Search Publications
Fundamental Properties and Distances of Large Magellanic Cloud Eclipsing Binaries. IV. HV 5936
Ribas, I.; Fitzpatrick, E. L.; Guinan, E. F. +2 more
We have determined the fundamental properties and distance of a fourth eclipsing binary (EB) system in the Large Magellanic Cloud, HV 5936 (~B0.5 V + ~B2 III). As in our previous studies, we combine ``classical'' EB light-curve and radial velocity curve analyses with modeling of the UV/optical spectral energy distribution of HV 5936 to produce a d…
Optical and near-infrared observations of the GRB020405 afterglow
Pian, E.; Palazzi, E.; Frontera, F. +33 more
We report on photometric, spectroscopic and polarimetric monitoring of the optical and near-infrared (NIR) afterglow of GRB020405. Ground-based optical observations, performed with 8 different telescopes, started about 1 day after the high-energy prompt event and spanned a period of ~ 10 days; the addition of archival HST data extended the coverag…
STIS Spectroscopy of the Central 10 Parsecs of M81: Evidence for a Massive Black Hole
Ford, Holland; Devereux, Nick; Tsvetanov, Zlatan +1 more
Spectroscopic observations of the central 10 pc of M81 were obtained with STIS on board the Hubble Space Telescope during Cycle 7. Measurements of the Hα+[N II] blend reveal a velocity field indicative of a rotating disk of gas. The two-dimensional velocity field has been modeled as a thin disk rotating in a spherical gravitational potential. Mini…
The Ionized Gas and Nuclear Environment in NGC 3783. II. Averaged Hubble Space Telescope/STIS and Far Ultraviolet Spectroscopic Explorer Spectra
Kaiser, Mary Elizabeth; Brandt, W. N.; Kaspi, Shai +14 more
We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer (FUSE). We have combined 18 STIS and five FUSE observations to obtain a high signal-to-noise ratio averaged spectrum spanning…
Trapping of Solar Energetic Particles by the Small-Scale Topology of Solar Wind Turbulence
Matthaeus, W. H.; Ruffolo, D.; Chuychai, P.
The transport of energetic particles perpendicular to the mean magnetic field in space plasmas has long been viewed as a diffusive process. However, there is an apparent conflict between recent observations of solar energetic particles (SEPs): (1) Impulsive solar flares can exhibit ``dropouts'' in which the SEP intensity near Earth repeatedly disa…
Large solar energetic particle events of cycle 23: A global view
Thompson, B. J.; Kaiser, M. L.; Howard, R. A. +4 more
We report on a study of all the large solar energetic particle (SEP) events that occurred during the minimum to maximum interval of solar cycle 23. The main results are: 1. The occurrence rate of the SEP events, long-wavelength type II bursts and the fast and wide frontside western hemispheric CMEs is quite similar, consistent with the scenario th…
Discovery of GRB 020405 and Its Late Red Bump
Piro, L.; Mitrofanov, I.; Axelrod, T. S. +41 more
We present the discovery of GRB 020405 made with the Interplanetary Network (IPN). With a duration of 60 s, the burst appears to be a typical long-duration event. We observed the 75 arcmin2 IPN error region with the Mount Stromlo Observatory's 50 inch robotic telescope and discovered a transient source that subsequently decayed and was …
The Nascent Solar Wind: Origin and Acceleration
Romoli, Marco; Teriaca, Luca; Poletto, Giannina +1 more
High-speed solar wind is known to originate in polar coronal holes, which, however, are made up of two components: bright, high-density regions known as ``plumes'' and dark, weakly emitting low-density regions known as ``interplumes.'' Recent space observations have shown that the width of UV lines is larger in interplume regions, while observatio…
New insights to the photometric structure of Blue Compact Dwarf galaxies from deep Near-Infrared studies. I. Observations, surface photometry and decomposition of surface brightness profiles
Papaderos, P.; Noeske, K. G.; Fricke, K. J. +1 more
We have analyzed deep Near Infrared (NIR) broad band images for a sample of Blue Compact Dwarf Galaxies (BCDs), observed with the ESO NTT and Calar Alto 3.6 m telescopes. The data presented here allows for the detection and quantitative study of the extended stellar low-surface brightness (LSB) host galaxy in all sample BCDs. NIR surface brightnes…
The Rotation of the Globular Cluster 47 Tucanae in the Plane of the Sky
Anderson, Jay; King, Ivan R.
We have used the Hubble Space Telescope (HST) to measure the component of rotation of 47 Tuc in the plane of the sky, using background stars of the SMC as a reference. The rotation is comparable to that in the line of sight, showing that the axis of rotation of the cluster is considerably inclined. We also give an improved value of the absolute pr…