SUPERMASSIVE BLACK HOLES - Santa Rosa Junior Collegeyataiiya/4D/SUPER MASSIVE BLACK HOLES.pdf ·...
Transcript of SUPERMASSIVE BLACK HOLES - Santa Rosa Junior Collegeyataiiya/4D/SUPER MASSIVE BLACK HOLES.pdf ·...
SUPERMASSIVE BLACK
HOLES
SRJC, Spring 2014-PHYS43
Thea Dumont
Kyle Cubba
They are a class of black holes
They are formidably larger than regular black holes
They are gigantic (100,000 X -- 1,000,000,000 X SOLAR MASS)
They are a source of quasars
They live in the center of galaxies
WHAT ARE THEY?
WOAH. THATS A LOT OF MASS!
but how big are they? _
For their mass, they’re Schwarzschild
radius (event horizon) is rather big.
Dividing the mass by the volume
defined by the Schwarzschild radius,
the density of most supermassive black
holes is less than that of water!
Schwarzschild radius is the radius at which light itself cannot escape
from the gravitational pull of the black hole. The surface this covers in
three dimensional space surrounding a black hole is known as its event
horizon.
The true density of any black hole is unknown, since it is impossible to
visually see what happens beyond the event horizon.
General relativity describes that there is a gravitational singularity at the
center of the black hole.
But then again, general relativity says a lot of things that no one seems
to know why.
Hippies say that they are wormholes to extradimensional universes.
black holes bend space-time
A normal star only curves space-time by a small amount;
But a black hole bends it to an asymptote.
Black Holes & Light Bending
Since black holes bend space-time, light
bends around black holes
Photon sphere
note the light
bending
occurring here
supermassive black hole
at the center of active galactic
nucleus
More examples of light bending
The “Einstein
Ring”
Proposed by
Albert Einstein
when coming
up with general
relativity.
Happens when a
bright object is
directly behind
massive object.
SUPERMASSIVE BLACK HOLES
& GALAXY FORMATION
Supermassive black holes are found in active galactic nuclei (AGN).
AGN is a compact center which emits high
intensity light of many wavelengths ranging
from radio to x-ray.
Quasars are a class of AGN species;
quasars have supermassive black holes at
their center and are surrounded by accretion
disks, relativistic jets spew from one or
either poles orthogonal to the disk plane.
Active galactic
nucleus
(AGN)
Ejected matter
The rotating speed of supermassive black holes and the rotating speed of
the AGN are the same. This leads to the mature formation of galactic
centers in host galaxies to supermassive black holes.
The presence of a supermassive black hole influences the galaxy to take
on a spheroidal shape (elliptical and spiral galaxies), as well as
condenses the galaxy. Influences galaxies to merge creating a spiral.
Galactic halo formation could also be explained by the presence of supermassive black holes.
The supermassive black hole in the sombrero galaxy (shown above) is measured to be1 billion times the mass of the sun, making it one of the largest known black holes!
How do we know this?
Black holes eject charged
particles in jets as they
accrete which we can spot.
When we inspect the nucleus of
galaxies, such as m87, and
there are these jets, this
implies there could be a
supermassive black hole
there.
Stars in the AGN seem to be
orbiting some unseen
massive object, this could
inferred to be a supermassive
black hole.
More material
being ejected
from a galactic
center. Notice
the accretion
disk around the
center.
Supermassive Black Holes & Light
Emission
Supermassive black holes can be found because of the large amount of
strong radio waves they emit because of the matter heating up in the
accretion
disk.
As the matter enters the black hole,
x-rays are produced; another way
researchers have to detect
supermassive black holes.
Sagittarius A* in the Milky Way
There is a supermassive
black hole in the central
bulge of the Milky Way,
located it the Sagittarius
constellation.
The supermassive black hole
is called Sagittarius A* or
Sgr A*
SGR A*
- is 40 million times more massive than our own sun
- has a radius of 6.7 light hours
- was first discovered in 1973 because of its large
amount of radio emissions
- is orbited by multiple star systems
Stars in orbit of
Sagittarius A*
Hurdling G2 Dust Cloud into
Supermassive black hole at Galactic
Center A dust cloud around 3
times the mass of the
earth is hurdling at
extremely high velocities
towards Sgr A*
Dust-Cloud Ripped Apart by Milky Way’s SMBH
What would it be like to
fall in one?
Most likely very unpleasant.
Risky: one wrong move
and you plunge into the
heart of a black hole
You’re probably cool
Done for: energy input is
required to keep you
from falling in
No escape: be prepared to
fall into an infinite abyss
You collapse into nothing
Spagettification
In a normal black hole, tidal
forces are strong and cause
elongation (spagettification)
because of the difference in
gravitational potential between
your feet and your head
Visualizing the Gravitational Vector Field
oh no!
The bright side:
at least you look trim
In a supermassive black hole, however, the tidal forces
are weaker since gravitational pull falls off at an inverse
square; you would be within the event horizon before
being pulled apart.
You never see the singularity, as the light falls into it and
never comes out.
BYE-BYE UNIVERSE
And
hello
Void!
The light
pouring in
from the
universe
collapses
into one
bright point
as you fall
into the
singularity
and are
obliterated
from history,
forever.
PURELY THEORETICALNO BASIS IN REALITY
end
Work Cited
1. Philip F. Hopkins et al. 2006 , “A Unified, Merger-driven Model of the Origin of Starbursts, Quasars, the Cosmic X-Ray Background,
Supermassive Black Holes, and Galaxy Spheroids,” Philip F. Hopkins et al. 2006 ApJS 163 1. Web, accessed 12 May 2014.
1. Marta Volonteri et al. (2003), “The Assembly and Merging History of Supermassive Black Holes in Hierarchical Models of Galaxy
Formation.” ApJ, 583-599. Web, accessed 12 May 2014.
1. Haehnelt, M. G. and Kauffmann, G. (2000), “The correlation between black hole mass and bulge velocity dispersion in hierarchical
galaxy formation models.” Monthly Notices of Royal Astronomical Society. 318: L35-L38. Web, accessed 12 May 2014.
1. Jarrett L.Johnson et al. (2013), “Supermassive Seeds for Supermassive Black Holes.” The Astrophysical Journal, 771. Web, accessed
12 May 2014.
5. Ander Hamilton. http://jila.colorado.edu/~ajsh/insidebh/ Journey to the Schwarzschild Black Hole, 2014.Web, accessed 12 May14
6. http://csep10.phys.utk.edu/astr162/lect/active/smblack.html