Search Publications
Angular Momentum Transport and Proton-Alpha-Particle Differential Streaming in the Solar Wind
Li, Xing; Habbal, Shadia Rifai; Li, Bo
The interplay between the proton-alpha-particle differential flow speed, vαp, and angular momentum transport in the solar wind is explored by using a three-fluid model. The force introduced by the azimuthal components is found to play an important role in the force balance for ions in interplanetary space, bringing the radial flow speed…
The Wind-ISM Interaction of α Tauri
Zank, Gary P.; Harper, Graham M.; Wood, Brian E. +2 more
Ultraviolet spectra of α Tau (K5 III) obtained by the Hubble Space Telescope (HST) show many emission lines affected by broad absorption from the strong wind of this red giant star. For the Mg II h and k lines there is also a narrow absorption feature in the midst of the wind absorption that has been interpreted as being from α Tau's wind-interste…
Analysis of Erupting Solar Prominences in Terms of an Underlying Flux-Rope Configuration
Sterling, Alphonse C.; Krall, Jonathan
Data from four solar prominence eruptions are analyzed so as to examine the flux-rope configuration at the onset of eruption and to test specific aspects of an analytic flux-rope model of solar eruptions. The model encompasses both prominence eruptions and coronal mass ejections (CMEs) as generic elements of a typical erupting flux-rope structure.…
Broadening of Resonantly Scattered Ultraviolet Emission Lines by Coronal Hole Outflows
Akinari, Nakagawa
Measurements by the Ultraviolet Coronagraph Spectrometer on board the Solar and Heliospheric Observatory have revealed that the widths of several ultraviolet emission lines are unexpectedly large in solar coronal holes. Here we investigate the line-broadening mechanisms for resonantly scattered emissions, which constitute the major part of the cor…
Jets or High-Velocity Flows Revealed in High-Cadence Spectrometer and Imager Co-observations?
Doyle, J. G.; Madjarska, M. S.; Curdt, W. +1 more
We report on active region EUV dynamic events observed simultaneously at high cadence with SOHO SUMER and TRACE. Although the features appear in the TRACE Fe IX/X 171 Å images as jets seen in projection on the solar disk, the SUMER spectral line profiles suggest that the plasma has been driven along a curved large-scale magnetic structure, a preex…
Fourier-Resolved Spectroscopy of Active Galactic Nuclei Using XMM-Newton Data. I. The 3-10 keV Band Results
Papadakis, I. E.; Kazanas, D.; Ioannou, Z.
We present the results from Fourier-resolved spectroscopy of archival XMM-Newton data of five AGNs, namely, Mrk 766, NGC 3516, NGC 3783, NGC 4051, and Ark 564. This work supplements an earlier study of MCG -6-30-15 and of several Galactic black hole candidate sources. Our results exhibit much larger diversity than for Galactic sources, a fact we a…
Constraining the Fundamental Parameters of the O-Type Binary CPD -41 7733
Gosset, E.; Rauw, G.; Sana, H.
Using a set of high-resolution spectra, we studied the physical and orbital properties of the O-type binary CPD -41 7733, located in the core of NGC 6231. We report the unambiguous detection of a secondary spectral signature and we derive the first SB2 orbital solution of the system. The period is 5.6815+/-0.0015 days, and the orbit has no signifi…
Solar Cycle Variation of Real CME Latitudes
Feng, Xueshang; Song, Wenbin; Hu, Yanqi
With the assumption of radial motion and uniform longitudinal distribution of coronal mass ejections (CMEs), we propose a method to eliminate projection effects from the apparent observed CME latitude distribution. This method has been applied to SOHO LASCO data from 1996 January to 2006 December. As a result, we find that the real CME latitude di…
Super Star Cluster NGC 1705-1: A Local Analog to the Birth Site of Long-Duration γ-Ray Bursts
Chen, Hsiao-Wen; Bloom, Joshua S.; Prochaska, Jason X.
Recent observations suggest that global properties of the host galaxies for long-duration γ-ray bursts (GRBs) are particularly well suited for creating the massive star progenitors of these GRBs. Motivated by the hypothesis that massive young star clusters located in metal-poor, low-metallicity galaxies are a natural birth site for GRB progenitors…
Damp Mergers: Recent Gaseous Mergers without Significant Globular Cluster Formation?
Forbes, Duncan A.; Brodie, Jean P.; Strader, Jay +1 more
Here we test the idea that new globular clusters (GCs) are formed in the same gaseous (``wet'') mergers or interactions that give rise to the young stellar populations seen in the central regions of many early-type galaxies. We compare mean GC colors with the age of the central galaxy starburst. The red GC subpopulation reveals remarkably constant…