Search Publications
The interstellar N2 abundance towards HD 124314 from far-ultraviolet observations
Andersson, B. -G.; McCandliss, Stephan R.; Knauth, David C. +1 more
The abundance of interstellar molecular nitrogen (N2) is of considerable importance: models of steady-state gas-phase interstellar chemistry, together with millimetre-wavelength observations of interstellar N2H+ in dense molecular clouds predict that N2 should be the most abundant nitrogen-bearing molecu…
Coronal plasma flows and magnetic fields in solar active regions. Combined observations from SOHO and NSO/Kitt Peak
Marsch, E.; Xia, L. D.; Wiegelmann, T.
During the early days of the SOHO mission, SUMER observed a few active regions (ARs) connected with sunspots on the Sun and took their images and spectra in various EUV emission lines. In addition to these spectroscopic data magnetograms of the photospheric footpoint regions of the AR loops were available from the MDI on SOHO and the National Sola…
X-ray reprocessing in Seyfert galaxies: Simultaneous XMM-Newton/BeppoSAX observations
Perola, G. C.; Bianchi, S.; Guainazzi, M. +2 more
We selected a sample of eight bright unobscured (at least at the iron line energy) Seyfert galaxies observed simultaneously by XMM-Newton and BeppoSAX, taking advantage of the complementary characteristics of the two missions. The main results of our analysis can be summarized as follows: narrow neutral iron lines are confirmed to be an ubiquitous…
Dawn: A journey in space and time
Russell, C. T.; Jaumann, R.; Keller, H. U. +18 more
By successively orbiting both 4 Vesta and 1 Ceres the Dawn mission directly addresses the long-standing goals of understanding the origin and evolution of the solar system. Ceres and Vesta are two complementary terrestrial protoplanets (one apparently ;wet; and the other ;dry;), whose accretion was probably terminated by the formation of Jupiter. …
Going Slitless: Images of Forbidden-Line Emission Regions of Classical T Tauri Stars Observed with the Hubble Space Telescope
Edwards, Suzan; Hartigan, Patrick; Pierson, Rachel
We have observed five classical T Tauri stars known to have strong forbidden-line emission with STIS in slitless mode on the Hubble Space Telescope. This technique makes it possible to image jets within a few tens of AU of their exciting sources, a region of great interest for models of accretion disks and jets. Slitless images generate emission-l…
Imaging of the Supernova Remnant Cassiopeia A with the Multiband Imaging Photometer for Spitzer (MIPS)
Egami, E.; Gehrz, R. D.; Krause, O. +20 more
We present new images of the supernova remnant (SNR) Cas A observed in the 24 and 70 µm bands of the Spitzer Space Telescope (Spitzer). The IR emission correlates well with the Si X-ray and optical [S II] emission but poorly with either the synchrotron-dominated radio structure or the continuum X-ray emission. The IR is therefore dominated b…
Deuterated Interstellar Polycyclic Aromatic Hydrocarbons
Tielens, A. G. G. M.; Allamandola, L. J.; Peeters, E. +3 more
We report infrared spectral evidence of deuterated interstellar polycyclic aromatic hydrocarbons (PAHs). Two bands are detected in the infrared emission from the ionization bar in Orion at 4.4 and 4.65 µm. The one at 4.65 µm is present at the 4.4 σ level, while the one at 4.4 µm is more tentative, with a σ equal to 1.9. An emissi…
First determination of the dynamical mass of a binary L dwarf
Duchêne, G.; Martín, E. L.; Bouy, H. +11 more
We present here the results of astrometric, photometric and spectroscopic observations leading to the determination of the orbit and dynamical masses of the binary L dwarf 2MASSW J0746425+2000321. High angular resolution observations spread over almost 4 years and obtained with the Hubble Space Telescope (HST), the ESO Very Large Telescope (VLT), …
A Very Low Luminosity X-Ray Flash: XMM-Newton Observations of GRB 031203
Watson, D.; O'Brien, P. T.; Reeves, J. N. +9 more
GRB 031203 was observed by XMM-Newton twice, first with an observation beginning 6 hr after the burst and again after 3 days. The afterglow had average 0.2-10.0 keV fluxes for the first and second observations of (4.2+/-0.1)×10-13 and (1.8+/-0.1)×10-13 ergs cm-2 s-1, respectively, decaying very slowly ac…
Chandra Observations of the X-Ray Environs of SN 1998bw/GRB 980425
Pian, E.; Kouveliotou, C.; Wijers, R. A. M. J. +8 more
We report X-ray studies of the environs of SN 1998bw and GRB 980425 using the Chandra X-Ray Observatory 1281 days after the gamma-ray burst (GRB). Eight X-ray point sources were localized, three and five each in the original error boxes, S1 and S2, assigned for variable X-ray counterparts to the GRB by BeppoSAX. The sum of the discrete X-ray sourc…