Black Hole Signature From Advective Disks
Explanation:
What does a black hole look like? If alone,
a
black hole
would indeed
appear
quite black, but many black hole candidates are part of
binary star systems.
So how does a
black hole binary system
look different from a
neutron star binary system?
The
above drawings
indicate it
is difficult to tell!
Recent theoretical work,
however, has provided a new way to tell them apart:
advective accretion flows (ADAFs).
A
black hole system so equipped
would appear much darker than a similar
neutron star
system. The difference is caused by the hot gas from the
ADAF disk
falling through the
event
horizon
of the black hole and disappearing - gas that would have emitted
much light were the central object only a neutron star.
Recent observations
of the soft X-ray transient
V404 Cyg
has yielded a
spectrum
much like an ADAF onto a
black hole
- and perhaps brighter than allowable from an ADAF onto a neutron
star.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
