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The continuum and narrow-line region of the narrow-line Seyfert 1 galaxy Mrk 766
Contini, M.; Rodríguez-Ardila, A.; Viegas, S. M.
We present the first spectroscopic observations in the interval 0.8-4.0 µm, complemented with existing Hubble Space Telescope ultraviolet (UV) and optical spectroscopy, of the narrow-line Seyfert 1 galaxy Mrk 766. The near-infrared spectrum is characterized by numerous permitted lines of HI, HeI, HeII and FeII, and forbidden lines of [SII], …
Statistical survey of earthbound interplanetary shocks, associated coronal mass ejections and their space weather consequences
Tappin, S. J.; Howard, T. A.
A comprehensive statistical analysis of events relevant to space weather over the 80 month period from January 1998 to August 2004 is presented. A database has been constructed using data from instruments from the SOHO, ACE, WIND and GOES spacecraft, as well as ground magnetometer data. Parameters investigated include times and epochs of halo and …
FUSE Determination of a Low Deuterium Abundance along an Extended Sight Line in the Galactic Disk
Moos, H. W.; Chayer, P.; Dupuis, J. +5 more
We present a study of the deuterium abundance along the extended sight line toward HD 90087 with the Far Ultraviolet Spectroscopic Explorer (FUSE). HD 90087 is a O9.5 III star located in the Galactic disk at a distance of ~2.7 kpc away from the Sun. Both in terms of distance and column densities, HD 90087 has the longest and densest sight line obs…
Energetic Neutral Atom Emissions from Titan Interaction with Saturn's Magnetosphere
Krimigis, S. M.; Mitchell, D. G.; Roelof, E. C. +3 more
The Cassini Magnetospheric Imaging Instrument (MIMI) observed the interaction of Saturn's largest moon, Titan, with Saturn's magnetosphere during two close flybys of Titan on 26 October and 13 December 2004. The MIMI Ion and Neutral Camera (INCA) continuously imaged the energetic neutral atoms (ENAs) generated by charge exchange reactions between …
Sculpting a Pre-planetary Nebula with a Precessing Jet: IRAS 16342-3814
Sahai, R.; Sánchez Contreras, C.; Le Mignant, D. +2 more
We have imaged the bipolar pre-planetary nebula IRAS 16342-3814 with the Keck adaptive optics (AO) system in four near-infrared bands in the 1.6-4.7 µm range. The lobes, which showed smoothly varying brightness distributions in previous optical images taken with the Hubble Space Telescope, have a limb-brightened appearance in the AO images, …
Isothermal Bias of the ``Filter Ratio'' Method for Observations of Multithermal Plasma
Schmelz, J. T.; DeLuca, E. E.; Weber, M. A. +1 more
An early result from the Transition Region and Coronal Explorer (TRACE) was that the EUV filter ratios for many narrow coronal loops (widths of a few arcseconds) were found to cluster within the small range 0.50-1.70, as functions of position along loop length. The most common interpretation is that the temperature along the loop is in fact nearly…
Properties of Resolved Star Clusters in M51
Whitmore, Bradley C.; Chandar, Rupali; Lee, Myung Gyoon
We present a study of compact star clusters in the nearby pair of interacting galaxies NGC 5194/5195 (M51), based on multifilter Hubble Space Telescope (HST) WFPC2 archival images. We have detected ~400 isolated, resolved clusters in five HST WFPC2 fields of the two-galaxy system. Due to our requirement that the clusters be detected based only on …
Abundances and Depletions of Interstellar Oxygen
Snow, Theodore P.; Rachford, Brian L.; Jensen, Adam G.
We report on the abundance of interstellar neutral oxygen (O I) for 26 sight lines, using data from the Far Ultraviolet Spectroscopic Explorer, the International Spectroscopic Explorer, and the Hubble Space Telescope. O I column densities are derived by measuring the equivalent widths of several ultraviolet absorption lines and subsequently fittin…
Luminosity and Mass Limits for the Progenitor of the Type Ic Supernova 2004gt in NGC 4038
Smartt, Stephen J.; Maund, Justyn R.; Schweizer, Francois
We report on our attempts to locate the progenitor of the Type Ic supernova SN 2004gt in NGC 4038. We use high-resolution HST ACS images of SN 2004gt and have compared them with deep pre-explosion HST WFPC2 F336W, F439W, F555W, and F814W images. We identify the SN location on the pre-explosion frames with an accuracy of 5 mas. We show that the pro…
Radial Distribution of Dust Grains around HR 4796A
Wahhaj, Z.; Lis, D. C.; Koerner, D. W. +4 more
We present high dynamic range images of circumstellar dust around HR 4796A that were obtained with MIRLIN at the Keck II telescope at λ=7.9, 10.3, 12.5, and 24.5 µm. We also present a new continuum measurement at 350 µm obtained at the Caltech Submillimeter Observatory. Emission is resolved in Keck images at 12.5 and 24.5 µm with…