Search Publications
Three-Dimensional Polarimetric Imaging of Coronal Mass Ejections
Davila, Joseph M.; Moran, Thomas G.
We present three-dimensional reconstructions of coronal mass ejections (CMEs), which were obtained through polarization analysis of single-view images recorded with the use of the Large Angle and Spectrometric Coronagraph (LASCO) C2 coronagraph on board the Solar and Heliospheric Observatory (SOHO) spacecraft. Analysis of a loop-like CME shows a c…
Evidence of Black Hole Spin in GX 339-4: XMM-Newton/EPIC-pn and RXTE Spectroscopy of the Very High State
Belloni, T.; Wijnands, R.; Fabian, A. C. +9 more
We have analyzed spectra of the Galactic black hole GX 339-4 obtained through simultaneous 76 ks XMM-Newton/EPIC-pn and 10 ks Rossi X-Ray Timing Explorer observations during a bright phase of its 2002-2003 outburst. An extremely skewed, relativistic Fe Kα emission line and ionized disk reflection spectrum are revealed in these spectra. Self-consis…
Detection of Lyman-α emission from a DLA galaxy: Possible implications for a luminosity-metallicity relation at z = 2-3
Fynbo, J. P. U.; Fall, S. M.; Møller, P.
In an ongoing programme to identify a sample of high z DLA galaxies we have found the long sought for case of a Lyα emitter seen in the centre of a broad DLA trough. This is the predicted ``textbook case'' of an intervening DLA galaxy if DLA galaxies are small, but would not be expected if intervening high redshift DLA galaxies have large gaseous …
Highly Ionized Gas Surrounding High-Velocity Cloud Complex C
Richter, Philipp; Tripp, Todd M.; Sembach, Kenneth R. +3 more
We present Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope observations of high-, intermediate-, and low-ion absorption in high-velocity cloud (HVC) Complex C along the lines of sight toward five active galaxies. Our purpose is to investigate the idea that Complex C is surrounded by an envelope of highly ionized material, arising…
Warm dust and aromatic bands as quantitative probes of star-formation activity
Förster Schreiber, N. M.; Roussel, H.; Sauvage, M. +1 more
We combine samples of spiral galaxies and starburst systems observed with ISOCAM on board ISO to investigate the reliability of mid-infrared dust emission as a quantitative tracer of star formation activity. The total sample covers very diverse galactic environments and probes a much wider dynamic range in star formation rate density than previous…
Comet nucleus size distributions from HST and Keck telescopes
Marsden, B. G.; Meech, K. J.; Hainaut, O. R.
The Wide Field Camera (WFC) on the Hubble Space Telescope and the Low Resolution Imaging Spectrograph (LRIS) on the Keck II telescope have been used to image 21 distant dynamically new, long-period (LP) and short-period (SP) Jupiter-family (JF) comet nuclei (near aphelion), as part of a long-term program to search for physical differences between …
Star Formation at z ~ 6: The Hubble Ultra Deep Parallel Fields
van Dokkum, P.; Bouwens, R. J.; Illingworth, G. D. +8 more
We report on the i-dropouts detected in two exceptionally deep Advanced Camera for Surveys fields (B435, V606, i775, and z850 with 10σ limits of 28.8, 29.0, 28.5, and 27.8, respectively) taken in parallel with the Ultra Deep Field Near-Infrared Camera and Multi-Object Spectrometer observations. Using an …
The Homogeneity of Interstellar Oxygen in the Galactic Disk
Meyer, David M.; Cartledge, Stefan I. B.; Lauroesch, J. T. +1 more
We present an analysis of high-resolution Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) observations of O I λ1356 and H I Lyα absorption in 36 sight lines that probe a variety of Galactic disk environments and include paths that range over nearly 4 orders of magnitude in f(H2), over 2 orders of magnitude in &l…
Hubble Space Telescope Observations of the White Dwarf Cooling Sequence of M4
Currie, Thayne; Rich, R. Michael; Gibson, Brad K. +7 more
We investigate in detail the white dwarf cooling sequence of the globular cluster Messier 4. In particular, we study the influence of various systematic uncertainties, both observational and theoretical, on the determination of the cluster age from the white dwarf cooling sequence. These include uncertainties in the distance to the cluster and the…
Orientation and propagation of current sheet oscillations
Sauvaud, J. -A.; Balogh, A.; Zhang, T. L. +6 more
Using the four-spacecraft Cluster system, we analyze rapid neutral sheet crossings near the Cluster apogee at about -18RE. In case studies of multiple oscillations of the locally quiet plasma sheet as well as in a statistical study of oscillations in dawn and dusk near-flank plasma sheet portions we typically obtain that locally these d…