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Parallax Beyond a Kiloparsec from Spatially Scanning the Wide Field Camera 3 on the Hubble Space Telescope by Riess, Adam G.; Casertano, Stefano; Anderson, Jay; Mackenty, John; Filippenko, Alexei V. is a scholarly article available to read on EtoBox.

What is Parallax Beyond a Kiloparsec from Spatially Scanning the Wide Field Camera 3 on the Hubble Space Telescope about?

We use a newly developed observing mode on the Hubble Space Telescope (HST) and Wide Field Camera 3 (WFC3), spatial scanning, to increase source sampling a thousand-fold and measure changes in source positions to a precision of 20--40 microarcseconds, more than an order of magnitude better than attainable in pointed observations. This observing mode can usefully measure the parallaxes of bright stars at distances of up to 5 kpc, a factor of ten farther than achieved thus far with HST. Long-period classical Cepheid variable stars in the Milky Way, nearly all of which reside beyond 1 kpc, are especially compelling targets for parallax measurements from scanning, as they may be used to anchor a determination of the Hubble constant to ~1%. We illustrate the method by measuring to high precision the parallax of a classical Cepheid, SY Aurigae, at a distance of more than 2 kpc, using 5 epochs of spatial-scan data obtained at intervals of 6 months. Rapid spatial scans also enable photometric measurements of bright Milky Way Cepheids---which would otherwise saturate even in the shortest possible pointed observations---on the same flux scale as extragalactic Cepheids, which is a necessity f

Author

Riess, Adam G.; Casertano, Stefano; Anderson, Jay; Mackenty, John; Filippenko, Alexei V.

Published

2014

Language

EN