Discovery of an outflow of the very low-mass star ISO 143

We discover that the very young very low-mass star ISO143 (M5) is driving an outflow based on spectro-astrometry of forbidden [SII] emission lines at 6716A and 6731A observed in UVES/VLT spectra. This adds another object to the handful of brown dwarfs and very low-mass stars (M5-M8) for which an outflow has been confirmed and which show that the T Tauri phase continues at very low masses. We find the outflow of ISO143 to be intrinsically asymmetric and the accretion disk to not obscure the outflow, as only the red outflow component is visible in the [SII] lines. ISO143 is only the third T Tauri object showing a stronger red outflow component in spectro-astrometry, after RW Aur (G5) and ISO217 (M6.25). We show here that including ISO143 two out of seven outflows confirmed in the very low-mass regime (M5-M8) are intrinsically asymmetric. We measure a spatial extension of the outflow in [SII] of up to 200-300 mas (about 30-50 AU) and velocities of up to 50-70 km/s. We furthermore detect line emission of ISO143 in CaII (8498), OI (8446), HeI (7065), and weakly in [FeII] (7155). Based on a line profile analysis and decomposition we demonstrate that (i) the CaII emission can be attributed to chromospheric activity, a variable wind, and the magnetospheric infall zone, (ii) the OI emission mainly to accretion-related processes but also a wind, and (iii) the HeI emission to chromospheric or coronal activity. We estimate a mass outflow rate of ISO143 of ~10^{-10} Msol/yr and a mass accretion rate in the range of ~10^{-8} to ~10^{-9} Msol/yer. These values are consistent with those of other brown dwarfs and very low-mass stars. The derived Mout/Macc ratio of 1-20% is not supporting previous findings of this number to be very large (>40%) for very low-mass objects.Comment: Accepted for publication at A&A; 9 pages, 5 figures. Minor changes due to language editin

Analysis of GeV-band gamma-ray emission from SNR RX J1713.7-3946

RX J1713.7-3946 is the brightest shell-type Supernova remnant (SNR) of the TeV gamma-ray sky. Earlier Fermi-LAT results on low-energy gamma-ray emission suggested that, despite large uncertainties in the background determination, the spectrum is inconsistent with a hadronic origin. We update the GeV-band spectra using improved estimates for the diffuse galactic gamma-ray emission and more than doubled data volume. We further investigate the viability of hadronic emission models for RX J1713.7-3946. We produced a high-resolution map of the diffuse Galactic gamma-ray background corrected for HI self-absorption and used it in the analysis of more than 5~years worth of Fermi-LAT data. We used hydrodynamic scaling relations and a kinetic transport equation to calculate the acceleration and propagation of cosmic-rays in SNR. We then determined spectra of hadronic gamma-ray emission from RX J1713.7-3946, separately for the SNR interior and the cosmic-ray precursor region of the forward shock, and computed flux variations that would allow to test the model with observations. We find that RX J1713.7-3946 is now detected by Fermi-LAT with very high statistical significance, and the source morphology is best described by that seen in the TeV band. The measured spectrum of RX J1713.7-3946 is hard with index gamma=1.53 +/- 0.07, and the integral flux above 500 MeV is F = (5.5 +/- 1.1)e-9 photons/cm^2/s. We demonstrate that scenarios based on hadronic emission from the cosmic-ray precursor region are acceptable for RX J1713.7-3946, and we predict a secular flux increase at a few hundred GeV at the level of around 15% over 10 years, which may be detectable with the upcoming CTA observatory.Comment: 9 pages, accepted for publication in Astronomy & Astrophysic

Using the Individual Development Plan as a Vehicle for Coaching and Communication

This capstone explores the underutilization of the Individual Development Plan (IDP) as a vehicle for communication and coaching at all organizational levels throughout the United States Coast Guard (USCG). The capstone will gather data through informal interviews using basic line questioning; exploring the IDP in the USCG, when and why it was developed, how it was designed to be used and how it is currently used. While many interviewees feel the IDP is in fact a useful tool, many Guardians (Coast Guard personnel) feel the IDP is not used appropriately and that supervisors and subordinates are neither adequately trained on how to use the tool properly, nor on how to effectively use the IDP as a coaching tool. The capstone looks critically at the IDP and recommends how training in the use and application of the IDP through the development of communication and coaching skills enhances the value and application of the IDP for all ranks within the USCG

