Strong Lensing Research

Image of smiley face lens

One consequence of Einstein's theory of general relativity is that as light travels through a gravitational field, it is deflected. This phenomenon is known as gravitational lensing, because the effects are similar to those of light traveling through a lens. For these effects to be measurable, enormous masses are required, e.g., a star, a galaxy, or something even bigger! One source of measurable gravitational lensing is the light from entire galaxies being deflected by the mass of a galaxy cluster, the largest gravitationally-bound objects in the Universe. In analogy with a physical lens, gravitational lenses can also have magnifiaction effects, increasing the apparent size of a galaxy, allowing astronomers to see features that would otherwise be too small to see.

A special case of gravitational lensing is so-called strong lensing, where the light is deflected to such a degree that multiple light rays leaving the same point, but traveling in different directions, can all be bent directly toward us, causing us to see multiple images of the source (like the mouth and sides of the smiley face in the accompanying picture).

As an undergraduate I did research with Professor Keren Sharon in strong gravitational lensing, as part of the Sloan Giant Arcs Survey (SGAS). My work involved modeling these strong lenses (i.e., clusters of galaxies, two of which make up the eyes of the smiley face in the picture) to determine their masses based on the color, shape, and other properties of the multiple images.

See my undergraduate honor's thesis on one particular lens, SDSS J1438+1454, here, or the paper that came out of that research here.