SONYC – Substellar Objects in Nearby Young Clusters – is a program to investigate the frequency and properties of young substellar objects with masses down to a few times that of Jupiter .
Here we present a census of very low mass objects in the \sim 1 Myr old cluster NGC1333 .
We analyze near-infrared spectra taken with FMOS/Subaru for 100 candidates from our deep , wide-field survey and find 10 new likely brown dwarfs with spectral types of M6 or later .
Among them , there are three with \gtrsim M9 and one with early L spectral type , corresponding to masses of 0.006 to \lesssim 0.02 M _ { \odot } , so far the lowest mass objects identified in this cluster .
The combination of survey depth , spatial coverage , and extensive spectroscopic follow-up makes NGC1333 one of the most comprehensively surveyed clusters for substellar objects .
In total , there are now 51 objects with spectral type M5 or later and/or effective temperature of 3200 K or cooler identified in NGC1333 ; 30-40 of them are likely to be substellar .
NGC1333 harbours about half as many brown dwarfs as stars , which is significantly more than in other well-studied star forming regions , thus raising the possibility of environmental differences in the formation of substellar objects .
The brown dwarfs in NGC1333 are spatially strongly clustered within a radius of \sim 1 pc , mirroring the distribution of the stars .
The disk fraction in the substellar regime is < 66 % , lower than for the total population ( 83 % ) but comparable to the brown dwarf disk fraction in other 2-3 Myr old regions .