Galactic Wind Signatures around High Redshift Galaxies

We carry out cosmological chemodynamical simulations with different strengths of supernova (SN) feedback and study how galactic winds from star-forming galaxies affect the features of hydrogen (HI) and metal (CIV and OVI) absorption systems in the intergalactic medium at high redshift. We find that the outflows tend to escape to low density regions, and hardly affect the dense filaments visible in HI absorption. As a result, the strength of HI absorption near galaxies is not reduced by galactic winds, but even slightly increases. We also find that a lack of HI absorption for lines of sight (LOS) close to galaxies, as found by Adelberger et al., can be created by hot gas around the galaxies induced by accretion shock heating. In contrast to HI, metal absorption systems are sensitive to the presence of winds. The models without feedback can produce the strong CIV and OVI absorption lines in LOS within 50 kpc from galaxies, while strong SN feedback is capable of creating strong CIV and OVI lines out to about twice that distance. We also analyze the mean transmissivity of HI, CIV, and OVI within 1 h$^{-1}$ Mpc from star-forming galaxies. The probability distribution of the transmissivity of HI is independent of the strength of SN feedback, but strong feedback produces LOS with lower transmissivity of metal lines. Additionally, strong feedback can produce strong OVI lines even in cases where HI absorption is weak. We conclude that OVI is probably the best tracer for galactic winds at high redshift.Comment: 16 pages, 16 figures, ApJ in press. Higher resolution version available at http://www.ociw.edu/~dkawata/research/papers.htm

A New Superwind Wolf-Rayet Galaxy Mrk 1259

We report the discovery of a starburst-driven wind (superwind) from the starburst nucleus galaxy Mrk 1259. The estimated number ratio of Wolf-Rayet (WR) to O stars amounts to ~0.09. While the nuclear emission-line region is due to usual photoionization by massive stars, the circumnuclear emission-line regions show anomalous line ratios that can be due to cooling shocks. Since the host galaxy seems to be a face-on disk galaxy and the excitation conditions of the circumnuclear emission-line regions show the spatial symmetry, we consider that we are seeing the superwind nearly from a pole-on view. Cooling shock models may explain the observed emission line ratios of the circumnuclear regions although a factor of 2 overabundance of nitrogen is necessary. All these suggest that the high-mass enhanced starburst occurred ~5X10^6 years ago in the nuclear region of Mrk 1259.Comment: To be published in the Astrophysical Journal Letters, 15 pages, 4 figure

Subaru Spectroscopy of the Gravitational Lens HST 14176+5226: Implications for a Large Cosmological Constan

We present new optical spectroscopy of the lens elliptical galax in the ``Einstein Cross'' lens system HST 14176+5226, using the Faint Object Camera and Spectrograph (FOCAS) of the Subaru t Our spectroscopic observations are aimed at measuring the stella dispersion of the lens galaxy, located at high redshift of z_L= as an important component to lens models. We have measured this 230 +- 14 km s^{-1} (1 sigma) inside 0.35 effective radi based on the comparison between the observed galaxy spectrum and templates of three G-K giants by means of the Fourier cross-corr To extract the significance of this information on the geometry universe which also affects the lensing of the background image, to fit three different lens models to the available data of the Provided that the lens galaxy has the structural and dynamical p (i.e., its radial density profile, core radius, and velocity ani similar to those of local elliptical galaxies, we calculate the function for the simultaneous reproduction of both the observed and newly measured velocity dispersion of the lens. Although the interval depends rather sensitively on the adopted lens models o parameters, our experiments suggest the larger likelihood for a cosmological constant, Omega_Lambda: formal 1 sigma lower Omega_Lambda in the flat universe ranges 0.73 to 0.97, where lower limit is basically unavailable. This method for determinin model is thus dependent on lens models but is insensitive to oth ambiguities, such as the dust absorption or the evolutionary eff galaxies. Exploring spectroscopic observations of more lens gala redshift may minimize the model uncertainties and thus place a m constraint on Omega_Lambda.Comment: 23 pages, 5 figures, accepted for publication in The Astronomical Journa

The square-lattice spiral magnet Ba_2CuGe_2O_7 in an in-plane magnetic field

The magnetic structure of Ba_2CuGe_2O_7 is investigated by neutron diffraction in magnetic fields applied along several directions in the $(a,b)$ plane of the crystal. In relatively weak fields, $H\lesssim 0.5$~T, the propagation vector of the spin-spiral rotates to form a finite angle with the field direction. This angle depends on the orientation of $H$ itself. The rotation of the propagation vector is accompanied by a re-orientation of the plane of spin rotation in the spiral. The observed behaviour is well described by a continuous-limit form of a free energy functional that includes exchange and Dzyaloshinskii-Moriya interactions, as well as the Zeeman energy and an empirical anisotropy term.Comment: 7 pages, 6 figure

Rumors of disease in the global village: outbreak verification.

