Zobrazeno 1 - 10
of 62
pro vyhledávání: '"Jefferys, W. H."'
Autor:
Wagner-Kaiser, R., Sarajedini, A., von Hippel, T., Stenning, D. C., van Dyk, D. A., Jeffery, E., Robinson, E., Stein, N., Anderson, J., Jefferys, W. H.
We use Hubble Space Telescope (HST) imaging from the ACS Treasury Survey to determine fits for single population isochrones of 69 Galactic globular clusters. Using robust Bayesian analysis techniques, we simultaneously determine ages, distances, abso
Externí odkaz:
http://arxiv.org/abs/1702.08856
Autor:
Jeffery, Elizabeth J., von Hippel, Ted, van Dyk, David A., Stenning, David C., Robinson, Elliot, Stein, Nathan, Jefferys, W. H.
Publikováno v:
ApJ, 828, 79 (2016)
In this paper we apply a Bayesian technique to determine the best fit of stellar evolution models to find the main sequence turn off age and other cluster parameters of four intermediate-age open clusters: NGC 2360, NGC 2477, NGC 2660, and NGC 3960.
Externí odkaz:
http://arxiv.org/abs/1611.00835
Autor:
Wagner-Kaiser, R., Stenning, D. C., Sarajedini, A., von Hippel, T., van Dyk, D. A., Robinson, E., Stein, N., Jefferys, W. H.
We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival ACS Treasury observations of 30 Galactic Globular Clusters to characterize two distinct stellar populations. A sophisticated Bayesian technique is employed to simultaneously s
Externí odkaz:
http://arxiv.org/abs/1609.01527
Autor:
Wagner-Kaiser, R., Stenning, D. C., Robinson, E., von Hippel, T., Sarajedini, A., van Dyk, D. A., Stein, N., Jefferys, W. H.
We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival ACS Treasury observations of Galactic Globular Clusters to find and characterize two stellar populations in NGC 5024 (M53), NGC 5272 (M3), and NGC 6352. For these three cluste
Externí odkaz:
http://arxiv.org/abs/1604.06074
Publikováno v:
Astrophys.J.658:391-395,2007
Currently there are two main techniques for independently determining the ages of stellar populations: main sequence evolution theory (via cluster isochrones) and white dwarf cooling theory. Open clusters provide the ideal environment for the calibra
Externí odkaz:
http://arxiv.org/abs/astro-ph/0611826
We present an update of our on-going effort to improve the precision of white dwarf cosmochronology via careful analyses of white dwarf photometry in open clusters. To improve the precision of white dwarf and main sequence age analysis, we are develo
Externí odkaz:
http://arxiv.org/abs/astro-ph/0411009
Autor:
Benedict, G. Fritz, McArthur, B. E., Fredrick, L. W., Harrison, T. E., Skrutskie, M. F., Slesnick, C. L., Rhee, J., Patterson, R. J., Nelan, E., Jefferys, W. H., van Altena, W., Montemayor, T., Shelus, P. J., Franz, O. G., Wasserman, L. H., Hemenway, P. D., Duncombe, R. L., Story, D., Whipple, A. L., Bradley, A. J.
Publikováno v:
Astron.J.126:2549,2003
We present an absolute parallax and relative proper motion for the central star of the planetary nebula NGC 6853 (The Dumbell). We obtain these with astrometric data from FGS 3, a white-light interferometer on {\it HST}. Spectral classifications and
Externí odkaz:
http://arxiv.org/abs/astro-ph/0307449
Publikováno v:
Astrophys.J. 592 (2003) 539-554; Erratum-ibid. 611 (2004) 621
We develop and describe a Bayesian statistical analysis to solve the surface brightness equations for Cepheid distances and stellar properties. Our analysis provides a mathematically rigorous and objective solution to the problem, including immunity
Externí odkaz:
http://arxiv.org/abs/astro-ph/0303656
Autor:
Benedict, G. F., McArthur, B. E., Forveille, T., Delfosse, X., Nelan, E., Butler, R. P., Spiesman, W., Marcy, G., Goldman, B., Perrier, C., Jefferys, W. H., Mayor, M.
Publikováno v:
Astrophys.J. 581 (2002) L115-L118
We report the first astrometrically determined mass of an extrasolar planet, a companion previously detected by Doppler spectroscopy. Radial velocities first provided an ephemeris with which to schedule a significant fraction of the {\it HST} observa
Externí odkaz:
http://arxiv.org/abs/astro-ph/0212101
Autor:
Benedict, G. Fritz, McArthur, B. E., Fredrick, L. W., Harrison, T. E., Slesnick, C. L., Rhee, J., Patterson, R. J., Skrutskie, M. F., Franz, O. G., Wasserman, L. H., Jefferys, W. H., Nelan, E., van Altena, W., Shelus, P. J., Hemenway, P. D., Duncombe, R. L., Story, D., Whipple, A. L., Bradley, A. J.
We present an absolute parallax and relative proper motion for the fundamental distance scale calibrator, delta Cep. We obtain these with astrometric data from FGS 3, a white-light interferometer on HST. Utilizing spectrophotometric estimates of the
Externí odkaz:
http://arxiv.org/abs/astro-ph/0206214