We present a large-scale millimeter continuum map of the Ophiuchus molecular cloud .
Nearly 11 square degrees , including all of the area in the cloud with A _ { V } \geq 3 magnitudes , was mapped at 1.1 mm with Bolocam on the Caltech Submillimeter Observatory ( CSO ) .
By design , the map also covers the region mapped in the infrared with the Spitzer Space Telescope .
We detect 44 definite sources , and a few likely sources are also seen along a filament in the eastern streamer .
The map indicates that dense cores in Ophiuchus are very clustered and often found in filaments within the cloud .
Most sources are round , as measured at the half power point , but elongated when measured at lower contour levels , suggesting spherical sources lying within filaments .
The masses , for an assumed dust temperature of 10 K , range from 0.24 to 3.9 M _ { \odot } , with a mean value of 0.96 M _ { \odot } .
The total mass in distinct cores is 42 M _ { \odot } , 0.5 to 2 % of the total cloud mass , and the total mass above 4 \sigma is about 80 M _ { \odot } .
The mean densities in the cores are quite high , with an average of 1.6 \mbox { $ { } \times 10 ^ { 6 } $ } cm ^ { -3 } , suggesting short free-fall times .
The core mass distribution can be fitted with a power law with slope \alpha = 2.1 \pm 0.3 for M > 0.5 M _ { \odot } , similar to that found in other regions , but slightly shallower than that of some determinations of the local IMF .
In agreement with previous studies , our survey shows that dense cores account for a very small fraction of the cloud volume and total mass .
They are nearly all confined to regions with \mbox { $A _ { V } $ } \geq 9 mag , a lower threshold than found previously .