NOAO >   Observing Info >   Approved Programs >   2016B-0160

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Program Information for 2016B-0160


PI: Alexandros Gianninas, U. of Oklahoma, alexg@nhn.ou.edu
Address: Department of Physics & Astronomy, 440 W. Brooks St., Norman, OK 73019 USA

CoI: Mukremin Kilic, U. of Oklahoma
CoI: Warren Brown, Harvard-Smithsonian Center for Astrophysics
CoI: Scott Kenyon, Harvard-Smithsonian Center for Astrophysics

Title: The ELM Survey: Finding the Shortest Period Binary White Dwarfs

Abstract: A new discovery space for short period binary white dwarfs (WDs) has opened up with the availability of 14,600 deg$^{2}$ of SDSS Data Release 9 photometry. The Extremely Low-Mass (ELM) Survey takes advantage of this photometry, and SDSS spectroscopy, to identify compact systems with orbital periods of 1 hr or less. To significantly increase the number of known merging WD systems, we have proposed to obtain spetroscopic observations of all candidates with $g leq$~19~mag and photometric colors consistent with ELM WDs ($M leq$ 0.3 M$_{odot}$). In previous runs, we obtained optical spectroscopy of about 200 candidates, and presented 20 new double degenerate systems with well-constrained orbits in Gianninas et al. (2015) and Brown et al. (2016). We have an additional set of $sim$20 confirmed ELM WDs that require follow-up spectroscopy to constrain their orbits. We request 5 nights of KPNO 4m time to follow-up these ELM WDs and to exploit a largely unexplored portion of the fall sky, which we have not been able to survey due to scheduling and bad weather. Our two major science goals are to discover detached gravitational wave sources for fundamental tests of General Relativity and to constrain the formation rate and space density of merging WDs. The latter is important for constraining the contribution of double degenerates to Type Ia and underluminous supernovae.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2016B):  KP-4m/KOSMOS -- 5n on Dec 05 - Dec 06 2016, Dec 21 - Dec 23 2016


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2016B-0160

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