminosity which is not due to instrumental selection effects. The origin of the Epeak – Liso correlation should be searched in the radiation mechanism of the prompt emission.
Molecular and atomic jets in young low-mass stars: Properties and origin
Authors: Cabrit Sylvie , Ferreira J. , Dougados C. 
Published: February 2011

AbstractThe key characteristics of molecular and atomic ejection from young stars are summarized, with emphasis on similarities across evolutionary stages, and the need for efficient magnetic collimation and ejection extracting a large fraction of the accretion power. The jet kinematics, and its dust and molecular content, are confronted to steady MHD jet models, and the probable contribution of non-steady processes is pointed out.
On the time variability of the HH jet ejection process
Authors: De Colle Fabio 
Published: February 2011

AbstractTwo-dimensional emission line images of the HH30 jet were recently used (De Colle et al. 2010) to recover the three-dimensional structure of the jet by applying standard tomographic technique (“Tikhonov regularization techniques”). In this paper I show that it is possible to determine the ejection history of the HH30 jet by directly comparing the outcome of numerical simulations with the results of the tomographic inversion. In particular, it is shown that the HH30 jet electron density map is best reproduced by assuming a velocity variation at the base of the jet with a large scale periodicity (with a period of ~3 yrs) added to small scales velocity variation (with periods ≲months).
Modelling of T Tauri jets with low mass accretion rate
Authors: Globus N. , Sauty C. , Cayatte V. , Meliani Z. , Lima J. J. G. , Tsinganos K. , Michaut C. 
Published: February 2011

AbstractWe show that low mass accreting T Tauri stars may have a strong stellar jet component which can effectively brake the star to the observed rotation speed. By means of meridional self similarity, we construct semi analytical solutions describing the complete dynamics and topology of the stellar component of the jet emerging from the corona of the star. We show two typical solutions with the same mass loss rate but different magnetic lever arms and jet radius, corresponding to differente phases of T Tauri star activity.