30 Years After The Detection Of SN1987A Neutrinos

30 years after the detection of SN1987A neutrinos

On February 23, 1987, just before 30 years from today, the neutrinos emitted from the supernova explosion SN1987A in the Large Magellanic Cloud, approximately 160,000 light-years away, reached the earth. Kamiokande, the predecessor detector of Super-Kamiokande, detected the 11 emitted neutrinos. Worldwide, it was the first instance of the detection of the emitted neutrinos from the supernova burst, and it served a big step toward resolving the supernova explosion system. In 2002, Dr. Masatoshi Koshiba, a Special University Professor Emeriuts of the University of Tokyo, was awarded a Nobel Prize in Physics for this achievement.

Before the explosion of supernova SN1987A (right) and after the explosion (left) Anglo-Australian Observatory/David Malin

Kamiokande, the pioneer of neutrino research

Kamiokande detector was a cylindrical water tank (16 m in diameter and height) with 1000 of the world’s largest photomultiplier tubes inside it, and it was laid 1000 m underground in Kamioka-town, Yoshiki-gun, (currently Hida-city) Gifu Prefecture, Japan. (Currently the site of Kamiokande is used for KamLAND experiment.) Kamiokande was devised by Prof. Koshiba who started the observation in 1983. Originally, it was constructed for detecting the proton decay phenomenon, but it was modified for the solar neutirno observation. By the end of 1986, the detector modification was completed and the observation began.

Inside of Kamiokande detector

Overview of Kamiokande detector

Prof. Koshiba working in the tank

Prof. Kajita and Prof. Nakahata (then PhD students) tuning up the data aquision system in the mine

The day of detection of the supernova neutrinos

On February 25, 1987, two days after the observation of supernova SN1987A through naked eyes, a fax was sent from Pennsylvania University to the University of Tokyo to inform them about the supernova explosion. Soon after receiving the fax, Prof. Yoji Totsuka asked the researcher in Kamioka to send the magnetic tapes that recorded the Kamiokande data. (At that time, the information network was not developed, so the data was delivered physically).

The fax sent from Pennsylvania University to inform about the supernova explosion.

On February 27, when the magnetic tapes arrived at the laboratory in Tokyo, Prof. Masayuki Nakahata (currently the spokesperson of Super-Kamiokande experiment), who was then a PhD student immediately started the analysis. On the morning of February 28, while Prof. Nakahata printed out the analysis plot between the detection time and number of photo-sensors that detect the light, Ms. Keiko Hirata, a Master’s student found a peak, obviously different from the noise in the distribution. It was the exact trace to detect the neutrinos from SN1987A. (A two minutes blank period due to a regular system maintenance is recorded in the plot, at a few minutes before the explosion. If the explosion occurred during this period, Kamiokande could not have detected the SN1987A neutrinos.) After a detailed analysis, it was clear that Kamiokande detected 11 neutrinos for 13 seconds after 16:35:35 on February 23, 1987.

THe magnetic tape recorded SN1987A data

The printout of Kamiokande data and the envelope which stores the printout in. “Keep carefully Y.T.” written by Prof. Youji Totsuka.

The printout of the data. Horizontal axis shows time (from right to left and one line as 10 seconds) and the vertical axis shows the number of hit photo-sensors of each event (approximately proportional to the energy of the event). The obvious peak is the signal of neutrinos from SN1987A. The blank period due to the detector maintainance was recorded a few minutes before the signal.

When Prof. Nakahata finished the analysis and reported to Prof. Koshiba on the morning of March 2, Prof. Koshiba instructed him to investigate the entire data for the presence of similar signals. Under a gag rule, researchers analyzed the 43 days data of Kamiokande on March 2 to March 6, and obtained conclusive evidence that the occurrence of the peak was only from the signal of the supernova SN1987A; further, they published these findings as an article. Here are the the signatures of researchers who wrote the article.

The subsequent development of neutrino research

The Kamiokande’s detection of the supernova neutrinos became a trigger to recognize the importance of neutrino research, and the construction of Super-Kamiokande, whose volume is about 20 times larger than that of Kamiokande, was approved. Super-Kamiokande started observation from 1996 and discovered the neutrino oscillation in 1998. In 2015, Prof. Takaaki Kajita was awarded the Nobel Prize in Physics for this achievement. SN1987A made a worldwide breakthrough in neutrino research, including the K2K experiment, T2K experiment and KamLAND experiment.

If a supernova explosion in our galaxy occurs now, Super-Kamiokande will detect approximately 8,000 neutrinos, almost 1000 times greater than those detected 30 years ago. Further, it is expected that the detailed mechanism of supernova explosion will be revealed and we will understand the stars or our universe in depth. In our galaxy, the supernova explosion is expected to occur once in every 30-50 years. It may occur at this very moment. The neutrinos from the supernova will be detected in mere 10 seconds. Super-Kamiokande continues the observation and will not miss any explosion moment.

Source

Nine facts about neutrinos

Images: Kamioka Observatory,

Happy International Women’s Day!

Today we celebrate International Women’s Day, a day in which we honor and recognize the contributions of women…both on Earth and in space.

Since the beginning, women have been essential to the progression and success of America’s space program.

Throughout history, women have had to overcome struggles in the workplace. The victories for gender rights were not achieved easily or quickly, and our work is not done.

