Transcript No Slide Title

LMC
SMC
Andromeda
and 2 dwarf
(size of
LMC/SMC)
galaxies
QSO 3C273+ jet
M85, S0
LMC
M87 Ellip
NGC 3310
M87 jet
M87 core and jet
Why was Hubble wrong that
Ellipticals evolve into Spirals?
• Ellipticals low angular momentum
• Spirals and no way to gain it
• Ellipticals have very little gas and dust
• Spirals have no way to gain it.
Galaxy Formation Scenario:
Black Holes at first
About 107 years after the BB: the first black holes
(BHs) formed as seeds
Gas collapses about the BHs to form QSOs =
Quasi Stellar Objects.
•The QSOs “turn on”
• Powered by the in-fall of the matter
•(think Niagra Falls, scaled “way up”).
•The gas doesn’t fall all the way into the black hole
• Due to angular mo. and also light pressure
Why do QSOs have their name?
Because they look like stars!
Galaxy
QSO
star
Scenario, cont.
If most of the “spin” of the system ends up in the
black hole => an elliptical and some times jets
These systems formed so long ago, that they have
turned all their gas into stars that they can.
Spirals are younger due to angular mo. slowing
down the gas in-fall, i.e. formed later and star
formation continues, so Hubble got the right (early
versus late) name.
QSOs , AGNs and Black holes
Why do we think QSOs are “powered” by
massive(106 -108 solar masses) or more black
holes?
(1)
• Objects are extremely luminous (10-100 times
a galaxy)
•If assume the redshift tells us their distance.
QSOs , AGNs and Black holes, cont.
(2)
•The intensity (brightness) varies on times < week.
•Information” is carried from one side to the other to
cause brightening
• Therefore the emitting region is ≤ 1 week light
across.
Remember: the distance to the star closest to the sun
is 4 light YEARS away!
=> A great deal of energy out of a very small space.
We know how much light stars make and it’s
impossible to have that compact a star system and not
have it turn into a black hole.
From estimated lifetime of QSO and brightness, can
calculate an in-fall rate and mass needed to make the
light ( L = GM( dM/dt)/R) where dM/dt = mass in-fall
rate, L = luminosity, R = radius of “stopping region”
just outside BH
=> Massive = 106-108 solar mass Black Holes exist at
cores of QSOs
QSOs , AGNs and Black holes, cont.
(3) The jets we see can only be easily explained by
spinning black holes.
QSOs , AGNs and Black holes, cont.
How do we get jets and radio lobes? Think
“boom” and direction of “boom” defined by the
spin axis of the black hole.
M87 core and jet
QSOs , AGNs and Black holes, cont.
AGNs = Active Galactic Nuclei which at their
most powerful are QSOs.
QSO’s and AGN much more numerous in the past.
Why do they die out? We don’t [really] know.
We say they used up most of fuel, but this is a
“dodge.”
Mais la vie n’est pas facile
[but life is not easy]
The “true” story of galaxy evolution is not
understood yet and we also have to ask as we do
about how people develop abilities and
personalities:
Do galaxies look they way they do because of
“inherited a characteristics” or because of
their environment?
Galaxies and collide and change
In simplest form: if galaxies collided
they can sweep out their gas and dust
and turn into S0s.
So, the higher the local density of galaxies the
fewer spirals we’ll see as the higher the
density,the higher the probability of collision
Galaxies and collide and change
And, when we go back in time, this is
more or less what we find...
The more distant clusters have more spirals and
fewer S0s and the nearby systems seem to be
nearly all ellipticals and S0s, and all clusters tend
to have most of their spirals near the outside as the
spirals are just falling in.
Galaxies caused by collisions?
Expanded
views
Expanded
view; Antenna
Galaxy
Whirlpool
galaxy
Connection to BB
The universe changing as we go back in time
(z)
Consistent with there being a “start” and the
formation of galaxies out of the “primoridal
mist”
Connection with BB, cont.
BB gives an age to universe and an expansion
rate.
