Cygnus X-I: Very much like classical binary.
Submilisecond flaring auto correction function
One difference: wind fed
Something has to happen at M>2.1 Msun. No other known force after neutron degeneracy collapse forever. SNR or WD, NS exceeds mass limit therefore collapse
for light m=p/c
R is Schwarzshild Radius
No information within this radius can escape
Singularity is formed: Event horizon
We can watch stuff fall in, to fall in takes forever.
All other information lost forever
They have no magnetic field. They do not pulse
Black holes have no hair
How can we observe them? Put one in a binary system (as seen above)
Accretion disk emits x-rays
Orbital time ~ R/c
Cygnus X-1 is the only black hole we are resonalbly certain of.
No upper limit on mass can grow forever.
Quasars (we think) form when enough mass is pulled into hole ~1-^ Msun
Things are tidally disrupted and then swallowed. There may be one in our galaxy.
pair production at singularity
Lose mass become lighter
Burst or gamma rays not detected.
Could have formed these in the early universe Primordial Black Holes
Birth ripple of a forming black hole detectors are being built