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Morphology and Kinematics of Planetary Nebulae. II. A Diabolo Model for NGC 3132
Morisset, C.; Monteiro, H.; Gruenwald, R. +1 more
We use a three-dimensional photoionization modeling tool to study the morphokinematic properties of the planetary nebula NGC 3132. We show that it is possible to reproduce the low-resolution observations (spectra and images) with an ellipsoidal shell. However, high-resolution observations, as those showing a density variation along the nebula and …
A Search for Rotational Modulation of X-Ray Centers on the Classical BE Star γ Cassiopeiae
Smith, Myron A.; Robinson, Richard D.
In this paper we discuss X-ray observations of γ Cas obtained in 1998 November with the Rossi X-Ray Timing Explorer (RXTE). The data were obtained nearly continuously over 54 hr, which is about twice the expected rotational period. An earlier RXTE light curve obtained in 1996 March over a 27 hr period showed X-ray flux arising from short-duration …
Solar energetic particle event and radio bursts associated with the 1996 July 9 flare and coronal mass ejection
Laitinen, T.; Torsti, J.; Klein, K. -L. +6 more
Using spaceborne particle and gamma-ray detection and radio diagnostics we study solar energetic particle (SEP) production in the 1996 July 9 event. This event is associated with an impulsive soft X-ray flare (9:10 UT) and a coronal mass ejection (CME). In a global classification the event is considered as mixed-impulsive. A sequence of accelerati…
Do All BA II Stars Have White Dwarf Companions?
Carpenter, Kenneth; Robinson, Richard; Böhm-Vitense, Erika +2 more
With the Hubble Space Telescope (HST) and the Goddard High Resolution Spectrograph (GHRS) we have observed four barium stars, three mild barium stars, and one weak G-band star in the ultraviolet spectral region. One barium star was observed with HST and the Space Telescope Imaging Spectrograph (STIS). The aim was to check the hypothesis that all t…
Non-equilibrium H_2 ortho-to-para ratio in two molecular clouds of the Galactic Center
Rodríguez-Fernández, N. J.; Martín-Pintado, J.; Fuente, A. +4 more
We present ISO observations of the S(0), S(1), S(2), and S(3) rotational lines of molecular hydrogen from two molecular clouds near the Galactic Center (GC). We have also measured continuum dust emission at infrared wavelengths with ISO and the rotational radio lines J=1-0 of 13CO and C18O and J=2-1 of C18O with th…
Detection of the Entropy of the Intergalactic Medium: Accretion Shocks in Clusters, Adiabatic Cores in Groups
Tozzi, Paolo; Norman, Colin; Scharf, Caleb
The thermodynamics of the diffuse, X-ray-emitting gas in clusters of galaxies is linked to the entropy level of the intracluster medium. In particular, models that successfully reproduce the properties of local X-ray clusters and groups require the presence of a minimum value for the entropy in the center of X-ray halos. Such a minimum entropy is …
First detections of FIRBACK sources with SCUBA
Clements, D. L.; Dole, H.; Lagache, G. +10 more
The FIRBACK (Far InfraRed BACKground) survey represents the deepest extensive 170 µm images obtained by the ISO satellite. The sources detected comprise about 10% of the Cosmic IR Background (CIB) seen by COBE, and, importantly, were observed at a wavelength near the peak of the CIB. Detailed follow-up of these sources should help pin down t…
Observations of the Trans-Neptunian Objects 1993 SC and 1996 TL66 with the Infrared Space Observatory
Jorda, L.; Rauer, H.; Keller, H. U. +7 more
Observations at 90 µm of the trans-Neptunian objects (TNOs), 1993 SC and 1996 TL66, using the Infrared Space Observatory (ISO) are reported. Five individual observations of 1993 SC were acquired giving a 2.7 σ detection (a confidence level of 99.6%). The signal level of 11.46+/-4.24 mJy has been modeled using a standard thermal mo…
Time Variability of Rotation in Solar Convection Zone From soi-mdi
Thompson, M. J.; Howe, R.; Christensen-Dalsgaard, J. +3 more
The variation of rotation in the convection zone over a period of two years from mid-1996 is studied using inversions of SOI-MDI data. We confirm the existence of near-surface banded zonal flows migrating towards the equator from higher latitudes, and reveal that these banded flows extend substantially beneath the surface, possibly to depths as gr…
The Tip of the Red Giant Branch Distance to the Large Magellanic Cloud
Zaritsky, Dennis; Sakai, Shoko; Kennicutt, Robert C., Jr.
We present the I-band luminosity function of the red giant branch stars in the Large Magellanic Cloud (LMC) using the data from the Magellanic Clouds Photometric Survey (MCPS). By selecting stars in uncrowded, low-extinction regions, we observe a discontinuity in the luminosity function at I0=14.54 mag. Identifying this feature with the…