Today, we strive to make sure that our legacy of inclusion and excellence lives on.

We have a long-standing cultural commitment to excellence that is largely driven by data, including data about our people. And our data shows progress is driven by questioning our assumptions and cultural prejudices – by embracing and nurturing all talent we have available, regardless of gender, race or other protected status, to build a workforce as diverse as our mission. This is how we, as a nation, will take the next giant leap in exploration.

As a world leader in science, aeronautics, space exploration and technology, we have a diverse mission that demands talent from every corner of America, and every walk of life.

So, join us today, and every day, as we continue our legacy of inclusion and excellence.

Happy International Women’s Day!

Learn more about the inspiring woman at NASA here: https://women.nasa.gov/

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matthewjopdyke

6 years ago

New Podcast: Starts With A Bang #35 - Do We Live In A Multiverse

There’s been a lot of speculative ideas put forth about the Multiverse, and I dare say that a great many of them are nothing more than wishful thinking. But that doesn’t mean the Multiverse itself is ill-motivated at all. Rather, if you take two of our best theories that have been well-confirmed in a wide variety of different ways, you’re going to find that you arrive at a bizarre but unavoidable picture: one of an inflating spacetime, eternal to the future, where regions that look like our Universe, complete with a hot Big Bang, are spawned continuously.

The evidence might not be there, observably, to confirm or deny the existence of a Multiverse. But as a theoretical consequence, it certainly has a motivation that’s far stronger than practically anyone realizes. Here’s the cosmic story.

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matthewjopdyke

7 years ago

As I write and as I share, my main three priorities in a more converged manner are 1. Biology, 2. Neurology, and 3. Physics, as I have described in this meme.

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5 years ago

Video for my newly released book, Pathway to the Stars: Part 7, Span of Influence. As always, it was fun putting it together. (Please help to get the word out! Thank you!) <3 "To be worthy to journey the stars, conditions must be such that if a group of explorers were to return home many millennia later, humanity will not have faded away into nothing. Instead, they will have preserved the homeworld and home solar system, and even improved upon the beauty, the abundance, and the ability of longevity of life in every way that is positive and possible."

Eliza Williams works with her team in the Pathway organization to increase her span of influence throughout the world. Journey with Vesha Celeste as she continues her adventures with Yesha Alevtina in the Virtual Universe, understanding more fully how Eliza's team has become the enigmatic propagator of the future. With tech cities spanning the Solar System yet hidden from those who have not been read-in, humanity will be breath taken to behold them. Eliza takes on some of the biggest titans of every industry and teaches them what she believes will fuel the future -- kindness, shared-well-being, compassion, and consent, or what she coins as Universal Ethics!

Span of Influence, ISBN: 9781951321055, LCCN: 2019918436

eBook: https://www.amazon.com/dp/B081XHLJ36

Paperback: https://www.amazon.com/dp/1951321073

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matthewjopdyke

4 years ago

Masks are up on store

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matthewjopdyke

6 years ago

Excellent Time to Cozy Up to Preparation for a Grand Space Adventure!

It takes a lot to travel beyond the limits of our Solar System. As such, the Christmas Edition of the two-novel literary masterpiece, with a side dish series going a little deeper in smaller portions of each major aspect of the two-novel series, Pathway to the Stars, despite being ridden with indie goofs, pauper challenges toward perfection, and ever-so-constantly updating text to improve the…

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matthewjopdyke

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Further Than Before: Pathway to the Stars, Part 1 - Audiobook Promo (Extended)

First of all, I want to thank my audience and let them know that it has been an honor working with my narrator, Graham Bessellieu. Despite being a newly publ...

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matthewjopdyke

8 years ago

Just a tune, courtesy of Balligomingo, Garrett Schwartz, Vic Levak, and Beverly Staunton that I've enjoyed for a while.

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matthewjopdyke

5 years ago

Pathway to the Stars: Part 9, Allure & Spacecraft "We cannot engage in human progression as solo artists, alone, and expect long-term and optimal results. While we can inspire momentum for a time, while working diligently, ultimately the laws of chaos will prevail unless we work together to preserve our world, our solar system, and our Universe." ~ Eliza Williams Vesha has completed her Virtual Universe training, and now she becomes immersed in missions and callings as never before! Enjoy as she tackles issues where society seems muddled in the chains of self-bondage, rather than moving forward with a bright and beautiful future for all. Joanne revisits a problem that can affect Eliza Williams' hopes for the future. Among Eliza's many goals within the Solar System to that end, related to space travel, is the construction of spacecraft being built just above Pluto! Enjoy this Space Opera as Eliza continues her quest to nurture humanity into a space-faring, world-preserving, and Universe-exploring civilization! She believes that the most significant step toward moving forward is kindness, and that kindness is the greatest strength we have! ISBN: 978-1951321093 LCCN: 2019918425eBook: https://smile.amazon.com/dp/B081XLG9JV Paperback: https://smile.amazon.com/dp/195132109X For more info: https://www.mjopublications.com https://smile.amazon.com/author/matthewopdyke Tags: #sciencefiction #scifi #spaceopera #fantasy #stem #astronomy #sentience #spacecraft #spaceelevator #wellbeing #author #matthewjopdyke #ebook #paperback #amazon

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