{"id":8124,"date":"2021-10-14T02:00:41","date_gmt":"2021-10-14T06:00:41","guid":{"rendered":"https:\/\/spaceandplanetarynewswire.com\/?p=8124"},"modified":"2021-10-14T02:00:41","modified_gmt":"2021-10-14T06:00:41","slug":"did-a-black-hole-eating-a-star-generate-a-neutrino-unlikely-new-study-shows","status":"publish","type":"post","link":"https:\/\/spaceandplanetarynewswire.com\/?p=8124","title":{"rendered":"Did a Black Hole Eating a Star Generate a Neutrino? Unlikely, New Study Shows"},"content":{"rendered":"
Artist\u2019s illustration of tidal disruption event AT2019dsg where a supermassive black hole spaghettifies and gobbles down a star. Some of the material is not consumed by the black hole and is flung back out into space.<\/figcaption><\/figure>\n

In October 2019, a high-energy neutrino slammed into Antarctica. The neutrino, which was remarkably hard to detect, peaked astronomers\u2019 interest: what could generate such a powerful particle? <\/p>\n

Researchers traced the neutrino back to a supermassive black hole that had just ripped apart and swallowed a star. Known as a tidal disruption event (TDE), AT2019dsg occurred just months earlier \u2014 in April 2019 \u2014 in the same region of the sky where the neutrino had come from. The monstrously violent event must have been the source of the powerful particle, astronomers said.  <\/p>\n

But new research casts doubt on that claim. <\/p>\n

In a study<\/a> published this month in the Astrophysical Journal<\/em>, researchers at the Center for Astrophysics | Harvard & Smithsonian and Northwestern University, present extensive new radio observations and data on AT2019dsg, allowing the team to calculate the energy emitted by the event. The findings show AT2019dsg generated nowhere near the energy needed for the neutrino; in fact, what it spewed out was quite \u201cordinary,\u201d the team concludes.<\/p>\n

Black Holes are Messy Eaters<\/strong><\/p>\n

While it may seem counterintuitive, black holes do not always swallow everything in reach.<\/p>\n

\u201cBlack holes are not like vacuum cleaners,\u201d says Yvette Cendes<\/a>, a postdoctoral fellow at the Center for Astrophysics who led the study.<\/p>\n

When a star wanders too close to a black hole, gravitational forces begin to stretch, or spaghettify, the star, Cendes explains. Eventually, the elongated material spirals around the black hole and heats up, creating a flash in the sky that astronomers can spot from millions of light years away. <\/p>\n

\u201cBut when there\u2019s too much material, black holes can\u2019t eat it all smoothly at once,\u201d says Kate Alexander<\/a>, a study co-author and postdoctoral fellow at Northwestern University who calls black holes \u2018messy eaters.\u2019 \u201cSome of the gas gets spewed back out during this process \u2014 like when babies eat, some of the food ends up on the floor or the walls.\u201d<\/p>\n

These leftovers get flung back into space in the form of an outflow, or jet \u2014 which, if powerful enough, could theoretically generate a subatomic particle known as a neutrino. <\/p>\n

An Unlikely Source for Neutrinos<\/strong><\/p>\n

Using the Very Large Array in New Mexico and Atacama Large Millimeter\/submillimeter Array (ALMA) in Chile, the team was able to observe AT2019dsg, some 750 million light years away, for more than 500 days after the black hole had started consuming the star. The extensive radio observations make AT2019dsg the most well-studied TDE to date and revealed that the radio brightness peaked around 200 days after the event began.<\/p>\n

According to the data, the total amount of energy in the outflow was equivalent to the energy radiated by the Sun over the course of 30 million years. While that may sound impressive, the powerful neutrino spotted on Oct. 1, 2019 would require a source 1,000 times more energetic.<\/p>\n

\u201cInstead of seeing the bright jet of material needed for this, we see a fainter radio outflow of material,\u201d Alexander explains. \u201cInstead of a powerful firehose, we see a soft wind.\u201d<\/p>\n

Cendes adds, \u201cIf this neutrino somehow came from AT2019dsg, it begs the question: Why haven\u2019t we spotted neutrinos associated with supernovae at this distance or closer? They are much more common and have the same energy velocities.\u201d<\/p>\n

The team concludes it\u2019s unlikely that the neutrino came from this particular TDE. If it did, however, astronomers are far from understanding TDEs and how they launch neutrinos.<\/p>\n

\u201cWe\u2019re probably going to check-in on this one again,\u201d says Cendes, who believes there\u2019s still much to learn. \u201cThis particular black hole is still feeding.\u201d<\/p>\n

TDE AT2019dsg was first discovered on April 9, 2019 by the Zwicky Transient Facility in Southern California. The neutrino, known as IceCube-191001A, was detected by the IceCube Neutrino Observatory in the South Pole six months later.<\/p>\n","protected":false},"excerpt":{"rendered":"

In October 2019, a high-energy neutrino slammed into Antarctica. The neutrino, which was remarkably hard to detect, peaked astronomers\u2019 interest: what could generate such a powerful particle?  Researchers traced the neutrino back to a supermassive black hole that had just ripped apart and swallowed a star. Known as a tidal disruption event (TDE), AT2019dsg occurred just…<\/p>\n","protected":false},"author":71,"featured_media":8127,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"fifu_image_url":"https:\/\/earimediaprodweb.azurewebsites.net\/Api\/v1\/Multimedia\/5da79b54-b649-455f-b8a9-033710c494c9\/Rendition\/low-res\/Content\/Public","fifu_image_alt":"Did a Black Hole Eating a Star Generate a Neutrino? Unlikely, New Study Shows","footnotes":""},"categories":[215],"tags":[],"class_list":["post-8124","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-stars"],"_links":{"self":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/8124","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/users\/71"}],"replies":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8124"}],"version-history":[{"count":1,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/8124\/revisions"}],"predecessor-version":[{"id":8126,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/8124\/revisions\/8126"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/media\/8127"}],"wp:attachment":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8124"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8124"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8124"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}