• The Effects of the 35 Day X-Ray Cycle on the Light Curve of HZ Herculis

      Grandi, S. A.; Hintzen, P. M. N. O.; Jensen, E. B.; Tydgren, A. E.; Scott, J. S.; Stickney, P. M.; Whelan, J. A. J.; Worden, S. P.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1974)
      We report extensive photoelectric UBV photometry of the variable star HZ Her, originally undertaken to discover possible correlations between variations in its 1.7 day light curve and the 35 day cycle of the X -ray source Her X -1. Correlations recently reported by other groups are confirmed. These, as well as other features observed, are provisionally analyzed using a model consisting of a primary star, filling its Roche lobe and being illuminated by X -rays. The X -rays are emitted in a beam fixed in a rotating, precessing, neutron star secondary. Additional light is being contributed by material being transferred from the primary to the secondary.
    • Electron-Scattering Line Profiles in Seyfert Galaxy Nuclei

      Weymann, R. J.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1969-07)
    • The Emission Lines in the Vicinity of Hydrogen Alpha in dMe Flare Star Spectra

      Worden, S. P.; Peterson, B. M.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1976)
      High resolution spectral data obtained in the vicinity of hydrogen alpha have been obtained for a number of dMe stars. Centrally reversed Ha emission profiles appear to be a general feature of dMe spectra. Possible mechanisms related to solar phenomena are discussed for forming this type of profile.
    • Energy Distribution in Spectra of Seyfert Galaxies and Quasistellar Sources

      Pacholczyk, A. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1967-05)
    • Evidence for a Non-Doppler Component in Redshifts of Normal Galaxies

      Tifft, W. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1972-05)
    • Evidence of Tidal Effects in Some Pulsating Stars. I CC Andromedae and Sigma Scorpii

      Fitch, W. S.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1966-10)
      Analyses of the light variation of the 6 Scuti star CC Andromedae and of the radial velocity variation of the ß Canis Majoris star 6 Scorpii, a single -line spectroscopic binary, indicate that the long period modulations exhibited are caused by tidal deformations induced in the hydrogen and /or helium ionization zones of each primary by a faint companion, resulting in surface zonal variations of the amplitude and phase of each primary's normal radial pulsations. The variations in the tide raising potential calculated at the center of the apparent disk of o Scorpii correlate very strongly with the observed variations in the phase zero -point of the fundamental pulsation. It is suggested that all the ß Canis Majoris and 6 Scuti stars exhibiting long period modulation, and probably also the RR Lyrae stars showing a Blazhko effect, do so because of tidal perturbations induced by faint companions.
    • Evolution in Galaxy Nuclei. I. Comparison of the Coma and Virgo Clusters

      Tifft, W. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1971-03)
      The correlation of nuclear magnitude with redshift in the Coma and Virgo Clusters is discussed. The two clusters are combined in a fitting process to determine a differential distance modulus of 3.47 ±0.05. Hubble velocities of the clusters are found to be 1284 ±45 and 6344 ±70. For a Virgo Cluster distance of 14.8 Mpc the Hubble constant is H = 86.3 ±3, subject to the usual major systematic errors. The effect of the redshift -magnitude correlation on the luminosity functions of the Coma and Virgo Cluster is discussed and can account for observed nonuniformity in the luminosity functions. The observed redshift distribution within clusters is interpreted as a uniform Hubble velocity upon which is superimposed a differential redshift not due to mass center motion. A combination of gravitational redshifts and radial mass motion induced in an evolving nuclear gravitational potential field is suggested to produce the differential redshifts. Galaxies are viewed as expanding systems evolving from dense cores with the redshift -magnitude correlation representing a form of evolutionary track. Clusters as a whole can be dynamically stable. The outflow of material is a source of inter- galactic bridges, intergalactic stellar haze, and various phenomena observed in galaxy envelopes. The concept of evolving galaxies has major consequences on cosmological models. Age dispersion in clusters and possible evolutionary corrections to galaxy redshifts and total luminosities both suggest that a new approach to a steady state concept is possible.
    • Fine Structure Within the Redshift-Magnitude Correlation for Galaxies : Proceedings of the 58th IAU Symposium (1973)

