A preliminary timing analysis of two intermediate polars: UU Col and Swift J0939.7-3224

We present the preliminary timing analysis of confirmed intermediate polar UU
Col and possible intermediate polar Swift J0939.7-3224 in the optical band with
the help of long-term, high-cadence continuous photometry from Transiting
Exoplanet Survey Satellite (TESS). For UU Col, we revise previously reported
orbital and spin periods as 3.464 $\pm$ 0.005 h and 863.74 $\pm$ 0.08 s,
respectively. Using the second harmonic of the beat frequency, the beat period
is estimated as $\sim$928 s. These findings indicate that UU Col is a disc-fed
dominated disc-overflow accretor. For J0939, we establish the spin period as
2671.8 $\pm$ 0.8 s and refine the provisionally suggested orbital period as
8.49 $\pm$ 0.03 h. The absence of beat frequency in J0939 signifies that it
might be a pure disc-fed accretor; however, an X-ray study of this source will
help to understand its true nature.