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Millions of Multiples: Detecting and Characterizing Close-separation Binary Systems in Synoptic Sky Surveys

Terziev, Emil and Law, Nicholas M. and Arcavi, Iair and Baranec, Christoph and Bloom, Joshua S. and Bui, Khanh and Burse, Mahesh P. and Chorida, Pravin and Das, H. K. and Dekany, Richard G. and Kraus, Adam L. and Kulkarni, S. R. and Nugent, Peter E. and Ofek, Eran and Punnadi, Sujit and Ramaprakash, A. N. and Riddle, Reed L. and Sullivan, Mark and Tendullkar, Shriharsh P. (2013) Millions of Multiples: Detecting and Characterizing Close-separation Binary Systems in Synoptic Sky Surveys. Astrophysical Journal Supplement Series, 206 (2). Art. No. 18. ISSN 0067-0049.

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The direct detection of binary systems in wide-field surveys is limited by the size of the stars' point-spread functions (PSFs). A search for elongated objects can find closer companions, but is limited by the precision to which the PSF shape can be calibrated for individual stars. Based on a technique from weak-lensing analysis, we have developed the BinaryFinder algorithm to search for close binaries by using precision measurements of PSF ellipticity across wide-field survey images. We show that the algorithm is capable of reliably detecting binary systems down to ≈1/5 of the seeing limit, and can directly measure the systems' position angles, separations, and contrast ratios. To verify the algorithm's performance we evaluated 100,000 objects in Palomar Transient Factory (PTF) wide-field-survey data for signs of binarity, and then used the Robo-AO robotic laser adaptive optics system to verify the parameters of 44 high-confidence targets. We show that BinaryFinder correctly predicts the presence of close companions with a <11% false-positive rate, measures the detected binaries' position angles within 1° to 4° (depending on signal-to-noise ratio and separation), and separations within 25%, and weakly constrains their contrast ratios. When applied to the full PTF data set, we estimate that BinaryFinder will discover and characterize ~450,000 physically associated binary systems with separations <2 arcsec and magnitudes brighter than m_R = 18. New wide-field synoptic surveys with high sensitivity and sub-arcsecond angular resolution, such as LSST, will allow BinaryFinder to reliably detect millions of very faint binary systems with separations as small as 0.1 arcsec.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Law, Nicholas M.0000-0001-9380-6457
Arcavi, Iair0000-0001-7090-4898
Baranec, Christoph0000-0002-1917-9157
Kraus, Adam L.0000-0001-9811-568X
Kulkarni, S. R.0000-0001-5390-8563
Nugent, Peter E.0000-0002-3389-0586
Ofek, Eran0000-0002-6786-8774
Riddle, Reed L.0000-0002-0387-370X
Additional Information:© 2013 American Astronomical Society. Received 2012 October 15; accepted 2013 April 16; published 2013 May 30. We thank Yanqin Wu for very useful discussions, and the Palomar Observatory staff for their superb support of Robo- AO and PTF operations. E.T. participated in the Summer Undergraduate Research Program (SURP) at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto. N.M.L. is a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto. The Dunlap Institute is funded through an endowment established by the David Dunlap family and the University of Toronto. The Robo-AO system is supported by collaborating partner institutions, the California Institute of Technology and the Inter-University Centre for Astronomy and Astrophysics, and by the National Science Foundation under Grant Nos. AST-0906060 and AST-0960343, by a grant from the Mt. Cuba Astronomical Foundation, and by a gift from Samuel Oschin. Observations were obtained with the Samuel Oschin Telescope at the Palomar Observatory as part of the Palomar Transient Factory project, a scientific collaboration between the California Institute of Technology, Columbia University, Las Cumbres Observatory, the Lawrence Berkeley National Laboratory, the National Energy Research Scientific Computing Center, the University of Oxford, and the Weizmann Institute of Science. A.L.K. was supported by NASA through Hubble Fellowship grant 51257.01 awarded by STScI, which is operated by AURA, Inc., for ANSA, under contract NAS 5-26555.
Funding AgencyGrant Number
Mt. Cuba Astronomical FoundationUNSPECIFIED
NASA Hubble Fellowship51257.01
NASANAS 5-26555
Subject Keywords:binaries: close; methods: data analysis; stars: statistics; surveys; techniques: image processing
Record Number:CaltechAUTHORS:20131108-093537237
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Official Citation:Millions of Multiples: Detecting and Characterizing Close-separation Binary Systems in Synoptic Sky Surveys Emil Terziev et al. 2013 ApJS 206 18
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42334
Deposited By: Jason Perez
Deposited On:08 Nov 2013 22:35
Last Modified:27 Oct 2017 03:40

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