Talk:KAGRA

Please edit this article

The next three sections on this talk page contain links to information that should have been put into the article. Instead the poster simply posted the links and assumed that someone else would do the editing and insert the information. Of these sections two were initiated by me, both asked someone in the know to update the article. I do not read Japanese, and am not at all the correct person to edit this article.

Please is there someone on the KAGRA team, some graduate student, anyone, willing to edit this article into a proper Wikipedia article. Look at the these two Wikipedia articles Virgo interferometer and LIGO for examples of what this article should be.

According to publicly disclosed figures, the English version of English averages about 255 million page-views a day. Wikipedia overall is the eighth most visited website. I am surprised that no one on the KAGRA team cares to reach this vast audience. The English Wikipedia gets over 250,000 visits per month from more than 50 nations! e.g. in October 2021, this list included Nambia (417k), Nigeria (312k), UAE (424k), India (1,200k), China (673k), Pakistan (500k), Philippines (480k) .

I am astounded that the Japanese science community does not see the need to create a proper Wikepedia article about one of their greatest accomplishments. This instrument is only the fourth in the world, and Japan is one of only two nations to build such an instrument on their own. Nick Beeson (talk) 03:25, 13 November 2021 (UTC)

Sources not yet incorporated into article

• Schilling, Govert (July 12, 2017). "KAGRA: Japan's Underground Einstein Wave Detector". Sky and Telescope.
• Somiya, Kentaro (28 Mar 2017). Status of Kagra. 8th Einstein Telescope Symposium (conference presentation). University of Birmingham.

104.153.72.218 (talk) 05:37, 4 October 2017 (UTC)

2018 is over

Almost the entire article reads as though it was written four years ago. It currently states, "is now likely to enter operation in 2018.…planned cryogenic operation…in 2019." Every reference without exception is, at this writing, more than 2 years old. Did it begin operation this year? It is nearly the end of 2018, they only have 27 days as of this writing to make that goal. Really, there must be some information on its status more recent than January 2017.Nick Beeson (talk) 12:14, 4 December 2018 (UTC)

@Nwbeeson: Yes, it operated in a simple "initial" iKAGRA configuration in March–April 2016, and in a more complete "baseline" bKAGRA "phase 1" configuration in April–May 2018. They hope to get it operating better in a "phase 2" configuration with meaningful astrophysical sensitivity in time to overlap with the year-long LIGO/VIRGO O3 science run beginning in late March 2019.

• Akutsu, T.; et al. (KAGRA collaboration) (20 November 2018). "KAGRA: 2.5 Generation Interferometric Gravitational Wave Detector". Nature Astronomy (published January 2019). arXiv:1811.08079.
• Akutsu, T.; et al. (KAGRA Collaboration et al.) (January 2018). "Construction of KAGRA: an underground gravitational-wave observatory". Progress of Theoretical and Experimental Physics. 2018 (1): 013F01. arXiv:1712.00148. doi:10.1093/ptep/ptx180.
• "Kagra Scientific Congress Newsletter, issue 3". 1 December 2018. JGW-M1809350.

209.209.238.189 (talk) 09:38, 14 December 2018 (UTC)

2019 is over

Almost the entire article reads as though it was written five years ago. It currently states, "is now likely to enter operation in 2018.…planned cryogenic operation…in late 2019." Almost very reference, with two exceptions, are at this writing, more than 3 years old. The two newer references say it will begin operation this month (December 2019). Will it begin operation this year? It is nearly the end of 2019, they only have 29 days as of this writing to make that goal. Really, there must be some information on its status more recent than January 2019.

