Bez tytulu slajdu

1
O n t h e T r a c k o f M o d e r n
P h y s i c s
A strange star
Is the black hole really black? And how heavy is
it? And how is it made inside?
European Southern Observatory http//www.eso.org

Black holes are probably quite colorful quickly
rotating ionized gas, imploding towards the
center contains heavy atoms, like iron, and its
emission lines are strongly shifted by the
Doppler effect. Fig. Krzysztof
Karwasz
Crab Nebula testifies the Supernova explosion in
1054AD, noted in Europe, China and by Indians
in New Mexico
Quasars - quasi-stellar radio sources, discovered
in 1961, now believed to be super-massive
(billion of M?) black holes in centers of distant
galaxies. The ionized gas quickly falling inside
the hole emits powerful radio-waves. Pulsars -
quickly rotating neutron stars which flares the
magnetic field around the space. The first
pulsar CP 191921 (1.3 s period of rotation) was
discovered in the constellation of Cygnus
(Swan) in 1967 by graduate student Jocelyn Bell
Burnell but the Nobel prize went to her
supervisor.
http//imagine.gsfc.nasa.gov/docs/science/know_l1/
supernovae.html
Evolution of stars depend on their mass. Those
above 8 Solar masses, at the end of the life,
were all the termonuclear fuel is burn into iron,
first collapse, and then explode into supernova.
A part of the mass is expelled and the remnants
form a core of about 20 km diameter made of
neutrons. The expelled material contains heavy
elements and can be re-cycled, to form a system,
like the Solar one.
Crab Nebula in X-rays
Cygnus Loop in X-rays
Remnants of supernovae are sources of radio
signals and also of X-ray radiation.
"Cygnus." Wikipedia.
Credits NASA Goddard Space Flight
Center http//imagine.gsfc.nasa.gov/docs/science/k
now_l1/pulsars.html
The neutron ball is similar to a giant atomic
nucleus with Z1057. With such a big compression,
neutrons start to "crowd-up", following the
Pauli's rule, which does not allow them to be in
the same quantum state. It is energetically
useful to replace some neutrons with protons, or
even by isolated quarks. It seems (A.R. Bodmer
1971 , E. Witten 1984) that the state of the
matter with a lowest possible energy level is a
mixture of the "normal" u and d quarks with
strange quarks s. It is solely the big mass of
the s quark (30 times more than that of u) which
protects us from falling the nucleus of 58Fe,
for example, to a quark state.
Strange quark droplets are a possible form of
hadronic matter, containing approximately equal
(and potentially very large) numbers of up, down,
and strange quarks inside a single hadronic bag.
Chandra X-ray observation of RX J1856.5-3754 (or
the C58 pulsar), the remnants of a supernova
noted on Earth in AD 1181, reveal that the
neutron star in the core has a temperature much
lower than expected. This suggests that a new
state of nuclear matter might exist inside the
star. CreditsNASA/CXC/CfA/P.Slane et
al. http//chandra.harvard.edu/photo/2002/0211/ind
ex.html
Free quarks
Confined quarks
Left 12C nucleus. Right a strange matter
droplet with A12.
The Grand Canyon is 30 km wide. A neutron star is
about 20 km in diameter, and a quark star is
about 12 km in diameter. (Illustration CXC/D.
Berry)
Astronomers still discuss if a real black hole
has been discovered. Sign-down these numbers
and check from time to time on internet, if they
are really BLACK X-ray transient XTE J1650-500
SS433 MilkyWay Star Cygnus X1 and HDE
226868 Seyfert-1 galaxy NGC 4593 Seyfert galaxy
MCG -6-30-15 Galaxy NGC 4486
RX J1856 in Optical Light This optical image of
RX J1856.5-3754 portrays a crowded region of star
formation. In comparison, the Chandra X-ray image
shows that RX J1856 outshines all of the other
sources in the field, indicating it is both
extremely hot and very small. Credit European
Southern Observatory Very Large Telescope
See aslo http//blackholes.stardate.org/