Search Publications
Escape of Lyα Emission in the Starburst Galaxy Markarian 357: a Wind's Far Side
Keel, William C.
Hubble Space Telescope imaging and slitless spectroscopy are used to examine where the strong Lyα emission escapes from the interstellar medium in the starburst galaxy Mrk 357. An Hα image shows that the ionized gas is mostly in a global wind, rather than associated with the individual star-forming regions seen in the optical and UV continuum. The…
Orbital period variation in close binaries from radial velocity data and magnetic activity cycles. II. HR 1099
Lanza, A. F.; Frasca, A.
We studied orbital period changes in the non-eclipsing close binary HR 1099, one of the most bright members of the RS CVn class of magnetically active binary systems. Intermediate-resolution optical spectroscopy and IUE archive spectra were used to build radial-velocity curves yielding epochs of superior conjunction with an accuracy of 0.01 days. …
High-resolution extreme ultraviolet spectroscopy of G191-B2B: structure of the stellar photosphere and the surrounding interstellar medium
Dreizler, S.; Barstow, M. A.; Hubeny, I. +8 more
We have continued our detailed analysis of the high-resolution (R= 4000) spectroscopic observation of the DA white dwarf G191-B2B, obtained by the Joint Astrophysical Plasmadynamic Experiment (J-PEX) normal incidence sounding rocket-borne telescope, comparing the observed data with theoretical predictions for both homogeneous and stratified atmosp…
PFS-MEX observation of ices in the residual south polar cap of Mars
Piccioni, G.; Hansen, G.; Grassi, D. +10 more
The Mars Express spacecraft has a highly inclined orbit around Mars and so has been able to observe the south pole of Mars in illuminated conditions at the end of the southern summer ( L=330). Spectra from the planetary Fourier spectrometer (PFS) short wavelength (SW) channel were recorded over the permanent ice cap to study its composition in ter…
A closer look at main belt asteroids 1: WF/PC images
Weiss, B. P.; Storrs, A. D.; Zellner, B. +3 more
We present new reconstructions of images of main belt Asteroids 9 Metis, 18 Melpomene, 19 Fortuna, 216 Kleopatra, and 624 Hektor, made with the uncorrected Wide-Field/Planetary Camera (WF/PC) on the Hubble Space Telescope (HST). Deconvolution with the MISTRAL algorithm demonstrates that these asteroids are clearly resolved. We determine diameters,…
An XMM-Newton Study of the Coronae of σ2 Coronae Borealis
Güdel, Manuel; Audard, Marc; Suh, Jin A. +1 more
We present results of XMM-Newton Guaranteed Time observations of the RS CVn binary σ2 Coronae Borealis. The spectra obtained with the Reflection Grating Spectrometers and the European Photon Imaging Camera MOS2 were simultaneously fitted with collisional ionization equilibrium plasma models to determine coronal abundances of various ele…
Low-energy absorption towards the ultra-compact X-ray binary 4U 1850-087 located in the globular cluster NGC 6712
Parmar, A. N.; Sidoli, L.; La Palombara, N. +1 more
We report the results of two XMM-Newton observations of the ultra-compact low-mass X-ray binary 4U 1850-087 located in the galactic globular cluster NGC 6712. A broad emission feature at 0.7 keV was detected in an earlier ASCA observation and explained as the result of an unusual Ne/O abundance ratio in the absorbing material local to the source. …
The Prominent Dust Emission Feature near 8.9 µm in Four H II Regions
Hayward, T. L.; Tielens, A. G. G. M.; Boogert, A. C. A. +2 more
We present a mid-infrared study of four H II regions based on the combination of Infrared Space Observatory (ISO) SWS observations with spatial information from SpectroCam-10 images and long-slit spectra. We report a prominent broad emission feature near 8.9 µm. The peak position and width of this feature do not resemble known polycyclic aro…
A statistical study of intense electric fields at 4-7 RE geocentric distance using Cluster
Buchert, S.; Karlsson, T.; Marklund, G. +3 more
Intense high-latitude electric fields (>150 mV/m mapped to ionospheric altitude) at 4 7 RE geocentric distance have been investigated in a statistical study, using data from the Cluster satellites. The orbit of the Cluster satellites limits the data collection at these altitudes to high latitudes, including the poleward part of the a…
Molecular Hydrogen in Orion as Observed by the Far Ultraviolet Spectroscopic Explorer
France, K.; McCandliss, S. R.
Diffuse far-ultraviolet stellar emission scattered by dust grains has been observed in a region near the Orion Nebula. In addition to the scattered stellar continuum, emission and absorption features produced by molecular hydrogen have been identified. In this Letter, we present an analysis of this absorption and fluorescent emission from molecula…