14,828 research outputs found
Simulations of dual morphology in spiral galaxies
Gas and stars in spiral galaxies are modelled with the DUAL code, using
hydrodynamic and N-body techniques. The simulations reveal morphological
differences mirroring the dual morphologies seen in B and K' band observations
of many spiral galaxies. In particular, the gaseous images are more flocculent
with lower pitch angles than the stellar images, and the stellar arm-interarm
contrast correlates with the degree of morphological decoupling.Comment: 4 pages, 4 figures, to appear in Disk of Galaxies: Kinematics,
Dynamics and Perturbations, ASP Conf. Series, 200
DSN acquisition of Magellan high-rate telemetry data
The Magellan Project levied the stringent requirement of a 98 percent high-rate telemetry data capture rate on the Deep Space Network (DSN) during the Magellan Prime Mapping Mission. To meet this requirement, the DSN undertook extensive development of the DSN Telemetry System, as well as extensive DSN operation planning and test and training. In actuality, the DSN substantially exceeded the requirement by achieving a Prime Mapping Mission high-rate telemetry data capture rate of 99.14 percent. This article details the DSN telemetry system development, and DSN operations planning and test and training. In addition, the actual high-rate telemetry data outages are comprehensively presented and analyzed
ABTRAJ on-site tracking prediction program
Computer program, ABTRAJ, provides Deep Space Network tracking stations with the capability of generating spacecraft predictions with on-site computers. The program is comprised of two major sections - the main prediction portion and a trajectory subroutine which spans the desired predict interval with spacecraft ephemeris data written on magnetic tapes
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