Questions tagged [supermassive-black-hole]
Questions regarding the most massive examples of black holes that typically reside at the centers of galaxies.
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Did the Grus star get expelled from the Milky way because it was accelerated by the Sagittarius A black hole?
On Wikipedia there is an article that says a star may have been expelled from the Milky Way because it interacted with Sagittarius A.
Sagittarius A* from Wikipedia:
In July 2019, astronomers reported ...
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Does the (relative) distance of the photon sphere from the center of a black hole vary according its mass?
I know that the photon circle or photon sphere is located at around 1.5 times the radius of the Schwarzschild event horizon, but wouldn't it be comparatively further out for smaller black holes?
After ...
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What do the symbols signify in Dr. Becky Smethurst's radiation pressure equation for black holes?
In her most recent video, "An ULTRAMASSIVE black hole has been discovered in a BRAND NEW way!", as well as a previous video, "How massive can black holes get?", Dr. Becky Smethurst ...
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How does Very Long Baseline Interferometry work?
According to internet sources, this technique increases the effective diameter of the telescope, thus improving the angular resolution of the telescope. However I don't understand how this actually ...
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What's the meaning of "hard supermassive black hole binary"?
In this paper, the authors state in the Introduction that
A hard SMBHB [SuperMassive Black Hole Binary] can eject surrounding stars to transfer their orbital energy and angular momentum, which may be ...
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Could we detect dark matter by black holes gaining unexplained mass?
Dark matter is said to interact only gravitationally, so it won't commonly form black holes by itself. But if a black hole is already there, and dark matter encounters the event horizon, it should go ...
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What is the rotational speed of Sagittarius A*?
Sagittarius A* is the Milky Way's own supermassive black hole. Up till recently, I used to think that Sagittarius A* was a static black hole, i.e. It had no rotational speed at all.
But after doing a ...
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Will the universe eventually merge completely into a single, enormous BH
I see other similar questions, but mine is more specific: If total merger into one BH is the ultimate endgame, then if the universe had no net angular momentum in the beginning, then wouldn't the ...
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Do all black holes, including stellar-mass ones, rotate at nearly the speed of light? Also, what exactly does that do to their shape?
From what I understand, astrophysicists have known for almost a decade that supermassive black holes seem to spin at incredible velocities; nearly the speed of light... In fact, some of the outer ...
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How many massive black holes exist in AGN-type galaxies?
Most galaxies have a massive (i.e., $m \gtrsim 10^5$ M$_{\odot}$) black hole in their center.
Is it known 1) theoretically and 2) observationally what fraction of these massive black holes (maybe as a ...
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What could cause a wind from an SMBH
In this paper, the author tests whether the Milky Way's Fermi bubbles could have been caused by an AGN-type explosion, or by a 'wind'. He comes to the conclusion that the wind may be "the same as ...
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How do I create well a weighted black hole mass function?
I'm running a set of simulations to study the evolution of Super Massive black holes.
In principle, I have the black hole masses and other property called merger tree weight in Mpc-3 unit which is ...
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Where is the barycenter of the Milky Way Galaxy?
Is the barycenter of the Milky Way Galaxy located within the supermassive black hole, or its event horizon, at the center of our galaxy?
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Why were only 4 days of data used in the M87 EHT observation?
I wonder why only 4 days of data were used in the M87 Event Horizon Telescope (EHT) observation. What is preventing you from obtaining a more detailed and clearer image over a longer period of time?
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What does "energy dumped into waves" mean?
In A Very Short Introduction: Black Holes by Katherine Blundell, the author discusses the merger of two black holes in a binary system:
The energy released in the merger of two supermassive black ...
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Could primordial black holes explain the SMBH in the galactic centers?
If there were enough primordial black holes (with the right mass) they could explain dark matter. Could they explain the gargantuan monster holes in the center of galaxies?
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Is the dark matter/baryonic matter ratio the same in galaxies with supermassive black holes?
My hypothesis is that if the ratio of dark matter/matter in galaxies with supermassive(weighing billions of suns) black holes are higher the black hole itself would be made of a large portion of dark ...
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Is the appearance of accretion disks of M87 and Sgr A* in EHT image, related to the nucleus being active or non-active?
I'm a newbie in this field so forgive me if I'm considering things wrong.
As much as I can see, the newly published image of the Sgr A* looks pretty much the same as M87 released years ago. I'm ...
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Why is the ring in this simulation of Sgr A* off center?
In the recent releases of images of Sgr A*, simulated versions of what they expected were included along side the actual images they were able to get. What confuses me about these simulated images (...
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Why do some supermassive black holes have a * in their name?
Sgr A*, M87*,... Several supermassive black holes (SMBHs) at the center of galaxies have a star (*) in their name. But many others do not. Is there a physical difference between the SMBHs that are ...
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Can the Universe itself be a black hole? [duplicate]
Can the Universe be a Black Hole?
Many years ago, after reading a book by Isaac Asimov (not a novel, but I forgot the title) I started wondering if it is be possible that the Universe itself is a ...
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What is the reason for Hercules A to emit huge fountains of Plasma?
Hercules A, a supermassive-blackhole situated in the galaxy 3C 348, emits Plasma as far as 1.5 million light years away !! Although the cause is poorly understood, what could be the possible cause for ...
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Have any HCSSs (supermassive black holes with a tight bunch of gravitationally bound stars) ever been detected?
This article from sciencealert states:
Astronomers think these two galactic cores could merge into one larger
black hole, sending huge gravitational waves rippling out across
spacetime. But if there'...
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Image of the black hole [duplicate]
The first ever image of a black hole shows a circular black central portion surrounded by an illuminated accretion disk.
If a black hole wraps spacetime completely around it, then in any direction it ...
