Search Publications
MERLIN Radio Detection of an Interaction Zone within a Binary Orion Proplyd System
O'Dell, C. R.; Henney, W. J.; Meaburn, J. +3 more
Presented here are high angular resolution MERLIN 5 GHz (6 cm) continuum observations of the binary proplyd system LV 1 in the Orion nebula, which consists of proplyd 168-326 SE and its binary proplyd companion 168-326 NW (separation 0.4"). Accurate astrometric alignment allows a detailed comparison between these data and published Hubble Space Te…
Temporal evolution of different temperature plasma during explosive events
Doyle, J. G.; Madjarska, M. S.
High cadence observations (10 s exposure time) obtained with the SUMER spectrometer on-board SoHO in the Ly 6 (20 000 K) and S VI (200 000 K) lines reveal new insight on the nature of explosive events. A time delay in the response of the S VI line with respect to the Ly 6 line has been observed, with the Ly 6 line responding with about 20-40 s ear…
New insights on the onsets of coronal mass ejections from soho
St. Cyr, O. C.; Plunkett, S. P.; Michels, D. J. +6 more
Coronal mass ejections (CMES) are among the most dramatic forms of transient activity occurring in the solar atmosphere. Despite over twenty years of research, many basic questions related to the physics of CMEs have remained unanswered. Observations with the LASCO and EIT experiments on SOHO, combined with recent theoretical modeling, have provid…
Is a Minor Merger Driving the Nuclear Activity in the Seyfert 2 Galaxy NGC 2110?
Arribas, Santiago; Heckman, Timothy; Pérez, Enrique +1 more
We report on a detailed morphological and kinematic study of the isolated nonbarred nearby Seyfert 2 galaxy NGC 2110. We combine integral field optical spectroscopy with long-slit and WFPC2 imaging available in the Hubble Space Telescope archive to investigate the fueling mechanism in this galaxy. Previous work (Wilson & Baldwin) concluded tha…
The nature of the X-ray transient SAX J1711.6-3808
Santos-Lleo, M.; Ubertini, P.; Bazzano, A. +8 more
SAX J1711.6-3808 is an X-ray transient in the Galactic bulge that was active from January through May of 2001 and whose maximum 1-200 keV luminosity was measured to be 5x 10-9 erg cm-2 s-1 which is less than ~ 25% of the Eddington limit, if placed at a distance equal to that of the galactic center. We study the X-r…
On the Recent History of Star Formation in the Blue Compact Dwarf Galaxy VII Zw 403
Tenorio-Tagle, G.; Muñoz-Tuñón, C.; Silich, S. +1 more
Here we attempt to infer the recent history of star formation in the BCD galaxy VII Zw 403, based on an analysis that accounts for the dynamics of the remnant generated either by an instantaneous burst or by a continuous star formation event. The models are restricted by the size of the diffuse X-ray-emitting region, the Hα luminosity from the sta…
STIS spectroscopy of newborn massive stars in SMC N81
Schaerer, D.; Martins, F.; Heydari-Malayeri, M. +2 more
Using Hubble Space Telescope observations with STIS, we study the main exciting stars of N81, a high excitation compact H II, region in the Small Magellanic Cloud (SMC). These far UV observations are the first spectroscopic measurements of stars in such a region and reveal features characteristic of an O6-O8 stellar type. The astonishing weakness …
Ultraviolet Imaging Polarimetry of the Seyfert 2 Galaxy Markarian 3
Cohen, Ross D.; Antonucci, Robert; Kishimoto, Makoto +3 more
We present ultraviolet (UV) imaging polarimetry data of the Seyfert 2 galaxy Mrk 3, taken by the Hubble Space Telescope. The polarized flux is found to be extended to ~1 kpc from the nucleus, and the position angles of polarization are centrosymmetric, confirming that the polarization is caused by scattering. We determine the location of the hidde…
The Extraordinary Cataclysmic Binary RU Pegasi: The Hottest White Dwarf in a Dwarf Nova?
Sion, Edward M.; Urban, Joel
We present the results of the first multicomponent synthetic spectral analysis of International Ultraviolet Explorer (IUE) archival spectra of the long-period dwarf nova RU Peg during quiescence. The best-fit, high-gravity, solar composition photosphere models yield Teff=50,000-53,000 K with scale factor distances of 250 pc. Optically t…
Evolution of a semicircular flux rope with two ends anchored in the photosphere
van Ballegooijen, A. A.; Lin, J.; Forbes, T. G.
We investigated a coronal magnetic configuration including a semicircular flux rope with two ends anchored in the photosphere. The background field is produced by two source regions on the photosphere. We study the evolution of this configuration in response to the gradual change in the background field, which is modeled by varying either the stre…