Coalescing mass and gravitational waves

[Enthalpy]

Hello dear friends!

 

I've read somewhere that mass falling in a black hole (...other compact massive objects should behave about the same way) adds to the mass of the hole AND is fully converted into radiated energy.

 

Is that correct? As mass falls into the gravity field, it loses potential energy so it should get lighter.

 

Also: if the masses of the hole and the falling object have their sum conserved, and light is created at the same time, which I believe is also a source of gravitation, would this create an abnormal gravitational wave: not quadripolar, not even transverse dipolar, but axial?

 

The observer should "feel" (if sensitive enough) a slight added pull at the same time as he sees the light emitted by the event. In case there's a trick with light propagating together with gravitation, we could imagine light being slowed down or deviated on its way to the observer, as opposed to gravitation.

 

Ideas? If possible in simple wording... Thank you!

[ajb]

I've read somewhere that mass falling in a black hole (...other compact massive objects should behave about the same way) adds to the mass of the hole AND is fully converted into radiated energy.

Are you talking about an accretion disk and the production of x-rays?

 

If so accretion disks around black holes can convert something like 10% of the mass into energy that is then carried off by x-rays. This is actually quite a big percentage, but far from all the mass.

[Enthalpy]

10% is far more than other known methods... I had read 100%, which must be false. If 10% are radiated and 90% add to the hole, everything is fine.