Search Publications
Radial Color Gradients in K+A Galaxies in Distant Clusters of Galaxies
Caldwell, Nelson; Rose, James A.; Bartholomew, Lindsay J. +1 more
Galaxies in rich clusters with z>~0.3 are observed to have a higher fraction of photometrically blue galaxies than their nearby counterparts. This raises the important question of what environmental effects can cause the termination of star formation between z~0.3 and the present. The star formation may be truncated because of ram pressure stri…
21-cm H I emission from the Damped Lyman-alpha absorber SBS 1543+593
Jenkins, E. B.; Brinks, E.; Bowen, D. V. +2 more
We detect 21-cm emission from the Low Surface Brightness (LSB) galaxy SBS 1543+593, which gives rise to a Damped-Lyalpha (DLyalpha ) absorption line in the spectrum of the background QSO HS 1543+5921 (ze = 0.807). We obtain an accurate measure of the velocity of the H I gas in the LSB galaxy, v = 2868 km s-1, and derive a mas…
Mid-Infrared Observations of the Mira Circumstellar Environment
Fazio, Giovanni G.; Marengo, Massimo; Karovska, Margarita +4 more
This Letter presents results from high angular resolution mid-IR imaging of the Mira AB circumbinary environment using the Mid-InfraRed Array Camera MIRAC3 at the NASA Infrared Telescope Facility. We resolved the dusty circumstellar envelope at 9.8, 11.7, and 18 µm around Mira A (ο Ceti) and measured the size of the extended emission. Strong…
Field line diffusion in solar wind magnetic turbulence and energetic particle propagation across heliographic latitudes
Veltri, P.; Zimbardo, G.; Pommois, P.
The transport of energetic particles in the heliosphere is strongly influenced by the magnetohydrodynamic turbulence found in the solar wind. This turbulence causes a magnetic field line random walk, which can explain the Ulysses observations at high heliographic latitudes of particles accelerated at corotating interaction regions (CIRs). A three-…
Modeling the Interstellar Medium-Stellar Wind Interactions of λ Andromedae and ɛ Indi
Zank, Gary P.; Wood, Brian E.; Müller, Hans-Reinhard
A numerical study is presented of the interaction between the partially ionized interstellar medium (ISM) and the stellar wind of the very active RS CVn-type binary star λ And (G8 IV-III+?). Similar to results found for the heliosphere-ISM interaction, a termination shock, a tangential discontinuity (the ``astropause''), and a bow shock are found …
An HST Study of Jovian Chromophores
Simon-Miller, Amy A.; Gierasch, Peter J.; Banfield, Don
A principal components analysis was performed on Hubble Space Telescope WFPC2 images of Jupiter from October 1995 and October 1996. Global maps in the F410M, F555W, F673N, and F953N filters were analyzed. These are continuum wavelengths in Jupiter's spectrum, sensitive to reflection from the visible cloud deck. The primary principal components cor…
Chandra Detection of the Radio and Optical Double Hot Spot of 3C 351
Bondi, M.; Brunetti, G.; Comastri, A. +4 more
In this Letter, we report a Chandra X-ray detection of the double northern hot spot of the radio quasar 3C 351. The hot spot has also been observed in the optical with the Hubble Space Telescope (R band) and with the 3.5 m Telescopio Nazionale Galileo (B band). The radio-to-optical and X-ray spectra are interpreted as the results of the synchrotro…
Deep colour-magnitude diagrams of LMC field stars imaged with HST
Santiago, B. X.; Gilmore, G. F.; Johnson, R. A. +2 more
We present deep photometry (V<~26) in V and I bands obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope for 7 fields ~5° away from the Large Magellanic Cloud centre. The fields contain, typically, 2000 stars each. Isochrones were fitted to the colour-magnitude diagrams in order to identify different star popu…
Electron density variations during ultraviolet transient events
Doyle, J. G.; Madjarska, M. S.; Teriaca, L.
% High-resolution temporal observations performed with the SUMER spectrometer on SOHO provide an opportunity to investigate the electron density variations in the `quiet-Sun' solar transition region due to UV transient events. Two datasets obtained in the density sensitive lines belonging to the O iv 1400 Å multiplet were searched for such events,…
On the Evolution of the Solar Photospheric and Coronal Magnetic Field
Schrijver, Carolus J.; Handy, Brian N.
The Extreme Ultraviolet Imaging Telescope (EIT) and the Michelsen Doppler Imager (MDI) instruments on the Solar and Heliospheric Observatory (SOHO) ran a coordinated observing campaign over the dates 1997 August 10-14. MDI generated 1.2" resolution magnetograms (0.6" pixels) of the solar photosphere at a nominal cadence of one minute while EIT obs…