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Does the density of a black hole decrease after releasing a large amount of Hawking radiation?
Is is true that the smaller a 'regular', stellar-mass black hole is, the denser it is inside of its event horizon? After all, if you look up (or calculate) the Schwarzschild radii of the Sun and the ...
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Is gravity affected by time dilation? [closed]
I just thought about what time realy is but I can't put my head around this so I was thinking that if time dilation happens at the edge of a black hole that just everything gets slower. But does ...
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Could quasars be interior to the event horizon of a SMBH?
My question is prompted by suspicion of three current ideas in astrophysics:
GR predicts a singularity at the center of a BH without regard to QM.
quasar hyper-luminosity is caused by an acretion ...
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Could a black hole's accretion disk be bright through natural means?
This question is based on this description of the Cormoran Supermassive Black Hole in the Orion Arm's website:
Surrounding this event horizon is an (apparently artificial) accretion
disk about 4AU in ...
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From where the light comes? [duplicate]
Gravitational field of a supermassive blackhole is so strong that even light cannot escape from it (eg. black hole in the core of M87). In this case when a blackhole tears a star,a bright disk of ...
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Has gain in mass from accretion onto a black hole been observed?
Have we observed a black hole directly gain mass via accretion? That is, have we observed the black hole to have mass $m_1$ at time $t_1$ and then observed its mass to be $m_2 > m_1$ at a later ...
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How can a black hole have a charge, or be charged?
So-called 'hairless' black holes (no-hair theory, or theorem?) , which is what real black holes are, can be described by just three characteristics: Mass, spin, and charge.
It is easy enough to ...
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Why is the Milky Way's SMBH inactive?
Our galaxy is not an active galactic nucleus (AGN). With so many stars and so much gas orbiting it, as explained here Central kiloparsec of Seyfert and inactive host galaxies: a comparison of two-...
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Does black hole singularity really exists with respective to relative frame of reference? [duplicate]
How can one describe this phenomena?
What are the factors that we should consider for solving such a problem?
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Can an entire star pass through the event horizon of a black hole unharmed?
Can there be any black hole big enough that a regular sized star can pass through its event horizon unharmed?
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What do stars in galaxies without supermassive black holes revolve around? [duplicate]
I still don't quite understand what the stars in galaxies without SBHs revolve around. I mean, the stars must orbit something. If the Sun suddenly disappeared, the planets wouldn't just continue in ...
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Could Sgr A* be a core of dark matter instead of a supermassive black hole?
A recent paper (related news) shows that Sgr A* at the center of the Milky Way galaxy could be a dark matter core, instead of a supermassive black hole, according to their calculation using the ...
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How do we know that supermassive black holes can gain mass by means other than merging with other supermassive black holes?
I just stumbled across the following answer "update" from 2013:
This just in, recent observations have ruled out the possibility that SMBHs gain mass only through merging with other black ...
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What is Hawking radiation? [closed]
Like the radiation the Sun gives out to sustain it's circular shape, will Hawking radiation sustain the black hole's shape?
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Would studying massive stars that are experiencing time dilation due to proximity to a black hole be useful?
I saw this question (Could a star closely orbit a black hole long enough for the star to have lost 0.5B+ years to time dilation?) and came up with an interesting thought. Massive stars live for less ...
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Hypothetically, could a civilization in a solar system near a supermassive blackhole use the blackhole as a huge gravity lens telescope?
I have heard of various proposals that use the massive gravity of stars to sort of focus light at and observe with a suitable telescope placed at such a distance, and I am assuming here that bigger ...
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Is there a closest free-return trajectory to a black hole?
The scenario I am imagining is a test particle falling from infinity with an initial off-center velocity. In Newtonian mechanics the path would be a hyperbola. But I assume that, near a black hole, ...
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Do any particles in AGN jets escape the galaxy?
I have read, at http://www.thestargarden.co.uk/Black-holes.html for example, that whole stars can be ejected from certain galaxies. "These are thought to have been part of a binary star system ...
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What keeps galaxies together?
The super massive black hole at the centre of Milky Way has a mass of about 4 million times that of our sun. Is this enough to keep the entire galaxy together, is it this black hole which keeps the ...
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How spaghettification is possible at the Event Horizon of a supermassive black hole?
if gravity is too strong then it will break a object apart as gravity is strong enough to break the chemical composition of object why we consider "Spaghettification" relevant in this case ?
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Why don't black holes quickly eat up the galaxy/universe?
It's my understanding that the radius of the event horizon of a black hole is proportional to it's mass.
Which means the surface area of a black hole is proportional to it's mass squared.
Lets just ...
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What is the effect of extinction in the accretion disk for black hole mass determination?
I've created a basic model of the accretion disk (AD) by summing up blackbodies following the temperature profile of the AD according to Shakura & Sunyaev (1973) (extensively used in the ...
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How can a supermassive black hole be 13 billion years old?
A supermassive black hole was discovered recently that is 13 billion years old. This blackhole is 1.6 billion times the mass of the sun. How can this blackhole have formed so quickly after the big ...
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Why are galactic nuclei yellow?
So we've seen millions of galaxies, and all of them have a bright, yellow nucleus. What is the cause of the yellowness? Is it because of aging stars, redshift from the SMBH, or something else?
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What came first: Galaxies or Stars? [duplicate]
In Stephen Hawking's A Brief History Of Time, the book mentions that "in regions that were slightly denser than average...galaxies were born." (pg 123). However, according to many other ...
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Why is there no color shift on the photo of the M87 black hole?
Last year, the first photo of a black hole in Messier 87 was published:
(Source: EHT)
It is quite obvious that about the lower half of the accretion disk is brighter.
This question (or rather, the ...
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