[1001.3099] Measuring the dark energy equation of state with LISA

Authors: Chris Van Den Broeck, M. Trias, B.S. Sathyaprakash, A.M. Sintes

Date: 18 Jan 2010

Abstract: The Laser Interferometer Space Antenna's (LISA's) observation of supermassive binary black holes (SMBBH) could provide a new tool for precision cosmography. Inclusion of sub-dominant signal harmonics in the inspiral signal allows for high-accuracy sky localization, dramatically improving the chances of finding the host galaxy and obtaining its redshift. Combined with the measurement of the luminosity distance, this could allow us to significantly constrain the dark energy equation-of-state parameter $w$ even with a single SMBBH merger at $z \lesssim 1$. Such an event can potentially have component masses from a wide range ($10ˆ5 - 10ˆ8 \Ms$) over which parameter accuracies vary considerably. We perform an in-depth study in order to understand (i) what fraction of possible SMBBH mergers allow for sky localization, depending on the parameters of the source, and (ii) how accurately $w$ can be measured when the host galaxy can be identified. We also investigate how accuracies on all parameters improve when a knowledge of the sky position can be folded into the estimation of errors. We find that $w$ can be measured to within a few percent in most cases, if the only error in measuring the luminosity distance is due to LISA's instrumental noise and the confusion background from Galactic binaries. However, weak lensing-induced errors will severely degrade the accuracy with which $w$ can be obtained, emphasizing that methods to mitigate weak lensing effects would be required to take advantage of LISA's full potential.

abs pdf

Jan 21, 2010

1001.3099 (/preprints)
2010-01-21, 13:05 [edit]

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