      Tifft, W. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1973-08-01)
      Previous work on the redshift- magnitude banding correlation is briefly reviewed. New tests of the concept are applied successfully to a second cluster (A2199) and the outer portions of the Coma cluster. Using more than 200 redshifts in Coma, Perseus, and A2199 the presence of a distinct band - related- periodicity in redshift is indicated. Finally, a new sample of accurate redshifts of bright Coma galaxies on a single band is presented, which shows a strong redshift periodicity of 220 km sec -1. An upper limit of 20 km sec -1 is placed on the internal Doppler component of motion in the Coma cluster. Redshift- magnitude bands are, therefore, now recognized to consist of discrete "spin states" organized into "spin groups" which show strong mor- phological associations. Bands are probably in turn organized into band systems. The individual spin states are suggested to represent distinct configurations of matter at the nuclear or fundamental particle structure level. Transitions between states in a time systematic sense of decreasing redshift (increasing internal binding) is suggested to occur in galaxy nuclei. Energy released in such transitions is suggested as the driving energy in radio sources and related objects.
    • Flattening of the Galactic Spheroid

      White, S. D. M.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1988-10)
    • G 240-72 -- A New Magnetic White Dwarf with Unusual Polarization

      Angel, J. R. P; Hintzen, P. M. N. O.; Strittmatter, P. A.; Martin, P. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1974)
      GD 240 72 ( =LP44 -113), a DC white dwarf, is found to show elliptical polarization. There is no evidence of variability. The circular component, typically 0.5 %,changes sign with wavelength, being negative in blue light a and positive in red. There is /relatively strong component of linear polarization, 1.4% in blue light.
    • Galaxies, The Redshift, and Gravity

      Tifft, W. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1974-04)
      When apparent velocities of galaxies in clusters, measured by the red - shift, are correlated against magnitude and morphology, strong non -dynamical correlations emerge. The details of the correlations are used to develop a logical theory for the existance of multiple substates of matter, presumably involving the substructure of fundamental particles. Transitions between substates in a time systematic sense are presumed to occur under the ultimate conditions existant in the cores of black holes in galaxy nuclei. Subsequent separation of states and the interrelations between galaxies require that different substates of matter be non -interactive gravitationally.
    • Galaxy Photometry. I. Techniques

      Tifft, W. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1973-01)
      Techniques for the derivation of nuclear magnitudes in galaxies are summarized. A new method for rapid estimation of nuclear magnitudes by iris photometry is presented and evaluated. It is concluded that with proper calibration, nuclear magnitudes for galaxies in clusters may be estimated with an uncertainty of about ±0.1 magnitude.
    • Ground Observations of Polarimetric Standards for the Hubble Space Telescope

      Tapia, S.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1988-06)
    • High Dispersion Observations of H alpha in the Suspected Brown Dwarf, White Dwarf Binary System G29-38

      Liebert, J.; Saffer, R. A.; Pilachowski, C. A.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1988-10)
      We report on high dispersion spectroscopy of the Ha absorption line of the cool DA white dwarf G 29 -38. This is the star for which a recently detected infrared excess has been suggested to be due to a possible brown dwarf companion by Zuckerman and Becklin (1986, 1987). Three echelle spectra obtained at the Multiple Mirror Telescope and at the Kitt Peak Mayall 4m telescope in 1987 December show no evidence for radial velocity variations larger than -'1.1 ± 8.7 km s -1 and are used to derive a weighted heliocentric radial velocity Vr = 33.7 ± 4.3 km s -1 for the white dwarf. No emission component from the hypothesized secondary star is detected. These negative results do not constitute strong evidence against the companion hypothesis, since the expected orbital velocity of the white dwarf component could be quite small, and the companion's line emission could be too faint to be detected. However, the observation of a sharp absorption line core restricts the possible rotation of the white dwarf to < 40 km s -1 and ensures that any surface magnetic field has a strength < 105 gauss. These results make it unlikely that the DA white dwarf has previously been in a cataclysmic variable accretion phase.
    • Infrared Radiation from the Seyfert Galaxy NGC 1068

      Pacholczyk, A. G.; Wisniewski, W. Z.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1966-11)
    • Infrared Speckle Observations of Binary Ross 614 AB: Combined Shift-and-Add and Zero-and-Add Analysis