Find QSOs back to a 1+z = 7 which is about
90% of the way back in the universe
Gas collapse must take place “quickly”.
Don’t know how:
CDM almost works and HDM doesn’t work
Stay tuned.
Summary
Brick wall breaks up into fragments.
How galaxies and QSOs started and if
they started before the first stars we don’t
know But simple myth is BHs => QSOs
=> galaxies.
We don’t understand how BHs or QSOs can
grow so quickly, and if we see QSOs much
further back, we may be embarrassed. And we
don’t really know how or why QSOs “die off.”
The “nay sayers”
Halton (Chip) Arp and the Burbidges (Geoff &
Margaret) : Redshifts don’t tell us the distances to
QSOs! Example: X-ray image. Are these objects
physically related or chance coincidences?
These X-ray bright
(easily detectable
with an X-ray
telescope) QSOs
appear connected,
but have wildly
different redshifts.
Nay sayers, cont.
But if these are physically connected, then either
the connections are unreasonably long (Gpc = 1000
Mpc = 1000 cluster of galaxy radii) or the redshifts
don’t tell us the distance.
Others, say these are chance coincidences. Chip,
Geoff and Margaret, say “No way, and z doesn’t tell
distance for QSOs and new physics is likely
involved.” Is this worse than L > 0?
Mini Summary:
Nearly all the measurements of:
expansion,
dark matter,
galaxy counts,
galaxy evolution,
age measurements,
element abundances,
cosmic microwave background
fit within our frame work of an expanding universe
and a Hot Big Bang
Observational Problems
When pushing the limits we’re always in danger
of screwing up. How much will stand the test of
time? Do we have the z versus distance correct
( Lambda not equal 0; SN)
Will our cluster counts hold up?
Will the CMB results remain consistent
with the standard predictions?
Will abundances be made to agree with
BBN? Will we find the cosmic web??
Conclusion
We think we’re on the right track, but
Stay tuned!
Theory Problems
What the heck is the dark energy?
Is dark matter a particle we can predict
or is the graitational effect due to branes
and other universes?
Do we really understand how light and dark
matter get distributed and how galaxies and
clusters form and evolve?
Have we really got BBN right?
Can we be sure we’re using the right model
of how CMB fluctuations formed?
Time Capsule Predictions
(1) The standard Dogma:
Inflation
L>0
WIMPS
the cosmic web,
all exist and will be found and or explained.
Time Capsule Predictions, cont.
(2) Branes:
No Inflation
L>0
No WIMPS
the cosmic web exists.
Other proof of parallel universes?
Time Capsule Predictions, cont.
(2) Branes:
No Inflation
L>0
No WIMPS
the cosmic web exists.
Other proof of parallel universes?
Time Capsule Predictions, cont.
(3) Nay Sayers:
Redshift seriously wrong and overall new physics
(but not Branes, not WIMPS, not L) is needed to
explain cosmology.
Time Capsule Predictions, cont.
(4) Prof. Ulmer’s ultra-conservative: in the end we
will be able to explain all we see with purely
currently known (verified in the lab) conventional
physics: No WIMPS (Wb about 0.1, within errors of
cluster, galaxy masses, and nucleo-synthesis); CMB
interpretation and measurements will not need a flat
universe or “extra physics” (WIMPs) to explain
galaxy and cluster formation, smooth CMB, and
CMB (and galaxy) “power distribution.” no L > 0
(SN measures wrong).
Time Capsule Predictions, cont.
(4) Prof. Kibblewhite’s ultra-ultra-conservative: in
the end we will be able to explain all we see with
purely currently known (verified in the lab)
conventional physics: No WIMPS (Wb about 0.1,
within errors on cluster, galaxy masses, and nucleosynthesis); CMB interpretation and measurements
can have a flat universe (GR is not right) no need for
extra physics to explain galaxy and cluster formation,
smooth CMB, and CMB (and galaxy) “power
distribution.” No L > 0 (SN measures wrong).