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 (Amax ∼ 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 three month period. The median sampling interval during this period is about 1 hour, and the 1σ 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 ≥ 0.01 are ruled out at the 95% confidence level for projected separations between 0.4− 2.4rE, where rE is the Einstein ring radius of the primary lens. Assuming that the primary is a G-dwarf with rE ∼ 3 AU our detection efficiency for this event is ∼ 60% for a companion with the mass and separation of Jupiter and ∼ 5% for a companion with the mass and separation of Saturn. Our efficiencies for planets like those around Upsilon And and 14 Her are > 75%. Subject headings: gravitational lensing, dark matter, planetary systems