Limits on stellar and planetary companions in microlensing event OGLE-1998-BUL-14

We present the PLANET photometric data set for OGLE-1998-BUL-14, a high-magnification (A(max) similar to 16) event alerted by the OGLE collaboration toward the Galactic bulge in 1998. The PLANET data set consists a total of 461 I-band and 139 V-band points, the majority of which was taken over a 3 month period. The median sampling interval during this period is about 1 hr,and the I sigma scatter over the peak of the event is 1.5%. The excellent data quality and high maximum magnification of this event make it a prime candidate to search for the short-duration, low-amplitude perturbations that are signatures of a planetary companion orbiting the primary lens. The observed light curve for OGLE-1998-BUL-14 is consistent with a single lens (no companion) within photometric uncertainties. We calculate the detection efficiency of the light curve to lensing companions as a function of the mass ratio and angular separation of the two components. We find that companions of mass ratio greater than or equal to 0.01 are ruled out at the 95% significance level for projected separations between 0.4 and 2.4r(E), where r(E) is the Einstein ring radius of the primary lens. Assuming that the primary is a G dwarf with r(E) similar to 3 AU, our detection efficiency for this event is similar to 60% for a companion with the mass and separation of Jupiter and similar to 5% for a companion with the mass and separation of Saturn. Our efficiencies for planets like those around nu And and 14 Her are >75%.