Invited review abstract

The low-mass end of the initial mass function (IMF) needs to be constrained to further current star formation theories and models. IC 4665 is a fairly young (~30Myr) star cluster and is 356pc distant towards the constellation Ophiuchus. Proper motion is low at -4 to -7.5 mas/yr and extinction is also low and present at Av~0.59 ± 0.15mag. WIRCam Y, J, H and Ks observations were made using the CFHT and spanned 10 cluster fields (of total footprint ~1.1sq.deg) and two control fields of 20'x20' each. Colour magnitude diagrams were used to compare the photometrically selected cluster member candidates to the 30Myr BT-SETTL model and previous radial velocity and/or spectroscopically confirmed cluster members. Contamination by field stars was assessed using the control fields. Masses were then assigned using the comparison model, before the lognormal and power law IMFs were calculated and compared to the IMFs derived for other open clusters.