My previous note, from a year ago, was inadequately answered by an anonymous editor. They cited useless test runs from years ago, which are not the same thing as testing equipment designed and built to make actual detections. Nick Beeson (talk) 12:14, 2 December 2019 (UTC)

KAGRA is now fully constructed, and mostly final tests of all equipment and commissioning of the whole experiment is done. As of December 2019 it is essentially operational. The coming weeks will be rechecks, calibration and first scientific runs, followed by more planning and possible incremental improvements and monitoring of the performance. It is too early to tell if it has fully design sensitivity yet, but first scientific observations will start in mid December 2019, possibly January 2020. https://gwdoc.icrr.u-tokyo.ac.jp/DocDB/0105/L1910543/002/KSCnewsletter_201908H.pdf and https://www.scientificamerican.com/article/inside-the-worlds-first-underground-gravitational-wave-detector/ contains some very recent information. There might be more, but a lot of it is in some blogs and conference notes, some in Japanese. Some extra technical information:

• Summary of observation plans: https://dcc.ligo.org/public/0161/P1900218/002/SummaryForObservers.pdf (last updated 11 Jul 2019)
• and more in https://dcc.ligo.org/public/0094/P1200087/057/ObservingScenarios.pdf (last updated 26 Sep 2019, no DOI number, as it is not published yet, as it is being still worked on),
• https://link.springer.com/content/pdf/10.1007%2Fs41114-018-0012-9.pdf (published April 2018, https://doi.org/10.1007/s41114-018-0012-9 ),
• there is also a publicly available list of detected event by all detectors, updated with very little delay to help scientific community with observations: https://gracedb.ligo.org/latest/ , no KARGA observations there, but it might take time to integrate software pipelines, etc. I would be looking at GraceDB tho, as it is possible there will be observations published even few days from now, if we are lucky (and there is something to observe).
• KARGA is joining O3 run of LIGO and Virgo, as we speak. In fact even if O3 run finishes within next 2 months, KARGA researchers will be formally a part of O3 run. To get more information it is probably best to contact some people involved in the projects.
• There is also plenty of related conferences: https://wiki.ligo.org/LSC/UpcomingConferencesAndMeetings to check for talks and hints where to search information.
• Some extra recent articles:
• https://arxiv.org/abs/1901.03053 (Vibration isolation system with a compact damping system for power recycling mirrors of KAGRA, January 2019)
• https://arxiv.org/abs/1901.03569 (First cryogenic test operation of underground km-scale gravitational-wave observatory KAGRA, Submitted and published: January 2019),
• https://arxiv.org/abs/1909.12033 (Quantum noise reduction techniques in KAGRA, September 2019),
• https://arxiv.org/abs/1910.08310 (Constraining the stochastic gravitational wave from string cosmology with current and future high frequency detectors, November 2019),
• https://arxiv.org/abs/1906.02866 (Prospects for improving the sensitivity of KAGRA gravitational wave detector, June 2019), the last one is more about possible upgrades, which will probably start in 2021.
• https://arxiv.org/abs/1910.00955 (An arm length stabilization system for KAGRA and future gravitational-wave detectors, submitted/published October 2019, last revision 2019-11-28, just few days ago)

81.6.34.246 (talk) 20:31, 10 December 2019 (UTC)

I still don't see a news that it joined observations for any time. Certainly this would be mentioned on the KAGRA website? --mfb (talk) 10:36, 27 December 2019 (UTC)

History

I removed all of the old text, which was entered in real time, and discussed the current struggles to get KAGRA up and running. It is now historical data and should be in a section titled "Development history" or simply "History". I do not know the history so I am unable to write that section. It is not relevant now that KAGRA is taking data, and has published results. Nick Beeson (talk) 01:39, 13 November 2021 (UTC)

KAGRA "broken" ?

