Search Publications
Missions
Journals
Publication Years
Dust Spirals and Acoustic Noise in the Nucleus of the Galaxy NGC 2207
Elmegreen, B. G.; Brinks, E.; Elmegreen, D. M. +6 more
Observations with the Hubble Space Telescope reveal an irregular network of dust spiral arms in the nuclear region of the interacting disk galaxy NGC 2207. The spirals extend from ~50 to ~300 pc in galactocentric radius, with a projected width of ~20 pc. Radiative transfer calculations determine the gas properties of the spirals and the inner disk…
The ISO-SWS 2.4-45.2 Micron Spectrum Toward Orion IR c2
Cernicharo, José; Vandenbussche, Bart; van Dishoeck, Ewine F. +4 more
The complete infrared spectrum from 2.4 to 45.2 µm toward the prototypical massive star-forming region Orion IRc2 is presented, obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO) at a resolving power λ/Δλ~1300-2500. A wealth of emission and absorption features is found, including H2…
Infrared array photometry of bulge globular clusters. I. Combined ground based JK and HST VI photometry of NGC 6553
Moneti, A.; Montegriffo, P.; Bica, E. +4 more
JK infrared photometry for the bulge globular cluster NGC 6553, combined with high resolution visual VI observations are presented and discussed in connection with the bulge metal rich population. The infrared data were taken with IRAC2 at ESO 2.2m telescope while the optical counterparts are from Hubble Space Telescope (HST). We find a mean magni…
HIPPARCOS and the age of the Galactic disc
Jimenez, Raul; Flynn, Chris; Kotoneva, Eira
We use the Hipparcos colour-magnitude diagram of field stars with Tycho colours to make a new minimum age estimate for the Galactic disc. The method is based on fits to the red envelope of subgiants in the Hipparcos colour-magnitude diagram with synthetic isochrones covering the range of disc metal abundance. The colours and luminosities of the is…
Boron in Very Metal Poor Stars
Lambert, David L.; Edvardsson, Bengt; Rebolo, Rafael +3 more
We have observed the B I 2497 A line to derive the boron abundances of two very metal-poor stars selected to help in tracing the origin and evolution of this element in the early Galaxy: BD +23 3130 and HD 84937. The observations were conducted using the Goddard High Resolution Spectrograph on board the Hubble Space Telescope. A very detailed abun…
Hubble Space Telescope WFPC2 Color-Magnitude Diagrams of Halo Globular Clusters in M33: Implications for the Early Formation History of the Local Group
Sarajedini, Ata; Schommer, Robert; Geisler, Doug +1 more
We have constructed color-magnitude diagrams for 10 globular clusters in the halo of the nearby spiral galaxy M33 based on Hubble Space Telescope Wide Field Planetary Camera 2 observations in the F555W (~V) and F814W (~I) filters. These data reveal the morphology of the horizontal branch (HB) and allow us to estimate the cluster metallicity using …
The solar origin of the January 1997 coronal mass ejection, magnetic cloud and geomagnetic storm
St. Cyr, O. C.; Webb, D. F.; Gopalswamy, N. +2 more
The magnetic cloud and geomagnetic storm on January 10-11, 1997 were associated with a halo-type Coronal Mass Ejection (CME) observed by the SOHO/LASCO coronagraphs near the sun on January 6. We summarize the solar activity related to this CME and the subsequent storm at Earth. This solar activity was remarkably weak and unimpressive. If the wide …
Anomalous Cooling of the Massive White Dwarf in U Geminorum Following a Narrow Dwarf Nova Outburst
Szkody, Paula; Sion, Edward M.; Cheng, F. H. +4 more
We obtained Hubble Space Telescope Goddard High-Resolution Spectrograph medium-resolution (G160M grating), phase-resolved spectroscopic observations of the prototype dwarf nova U Geminorum during dwarf nova quiescence, 13 days and 61 days following the end of a narrow outburst. The spectral wavelength ranges were centered on three different line r…
HST/GHRS observations of AM Herculis
Gänsicke, B. T.; Beuermann, K.; Szkody, P. +2 more
We present phase-resolved spectroscopy of AM Herculis obtained with the HST/GHRS when the system was in a high state. The ultraviolet light curve shows a quasi-sinusoidal modulation, which can be explained by a hot spot on the rotating white dwarf. The broad Lyalpha absorption expected for photospheric radiation of a moderately hot white dwarf is …
The Hot Stars of Old Open Clusters: M67, NGC 188, and NGC 6791
O'Connell, Robert W.; Bohlin, Ralph C.; Landsman, Wayne +4 more
We analyze ultraviolet (~1500 Å) images of the old open clusters M67, NGC 188, and NGC 6791 obtained with the Ultraviolet Imaging Telescope (UIT) during the second flight of the Astro observatory in 1995 March. Twenty stars are detected on the UIT image of M67, including 11 blue stragglers, seven white dwarf candidates, and the yellow giant-white …