deletions | additions       diff --git a/sky.tex b/sky.tex  index 9f52b02..2ccc1e4 100644  --- a/sky.tex  +++ b/sky.tex 
...
Having discussed how GW observations can measure the intrinsic properties of their source systems, we now consider the measurement of extrinsic parameters such as source location. On their own, these are not useful for understanding the physics of compact objects, but they are central to the success of multimessenger astronomy.  We characterize sky localization using credible regions (CRs), regions,  the smallest sky area that encompasses a given total posterior probability. The CR credible region  for a total posterior probability $p$ is defined as \begin{equation}  \mathrm{CR}_p = \underset{A}{\arg\!\max} \int_A \mathrm{d}\boldsymbol{\Omega} P_{\Omega}(\boldsymbol{\Omega}),  \label{eq:CR}  \end{equation}  where $P_{\Omega}(\boldsymbol{\Omega})$ is the posterior probability density PDF  over sky position $\boldsymbol{\Omega}$, and $A$ is the sky area integrated over. over \citep{Sidery_2014}.  We also consider the searched area, area $A_\ast$,  the area of the smallest CR credible region  that includes the true location. For electromagnetic observatories to be able to conduct follow-up of a GW detection, they need an accurate sky location. This must be provided promptly, while there is still a visible transient. The full spinning PE is computationally expensive and so slow to compute. There are alternative methods that can provide sky localization more quickly. The most expedient is \textsc{bayestar}, this uses output from the detection pipeline to rapidly compute sky position \citep{Singer_2014}.