NOAO >   Observing Info >   Approved Programs >   2017A-0052

Small NOAO Logo

Program Information for 2017A-0052


PI: Edward W Olszewski, U. of Arizona, edwardwolszewski@gmail.com
Address: Steward Obs, 933 N Cherry Ave, Tucson, AZ 85721 USA

CoI: Abhijit Saha, NOAO
CoI: Tim Axelrod, U. of Arizona
CoI: Jay Holberg, U. of Arizona
CoI: Sean Points, CTIO
CoI: Thomas Matheson, NOAO
CoI: Gautham Narayan, U. of Arizona
CoI: Chris Stubbs, Harvard U.
CoI: Larry Camarota, U. of Arizona
CoI: Annalisa Calamida, NOAO
CoI: Roberto Raddi, Warwick, UK
CoI: Nicola Gentile Fusillo, Warwick, UK

Title: Southern White Dwarf Flux Standards

Abstract: This is the fourth time the TAC has seen this proposal. In the first three, we were granted 5 nights in 2015B, 5 in 2016A, and 4 in 2016B. We have had 2 good nights and perhaps another half of a cloudy night out of the first ten nights (Sept 2015, Feb 2016, May 2016), with 4 nights in Oct 2016 to come. We can finish this project if we get some clear time in Oct 2016 and get this fourth proposal accepted. We are establishing a set of faint hot white dwarfs with fully radiative pure hydrogen atmospheres as flux standards. Spectroscopy from the ground yields their temperatures and gravities, from which their SEDs are modeled. Photometry from space (free of terrestrial atmosphere) with HST tests and provides zeropoints on the HST scale for these SEDs, while also determining interstellar reddening. We have shown in a recent paper that the method yields panchromatic accuracy to a few millimag rms. Our set of stars currently covers the celestial equator and northern polar and mid-declinations. The data for these are all in hand, including a total of 78 orbits of HST imaging. However, equivalent suitable objects are harder to identify in the south, where LSST will point. We have assembled a list of candidates from extant sources, and other putative candidates from proper motion results, and in the past year have obtained spectroscopic confirmation with SOAR/GOODMAN for $sim$15 of them. In order to serve as fundamental standards for deep surveys, we need confirmed DA (Hydrogen) purely radiative WD with T$_{eff}>25000$K, and m$_V>18$, with later HST imaging.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2017A):  SOAR/Goodman -- 3n on May 24 - May 26 2017
Run 2 (2017A):  SOAR/Goodman -- 2n on Feb 21 - Feb 22 2017


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 >   2017A-0052

noaoprop-help@noao.edu

Small NOAO Logo