Search Publications
ISO-SWS observations of interstellar solid 13CO2: heated ice and the Galactic 12C/13C abundance ratio
de Graauw, Th.; Prusti, T.; van Dishoeck, E. F. +7 more
We present observations of the stretching mode of 13CO_2 ice along 13 lines of sight in the Galaxy, using the Short Wavelength Spectrometer on board of the Infrared Space Observatory (ISO-SWS). Remarkable variations are seen in the absorption band profile in the different lines of sight. The main feature is attributed to 13CO…
Creating Spectral Templates from Multicolor Redshift Surveys
Dickinson, Mark; Budavári, Tamás; Csabai, István +2 more
Understanding how the physical properties of galaxies (e.g., their spectral type or age) evolve as a function of redshift relies on having an accurate representation of galaxy spectral energy distributions. While it has been known for some time that galaxy spectra can be reconstructed from a handful of orthogonal basis templates, the underlying ba…
Magnetic Geometry and Dynamics of the Fast Coronal Mass Ejection of 1997 September 9
Burkepile, J. T.; Chen, J.; Howard, R. A. +6 more
A coronal mass ejection (CME) was observed on 1997 September 9 by the Mauna Loa Solar Observatory Mark III K-coronameter (MK3) and by the LASCO C2/C3 and EIT instruments on board the SOHO spacecraft. Magnetograms and EIT images obtained on days leading up to the eruption show a neutral line that appears to correspond to the site of the eruption. T…
Molecular Gas, Dust, and Star Formation in the Barred Spiral NGC 5383
Sheth, Kartik; Vogel, Stuart N.; Regan, Michael W. +1 more
We have mapped the barred spiral NGC 5383 using the Berkeley-Illinois-Maryland Association millimeter-wave array for observations of CO (J=1-0), the Palomar 1.5 m telescope for Hα and optical broadband, and the Kitt Peak 1.3 m telescope for near-IR broadband. We compare the observed central gas and dust morphology to the predictions of recent hydr…
In Situ Dust Measurements From within the Coma of 1P/Halley: First-Order Approximation with a Dust Dynamical Model
Fulle, M.; Levasseur-Regourd, A. C.; McBride, N. +1 more
In situ measurements of the light locally scattered by cometary dust, as well as the local dust spatial density, are only available for one comet, 1P/Halley. These data were returned from the Optical Probe Experiment (OPE) and the Dust Impact Detection System (DID) aboard the European Space Agency spacecraft Giotto. Due to a detailed calibration o…
Physical Properties of the Nucleus of Comet 2P/Encke
Fernández, Yanga R.; Weaver, Harold A.; A'Hearn, Michael F. +6 more
We report a new study of the nucleus of Comet 2P/Encke, which the CONTOUR spacecraft is scheduled to encounter in November 2003. During the comet's close approach to Earth in July 1997, we measured the mid-infrared thermal and optical scattered continua with data from the TIMMI instrument (imaging) at the ESO 3.6-m telescope (wavelength λ from 8 t…
Age and metallicity gradients in the Galactic Bulge. A differential study using HST/WFPC2
Gilmore, G.; Feltzing, S.
The Galactic Bulge has long been assumed to be a largely old stellar population. However, some recent studies based on observations with the HST WF/PC-1 and WFPC2 of stars in the Galactic Bulge have concluded that the old population may not make up more then 30% of the total. Other studies using HST/WFPC2 differential studies of `Bulge' globular c…
Solar shear flows deduced from helioseismic dense-pack samplings of ring diagrams
Thompson, M. J.; Hill, F.; Toomre, J. +3 more
We report on large-scale horizontal flows in the solar convection zone and their variability in time and space using a local-helioseismology technique known as ring-diagram analysis. By performing this analysis on a dense mosaic of individual regions on the solar disk, i.e., a `Dense-Pack' sampling, and repeating the analysis periodically on sever…
Deep 10 and 18 Micron Imaging of the HR 4796A Circumstellar Disk: Transient Dust Particles and Tentative Evidence for a Brightness Asymmetry
Ghez, A. M.; Telesco, C. M.; Prato, L. +9 more
We present new 10.8 and 18.2 µm images of HR 4796A, a young A0 V star that was recently discovered to have a spectacular, nearly edge-on, circumstellar disk prominent at ~20 µm (Jayawardhana and coworkers; Koerner and coworkers). These new images, obtained with OSCIR (the University of Florida Observatory Spectrometer/Camera for the In…
SOHO and radio observations of a CME shock wave
St. Cyr, O. C.; Romoli, M.; Gopalswamy, Nat +7 more
A 1200 km s-1 Coronal Mass Ejection was observed with the SOHO instruments EIT, LASCO and UVCS on June 11, 1998. Simultaneously, Type II radio bursts were observed with the WAVES experiment aboard the Wind spacecraft at 4 MHz and by ground-based instruments at metric wavelengths. The density in the shock wave implied by the higher frequ…