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Deconstructing NGC 7130
Heckman, T. M.; Levenson, N. A.; Weaver, K. A. +2 more
Observations of the Seyfert 2 and starburst galaxy NGC 7130 with the Chandra X-Ray Observatory illustrate that both of these phenomena contribute significantly to the galaxy's detectable X-ray emission. The active galactic nucleus (AGN) is strongly obscured, buried beneath column density NH>1024cm-2, and it is m…
Far Ultraviolet Spectroscopic Explorer Measurements of Interstellar Fluorine
Federman, S. R.; Lambert, David L.; Smith, V. V. +1 more
The source of fluorine is not well understood, although core-collapse supernovae, Wolf-Rayet stars, and asymptotic giant branch stars have been suggested. A search for evidence of the ν-process during Type II supernovae is presented. Absorption from interstellar F I is seen in spectra of HD 208440 and HD 209339A acquired with the Far Ultraviolet S…
The Ultraviolet Spectrum of η Carinae: Investigation of the Ejecta Absorption
Gull, T. R.; Nielsen, K. E.; Vieira Kober, G.
We have investigated the far- through mid-UV (1150-2360 Å) spectrum of η Carinae during the late stages of its broad maximum using the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) moderate dispersion echelle modes. The η Car spectrum is a mixture of absorption and emission lines from the surrounding nebula superimposed …
Nonlinear Alfvén, magnetosonic, sound, and electron inertial waves in fluid formalism
Stasiewicz, K.
A fluid model of nonlinear electron and ion inertial waves in anisotropic plasmas is presented. The model has been verified for plasma beta (ratio of kinetic/magnetic pressures) in a range between 0.1 and 15. It is shown that warm plasmas support four types of nonlinear waves, which correspond to four linear modes, Alfvénic, magnetosonic, sound, a…
Metallicities of the β Cephei stars from low-resolution ultraviolet spectra
Niemczura, E.; Daszyńska-Daszkiewicz, J.
We derive basic stellar parameters (angular diameters, effective temperatures, metallicities) and interstellar reddening for all β Cephei stars observed during the IUE satellite mission, including those belonging to three open clusters. The parameters are derived by means of an algorithmic procedure of fitting theoretical flux distributions to the…
On the Afterglow and Host Galaxy of GRB 021004: A Comprehensive Study with the Hubble Space Telescope
Pian, E.; Kouveliotou, C.; Tanvir, N. +24 more
We report on Hubble Space Telescope (HST) observations of the late-time afterglow and host galaxy of GRB 021004 (z=2.33). Although this gamma-ray burst (GRB) is one of the best observed so far in terms of sampling in the time domain, multiwavelength coverage, and polarimetric observations, there is substantial disagreement between different interp…
The DEEP Groth Strip Survey. I. The Sample
Weiner, Benjamin J.; Illingworth, Garth D.; Rhodes, Jason +18 more
The Deep Extragalactic Exploratory Probe (DEEP) is a multiphase research program dedicated to the study of the formation and evolution of galaxies and of large-scale structure in the distant universe. This paper describes the first five-year phase, denoted DEEP1. A series of 10 DEEP1 papers will discuss a range of scientific topics (e.g., the stud…
Erosion by flowing Martian lava: New insights for Hecates Tholus from Mars Express and MER data
Greeley, Ronald; Williams, David A.; Neukum, Gerhard +2 more
We have used new compositional information on Martian basaltic rocks from the Mars Exploration Rover Spirit and data from new stereo imaging by the High Resolution Stereo Camera (HRSC) on the Mars Express orbiter to constrain an existing analytical-numerical computer model to assess the potential of Martian lavas to form lava channels by erosion o…
Automated Boundary-extraction And Region-growing Techniques Applied To Solar Magnetograms
Gallagher, Peter T.; McAteer, R. T. James; Ireland, Jack +1 more
We present an automated approach to active region extraction from full-disc MDI longitudinal magnetograms. This uses a region-growing technique in conjunction with boundary-extraction to define a number of enclosed contours as belonging to separate regions of magnetic significance on the solar disc. This provides an objective definition of active …
A Possible Third Component in the L Dwarf Binary System DENIS-P J020529.0-115925 Discovered with the Hubble Space Telescope
Martín, E. L.; Bouy, H.; Bouvier, J. +1 more
We present results showing that the multiple system DENIS-P J020529.0-115925 is likely to be a triple system of very low mass stars and brown dwarfs. The secondary of this previously known binary system shows a clear elongation on six images obtained at six different epochs. Significant residuals remain after point-spread function (PSF) subtractio…