Search Publications
Galactic Extinction from Colors and Counts of Field Galaxies in WFPC2 Frames: An Application to GRB 970228
Fruchter, Andrew S.; González, Rosa A.; Dirsch, Boris
We develop the ``simulated extinction method'' to measure average foreground Galactic extinction from field galaxy number counts and colors. The method comprises simulating extinction in suitable reference fields by changing the isophotal detection limit. This procedure takes into account selection effects; in particular, the change in the isophot…
Plasma and Warm Dust in the Collisional Ring Galaxy VII ZW 466 from VLA and ISO Observations
Appleton, P. N.; Charmandaris, V.; Ghigo, F. +4 more
We present the first mid-infrared (mid-IR) (5-15 µm) and radio continuum (λ=20, 6, and 3.6 cm) observations of the star-forming collisional ring galaxy VII Zw 466 and its host group made with the Infrared Space Observatory (ISO) and the NRAO Very Large Array. A search was also made for CO line emission in two of the galaxies with the Onsala …
The Search for Solar Gravity-Mode Oscillations: an Analysis Using ULYSSES Magnetic Field Data
Denison, David G. T.; Walden, Andrew T.
In 1995 Thomson, Maclennon, and Lanzerotti (TML) reported on work where they carried out a time-series analysis of energetic particle fluxes measured by Ulysses and Voyager 2 and concluded that solar g-mode oscillations had been detected. The approach is based on finding significant peaks in spectra using a statistical F-test. Using three sets of …
Hubble Space Telescope/Faint Object Spectrograph Observations of M87:Lyα Emission from the Active Galactic Nucleus
Sembach, Kenneth R.; Canizares, Claude R.; Sankrit, Ravi
The Faint Object Spectrograph on the Hubble Space Telescope was used to obtain spectra of the central region of M87. These spectra cover the wavelength range 1140-1606 Å and have a resolution of ~1 Å. The nuclear continuum is clearly visible in the spectra. The only strong line that is observed is Lyα, which has a velocity width of about 3000 km s…
Heating and Acceleration of the Solar Wind via Gravity Damping of Alfvén Waves
Noci, Giancarlo; Poletto, Giannina; Mullan, Dermott +1 more
In this paper we present a two-fluid model for the heating of the solar corona and acceleration of the solar wind, based on the dissipation of Alfvén waves by gravity damping. This mechanism was proposed by Khabibrakhmanov & Mullan but has not previously been applied in modeling efforts. After extending the Khabibrakhmanov & Mullan theory …
A Detailed Analysis of the Stellar and Nebular IUE Spectrum of the Peculiar ``O VI Sequence'' Planetary Nebula NGC 40
Feibelman, Walter A.
A detailed analysis of archival individual and co-added low- and high-dispersion IUE spectra of the planetary nebula NGC 40 has been performed, using NEWSIPS extracted spectra. More than 50 emission lines and numerous absorption features have been identified, and emission-line fluxes and equivalent widths were measured. Terminal wind velocities fr…
The Eclipsing Cataclysmic Variable V347 Puppis Revisited
Hubeny, Ivan; Diaz, Marcos P.
An observational study of the nova-like cataclysmic binary V347 Pup (LB 1800) is presented. An analysis of optical and UV spectroscopy is made with the aim of defining the physical properties of the binary system and of the accretion disk. The study of the line profile behavior and the determination of the primary radial velocity are pursued using…
Far-Infrared Polarization of the Quasar 3C 279
Laureijs, R. J.; Klaas, Ulrich; Clavel, Jean
We present the first far-infrared (FIR) polarization results of the OVV quasar 3C 279 obtained with ISOPHOT for two epochs in 1996 and 1997. We describe its integral polarization properties at a wavelength of 170 µm, where the source shows a maximum in its energy distribution. After a γ-ray flare in 1996 January, a polarization of 23% closel…
The Boron Abundance of the Orion G-Dwarf Member BD -05°1317
Cunha, Katia; Smith, Verne V.; Lambert, David L.
The boron abundance is derived for the young Orion solar-type member BD -05°1317 from Hubble Space Telescope Goddard High Resolution Spectrograph spectra of the B I resonance lines near 2497 Å. The abundance of logɛ(B)=2.1+/-0.2 is ~0.6-0.7 dex below solar. As this young pre-main-sequence star has an undepleted lithium abundance, such a low boron …
Young Stars and Nonstellar Emission in the Aligned Radio Galaxy 3C 256
Dickinson, Mark; Djorgovski, S. G.; McCarthy, Patrick J. +8 more
We present ground-based images of the z=1.824 radio galaxy 3C 256 in the standard BVRIJHK filters and an interference filter centered at 8800 Å, a Hubble Space Telescope image in a filter dominated by Lyα emission (F336W), and spectra covering rest-frame wavelengths from Lyα to [O III] λ5007. Together with published polarimetry observations, we us…