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We present an Advanced LIGO and Advanced Virgo search for sub-solar mass ultracompact objects in data obtained during Advanced LIGO ’ s second observing run .
In contrast to a previous search of Advanced LIGO data from the first observing run , this search includes the effects of component spin on the gravitational waveform .
We identify no viable gravitational wave candidates consistent with sub-solar mass ultracompact binaries with at least one component between 0.2 - 1.0 \thinspace M _ { \odot } .
We use the null result to constrain the binary merger rate of ( 0.2 \thinspace M _ { \odot } , 0.2 \thinspace M _ { \odot } ) binaries to be less than 3.7 \times 10 ^ { 5 } \thinspace \mathrm { Gpc } ^ { -3 } \mathrm { yr } ^ { -1 } and the binary merger rate of ( 1.0 \thinspace M _ { \odot } , 1.0 \thinspace M _ { \odot } ) binaries to be less than 5.2 \times 10 ^ { 3 } \thinspace \mathrm { Gpc } ^ { -3 } \mathrm { yr } ^ { -1 } .
Sub-solar mass ultracompact objects are not expected to form via known stellar evolution channels , though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with sub-solar masses .
Assuming a particular primordial black hole formation model , we constrain a population of merging 0.2 \thinspace M _ { \odot } black holes to account for less than 16 % of the dark matter density and a population of merging 1.0 \thinspace M _ { \odot } black holes to account for less than 2 % of the dark matter density .
We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict sub-solar mass binaries .