Team discovers new way supermassive black holes are 'fed'

January 14, 2019, Tel Aviv University
Artistic impression of a gas disk feeding a massive black hole while emitting radiation. Credit: NASA

Supermassive black holes weigh millions to billions times more than our sun and lie at the center of most galaxies. A supermassive black hole several million times the mass of the sun is situated in the heart of our very own Milky Way.

Despite how commonplace supermassive are, it remains unclear how they grow to such enormous proportions. Some black holes constantly swallow gas in their surroundings, some suddenly swallow whole stars. But neither theory independently explains how supermassive black holes can "switch on" so unexpectedly and keep growing so fast for a long period.

A new Tel Aviv University-led study published today in Nature Astronomy finds that some supermassive black holes are triggered to grow, suddenly devouring a large amount of gas in their surroundings.

In February 2017, the All Sky Automated Survey for Supernovae discovered an event known as AT 2017bgt. This event was initially believed to be a "star swallowing" event, or a "tidal disruption" event, because the radiation emitted around the black hole grew more than 50 times brighter than what had been observed in 2004.

However, after extensive observations using a multitude of telescopes, a team of researchers led by Dr. Benny Trakhtenbrot and Dr. Iair Arcavi, both of TAU's Raymond & Beverly Sackler School of Physics and Astronomy, concluded that AT 2017bgt represented a new way of "feeding" black holes.

"The sudden brightening of AT 2017bgt was reminiscent of a tidal disruption event," says Dr. Trakhtenbrot. "But we quickly realized that this time there was something unusual. The first clue was an additional component of light, which had never been seen in tidal disruption events."

Dr. Arcavi, who led the , adds, "We followed this event for more than a year with telescopes on Earth and in space, and what we saw did not match anything we had seen before."

The observations matched the theoretical predictions of another member of the research team, Prof. Hagai Netzer, also of Tel Aviv University.

"We had predicted back in the 1980s that a black hole swallowing gas from its surroundings could produce the elements of light seen here," says Prof. Netzer. "This new result is the first time the process was seen in practice."

Astronomers from the U.S., Chile, Poland and the U.K. took part in the observations and analysis effort, which used three different space telescopes, including the new NICER telescope installed on board the International Space Station.

One of the ultraviolet images obtained during the data acquisition frenzy turned out to be the millionth image taken by the Neil Gehrels Swift Observatory—an event celebrated by NASA, which operates this space mission.

The research team identified two additional recently reported events of black holes "switched on," which share the same emission properties as AT 2017bgt. These three events form a new and tantalizing class of black hole re-activation.

"We are not yet sure about the cause of this dramatic and sudden enhancement in the black holes' feeding rate," concludes Dr. Trakhtenbrot. "There are many known ways to speed up the growth of giant black holes, but they typically happen during much longer timescales."

"We hope to detect many more such events, and to follow them with several telescopes working in tandem," says Dr. Arcavi. "This is the only way to complete our picture of black hole growth, to understand what speeds it up, and perhaps finally solve the mystery of how these giant monsters form."

Explore further: Student simulates thousands of black holes

More information: Benny Trakhtenbrot et al, A new class of flares from accreting supermassive black holes, Nature Astronomy (2019). DOI: 10.1038/s41550-018-0661-3

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dsylvan
not rated yet Jan 15, 2019
Title of article:
"Team discovers new way supermassive black holes are 'fed'."

From article:
"We are not yet sure about the cause of this dramatic and sudden enhancement in the black holes' feeding rate," concludes Dr. Trakhtenbrot.

Frustrating.
dsylvan
2 / 5 (1) Jan 15, 2019
Is physorg only interested in eyeballs and not the minds behind them?
johnqsmith
1 / 5 (1) Jan 15, 2019
If they found out anything, it looks like they want to keep it secret.
jonesdave
3.9 / 5 (8) Jan 15, 2019
Is physorg only interested in eyeballs and not the minds behind them?


TBF, dsylvan, if you highlight that headline, and paste it into Google, you'll find that it pops up on a number of sites. Remember, this is just a science news aggregate, and there are plenty of others, and they just take their stuff from PRs from various institutions. Many of the people doing the PRs for those institutions may not be well versed in the relevant science.
dsylvan
5 / 5 (1) Jan 15, 2019
...Remember, this is just a science news aggregate, and there are plenty of others, and they just take their stuff from PRs from various institutions. Many of the people doing the PRs for those institutions may not be well versed in the relevant science.

Thanks for the reminder jonesdave. I shouldn't blame just physorg for what is a systemic problem---and I should especially stop complaining about it on their website...
torbjorn_b_g_larsson
5 / 5 (2) Jan 16, 2019
Title of article:
"Team discovers new way supermassive black holes are 'fed'."