Emerging infectious diseases and the growth of information technology have produced new demands and possibilities for disease surveillance and response. Increasing numbers of outbreak reports must be assessed rapidly so that control efforts can be initiated and unsubstantiated reports can be identified to protect countries from unnecessary economic damage. The World Health Organization has set up a process for timely outbreak verification to convert large amounts of data into accurate information for suitable action. We describe the context and processes of outbreak verification and information dissemination

Magneto-Conductance Anisotropy and Interference Effects in Variable Range Hopping

We investigate the magneto-conductance (MC) anisotropy in the variable range hopping regime, caused by quantum interference effects in three dimensions. When no spin-orbit scattering is included, there is an increase in the localization length (as in two dimensions), producing a large positive MC. By contrast, with spin-orbit scattering present, there is no change in the localization length, and only a small increase in the overall tunneling amplitude. The numerical data for small magnetic fields $B$, and hopping lengths $t$, can be collapsed by using scaling variables $B_\perp t^{3/2}$, and $B_\parallel t$ in the perpendicular and parallel field orientations respectively. This is in agreement with the flux through a `cigar'--shaped region with a diffusive transverse dimension proportional to $\sqrt{t}$. If a single hop dominates the conductivity of the sample, this leads to a characteristic orientational `finger print' for the MC anisotropy. However, we estimate that many hops contribute to conductivity of typical samples, and thus averaging over critical hop orientations renders the bulk sample isotropic, as seen experimentally. Anisotropy appears for thin films, when the length of the hop is comparable to the thickness. The hops are then restricted to align with the sample plane, leading to different MC behaviors parallel and perpendicular to it, even after averaging over many hops. We predict the variations of such anisotropy with both the hop size and the magnetic field strength. An orientational bias produced by strong electric fields will also lead to MC anisotropy.Comment: 24 pages, RevTex, 9 postscript figures uuencoded Submitted to PR

Giant Lya nebulae associated with high redshift radio galaxies

We report deep Keck narrow-band Lya images of the luminous z > 3 radio galaxies 4C 41.17, 4C 60.07, and B2 0902+34. The images show giant, 100-200 kpc scale emission line nebulae, centered on these galaxies, which exhibit a wealth of morphological structure, including extended low surface brightness emission in the outer regions, radially directed filaments, cone-shaped structures and (indirect) evidence for extended Lya absorption. We discuss these features within a general scenario where the nebular gas cools gravitationally in large Cold Dark Matter (CDM) halos, forming stars and multiple stellar systems. Merging of these ``building'' blocks triggers large scale starbursts, forming the stellar bulges of massive radio galaxy hosts, and feeds super-massive black holes which produce the powerful radio jets and lobes. The radio sources, starburst superwinds and AGN radiation then disrupt the accretion process limiting galaxy and black hole growth, and imprint the observed filamentary and cone-shaped structures of the Lya nebulae.Comment: 36 Pages, including 8 Postscript figures. Accepted for publication in the Astrophysical Journa

High-Resolution Submillimeter Imaging of the Ly-alpha Blob1 in SSA 22

We present ~2" resolution submillimeter observations of the submillimeter luminous giant Ly-alpha blob (LAB1) in the SSA 22 protocluster at redshift z=3.1 with the Submillimeter Array (SMA). Although the expected submillimeter flux density is 16 mJy at 880 micron, no emission is detected with the 2".4 x 1".9 (18 x 14 kpc) beam at the 3 sigma level of 4.2 mJy beam^{-1} in the SMA field of view of 35". This is in contrast to the previous lower angular resolution (15") observations where a bright (17 mJy) unresolved submillimeter source was detected at 850 micron toward the LAB1 using the Submillimeter Common-User Bolometer Array on the James Clerk Maxwell Telescope. The SMA non-detection suggests that the spatial extent of the submillimeter emission of LAB1 should be larger than 4" (>30 kpc). The most likely interpretation of the spatially extended submillimeter emission is that starbursts occur throughout the large area in LAB1. Some part of the submillimeter emission may come from spatially extended dust expelled from starburst regions by galactic superwind. The spatial extent of the submillimeter emission of LAB1 is similar to those of high redshift radio galaxies rather than submillimeter galaxies.Comment: 7 pages, 5 figures, accepted for publication in Ap