It's all very murky on the internet, with very little info released, but it seems that KAGRA is not working properly. By 2020 KAGRA was supposed to be operating at around the sensitivity of VIRGO, but it is now only expected to be at around 1% of that by the end of 04 - which is end of 2023! [1]. This issue really should be noted in this page. (To be honest it's very strange IMO that almost no one on journalism seems interested that a $160m observatory, that took a decade to build, doesn't work) Fig (talk) 15:47, 2 January 2022 (UTC)

According to this article [1] KAGRA's not "broken," it's just delayed due to COVID. Apparently it was left in a "simple configuration" when everyone went to remote work and they still are planning to upgrade it after they can return from remote work. [1] https://www.symmetrymagazine.org/article/japans-kagra-searches-the-sky-for-gravitational-waves 199.111.226.110 (talk) 17:42, 6 January 2022 (UTC)

Here is some more detail: "During O3GK, KAGRA typically had a BNS range of 600 kilo-parsecs (kpc) and a duty cycle (the percentage of time spent collecting astrophysical data) of 53.2%. Severe weather conditions were to blame for some part of the long downtime. Seismic noise caused by sea waves can reach KAGRA’s underground tunnels. In stormy weather, this seismic noise disturbs the stabilization of KAGRA’s mirrors, and it is difficult to keep the interferometer in observation mode. This problem is a task for the future." [2] Fig (talk) 22:03, 13 August 2022 (UTC)

Another good article digging into KAGRA's serious problems: [3] . Seems to me there's enough for a section now, focussing on why it isn't working. Fig (talk) 12:27, 2 June 2023 (UTC)

Kagra long term sensitivity

Hi,

First off - I've never done one of these comments before (I have made a few edits to pages here and there) so apologies if I do this wrong...

I was browsing through this KAGRA page and saw this comment in the intro section: "It is expected to have an operational sensitivity equal to, or greater than, LIGO and Virgo." - with that comment evidenced via a link to <https://www.businessinsider.com/earth-gravitational-wave-detector-ligo-virgo-upgrade-einstein-2019-10?r=US&IR=T>.

But I don't see anything in that article (which is a story in a non-technical publication) saying that KAGRA will ever end up being more sensitive than LIGO. It does say that the addition of KAGRA to the GW detector network will improve accuracy - which it will, once it is sensitive enough - because it will improve triangulation. But it doesn't say it will be able to make more distant detections than LIGO. And, from my reading of LIGO (including technical papers, and the excellent twice-yearly semi-technical newsletters), I've never got the feeling that KAGRA would ever end up more sensitive than LIGO. It has some extra benefits (underground), but it is smaller.

I've not got a definitive "KAGRA will never be as sensitive as LIGO" reference though. However, as one example, this webpage - which is a 2019 report from the "KAGRA Collaboration, LIGO Scientific Collaboration, and Virgo Collaboration" teams, shows, in 'Table 1' on p.4, that the projected sensitivities for LIGO in Observing period "O5" (the next one, O4, is expected to start in March 2023, currently), are, for Black Hole / Black Hole mergers ('BBH'), 2500 megaparsecs for LIGO and 'only' 1200 Mpc for KAGRA. Now 1200 Mpc is a blooming long way (~4 billion light years!)... but it is only half the projected sensitivity of LIGO. These are only projections of course - but they are on a more solid footing for LIGO than KAGRA because of the former's proven track record and experience.

So, I think the above sentence is incorrect. I don't think it will have been from any malice or bad intent; just a misinterpretation.

Should I remove the sentence? I've only added, tweaked, and corrected before. Removing information is a bit more impacting. Should someone review my thinking?

Or - perhaps it would be better to change the sentence, perhaps to "It is expected to eventually have an operational sensitivity approaching that of LIGO and Virgo.", and replace the current 'Business Insider' link with a link to the 2019 Collaborations report I mention above - ?

Thanks, Gordon Gordon Panther (talk) 13:37, 24 October 2022 (UTC)

Yes, remove that sentence. Business Insider is not an appropriate source. I would rather see current and planned sensitivity curves, like those in the LIGO article. It's very clear that LIGO is operating at the limit of quantum noise, and I can't imagine how KAGRA would exceed that, unless it used larger test masses or longer arms or different lasers or something. 67.198.37.16 (talk) 17:42, 23 March 2024 (UTC)