From the Top to the Bottom of the Main Sequence: A Complete Mass Function of the Young Open Cluster M35

We present very deep and accurate photometry of the open cluster M35 (VRIcfilters). We have covered a region of 27.5x27.5 square arcmin. The data range from Ic=12.5 to 23.5 mag, and the color intervals are0.4\le(V-I)c\le3.0, 0.5\le(R-I)c\le2.5. Roughly, these values span from 1.6M_\odot down to the substellar limit. By using the location of the stars oncolor-magnitude and color-color diagrams, we have selected candidate members ofthis cluster. We have merged our sample with previously published data andobtained a color-magnitude diagram for the complete stellar population of thecluster, covering the spectral range early B - mid M. The Mass Functionincreases monotonically, when plotted in a log-log form, until it reaches ~0.8M_\odot (\alpha=2.59). It remains shallower for less massive stars (\alpha=0.81for 0.8-0.2 M_\odot), whereas a decrease ins observed for stars close to thesubstellar regime. The total mass of the cluster is ~1600 M_\odot in the areacovered by this study.Comment: Accepted ApJ (Jan 10, 2001 issue