Bernat, David and Bouchez, Antonin H. and Ireland, Michael and Tuthill, Peter and Martinache, Frantz and Angione, John and Burruss, Rick S. and Cromer, John L. and Dekany, Richard G. and Guiwits, Stephen R. and Henning, John R. and Hickey, Jeff and Kibblewhite, Edward and McKenna, Daniel L. and Moore, Anna M. and Petrie, Harold L. and Roberts, Jennifer and Shelton, J. Chris and Thicksten, Robert P. and Trinh, Thang and Tripathi, Renu and Troy, Mitchell and Truong, Tuan and Velur, Viswa and Lloyd, James P. (2010) A Close Companion Search Around L Dwarfs Using Aperture Masking Interferometry and Palomar Laser Guide Star Adaptive Optics. Astrophysical Journal, 715 (2). pp. 724-735. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20100609-133615383
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We present a close companion search around 16 known early L dwarfs using aperture masking interferometry with Palomar laser guide star adaptive optics (LGS AO). The use of aperture masking allows the detection of close binaries, corresponding to projected physical separations of 0.6-10.0 AU for the targets of our survey. This survey achieved median contrast limits of ΔK ~ 2.3 for separations between 1.2λ/D-4λ/D and ΔK ~ 1.4 at 2/3λ/D. We present four candidate binaries detected with moderate-to-high confidence (90%-98%). Two have projected physical separations less than 1.5 AU. This may indicate that tight-separation binaries contribute more significantly to the binary fraction than currently assumed, consistent with spectroscopic and photometric overluminosity studies. Ten targets of this survey have previously been observed with the Hubble Space Telescope as part of companion searches. We use the increased resolution of aperture masking to search for close or dim companions that would be obscured by full aperture imaging, finding two candidate binaries. This survey is the first application of aperture masking with LGS AO at Palomar. Several new techniques for the analysis of aperture masking data in the low signal-to-noise regime are explored.
|Additional Information:||© 2010 The American Astronomical Society. Received 2010 January 22; accepted 2010 March 28; published 2010 May 3. We thank the staff and telescope operators of the Palomar Observatory for their support. David Bernat thanks Jason Wright for many helpful discussions about the analytical techniques developed within this paper. We thank the Palomar staff for many nights of assistance at the Palomar Hale telescope. This work was supported in part by the National Science Foundation under award numbers AST-0905932 and AST-0705085. The Hale telescope at Palomar Observatory is operated as part of a collaborative agreement between Caltech, JPL, and Cornell University. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, and is funded by the National Aeronautics and Space Administration, and the National Science Foundation. Facilities: Hale(LGS AO)|
|Subject Keywords:||binaries: general; brown dwarfs; stars: low-mass; techniques: high angular resolution|
|Classification Code:||PACS: 95.75.Qr; 97.80.Fk; 97.20.Vs; 95.85.Kr; 97.10.Nf.|
|Official Citation:||David Bernat et al 2010 ApJ 715 724 doi: 10.1088/0004-637X/715/2/724|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||13 Jun 2010 03:48|
|Last Modified:||26 Dec 2012 12:07|
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