Beers, Timothy C. and Flynn, Chris and Rossi, Silvia and Sommer-Larsen, Jesper and Wilhelm, Ronald and Marsteller, Brian and Lee, Young Sun and De Lee, Nathan and Krugler, Julie and Deliyannis, Constantine P. and Simmons, Andrew T. and Mills, Elisabeth and Zickgraf, Franz-Josef and Holmberg, Johan and Önehag, Anna and Eriksson, Anders and Terndrup, Donald M. and Salim, Samir and Andersen, Johannes and Nordström, Birgitta and Christlieb, Norbert and Frebel, Anna and Rhee, Jaehyon (2007) Broadband UBVR_CI_C Photometry of Horizontal-Branch and Metal-poor Candidates from the HK and Hamburg/ESO Surveys. I. Astrophysical Journal Supplement Series, 168 (1). pp. 128-139. ISSN 0067-0049 http://resolver.caltech.edu/CaltechAUTHORS:20100818-152000552
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We report broadband UBV and/or BVR_CI_C CCD photometry for a total of 1857 stars in the thick-disk and halo populations of the Galaxy. The majority of our targets were selected as candidate field horizontal-branch or other A-type stars (FHB/A, N = 576), or candidate low-metallicity stars (N = 1221), from the HK and Hamburg/ESO objective-prism surveys. Similar data for a small number of additional stars from other samples are also reported. These data are being used for several purposes. In the case of the FHB/A candidates they are used to accurately separate the lower gravity FHB stars from various higher gravity A-type stars, a subsample that includes the so-called blue metal poor stars, halo and thick-disk blue stragglers, main-sequence A-type dwarfs, and Am and Ap stars. These data are also being used to derive photometric distance estimates to high-velocity hydrogen clouds in the Galaxy and for improved measurements of the mass of the Galaxy. Photometric data for the metal-poor candidates are being used to refine estimates of stellar metallicity for objects with available medium-resolution spectroscopy, to obtain distance estimates for kinematic analyses, and to establish initial estimates of effective temperature for analysis of high-resolution spectroscopy of the stars for which this information now exists.
|Additional Information:||© 2007 The American Astronomical Society. Received 2006 July 28; accepted 2006 September 13. We are thankful to the ESO/Danish 1.5 m, WIYN 0.9 m, NOAO, and MDM time assignment committees for awards of the significant amounts of telescope time required for this project, and for the patience to await the results. We are also grateful for the excellent support that we received at the telescopes. T. C. B., Y. L., B. M., and N. D. acknowledge partial support from grants AST 00-98508, AST 00-98549, AST 02-05815, AST 04-06784, and PHY 02-16783, Physics Frontier Centers/ JINA: Joint Institute for Nuclear Astrophysics, awarded by the US National Science Foundation. J. K. acknowledges partial support from the Honors College at Michigan State University, in the form of a Professorial Assistantship. C. F. acknowledges partial support from the Danish National Research Foundation and the Carlberg Foundation. S. R. acknowledges partial support from the Brazilian institutions FAPESP, CNPq, and Capes. C. P. D. acknowledges partial support from grant AST 02-06202, awarded by the US National Science Foundation. D. T. and S. S. acknowledge partial support from grant AST 02-05789, awarded by the US National Science Foundation, and from the Ohio State Program for the Enhancement of Graduate Studies (PEGS). J. A. and B. N. thank the Carlsberg Foundation and the Swedish and Danish Natural Science Research Councils for partial financial support of this work. N. C. acknowledges partial support from the Deutsche Forschungsgemeinschaft through grants Ch 214/3 and Re 353/44. N. C. is a research fellow of the Royal Swedish Academy of Sciences supported by a grant from the Knut and Alice Wallenberg Foundation. A. F. acknowledges partial support from grant DP0342613, awarded by the Australian Research Council.|
|Subject Keywords:||stars : early-type; stars : horizontal-branch; stars : Population II; techniques : photometric|
|Official Citation:||Timothy C. Beers et al 2007 ApJS 168 128 doi: 10.1086/509324|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||23 Aug 2010 22:14|
|Last Modified:||26 Dec 2012 12:20|
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