%0 Journal Article
%T Photometry of K2 Campaign 9 bulge data
%A A. Gould
%A A. Udalski
%A B. S. Gaudi
%A C. Ranc
%A G. Barentsen
%A M. Penny
%A R. Poleski
%J -
%D 2019
%R 10.1051/0004-6361/201834544
%X In its Campaign 9, K2 observed dense regions toward the Galactic bulge in order to constrain the microlensing parallaxes and probe for free-floating planets. Photometric reduction of the K2 bulge data poses a significant challenge due to a combination of the very high stellar density, large pixels of the <i>Kepler<i/> camera, and the pointing drift of the spacecraft. Here we present a new method to extract K2 photometry in dense stellar regions. We extended the Causal Pixel Model developed for less-crowded fields, first by using the pixel response function together with accurate astrometric grids, second by combining signals from a few pixels, and third by simultaneously fitting for an astrophysical model. We tested the method on two microlensing events and a long-period eclipsing binary. The extracted K2 photometry is an order of magnitude more precise than the photometry from other method
%U https://www.aanda.org/articles/aa/full_html/2019/07/aa34544-18/aa34544-18.html