An Unusual IR-Bright Arc

K-band (2.2 micron) UFTI imaging obtained by Alastair Edge in Spring 2001 uncovered a very unusual infrared-bright arc associated with a distant galaxy cluster. This "filament" extends over about 15 arcseconds on the sky and, compared with other arcs, is relatively straight though with a series of "kinks". The kinks are thought to be caused by the gravitational influence of unseen material on the arc. The arc itself is caused by a massive galaxy cluster that bends light from background galaxies.

Gravitational arcs are discussed in more detail here.

Our thanks to Dr Edge (University of Durham, U.K.) for allowing us to reproduce his data.