We present a high-precision measurement of the parallax for the 12-day Cepheid SS Canis Majoris, obtained via spatial scanning with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) . Spatial scanning enables astrometric measurements with a precision of 20–40 μ as, an order of magnitude better than pointed observations. SS CMa is the second Cepheid targeted for parallax measurement with HST and is the first of a sample of 18 long-period (≳10 days) Cepheids selected in order to improve the calibration of their period–luminosity relation and eventually permit a determination of the Hubble constant H 0 to better than 2%. The parallax of SS CMa is found to be 348 ± 38 μ as, corresponding to a distance of 2.9 ± 0.3 kpc. We also present a refinement of the static geometric distortion of WFC3 obtained using spatial scanning observations of calibration fields, with a typical magnitude ≲0.01 pixels on scales of 100 pixels.
CITATION STYLE
Casertano, S., Riess, A. G., Anderson, J., Anderson, R. I., Bowers, J. B., Clubb, K. I., … Upadhya, G. (2016). PARALLAX OF GALACTIC CEPHEIDS FROM SPATIALLY SCANNING THE WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE: THE CASE OF SS CANIS MAJORIS. The Astrophysical Journal, 825(1), 11. https://doi.org/10.3847/0004-637x/825/1/11
Mendeley helps you to discover research relevant for your work.