Search Publications
On the X-Ray Source Luminosity Distributions in the Bulge and Disk of M31: First Results from the XMM-Newton Survey
Mason, Keith O.; Cordova, France A.; Trudolyubov, Sergey P. +2 more
We present luminosity distributions for the X-ray sources detected with XMM-Newton in the bulge and disk of the Andromeda galaxy (M31). The disk is clearly lacking the bright sources that dominate X-ray emission from the bulge. This is the first convincing evidence of a difference between bulge and disk X-ray populations in M31. Our results are in…
An Upper Limit on the Temporal Variations of the Solar Interior Stratification
Eff-Darwich, A.; Korzennik, S. G.; Jiménez-Reyes, S. J. +1 more
We have analyzed changes in the acoustic oscillation eigenfrequencies measured over the past 7 years by the GONG, MDI, and LOWL instruments. The observations span the period from 1994 to 2001 that corresponds to half a solar cycle, from minimum to maximum solar activity. These data were inverted to look for a signature of the activity cycle on the…
Discovery of an Old, Nearby, and Overlooked Supernova Remnant Centered on the Southern Constellation Antlia Pneumatica
McCullough, P. R.; Fields, Brian D.; Pavlidou, Vasiliki
We report the discovery of a supernova remnant (SNR) with an angular diameter of 24°, centered on the southern constellation Antlia Pneumatica. The SNR is detected well in Hα and X-rays. Within the Antlia SNR's outline, a marginally significant feature is detected in the 1.8 MeV gamma-ray line of the radioisotope 26Al. At an estimated d…
The O I Line Emission in Active Galactic Nuclei Revisited
Pastoriza, M. G.; Prato, L.; Rodríguez-Ardila, A. +2 more
UV, visible, and near-infrared spectroscopy is used to study the transitions of neutral oxygen leading to the emission of broad O I λ8446, λ11287, and λ1304 in active galactic nuclei. From the strength of the former two lines, contrary to the general belief, we found that in six of seven galaxies, Lyβ fluorescence is not the only mechanism respons…
Polar Coronal Jets at Solar Minimum
Gurman, J. B.; Raymond, J. C.; Dobrzycka, D. +2 more
We present an analysis of six polar coronal jets observed by the Ultraviolet Coronagraph Spectrometer (UVCS) at solar minimum (1996). Four of the events were also recorded by the Extreme-Ultraviolet Imaging Telescope (EIT) and/or the Large Angle Spectrometric Coronagraph (LASCO) C2 coronagraph. We compared the jets with others recorded in 1997. We…
Searching for the Signature of the Magnetic Fields at the Base of the Solar Convection Zone with Solar Cycle Variations of p-Mode Travel Time
Chou, Dean-Yi; Serebryanskiy, Alexander
We study the solar cycle variations of the solar p-mode travel time for different wave packets to probe the magnetic fields at the base of the solar convection zone. We select the wave packets that return to the same spatial point after traveling around the Sun with integral number of bounces. The change in one-bounce travel time at solar maximum …
Temperature and Density Measurements in a Quiet Coronal Streamer
Warren, Harry P.; Warshall, Andrew D.
Many previous studies have used emission line or broadband filter ratios to infer the presence of temperature gradients in the quiet solar corona. Recently it has been suggested that these temperature gradients are not real, but result from the superposition of isothermal loops with different temperatures and density scale heights along the line o…
The Binary Central Star of the Planetary Nebula A35
Bianchi, L.; Herald, J. E.
Using new Far Ultraviolet Spectroscopic Explorer (FUSE) observations in conjunction with Space Telescope Imaging Spectrograph (STIS) and International Ultraviolet Explorer archive data, we have modeled both components of the binary central star of the planetary nebula A35. The white dwarf (the ionizing star) was modeled using the non-LTE, plane-pa…
Extragalactic Globular Cluster Planetary Nebulae: Discovery of a Planetary Nebula in the NGC 5128 Globular Cluster G169 Using the Magellan I Baade Telescope
Minniti, Dante; Rejkuba, Marina
We report the discovery of a planetary nebula in the globular cluster G169 of the giant elliptical galaxy NGC 5128, based on spectroscopy with the Magellan I Baade 6.5 m telescope at Las Campanas Observatory. G169 appears to be a typical metal-rich globular cluster in NGC 5128 with MV=-8.2. Its planetary nebula also appears to be a typi…
Detailed Analysis of Nearby Bulgelike Dwarf Stars. I. Stellar Parameters, Kinematics, and Oxygen Abundances
Barbuy, Beatriz; Pompéia, Luciana; Grenon, Michel
High-resolution échelle spectra were obtained with the Fiber-fed Extended Range Optical Spectrograph at the 1.5 m ESO telescope for 35 nearby bulgelike stars with metallicities in the range -0.8<=[Fe/H]<=+0.4. Geneva photometry, astrometric data from Hipparcos, and radial velocities from CORAVEL are available for these stars. From Hipparcos …