LIGO Seminar

With two confirmed observations of gravitational wave (GW) events, the
era of GW astronomy has begun, however, a coincident observation of an
electromagnetic (EM) counterpart has yet to be produced. In order to
reliably identify and link potential EM counterparts, a major
challenge to overcome is to find effective selection criteria to
reduce the number of false-positives in telescope images. Specifically
in the case of wide-field telescopes, differential image analysis
suffers from imperfect image subtraction, in part due to variations of
the point-spread function across the image.

I will discuss a pipeline that was developed to address this issue.
Using a dedicated metric in a shapelet space, the point-likeness of
image residuals can be characterized and artifacts rejected with good
certainty. The pipeline has been used on a set of both PTF and DECam
images with representative sky coverage, removing on average up to
99.95% of all image subtraction artifacts.

Surveying the sky for transients using the pipeline on archival
images, I extracted a realistic rate of false-positives to be expected
from LIGO-Virgo probability skymaps.