Galaxy-galaxy Flexion: weak lensing to second order

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Title: Galaxy-galaxy Flexion: weak lensing to second order
Author(s): Goldberg, David; Bacon, David
Keywords: Galaxies: Halos; Galaxies: Structure; Gravitational Lensing
Date: 2007-11-26
Abstract: In this paper, we develop a new gravitational lensing inversion technique. While traditional approaches assume that the lensing field varies little across a galaxy image, we note that this variation in the field can give rise to a “Flexion” or bending of a galaxy image, which may then be used to detect a lensing signal with increased signal to noise. Since the significance of the Flexion signal increases on small scales, this is ideally suited to galaxy-galaxy lensing. We develop an inversion technique based on the “Shapelets” formalism of Refregier (2003). We then demonstrate the proof of this concept by measuring a Flexion signal in the Deep Lens Survey. Assuming an intrinsically isothermal distribution, we find from the Flexion signal alone a velocity width of vc = 221±12km/s for lens galaxies of r < 21.5, subject to uncertainties in the intrinsic Flexion distribution.
Citation: The Astrophysical Journal, 619: pp. 741-748.
URI: http://arxiv.org/abs/astro-ph/0406376v2; http://hdl.handle.net/1860/1923
In Collections: Drexel Research

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