The standard aperture ellipse (area of detection) is defined by the infrared isophote at the K s band (roughly 2.2 μm wavelength) of 20 mag/arcsec. Gathering the overall luminous flux of the galaxy has been employed by at least four methods: the first being a circular aperture extending 7 arcseconds from the center, an isophote at 20 mag/arcsec, a "total" aperture defined by the radial light distribution that covers the supposed extent of the galaxy, and the Kron aperture (defined as 2.5 times the first-moment radius, an integration of the flux of the "total" aperture).