We present proper motion measurements of 37 jets and HH objects in the Carina Nebula measured in two epochs of H alpha images obtained similar to 10 yr apart with Hubble Space Telescope/Advanced Camera for Surveys (ACS). Transverse velocities in all but one jet are faster than greater than or similar to 25 km s(-1), confirming that the jet-like H alpha features identified in the first epoch images trace outflowing gas. Proper motions constrain the location of the jet-driving source and provide kinematic confirmation of the intermediate-mass protostars that we identify for 20/37 jets. Jet velocities do not correlate with the estimated protostar mass and embedded driving sources do not have slower jets. Instead, transverse velocities (median similar to 75 km s(-1)) are similar to those in jets from low-mass stars. Assuming a constant velocity since launch, we compute jet dynamical ages (median similar to 10(4) yr). If continuous emission from inner jets traces the duration of the most recent accretion bursts, then these episodes are sustained longer (median similar to 700 yr) than the typical decay time of an FU Orionis outburst. These jets can carry appreciable momentum that may be injected into the surrounding environment. The resulting outflow force, dp/dt, lies between that measured in low- and high-mass sources, despite the very different observational tracers used. Smooth scaling of the outflow force argues for a common physical process underlying outflows from protostars of all masses. This latest kinematic result adds to a growing body of evidence that intermediate-mass star formation proceeds like a scaled-up version of the formation of low-mass stars.

We combine state-of-the-art models for the production of stellar radiation and its transfer through the interstellar medium (ISM) to investigate ultraviolet-line diagnostics of stars, the ionized and the neutral ISM in star-forming galaxies. We start by assessing the reliability of our stellar population synthesis modelling by fitting absorption-line indices in the ISM-free ultraviolet spectra of 10 Large Magellanic Cloud clusters. In doing so, we find that neglecting stochastic sampling of the stellar initial mass function in these young (similar to 10-100 Myr), low-mass clusters affects negligibly ultraviolet-based age and metallicity estimates but can lead to significant overestimates of stellar mass. Then, we proceed and develop a simple approach, based on an idealized description of the main features of the ISM, to compute in a physically consistent way the combined influence of nebular emission and interstellar absorption on ultraviolet spectra of star-forming galaxies. Our model accounts for the transfer of radiation through the ionized interiors and outer neutral envelopes of short-lived stellar birth clouds, as well as for radiative transfer through a diffuse intercloud medium. We use this approach to explore the entangled signatures of stars, the ionized and the neutral ISM in ultraviolet spectra of star-forming galaxies. We find that, aside from a few notable exceptions, most standard ultraviolet indices defined in the spectra of ISM-free stellar populations are prone to significant contamination by the ISM, which increases with metallicity. We also identify several nebular-emission and interstellar-absorption features, which stand out as particularly clean tracers of the different phases of the ISM.

We investigate the physics of charged-particle acceleration at spherical shocks moving into a uniform plasma containing a turbulent magnetic field with a uniform mean. This has applications to particle acceleration at astrophysical shocks, most notably, to supernovae blast waves. We numerically integrate the equations of motion of a large number of test protons moving under the influence of electric and magnetic fields determined from a kinematically defined plasma flow associated with a radially propagating blast wave. Distribution functions are determined from the positions and velocities of the protons. The unshocked plasma contains a magnetic field with a uniform mean and an irregular component having a Kolmogorov-like power spectrum. The field inside the blast wave is determined from Maxwell's equations. The angle between the average magnetic field and unit normal to the shock varies with position along its surface. It is quasi-perpendicular to the unit normal near the sphere's equator, and quasi-parallel to it near the poles. We find that the highest intensities of particles, accelerated by the shock, are at the poles of the blast wave. The particles "collect" at the poles as they approximately adhere to magnetic field lines that move poleward from their initial encounter with the shock at the equator, as the shock expands. The field lines at the poles have been connected to the shock the longest. We also find that the highest-energy protons are initially accelerated near the equator or near the quasi-perpendicular portion of the shock, where the acceleration is more rapid.

Wireless extension of serial communication of RS232 standard, with using RF transceivers RFM12BP type, with transmissions errors correction. Device will be batery powered and low power consumption is required.

This thesis deals with the design and the realization of the radiocommunication monitor for the 868 MHz band. In the thesis, a description of licence-free radio bands complying ITU recommendations and ETSI standards is given. A special attention is paid to the 863 MHz - 870 MHz band. The transceiver CC1020 that forms the base for the monitor is described in detail. The circuit design, the monitor assembly and the firmware creation are presented step by step. The radiocommunication monitor is portable and battery powered. The monitor is able to display RF signals in the 868 MHz band, to indicate the frequency error of the transmitter and to receive FSK modulated signal. Demodulated data can be transferred to the personal computer via the USB.

