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A Relationship Between Transition Region Brightenings, Abundances, and Magnetic Topology
Fletcher, Lyndsay; Young, Peter R.; Schmieder, Brigitte +5 more
We present multi-instrument observations of active region (AR) 8048, made between 3 June and 5 June 1997, as part of the SOHO Joint Observing Program 33. This AR has a sigmoid-like global shape and undergoes transient brightenings in both soft X-rays and transition region (TR) lines. We compute a magneto-hydrostatic model of the AR magnetic field,…
Large scale ionization of the Radio Arc region by the Quintuplet and the Arches clusters
Rodríguez-Fernández, N. J.; Martín-Pintado, J.; de Vicente, P.
We present an analysis of selected fine structure lines (Ne Ii 12.8 mu m, Ne IiI 15.6 mu m, S Iii 18.7 and 33.5 mu m, O Iii 52 and 88 mu m, N Ii 122 mu m and N IiI 57 mu m) observed with the Infrared Space Observatory (ISO) toward the Radio Arc in the Galactic center region (GCR). Most of the data were retrieved from the ISO Data Archive. We study…
Photoevaporating Flows from the Cometary Knots in the Helix Nebula (NGC 7293)
Henney, W. J.; Raga, A. C.; López-Martín, L. +2 more
We explain the Hα emission of the cometary knots in the Helix Nebula (NGC 7293) with an analytical model that describes the emission of the head of the globules as a photoevaporated flow produced by the incident ionizing radiation of the central star. We compare these models with the Hα emission obtained from the Hubble Space Telescope (HST) archi…
Interpretation of coronal off-limb spectral line width measurements
Moran, T. G.
Spectral line widths measured above the solar limb have been used to infer wave velocity amplitude height dependencies, supporting Alfven wave coronal heating and wave driven solar wind models. Comparison of the inferred amplitude/density dependence with a constant magnetic field strength, undamped wave propagation model have shown good agreement,…
Simultaneous XMM-Newton and BeppoSAX observation of the Seyfert I galaxy IC 4329A
Gondoin, P.; Parmar, A. N.; Oosterbroek, T. +3 more
We report on a simultaneous XMM-Newton and BeppoSAX observation of the Seyfert 1 galaxy IC 4329A performed in 2001 January. Above 1 keV, EPIC spectra show a narrow Fe K emission line at 6.42+0.04-0.03 keV with an equivalent width of 43+/-1 eV. An absorption edge is detected at 7.1+/-0.4 keV in the source rest frame that has n…
EPIC Simulations of Bright Companions to Neptune's Great Dark Spots
Sromovsky, L. A.; Showman, A. P.; Dowling, T. E. +1 more
We present a three-dimensional model of the bright companion clouds associated with Neptune's Great Dark Spots (GDSs). Our results support the hypothesis that the bright companions of the southern-hemisphere GDS discovered in 1989 and of the northern-hemisphere GDS discovered in 1994 are methane clouds that form at or just below the tropopause and…
When Did the Hubble Sequence Appear?: Morphology, Color, and Number-Density Evolution of the Galaxies in the Hubble Deep Field North
Yamada, Toru; Kajisawa, Masaru
Using the HST WFPC2/NICMOS archival data of the Hubble Deep Field North, we constructed a nearly complete sample of the MV < -20 (~ L* + 1) galaxies to z = 2, and investigate when the Hubble sequence appeared, namely, the evolution of the morphology, colors, and the comoving number density of the sample. Even if taking int…
Infrared Space Observatory Spectra of R Coronae Borealis Stars. I. Emission Features in the Interval 3-25 Microns
Rao, N. Kameswara; Lambert, David L.; Pandey, Gajendra +1 more
Infrared Space Observatory 3-25 µm spectra of the R Coronae Borealis stars V854 Cen, R CrB, and RY Sgr are presented and discussed. Sharp emission features coincident in wavelength with the well-known unidentified emission features are present in the spectrum of V854 Cen but not in the spectra of R CrB and RY Sgr. Since V854 Cen is not parti…
Coronal Inflows and Sector Magnetism
Sheeley, N. R., Jr.; Wang, Y. -M.
We have remeasured the rate of coronal inflows during 1996-2001, taking into account multiple occurrences per day, and have displayed the results in Carrington stack plots to study their long-term behavior. The stack plots show long-lived recurrence patterns related to the sectorial component of the Sun's large-scale field. In particular, most inf…
A 2000 Kilometer per Second ``Pristine'' Post-asymptotic Giant Branch Wind in the Proto-planetary Nebula He 3-1475
Sahai, R.; Sánchez Contreras, C.
We analyze (archival) Space Telescope Imaging Spectrograph long-slit Hα spectra of the proto-planetary nebula He 3-1475. We find two remarkable blueshifted absorption features arising from the inner ~5×1016 cm of the nebula, revealing the presence of two different winds outflowing at high velocity from the central star. The kinematic ag…