Browsing by Author "Pritzl, Barton J."

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    Erratum: "Variable Stars in the Unusual, Metal-Rich Globular Cluster NGC 6388" [Astron. J. 124, 949 (2002)]
    (2003) Pritzl, Barton J.; Smith, Horace A.; Catelan, Márcio; Sweigart, Allen V.
    In Tables 4 and 5, we inadvertently listed Modified Heliocentric Julian Dates instead of ordinary Heliocentric Julian Dates as indicated in the table headings. To make the listed dates match the table headings, 0.5 should be added to the listed dates. Corrected tables with ordinary Heliocentric Julian Dates are given below. We thank Christine Clement, who noticed this error and brought it to our attention....
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    Looking for the Building Blocks of the Galactic Halo: Variable stars in the Fornax, Bootes I, Canes Venatici II Dwarfs and in NGC2419
    (2009) Greco, Claudia; Clementini, Gisella; Held, Enrico E.; Poretti, Ennio; Catelan, Márcio; Federici, Luciana; Gullieuszik, Marco; Maio, Marcella; Ripepi, Vincenzo; Dall'Ora, Massimo; di Fabrizio, Luca; Kinemuchi, Karen; di Criscienzo, Marcella; Marconi, Marcella; Musella, Ilaria; Rest, Armin; de Lee, Nathan; Pritzl, Barton J.; Smith, Horace
    Looking for the building blocks of the Galactic Halo we have investigated and compared the properties of the RR Lyrae stars in a number of different stellar systems inside and outside the Milky Way.
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    RR Lyrae in the LMC: Insights Into the Oosterhoff Phenomenon
    (2013) Kuehn, Charles A; Smith, Horace A.; Catelan, Marcio; Jeon, Young-Beom; Nemec, James M.; Walker, Alistair R.; Kunder, Andrea; Dame, Kyra; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura
    Although more than eight decades have passed since P. Th. Oosterhoff drew attention to differences in the properties of RR Lyrae variables in globular clusters, the origin and significance of the Oosterhoff groups remain unclear. Nonetheless, the accumulation of extensive new observations of RR Lyrae stars in globular clusters of the Milky Way and Local Group galaxies allows a fresh look at the phenomenon. Insights come not only from surveys of variables within the original Oosterhoff groups I and II but also from recent observations of the Oosterhoff-intermediate systems found especially in smaller Local Group galaxies. We will compare properties of RR Lyrae in several systems to investigate what they reveal about system-to-system differences of transition temperature between fundamental-mode and first overtone pulsators and of horizontal branch luminosity. Both transition temperature and horizontal branch luminosity have at various times been credited as playing roles in the creation of the Oosterhoff dichotomy....
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    Variable Stars in Metal-Rich Globular Clusters: NGC 6304 and NGC 6569
    (2002) Pritzl, Barton J.; Smith, Horace A.; Catelan, Marcio; Sweigart, Allen V.
    It has recently become evident that the RR Lyrae in metal-rich globular clusters ([Fe/H]> -1.0) have properties different from those of metal-rich RR Lyrae found in the field. In particular, they have longer periods than field RR Lyrae of similar metallicities, implying that the cluster RR Lyrae are more luminous than their field counterparts. Because RR Lyrae stars are major Population II standard candles, this finding has consequences for the ages of globular clusters and the galactic and extragalactic distance scales. We propose observations with the YALO telescope to obtain B,V CCD photometry of the RR Lyrae in the metal-rich globular clusters NGC 6304 and NGC 6569. These data will be used to obtain accurate periods and light curves for the RR Lyrae and will be compared to those in other systems to determine their relative luminosities. Direct comparisons will also be made to the other metal-rich globular clusters known to contain RR Lyrae.