Search Publications
Monte Carlo Simulation of Directivity of Interplanetary Radio Bursts
MacDowall, R. J.; Kaiser, M. L.; Thejappa, G.
We have developed a Monte Carlo simulation code to study the effects of refraction due to spatial variation of the solar wind density and scattering due to random density fluctuations on directivities, time profiles, and sizes and positions of the apparent sources of the interplanetary type II and type III radio bursts excited at the fundamental (…
A Streamer Ejection with Reconnection Close to the Sun
Warren, H. P.; Sheeley, N. R., Jr.; Wang, Y. -M.
We previously described coronal events that expand gradually outward over an interval of 1-2 days and then suddenly tear apart in the coronagraph's 2-6 Rsolar field of view to form an outgoing flux rope and an inward system of collapsing loops. Now, we combine LASCO white-light images of the outer corona with spectrally resolved EIT ima…
Deviations from He I Case B Recombination Theory and Extinction Corrections in the Orion Nebula
Martin, P. G.; Blagrave, K. P. M.; Dufour, R. J. +4 more
We are engaged in a comprehensive program to find reliable elemental abundances in and probe the physical structure of the Orion Nebula, the brightest and best-resolved H II region. In the course of developing a robust extinction correction covering our optical and UV FOS and STIS observations, we examined the decrement within various series of He…
The Width of a Solar Coronal Mass Ejection and the Source of the Driving Magnetic Explosion: A Test of the Standard Scenario for CME Production
Moore, Ronald L.; Sterling, Alphonse C.; Suess, Steven T.
We show that the strength (BFlare) of the magnetic field in the area covered by the flare arcade following a CME-producing ejective solar eruption can be estimated from the final angular width (Final θCME) of the CME in the outer corona and the final angular width (θFlare) of the flare arcade: BFlare~1.4…
Calibration of Seismic Signatures of Active Regions on the Far Side of the Sun
Hill, F.; Lindsey, C.; González Hernández, I.
Synoptic maps of the far hemisphere of the Sun calculated from seismic holography have proven to be very reliable in localizing large active regions before they rotate onto the visible hemisphere. We show here the first results toward a calibration of the far-side signatures of active regions in terms of active region size and magnetic field stren…
Phase-resolved Spectroscopy of the Vela Pulsar with XMM-Newton
Caraveo, P. A.; De Luca, A.; Manzali, A.
The ~104 yr old Vela Pulsar represents the bridge between the young Crab-like and the middle-aged rotation-powered pulsars. Its multiwavelength behavior is due to the superposition of different spectral components. We take advantage of the unprecedented harvest of photons collected by XMM-Newton to assess the Vela Pulsar spectral shape …
Quiet-Sun Magnetic Fields from Space-borne Observations: Simulating Hinode's Case
Bellot Rubio, L. R.; del Toro Iniesta, J. C.; Orozco Suárez, D.
We examine whether it is possible to derive the field strength distribution of quiet-Sun internetwork regions from very high spatial resolution polarimetric observations in the visible. In particular, we consider the case of the spectropolarimeter attached to the Solar Optical Telescope aboard Hinode. Radiative magnetoconvection simulations are us…
The Fourth Positive System of Carbon Monoxide in the Hubble Space Telescope Spectra of Comets
Weaver, Harold A.; Feldman, Paul D.; Lupu, Roxana E. +1 more
The rich A1Π-X1Σ+ system of carbon monoxide accounts for most spectral features seen in long-slit HST STIS observations of comets 153P/Ikeya-Zhang, C/2001 Q4 (NEAT), and C/2000 WM1 (LINEAR), as well as in the HST GHRS spectrum of comet C/1996 B2 (Hyakutake). A detailed CO fluorescence model is developed …
X-Ray, UV, and Optical Observations of Supernova 2006bp with Swift: Detection of Early X-Ray Emission
Campana, S.; Pian, E.; Greiner, J. +21 more
We present results on the X-ray and optical/UV emission from the Type II-P supernova (SN) 2006bp and the interaction of the SN shock with its environment, obtained with the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) on board Swift. SN 2006bp is detected in X-rays at a 4.5 σ level of significance in the merged XRT data from days 1 to 12 …
Spectral Evolution of NGC 1313 X-2: Evidence against the Cool Disk Model
Feng, Hua; Kaaret, Philip
The presence of a cool multicolor disk component with an inner disk temperature kT=~0.1-0.3 keV at a luminosity L>1040 ergs s-1 has been interpreted as evidence that the ultraluminous X-ray source NGC 1313 X-2 harbors an intermediate-mass black hole (IMBH). The temperature of a disk component should vary with luminosity as…