Search Publications
Programs for laser-AO assisted integral-field spectrometers on ionized flows
Cecil, Gerald
An AO-assisted integral-field spectrograph is becoming the most efficient tool with which to explore ionized gas outflows. It maps faint spectral lines that diagnose cloud dust content, gas pressure, excitation mechanism, and chemical abundances. Coupled with recent improvements in photoionization models, the total mass hence flow energetics can b…
Establishing Observational Baselines for Two δ Scuti Variables: V966 Herculis and V1438 Aquilae
Hintz, Eric G.; Rose, Michael B.; Bush, Tabitha C. +1 more
We have examined the previously understudied δ Scuti stars V966 Herculis and V1438 Aquilae. We find that V966 Her is a stable pulsator with a refined period of 0.1330302 days with a full V amplitude of 0.096 mag. We also find that V966 Her has an average radial velocity of +7.8 km s-1, a full radial velocity amplitude of 7.6 km s-1…
On the variability of Saturn's equatorial jet at cloud top level
Hueso, R.; Sánchez-Lavega, A.; Pérez-Hoyos, S.
Saturn's Equatorial jet is apparently highly variable in wind speed at the upper cloud level with changes, between 1980-81 and 1994-2004, amounting up to a 40% in its peak value. However, there is some controversy if this is a real change in the winds or an effect due to clouds placed at different altitude levels where a vertical wind shear is pre…
Unveiling the Nature of INTEGRAL Sources Through Optical Spectroscopy
Masetti, Nicola
Since its launch on October 2002 the INTEGRAL satellite is performing an deep survey of the hard X-ray sky with unprecedented sensitivity and positional accuracy. This allowed pinpointing, through positional cross-correlation with catalogs at longer wavelengths, possible optical/near-infrared candidates for the hard X-ray sources of still unknown …
The evolution of QSO host colours
Schramm, Malte; Wisotzki, Lutz; Jahnke, Knud +1 more
We summarise the evidence that the hosts of luminous QSOs are systematically bluer than normal (inactive) galaxies of comparable morphological type. We particularly emphasize the importance of performing such studies in a comparative way, placing QSO hosts in a context of the overall galaxy population.
Search for cyclotron lines in INTEGRAL/SPI spectra of Vela X-1
von Kienlin, A.; Schanne, S.; Kretschmar, P. +5 more
The wind-accreting X-ray binary pulsar Vela X-1 has been observed during the two INTEGRAL Core Program observations of the Vela region in June July and November December 2003. Preliminary results on time averaged and time resolved spectra of INTEGRAL/SPI for the two observation epochs are presented. Time averages have been used in order to increas…
Corrigendum: Titan Radar Mapper observations from Cassini's T3 fly-by
Stiles, B.; Kelleher, K.; Callahan, P. +32 more
Stochastic Acceleration of Energetic Particles in the Magnetosphere of Saturn
Martínez-Gómez, E.; Durand-Manterola, H. J.; Tejada, H. Pérez de
Voyager's plasma probe observations suggest that there are at least three fundamentally different plasma regimes in Saturn: the hot outer magnetosphere, the extended plasma sheet, and the inner plasma torus. At the outer regions of the inner torus some ions have been accelerated to reach energies of the order of 43 keV. We develop a model that cal…
The Characteristics of the Cool Component of the Cataclysmic Variable AE Aquarii from Hipparcos Observations
Friedjung, M.
The parallax of the cataclysmic binary AE Aquarii, found using the Hipparcos satellite, is combined with published infrared observations. Indications are obtained that the cool component is somewhat above the main sequence. However, this result is not absolute because of the errors and uncertainties.
Measuring the Mass of 4U 0900-40 Dynamically
Boyd, Patricia T.; Dolan, J. F.; Etzel, Paul B.
Accurate measurements of neutron star masses are needed to constrain the equation of state of neutron star matter-of importance to both particle physics and the astrophysics of neutron stars-and to identify the evolutionary track of the progenitor stars that form neutron stars. The best measured values of the mass of 4U 0900-40 (=Vela XR-1), 1.86+…