Limits on the cosmological abundance of supermassive compact objects from a search for multiple imaging in compact radio sources.
Using very long baseline interferometry we have searched a sample of 300 compact radio sources for examples of multiple imaging produced by gravitational lensing; no multiple images were found with separations in the angular range 1.5--50 milliarcsec. This null result allows us to place a limit on the cosmological abundance of intergalactic supermassive compact objects in the mass range approximately 10(6)M( middle dot in circle) to approximately 10(8)M( middle dot in circle); such objects cannot make up more than approximately 1% of the closure density ( 95% confidence). A uniformly distributed population of supermassive black holes forming soon after the big bang does not, therefore, contribute significantly to the dark matter content of the Universe.
Wilkinson
P N
PN
University of Manchester, Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL, United Kingdom.
Henstock
D R
DR
Browne
I W
IW
Polatidis
A G
AG
Augusto
P
P
Readhead
A C
AC
Pearson
T J
TJ
Xu
W
W
Taylor
G B
GB
Vermeulen
R C
RC