Using archival Far Ultraviolet Spectroscopic Explorer (FUSE) and Hubble Space Telescope (HST) data, we have assembled a survey of eight sight lines through high-velocity cloud Complex C. Abundances of the observed ion species vary significantly for these sight lines, indicating that Complex C is not well characterized by a single metallicity. Reliable metallicities based on [O I/H I] range from 0.1 to 0.25 Z⊙. Metallicities based on [S II/H I] range from 0.1 to 0.6 Z⊙, but the trend of decreasing abundance with H I column density indicates that photoionization corrections may affect the conversion to [S/H]. We present models of the dependence of the ionization correction on H I column density; these ionization corrections are significant when converting ion abundances to elemental abundances for S, Si, and Fe. The measured abundances in this survey indicate that parts of the cloud have a higher metallicity than previously thought and that Complex C may represent a mixture of " Galactic fountain " gas with infalling low-metallicity gas. We find that [S/O] and [Si/O] have a solar ratio, suggesting little dust depletion. Further, the measured abundances suggest an overabundance of O, S, and Si relative to N and Fe. The enhancement of these α-elements suggests that the bulk of the metals in Complex C were produced by Type II supernovae and then removed from the starforming region, possibly via supernova-driven winds or tidal stripping, before the ISM could be enriched by N and Fe.

We analyze HST and FUSE ultraviolet spectroscopic data for 11 sight lines passing through the infalling high-velocity cloud (HVC) Complex C. These sight lines pass through regions with H I column densities in the range N H I = 1018.1 -1020.1 cm-2. From [OI/HI] abundances, we find that Complex C metallicities range from 0.09 to 0.29 Z⊙, with a column density weighted mean of 0.13 Z ⊙. Nitrogen (N I) is underabundant by factors of (0.01 -0.07)(N/H)⊙, significantly less than oxygen relative to solar abundances. This pattern suggests nucleosynthetic enrichment by Type II SNe, consistent with an origin in the Galactic fountain or infalling gas produced in winds from Local Group galaxies. The range of metallicity and its possible (2 σ) dependence on NH I could indicate some mixing of primordial material with enriched gas from the Milky Way, but the mixing mechanism is unclear. We also investigate the significant highly ionized component of Complex C, detected in C IV, Si IV, and O VI, but not in N V. High-ion column density ratios show little variance and are consistent with shock ionization or ionization at interfaces between Complex C and a hotter surrounding medium. Evidence for the former mechanism is seen in the Mrk 876 line profiles, where the offset in line centroids between low and high ions suggests a decelerating bow shock.

We use spectroscopic data from the Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) to study the wide range of ionization states of the "highly ionized high-velocity clouds" (HVCs). Studied extensively in O VI absorption, these clouds are usually assumed to be infalling gas in the Galactic halo at distances less than 50 kpc. An alternative model attributes the O VI (and O VII X-ray absorption) to cosmological structures of low-density, shock-heated intergalactic gas, distributed over 1-3 Mpc surrounding the Milky Way. The latter interpretation is unlikely, owing to the enormous required mass of gas (4 × 1012 M⊙). Our detection, in 9 of 12 sight lines, of low-ionization stages (C II/III/IV; Si II/III/IV) at similar high velocities as O vi requires gas densities far above that (nH ≈ 5 × 10-6 cm-3) associated with the warm-hot intergalactic medium (WHIM). These HVCs are probably cooling, multiphase gas in the Galactic halo, bow shocks, and interfaces between clouds falling through a hot, rotating gaseous halo. The velocity segregation of these HVCs in Galactic coordinates is consistent with a pattern in which infalling clouds reflect the sense of Galactic rotation, with peculiar velocities superposed.

Using archived data from the Chandra X-ray telescope, we have extracted the diffuse X-ray emission from 49 equal-mass interacting/merging galaxy pairs in a merger sequence, from widely separated pairs to merger remnants. After the removal of contributions from unresolved point sources, we compared the diffuse thermal X-ray luminosity from hot gas (L X(gas)) with the global star formation rate (SFR). After correction for absorption within the target galaxy, we do not see a strong trend of L X(gas)/SFR with the SFR or merger stage for galaxies with SFR > 1 Myr-1. For these galaxies, the median L X(gas)/SFR is 5.5 ×1039 ((erg s-1)/Myr-1)), similar to that of normal spiral galaxies. These results suggest that stellar feedback in star-forming galaxies reaches an approximately steady-state condition, in which a relatively constant fraction of about 2% of the total energy output from supernovae and stellar winds is converted into X-ray flux. Three late-stage merger remnants with low SFRs and high K-band luminosities (L K ) have enhanced L X(gas)/SFR; their UV/IR/optical colors suggest that they are post-starburst galaxies, perhaps in the process of becoming ellipticals. Systems with L K < 1010 L have lower L X(gas)/SFR ratios than the other galaxies in our sample, perhaps due to lower gravitational fields or lower metallicities. We see no relation between L X(gas)/SFR and Seyfert activity in this sample, suggesting that feedback from active galactic nuclei is not a major contributor to the hot gas in our sample galaxies.

京都大学 / 0048 / 新制・論文博士 / 博士(理学) / 乙第12813号 / 論理博第1539号 / 新制||理||1577(附属図書館) / 31300 / (主査)教授 嶺重 慎, 准教授 前田 啓一, 教授 長田 哲也 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DFAM