We report the discovery of two new candidate stellar systems in the constellation of Cetus using the data from the first two years of the Dark Energy Survey ( DES ) .
The objects , DES J0111 - 1341 and DES J0225 + 0304 , are located at a heliocentric distance of \sim 25 \mathrm { kpc } and appear to have old and metal-poor populations .
Their distances to the Sagittarius orbital plane , \sim 1.73 \mathrm { kpc } ( DES J0111 - 1341 ) and \sim 0.50 \mathrm { kpc } ( DES J0225 + 0304 ) , indicate that they are possibly associated with the Sagittarius dwarf stream .
The half-light radius ( r _ { \mathrm { h } } \simeq 4.55 \mathrm { pc } ) and luminosity ( M _ { V } \simeq + 0.3 ) of DES J0111 - 1341 are consistent with it being an ultrafaint stellar cluster , while the half-light radius ( r _ { \mathrm { h } } \simeq 18.55 \mathrm { pc } ) and luminosity ( M _ { V } \simeq - 1.1 ) of DES J0225 + 0304 place it in an ambiguous region of size–luminosity space between stellar clusters and dwarf galaxies .
Determinations of the characteristic parameters of the Sagittarius stream , metallicity spread ( -2.18 \lesssim \mathrm { [ Fe / H ] } \lesssim - 0.95 ) and distance gradient ( 23 \mathrm { kpc } \lesssim \mathrm { D } _ { \sun } \lesssim 29 \mathrm { kpc } ) , within the DES footprint in the Southern hemisphere , using the same DES data , also indicate a possible association between these systems .
If these objects are confirmed through spectroscopic follow-up to be gravitationally bound systems and to share a Galactic trajectory with the Sagittarius stream , DES J0111 - 1341 and DES J0225 + 0304 would be the first ultrafaint stellar systems associated with the Sagittarius stream .
Furthermore , DES J0225 + 0304 would also be the first confirmed case of an ultrafaint satellite of a satellite .