      Davey, B. L. K.; Cocke, W. J.; Bates, R. H. T.; McCarthy, D. W., jr.; Christou, J. C.; Cobb, M. L.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1988-12)
      One -dimensional infrared speckle scans of Ross 614 AB were recorded at a wavelength of 2.2μm. For each scan an estimate of the instantaneous quality of the seeing was calculated and the scan was binned accordingly. The three bins corresponding to the three best seeing conditions were further processed by applying the shift -and -add algorithm to the set of images contained within each bin, thereby generating three shift- and -add images with differing shift -and -add point -spread- functions. After windowing the shift -and -add images (using edge -extension) to reduce the effect of contamination, we have obtained parameters corresponding to the separation and brightness ratio of a two component model of the double star Ross 614 AB by deconvolving the three shift -and -add images with the aid of the zero-and -add technique. Least squares analysis on the positions of the clusters of zeros found from zero- and -add yields a separation of 1.04 arcseconds and a brightness ratio of 4.3 for the binary system at this wavelength. An extension of the processing, which takes explicit account of the nonlinear motion of the scanning mechanism gives improved estimates of 1.04 arcseconds and 3.9 for the separation and brightness ratio, respectively.
    • Infrared Variability of the Seyfert Galaxy NGC 1068

      Pacholczyk, A. G.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1970-06)
      Observations of NGC 1068 at 2.2y indicate variability with a timescale of a few days, implying that the size of the infrared emitting region is not larger than a few times 1015 cm. This limit on size is incompatible with the interpretation of infrared radiation by remission from dust grains, by synchrotron emission in a uniform model, and by synchrotron emission from many compact sources within the same object ( "irtrons".). The infrared observations of NGC 1068 could be explained in terms of a nonuniform spherically symmetric synchrotron source with a radial dependence of the flux and of the frequency at which the source becomes optically thick.
    • Interstellar C2, CH, and CN in Translucent Molecular Clouds

      van Dishoeck, E. F.; Univ Arizona, Steward Observ; Black, J. H. (Steward Observatory, The University of Arizona (Tucson, Arizona), 1988-12)
      Optical absorption line techniques have been applied to the study of a number of translucent molecular clouds in which the total column densities are large enough that substantial molecular abundances can be maintained. Results are presented for a survey of absorption lines of interstellar C2, CH, and CN. Detections of CN through the A2II -X2E+ (1,0) and (2,0) bands of the red system are reported, and are compared with observations of the blue system for one line of sight. The population distributions in C2 provide diagnostic information on temperature and density. The measured column densities of the three species can be used to test details of the theory of molecule formation in clouds where photo -processes still play a significant role. The C2 and CH column densities are strongly correlated with each other and probably also with the H2 column density. In contrast, the CN column densities are found to vary greatly from cloud to cloud. The observations are discussed with reference to detailed theoretical models.
    • Investigation of the Cancer Cluster of Galaxies

      Tifft, W. G.; Jewsbury, C. P.; Sargent, T. A.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1973-04)
    • The Ionization and Thermal Equilibrium of a Gas Excited by Ultraviolet Synchrotron Radiation

      Williams, R. E.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1966-10)
      The ionization and thermal balances are considered for a gas that is ionized by a dilute radiation field, taking into account the diffuse ionizing radiation produced by the gas. A number of models are constructed in which the electron temperature and the ionization of the elements H, He, C, N, 0, Ne, and Mg are determined for optically thin and optically thick gases ionized by ultraviolet synchrotron radiation under different conditions. Conclusions are then drawn about the general characteristics of ionization by synchrotron radiation. It is shown that, in an optically thin gas, because of the insensitive frequency- dependence of synchrotron radiation each element occupies a number of different stages of ionization at any one point in the gas. It is also shown that in an optically thick gas the heavy elements remain ionized to much greater distances from the source than hydrogen and helium, and that the gas becomes thermally unstable when H and He have become almost completely neutral. In addition, observations of the emission -line intensities of the Crab Nebula are compared with a model of this object. Considerable disagreement exists between the observed and predicted intensities, and possible reasons for the discrepancy are discussed.