Properties of H₂O Masers and Their Associated Sources in Sagittarius B2

We present high-resolution Karl G. Jansky Very Large Array observations of the 22 GHz H 2 O maser line in the extended Sagittarius B2 cloud. We detect 499 H 2 O masers across the observed velocities between −39 and 172 km s −1 . To investigate the nature of the masers, we analyze their spatial distribution and crossmatch with catalogs of H II regions and protostellar cores. 62% of masers are associated with protostellar cores and 32% with H II regions. The nature of the remaining 6% of sources was not established but is likely associated with protostellar cores. Based on the spatial extent of the groups of masers, we classify them as either outflow-associated or young stellar object (YSO)–associated. We identify 144 unique sites of maser emission: 23 are associated with H II regions and 94 with protostellar cores, of which 33 are associated with protostellar outflows and 18 with YSOs. The outflow-associated H 2 O maser emission is confined to within <2000 au of the central continuum source, despite shocked SiO emission extending over tens of thousands of astronomical units. The YSO-associated masers show a lack of detections at 5 < V rel < 30 km s −1 , which we suggest may be due to maser self-absorption. We show how H 2 O masers trace the large-scale material flow in Sgr B2 North, also seen in SiO and millimeter continuum emission. Finally, we find that protostellar cores with associated H 2 O masers tend to have brighter 3 mm continuum emission on average, although there is no strong correlation between maser brightness and continuum flux.