Arp 299: Black Holes in
Colliding Galaxies 
From NASA’s Astronomy
Picture of the Day
Is only one black hole
spewing high energy radiation -- or two? 
To help find out,
astronomers trained NASA's
Earth-orbiting NuSTAR and Chandra telescopes on Arp
299, the enigmatic colliding galaxies expelling the radiation. 
The two galaxies of Arp 299 have
been locked in a gravitational
combat for millions of years, while their central black holes will
soon do battle themselves. 
Featured, the
high-resolution visible-light image was taken by Hubble, while the superposed
diffuse glow of X-ray
light was imaged by NuSTAR and shown in false-color red, green, and
blue. NuSTAR observations
show that only one of the central
black holes is seen fighting its way through a region of gas and dust
-- and so absorbing matter and emitting X-rays. 
The energetic radiation,
coming only from the galaxy center on the right, is surely created nearby -- but outside --
the central black
hole's event
horizon. 
In a billion years or
so, only one composite galaxy will
remain, and only one central
supermassive black hole. Soon thereafter, though, another galaxy may enter
the fray.
Image Credit: NASA, JPL-Caltech, GSFC, Hubble, NuSTAR

 