From article:
"We are not yet sure about the cause of this dramatic and sudden enhancement in the black holes' feeding rate," concludes Dr. Trakhtenbrot.

Frustrating.


I am sure it is frustrating to them too, but as it happens it is not a click bait title (much) since they did discover a new mode. Welcome to science, progress through frustration, no easy pre-digested media talking points.

If they found out anything, it looks like they want to keep it secret.


That joke - if it is one - does not work since scientists cannot keep stuff secret (except between publications), they live on *revealing* "nature's secrets".
rrwillsj
not rated yet Jan 16, 2019
john, you shouldn't waste your energy in fear of the MIB.

However, you do seem to have good reason to concern yourself with the threat from the MIW.

I would suggest you get a shoovel & start digging a very deep hole to hide in.

I promise. pinky-swear. I'll send you a singing telegram when you can stop digging.
RealityCheck
1 / 5 (3) Jan 17, 2019
@torbjorn_b_g_larsson.
...scientists cannot keep stuff secret (except between publications), they live on *revealing* "nature's secrets".
I'm very glad you included that rider "except between publication" in parentheses, mate. Because when I pointed out to some here that I was perforce keeping some things secret until I am ready to publish my work 'complete' instead of 'piecemeal', they were uncomprehending of that obvious scientific-publication-imperative of 'intervening secrecy', especially when novel/original/complex work is involved. Thanks for making that clear for those who were less than polite when I previously informed them of that very same 'secrecy imperative' that you just confirmed was normal practice for mainstream science work/publication. If I get any future hassles from anyone on that 'secrecy' score, I shall refer them to your post instead of arguing with them. Thanks again for your correct understanding/support on that score, mate. :)
jonesdave
3.7 / 5 (6) Jan 17, 2019
I'm very glad you included that rider "except between publication" in parentheses, mate. Because when I pointed out to some here that I was perforce keeping some things secret until I am ready to publish my work 'complete' instead of 'piecemeal', they were uncomprehending of that obvious scientific-publication-imperative of 'intervening secrecy', especially when novel/original/complex work is involved. Thanks for making that clear for those who were less than polite when I previously informed them of that very same 'secrecy imperative' that you just confirmed was normal practice for mainstream science work/publication. If I get any future hassles from anyone regarding that 'secrecy' score, I shall refer them to your post instead of arguing with them. Thanks again for your correct understanding/support on that score, mate. :)


You are not a scientist, and you'll never publish in a respectable journal. Ergo, your inane rantings are just that.
RealityCheck
1 / 5 (2) Jan 17, 2019
@jonesdave.
I'm very glad you included that rider "except between publication" in parentheses, mate. Because when I pointed out to some here that I was perforce keeping some things secret until I am ready to publish my work 'complete' instead of 'piecemeal', they were uncomprehending of that obvious scientific-publication-imperative of 'intervening secrecy', especially when novel/original/complex work is involved. Thanks for making that clear for those who were less than polite when I previously informed them of that very same 'secrecy imperative' that you just confirmed was normal practice for mainstream science work/publication. If I get any future hassles from anyone regarding that 'secrecy' score, I shall refer them to your post instead of arguing with them. Thanks again for your correct understanding/support on that score, mate.
You are not a scientist, and you'll never publish in a respectable journal.....
Envy. Malice. Denial. You have no idea, jd. Stop it.
jonesdave
3.4 / 5 (5) Jan 17, 2019
Envy. Malice. Denial. You have no idea, jd. Stop it.


Lol. Take your crap to a physics forum, woo boy. You have nothing, other than misunderstanding. Correct? (rhetorical)
RealityCheck
1 / 5 (2) Jan 17, 2019
ps: @jonesdave.

While you're here, do yourself a favor and check out yet another Supernovae Type Ia 'variation'...

https://phys.org/...ell.html

...it makes naive/simplistic 'standard candle' assumptions/interpretations ludicrous for claiming 'expanding universe'. I long pointed out (to you, RNP, IMP-9 etc) that 'local' dynamics, constituents/bodies, surrounding/intervening processes/material etc, make any 'standard candle' based claims as to what's actually happening 'there' highly SPECULATIVE; and hence invalid for BB/Inflation/Expansion claims. Maybe you'd like to read back all my posts where I long pointed out all these things, jd. Then maybe you might get an idea how correct/scientific I've been all along (while you/gang were busy trolling, ignoring, denying, insulting, opining from your own inculcated ignorance re the evolving scientific reality I tried to give you 'heads up' about for years). Good luck, jd. :)

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