Search Publications
ISO Spectroscopy of Gas and Dust: From Molecular Clouds to Protoplanetary Disks
van Dishoeck, Ewine F.
Observations of interstellar gas-phase and solid-state species in the 2.4 200 m range obtained with the spectrometers on board the Infrared Space Observatory (ISO) are reviewed. Lines and bands caused by ices, polycyclic aromatic hydrocarbons, silicates, and gas-phase atoms and molecules (in particular H2, CO, H2O, OH, and CO…
Intensity variation of large solar energetic particle events associated with coronal mass ejections
Krucker, S.; Howard, R. A.; Gopalswamy, N. +2 more
We studied the coronal mass ejections (CMEs) and flares associated with large solar energetic particle (SEP) events of solar cycle 23 (1996-2002) in order to determine what property of the solar eruptions might order the SEP intensity. The SEP events were divided into three groups: (1) events in which the primary CME was preceded by one or more wi…
Observations and Modeling of a Filament on the Sun
van Ballegooijen, A. A.
Hα observations of a filament were obtained at the Swedish Vacuum Solar Telescope in 1998 June. The U-shaped filament has a prominent barb that exhibits interesting fine structure and internal motions. A three-dimensional magnetic model of the filament is presented. The model is based on a National Solar Observatory (Kitt Peak) magnetogram and is …
Color-selected Galaxies at z ~ 6 in the Great Observatories Origins Deep Survey
Stern, D.; Dickinson, M.; Ferguson, H. C. +15 more
We report early results on galaxies at z~6 selected from Hubble Space Telescope imaging for the Great Observatories Origins Deep Survey. Spectroscopy of one object with the Advanced Camera for Surveys grism and from the Keck and Very Large Telescope observatories shows a strong continuum break and asymmetric line emission, identified as Lyα at z=5…
The Profiles of the 3-12 Micron Polycyclic Aromatic Hydrocarbon Features
Hony, S.; Tielens, A. G. G. M.; Allamandola, L. J. +4 more
We present spectra of the 3.3 µm and 11.2 µm polycyclic aromatic hydrocarbon (PAH) features of a large number of stellar sources, planetary nebulae, reflection nebulae, H II regions, and galaxies, obtained with Infrared Space Observatory Short Wavelength Spectrometer. Clear variations are present in the profiles of these features. Most…
Polycyclic Aromatic Hydrocarbon Contribution to the Infrared Output Energy of the Universe at z ~= 2
Le Floc'h, E.; Dole, H.; Lagache, G. +10 more
We present an updated phenomenological galaxy evolution model to fit the Spitzer 24, 70, and 160 µm number counts, as well as all the previous mid- and far-infrared observations. Only a minor change of the comoving luminosity density distribution in the previous model (Lagache, Dole, & Puget), combined with a slight modification of the s…
XMM-Newton Observation of Solar Wind Charge Exchange Emission
Kuntz, K. D.; Snowden, S. L.; Collier, M. R.
We present an XMM-Newton spectrum of diffuse X-ray emission from within the solar system. The spectrum is dominated by probable C VI lines at 0.37 and 0.46 keV, an O VII line at 0.56 keV, O VIII lines at 0.65 and ~0.8 keV, Ne IX lines at ~0.92 keV, and Mg XI lines at ~1.35 keV. This spectrum is consistent with that expected from charge exchange em…
Emergence of magnetic flux from the convection zone into the corona
O'Shea, E.; Galsgaard, K.; Moreno-Insertis, F. +2 more
Numerical experiments of the emergence of magnetic flux from the uppermost layers of the solar interior to the photosphere and its further eruption into the low atmosphere and corona are carried out. We use idealized models for the initial stratification and magnetic field distribution below the photosphere similar to those used for multidimension…
XMM-Newton EPIC observations of 21 low-redshift PG quasars
Porquet, D.; Reeves, J. N.; Brinkmann, W. +1 more
We present an X-ray spectral analysis of 21 low redshift quasars observed with XMM-Newton EPIC. All the sources are Palomar Green quasars with redshifts between 0.05 and 0.4 and have low Galactic absorption along the line-of-sight. A large majority of quasars in the sample (19/21) exhibit a significant soft excess below ∼1-1.5 keV, whilst two obje…
Perennial water ice identified in the south polar cap of Mars
Sotin, C.; Drossart, Pierre; Forni, O. +39 more
The inventory of water and carbon dioxide reservoirs on Mars are important clues for understanding the geological, climatic and potentially exobiological evolution of the planet. From the early mapping observation of the permanent ice caps on the martian poles, the northern cap was believed to be mainly composed of water ice, whereas the southern …