Abstract

We announce the discovery of the Crater 2 dwarf galaxy, identified in imaging data of the VLT Survey Telescope ATLAS survey. Given its half-light radius of similar to 1100 pc, Crater 2 is the fourth largest satellite of the MilkyWay, surpassed only by the Large Magellanic Cloud, Small Magellanic Cloud and the Sgr dwarf. With a total luminosity of M-V approximate to -8, this galaxy is also one of the lowest surface brightness dwarfs. Falling under the nominal detection boundary of 30 mag arcsec(-2), it compares in nebulosity to the recently discovered Tuc 2 and Tuc IV and UMa II. Crater 2 is located similar to 120 kpc from the Sun and appears to be aligned in 3D with the enigmatic globular cluster Crater, the pair of ultrafaint dwarfs Leo IV and Leo V and the classical dwarf Leo II. We argue that such arrangement is probably not accidental and, in fact, can be viewed as the evidence for the accretion of the Crater-Leo group.