W. Kent Ford

Extended rotation curves of high-luminosity spiral galaxies. IV - Systematic dynamical properties, SA through SC

For a sample of 10 high-luminosity spiral galaxies, Sa through Sc, we have obtained accurate rotation curves which extend to about 80% of the de Vaucouleurs radii.

Rotational properties of 23 Sb galaxies

We have obtained major axis spectra for 23 Sb galaxies in a sample chosen to encompass a wide range of radii, masses, and luminosities. These are generally field galaxies of high inclination, and our spectrograms extend, on the average, to about three quarters of the isophotal radius, R/sub 25/. The Sb rotation curves exhibit many of the systematic trends with luminosity shown by the Scs studied previously. Velocities in small, low-luminosity, low-mass Sb galaxies rise gently to a maximum rotational velocity in a large fraction of their isophotal radius; velocities in large, high-luminosity, high-mass Sb galaxies reach their (higher) rotational velocity in only a small fraction of their isophotal radius. However, rotational velocities span a range of higher values for Sb than for Sc galaxies.

THE SPECTRUM OF THE 1967 SUPERNOVA IN NGC 3389 AND HΑ VELOCITIES IN THE GALAXY

Two spectrograms of the 1967 supernova in NGC 3389 were obtained on March 7 and March 8. The supernova is of Type I, with broad unidentified emission features that resemble features in supernova spectra studied earlier by Minkowski (1939). No hydrogen emission is observed. A third spectrogram, with both the supernova and the brightest regions of the galaxy on the slit, reveals Ha emission within the galaxy. For this position angle, the velocity variation within the galaxy has been measured.

Astronomical Uses of Cascade Intensifies

Publisher Summary This chapter reviews measurements made at laboratory on the operating characteristics of a two-stage cascade image intensifier developed by the Electron Tube Division of RCA for the Carnegie Committee. Some of the equipment that has been built for the use of the telescope is also described. The cascade tube described in the chapter is the RCA Type C33011. This is a high quality version of the C70056 developmental image tube. The tube includes an S.20 photocathode, a single electron-multiplier of the phosphor-photocathode type, and a final output screen with a fine-grain P.11 phosphor. The cascade intensifiers developed for the Carnegie Committee have demonstrated their usefulness in a variety of astronomical applications. At the present time, the limitations of the cascade system are primarily those associated with the transfer optics. Because of their sensitivity, reliability, and ease of operation, these tubes are particularly suited for a number of routine astronomical observations.

Application Of Image Intensifiers In Astronomical Observations

Over the last ten years, the application of image intensifiers in astronomical observations has become a routine procedure. This year at Kitt Peak National Observatory, 45% of the time on the 2.1-meter telescope is scheduled for image intensifier work. Most of this is work that requires a dark sky for spectroscopic observa-tions of faint stars and galaxies, and so nearly 90% of the available dark time on the telescope is scheduled for observations with some sort of image intensifier being the primary detector. Similar scheduling of intensifiers can be found at many observatories around the world. I would like to review the current application of some of these devices in astronomy and discuss their advantages and limitations.