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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents



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ID: 559403.0, MPI für Astronomie / Publikationen_mpia
First Keck Interferometer measurements in self-phase referencing mode: spatially resolving circum-stellar line emission of 48 Lib
Authors:Pott, J. U.; Woillez, J.; Ragland, S.; Wizinowich, P. L.; Eisner, J. A.; Monnier, J. D.; Akeson, R. L.; Ghez, A. M.; Graham, J. R.; Hillenbrand, L. A.; Millan-Gabet, R.; Appleby, E.; Berkey, B.; Colavita, M. M.; Cooper, A.; Felizardo, C.; Herstein, J.; Hrynevych, M.; Medeiros, D.; Morrison, D.; Panteleeva, T.; Smith, B.; Summers, K.; Tsubota, K.; Tyau, C.; Wetherell, E.
Language:English
Publisher:SPIE
Place of Publication:Bellingham, Wash.
Date of Publication (YYYY-MM-DD):2010
Title of Proceedings:Optical and Infrared Interferometry II
Start Page:77340P-77340P
End Page:6
Title of Series:SPIE
Volume (in Series):7734
Name of Conference/Meeting:Optical and Infrared Interferometry II
Review Status:not specified
Audience:Experts Only
Abstract / Description:Recently, the Keck interferometer was upgraded to do self-phase-referencing (SPR) assisted K-band spectroscopy at R ~ 2000. This means, combining a spectral resolution of 150 km/s with an angular resolution of 2.7 mas, while maintaining high sensitiviy. This SPR mode operates two fringe trackers in parallel, and explores several infrastructural requirements for off-axis phase-referencing, as currently being implemented as the KI-ASTRA project. The technology of self-phasereferencing opens the way to reach very high spectral resolution in near-infrared interferometry. We present the scientific capabilities of the KI-SPR mode in detail, at the example of observations of the Be-star 48 Lib. Several spectral lines of the cirumstellar disk are resolved. We describe the first detection of Pfund-lines in an interferometric spectrum of a Be star, in addition to Br γ. The differential phase signal can be used to (i) distinguish circum-stellar line emission from the star, (ii) to directly measure line asymmetries tracing an asymetric gas density distribution, (iii) to reach a differential, astrometric precision beyond single-telescope limits sufficient for studying the radial disk structure. Our data support the existence of a radius-dependent disk density perturbation, typically used to explain slow variations of Be-disk hydrogen line profiles.
Comment of the Author/Creator:Date: 2010, July 1, 2010
External Publication Status:published
Document Type:Conference-Paper
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/abs/2010SPIE.7734E..21P [ID No:1]
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