Review Reports

Round 1

Reviewer 1 Report

Please find my review comments attached.

Comments for author File: Comments.pdf

Author Response

Please find the replies to Reviewer 1 attached below.

Author Response File: Author Response.pdf

Reviewer 2 Report

Cahillane and Mansell have written an extensive review of the efforts undertaken to improve the LIGO detectors for next observation run. Additionally they have provided a nice introduction and background for the reader to appreciate how these detectors are operated in practise. This will no doubt serve as a useful reference for readers. Overall it is well written, it feels brief in parts but relevant citations are provided for readers to dig into further if they need. I recommend it for publication. A few comments that the author may want to address but they are very minor: Eq 2, x and y not used in the equation, h_x and h_+ a function of x,y? line 122: single sentence paragraph places a heavy emphasis on the newtonian callibrator here. Are they expected to significantly help in O4? As a general style note though, single sentence paragraphs are used a lot in this manuscript. Which at times makes it feel like I am reading a bullet point list. line 233: Style comment: "The are two main types of noise." to "The are two main types of noise:" and then list the two rather than paragraphs. This could be applied in other places with multiple short sentences to increase the readability.

Author Response

Please see the attachment for responses to Reviewer 2

Author Response File: Author Response.pdf