Photon-Photon Interactions via Rydberg Blockade

We develop the theory of light propagation under the conditions of electromagnetically induced transparency in systems involving strongly interacting Rydberg states. Taking into account the quantum nature and the spatial propagation of light, we analyze interactions involving few-photon pulses. We show that this system can be used for the generation of nonclassical states of light including trains of single photons with an avoided volume between them, for implementing photon-photon gates, as well as for studying many-body phenomena with strongly correlated photons

Quasi-elastic neutrino charged-current scattering cross sections on oxygen

The charged-current quasi-elastic scattering of muon neutrinos on oxygen target is computed for neutrino energies between 200 MeV and 2.5 GeV using the relativistic distorted-wave impulse approximation with relativistic optical potential, which was earlier successfully applied to describe electron-nucleus data. We study both neutrino and electron processes and show that the reduced exclusive cross sections for neutrino and electron scattering are similar. The comparison with the relativistic Fermi gas model (RFGM), which is widely used in data analyses of neutrino experiments, shows that the RFGM fails completely when applied to exclusive cross section data and leads to overestimated values of inclusive and total cross sections. We also found significant nuclear-model dependence of exclusive, inclusive and total cross sections for about 1 GeV energy.Comment: 30 pages, 11 figures; final version to appear in Phys. Rev.

Strong-coupling effects in the relaxation dynamics of ultracold neutral plasmas

We describe a hybrid molecular dynamics approach for the description of ultracold neutral plasmas, based on an adiabatic treatment of the electron gas and a full molecular dynamics simulation of the ions, which allows us to follow the long-time evolution of the plasma including the effect of the strongly coupled ion motion. The plasma shows a rather complex relaxation behavior, connected with temporal as well as spatial oscillations of the ion temperature. Furthermore, additional laser cooling of the ions during the plasma evolution drastically modifies the expansion dynamics, so that crystallization of the ion component can occur in this nonequilibrium system, leading to lattice-like structures or even long-range order resulting in concentric shells

Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 2: Advanced energy conversion systems. Part 3: Direct energy conversion cycles

For abstract, see N76-23680

Stochastic re-acceleration and magnetic-field damping in Tycho's supernova remnant

A number of studies suggest that shock acceleration with particle feedback and very efficient magnetic-field amplification combined with Alfv\'{e}nic drift are needed to explain the rather soft radio spectrum and the narrow rims observed for Tycho's SNR. We show that the broadband spectrum of Tycho's SNR can alternatively be well explained when accounting for stochastic acceleration as a secondary process. The re-acceleration of particles in the turbulent region immediately downstream of the shock should be efficient enough to impact particle spectra over several decades in energy. The so-called Alfv\'{e}nic drift and particle feedback on the shock structure are not required in this scenario. Additionally, we investigate whether synchrotron losses or magnetic-field damping play a more profound role in the formation of the non-thermal filaments. We solve the full particle transport equation in test-particle mode using hydrodynamic simulations of the SNR plasma flow. The background magnetic field is either computed from the induction equation or follows analytic profiles, depending on the model considered. Fast-mode waves in the downstream region provide the diffusion of particles in momentum space. We show that the broadband spectrum of Tycho can be well explained if magnetic-field damping and stochastic re-acceleration of particles are taken into account. Although not as efficient as standard DSA, stochastic acceleration leaves its imprint on the particle spectra, which is especially notable in the emission at radio wavelengths. We find a lower limit for the post-shock magnetic-field strength $\sim330\,\mathrm{\mu G}$, implying efficient amplification even for the magnetic-field damping scenario. For the formation of the filaments in the radio range magnetic-field damping is necessary, while the X-ray filaments are shaped by both the synchrotron losses and magnetic-field damping.Comment: 14 pages, 10 figures, accepted for publication in Astronomy and Astrophysic

On knotted streamtubes in incompressible hydrodynamical flow and a restricted conserved quantity

For certain families of fluid flow, a new conserved quantity -- stream-helicity -- has been established.Using examples of linked and knotted streamtubes, it has been shown that stream-helicity does, in certain cases, entertain itself with a very precise topological meaning viz, measure of the degree of knottedness or linkage of streamtubes.As a consequence, stream-helicity emerges as a robust topological invariant.Comment: This extended version is the basically a more clarified version of the previous submission physics/0611166v