Mathematics – Logic
Scientific paper
Nov 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993natur.366..242h&link_type=abstract
Nature, Volume 366, Issue 6452, pp. 242-245 (1993).
Mathematics
Logic
91
Scientific paper
QUASARS have long been known to vary in magnitude1, and it now appears that all quasars are to some extent variable2. In a few extreme cases, quasar luminosities have varied over several magnitudes on a timescale of months; this behaviour is normally accompanied by other phenomena (such as radio emission or enhanced polarization) indicative of processes intrinsic to the quasars. Long-term luminosity variations, while less dramatic, are much more common, but their origin remains poorly understood. Here I investigate this longer-term behaviour for a sample of approximately 300 quasars at redshifts ranging from 1 to 3, whose optical magnitudes have been measured periodically for 17 years. I show that there is a positive correlation between the timescale of variability and the average luminosity, but little evidence for an increase in timescale due to redshift (and hence time dilation). These findings are inconsistent with any known variability mechanism intrinsic to quasars, but can be explained by gravitational lensing of the quasar images by compact substellar objects along the lines of sight. If this interpretation is correct, the population of lensing objects must have a density of at least 0.1 of the critical cosmological density.
No associations
LandOfFree
Gravitational microlensing, quasar variability and missing matter does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Gravitational microlensing, quasar variability and missing matter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gravitational microlensing, quasar variability and missing matter will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-811937