Day 1 Lectures
Questions about the lectures from Day 1 can be posted here:
- Public Data - Martin Beroiz
- Detector Overview - Jenne Driggers
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Hello world!
Here in Paris, the study hub is getting ready!
We’re all excited about the workshop.
E
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Hi, can you enable the chat option on the youtube live stream? I am unable to join ZOOM somehow.
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I have a question from the Public Data talk by Martin Beroiz. He mentioned that LIGO has various detection pipelines. Can there be a further elaboration on what these detection pipelines exactly are?
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Saksham you can find a list of pipelines here:
https://www.gw-openscience.org/software/
Some are based on matching filter using as model the coalescence of binary objects (pyCBC,gstLAL, …)
Others are more wide-open to any kind of signals so they catch of excess power in the Time-Frequency domain (cWB, …)
In that page you see also other utilities/algorithms used not for detection but for estimation of the signal parameters (like the sky direction or masses,…)
And a lot of other stuff!
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Hi! I am working through the first day’s tutorials and am able to run the code/get through the “Quiz Questions” but I have no real understanding of what an FFT, ASD, and a Q-Transform actually are. I have a basic understanding of what a Fourier Transform is/how it works but I am only a rising sophomore in college and haven’t encountered it in its full mathematical rigor yet. Will any of these processes be explained in-depth at some point in the workshop or does anybody know of any resources that could aid my understanding? Is this even the right place to be asking this question? Thanks.
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Hi @AndrewValentini ,
Thank you for the question!
These topics are covered in the introductory material. Notice that there are associated lecture videos as well. These materials are relatively new - I’d welcome your help in improving them.
Oh! You might also like the Signal Processing Tutorial.
Good luck!
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Wow. This is great. Thank you for all of the work put into this!
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I enjoyed the first day lecture. Can you please explain in layman’s terms why most of the signals which generate GW happen to be in the 10-a few KHz in frequency?
I mean 10Hz - A few KHz
Hello frowdow,
This range of 10Hz to 10kHz that you are mentioning is actually the favored detection range for actual terrestrial interferometers. Since the best sensitivity is reached for these frenquencies, the detection done today are all in this range, but gravitational waves span a much larger range, depending on the source.
You can see on Wikipedia the different sources of waves and their frequency range, and in this article (Fig. 1) the frequency span of Binary Coalescence coinciding with LIGO interferometers’s sensitivity.
I hope that I have answered your question.
Why does frequency peaks at 500 Hz in the advanced LIGO and A+ design sensitivity?
(Fig 5, arixv 2202.00847)
Hi Felix,
Thanks for the reply. After reading your reply, I realized that it was a stupid question, especially after yesterday’s talk on the sensitivity and noise performance of the LIGO detectors,
@Dhavluu The sensitivity curve is a sum of many different noise sources, and the exact shape depends on the design of the detectors. You can see some notes about different sources of noise for LIGO in the “Introduction to noise” notebook, along with a reference to a more detailed paper.
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Not at all! No question is stupid, and in any case having it posted in this channel might help other people.
I’m glad I could help bringing an answer
Why do some data frames are not 100%
@KyleCarlo The LIGO and Virgo detectors are not observing at all times. Each strain file corresponds to 4096 seconds of wall clock time, but the fraction shows what percentage of the time contains observing mode data.