6 Geller et al. the single-measurement RV precision for that star. We adopt a floor to our precision at 0.5 km s − $^{1}$, as found for our narrow-lined stars, and shown by the break in the dashed line in Figure 5. Cluster Field Ampl. (Number) 69.0 ± 2.0 2.4 ± 0.4 RV (km s − $^{1}$) -8.17 ± 0.05 13 ± 4 σ (km s − $^{1}$) 0.92 ± 0.08 34 ± 4 dard error of the v sin i measurements $^{6}$, the e/i value (see Section 4.2), the calculated RV membership proba- bility (P$_{RV}$ , see Section 4.1), the proper-motion member- ship probability from McNamara & Sekiguchi (1986a) ( P$_{PM}$ 1 ) and Cudworth (1971) ( P$_{PM}$ 2 ), where available, and then, the classification of the object (see Section 4.3). For RV-variable stars with orbital solutions, we present the center-of-mass ( γ ) RV with the derived error in place of the mean RV and its standard error, and add the com- ment SB1 or SB2 for single- and double-lined binaries, respectively. Additionally, for binaries without orbital solutions that appear to be double-lined, we add the com- ment of SB2. Finally, for purposes of future research we include seven rapid rotators for which we have been un- able to derive RVs from our spectra, and label them with the comment RR. Fig. 5.— RV measurement precision as a function of the average v sin i (in km s − $^{1}$) for single lined stars with ≥ 3 ob- servations. The bins are v sin i of ≤ 10 km s − $^{1}$, 10 - 20 km s − $^{1}$and 20 - 80 km s − $^{1}$, chosen to provide sufficiently large samples. The gray horizontal bars indicate the bin sizes for each point. The black vertical error bars show the one sigma errors on the precision fit values. The dotted line shows the fit to these data, and provided in Equation 1; we impose a floor to our precision at 0.5 km s − $^{1}$. 4.1. Membership The RV distribution of M35 is clearly distinguished from that of the field when we plot a histogram of the mean RVs for the observed stars in our stellar sample. In Figure 6, we show a histogram of the mean RVs for stars with ≥ 3 RV measurements whose standard deviations are < 2 km s − $^{1}$, as well as the γ -RVs for binary stars with orbital solutions, thus excluding from the fit any RV variables whose γ -RVs are unknown. The cluster shows a well-defined peak rising above the broad distribution of the field stars. We simultaneously fit one-dimensional Gaussian functions, F$_{c}$ ( v ) and F$_{f}$ ( v ), to represent the cluster and field RV distributions, respectively, and then use these fits to calculate RV membership probabilities for each individual star. We compute the membership probability P$_{RV}$ ( v ) with the usual formula: We lack sufficient observations to perform this same analysis using observations in the 637.5 nm region or for observations taken after the spring of 2008 (see Sec- tion 2.2). Therefore, for the 129 stars that do not have any observations in the 512.5 nm region ( ∼ 11% of our ob- served stars), we visually inspect the spectra and CCFs. For narrow-lined stars, we set the precision to 0.5 km s − $^{1}$, and for rotating stars we set the precision to 1.0 km s − $^{1}$. We can then use this RV precision value for a given star to determine whether our observations for this star are constant or variable in velocity (see Section 4.2). We note that only 13 of these stars have sufficient observa- tions for their RVs to be considered final, and only 2 are probable members. P$_{RV}$ ( v ) = F$_{c}$ ( v ) F$_{f}$ ( v ) + F$_{c}$ ( v ) (2) 4. RESULTS (Vasilevskis et al. 1958). We plot these Gaussian fits in Figure 6 with the dashed lines, and show the fit param- eters in Table 1. For a given single star, we use the mean RV to com- pute the RV membership probability. For a given binary star with an orbital solution, we compute the RV mem- bership probability from the γ -RV. For RV-variable stars without orbital solutions, the γ -RVs are not known, and therefore we cannot calculate RV membership probabil- ities. For these stars, we provide a preliminary member- ship classification, described in Section 4.3. The full M35 database is available with the electronic version of this paper; here we show a sample of our re- sults in Table 3. The first column in Table 3 contains the WOCS identification number ( ID$_{W}$ ). These num- bers are defined in the same manner as in Hole et al. (2009), with the cluster center set at α = 6 $^{h}$9$^{m}$7 . $^{s}$5 and δ = +24 $^{◦}$20$^{′}$28′′ (J2000). Next we give the corresponding IDs from Meibom et al. (2009), McNamara & Sekiguchi (1986a) and Cudworth (1971) ( ID$_{M}$ , ID$_{Mc}$ and ID$_{C}$ ). The next few columns provide the right ascension ( RA ), declination ( DEC ), the BV photometry and the source number ( S ) for this photometry (see Section 2.1). Next, we show the number of RV measurements ( N ) and the mean and standard error of the RV measurements. For stars with only one RV measurements, we show the single-measurement RV precision instead of the standard error. Next we provide this single-measurement RV pre- cision ( σ$_{i}$ , derived using equation 1), the mean and stan- 6 For double-lined binaries and stars with no observation in the 512.5 nm region, we do not derive a v sin i value. For stars with only one measurement in the 512.5 nm region, we convert the 1-sigma error on the FWHM (derived from the Gaussian fit to the CCF peak) to an error on the v sin i using the fit shown in Figure 3. As this relationship is not linear, we provide the mean of the derived upper and lower errors on v sin i . TABLE 1 Gaussian Fit Parameters For Cluster and Field RV Distributions