<p>The <a href="https://www.ligo.org/science/Publication-O2Catalog/" rel="nofollow noreferrer">LIGO science collaboration site</a> is the official source (highlighting is from me):</p>
<blockquote>
<p>Of the ten BBH systems in our catalog, six have estimated distances of about a Gigaparsec (1 Gpc = 1 billion parsecs) or more: the most distant source (which was also the heaviest) is <strong>GW170729, at a distance of 2.76 Gpc, or about 9 billion light-years</strong>, while the closest source is GW170608 which is 0.32 Gpc (or about 1 billion light years distant).</p>
</blockquote>

CC BY-SA 4.0
2021-06-29T09:31:43.517Z
2021-06-29T09:31:43.517Z
B--rian
<p>GW170729 was gravitational wave signal's detected by the Virgo and LIGO detectors. I read the following in a news report:</p>

<blockquote>
  <p>Known as GW170729, in accordance with the date of its discovery (in US
  format), the gravitational wave that astronomers can listen in to was
  caused by the formation of a black hole more than 80 times as massive
  as our sun and about nine billion light years away. (<a href="https://www.smh.com.au/national/astrophysics-will-explode-scientists-hear-10-black-holes-merging-20181203-p50jub.html" rel="nofollow noreferrer">Source</a>)</p>
</blockquote>

<p>I am specifically interested in the claim that it comes from 9-billion light years away. I have been unable to find a good source to back this claim up. </p>

<p>How accurate is this claim? Please provide a source for your answer and where applicable, a simple explanation of how the data backs this up. More information about this event can be found <a href="https://cplberry.com/2018/12/07/o2-catalogue/" rel="nofollow noreferrer">here</a>.</p>

CC BY-SA 4.0
2019-01-14T00:54:20.317Z
Hi, Stringers, welcome to Astronomy Stack Exchange. Have you looked at any of the papers LIGO/VIRGO put out (like https://arxiv.org/abs/1811.12907)? They do report the distance in the papers, although it might be listed in megaparsecs, rather than light-years. [Wikipedia](https://en.wikipedia.org/wiki/List_of_gravitational_wave_observations) has the data, too, although the primary sources (the papers) are often the better ones to go to first.
HDE 226868
CC BY-SA 4.0
2019-01-14T01:25:34.787Z
I did try to read the paper you've linked earlier but I had trouble finding what I was looking for. It's definitely helpful to know that it's listed in a different format. On the Wikipedia page, it appears the information I want is in the Luminosity Distance field, which here is also in Megaparsecs.
Stringers
CC BY-SA 4.0
2019-01-14T12:40:56.153Z
In general terms, the exact shape, as well as the intensity of the gravity wave is enough to work out both the size of the black holes and their distance. Smaller BHs closer to us would produce a different pattern
Steve Linton
CC BY-SA 4.0
2019-01-15T18:34:58.603Z
@Stringers Luminosity distance is the important thing here. Other distances would be calculated from it. BTW as you can see uncertainties are very high so you can pretty much pick a number.
Mithoron
<black-hole><observational-astronomy><gravitational-waves>
How far away was the binary black hole that produced GW170729?
Stringers
# How far away was the binary black hole that produced GW170729?

(Asked by: username_0 on 2019-01-14)

GW170729 was gravitational wave signal's detected by the Virgo and LIGO detectors. I read the following in a news report:

> Known as GW170729, in accordance with the date of its discovery (in US
> format), the gravitational wave that astronomers can listen in to was
> caused by the formation of a black hole more than 80 times as massive
> as our sun and about nine billion light years away. ([Source](https://www.smh.com.au/national/astrophysics-will-explode-scientists-hear-10-black-holes-merging-20181203-p50jub.html))

I am specifically interested in the claim that it comes from 9-billion light years away. I have been unable to find a good source to back this claim up.

How accurate is this claim? Please provide a source for your answer and where applicable, a simple explanation of how the data backs this up. More information about this event can be found [here](https://cplberry.com/2018/12/07/o2-catalogue/).

**Tags:** black-hole, observational-astronomy, gravitational-waves
> **Comments:**
> **username_1**: Hi, Stringers, welcome to Astronomy Stack Exchange. Have you looked at any of the papers LIGO/VIRGO put out (like https://arxiv.org/abs/1811.12907)? They do report the distance in the papers, although it might be listed in megaparsecs, rather than light-years. [Wikipedia](https://en.wikipedia.org/wiki/List_of_gravitational_wave_observations) has the data, too, although the primary sources (the papers) are often the better ones to go to first.  
> **username_0**: I did try to read the paper you've linked earlier but I had trouble finding what I was looking for. It's definitely helpful to know that it's listed in a different format. On the Wikipedia page, it appears the information I want is in the Luminosity Distance field, which here is also in Megaparsecs.  
> **username_2**: In general terms, the exact shape, as well as the intensity of the gravity wave is enough to work out both the size of the black holes and their distance. Smaller BHs closer to us would produce a different pattern  
> **username_3**: @Stringers Luminosity distance is the important thing here. Other distances would be calculated from it. BTW as you can see uncertainties are very high so you can pretty much pick a number.  

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## 1 answers

### Answer by username_4 on 2021-06-29. Score: 2

The [LIGO science collaboration site](https://www.ligo.org/science/Publication-O2Catalog/) is the official source (highlighting is from me):

> Of the ten BBH systems in our catalog, six have estimated distances of about a Gigaparsec (1 Gpc = 1 billion parsecs) or more: the most distant source (which was also the heaviest) is **GW170729, at a distance of 2.76 Gpc, or about 9 billion light-years**, while the closest source is GW170608 which is 0.32 Gpc (or about 1 billion light years distant).


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