MGAB-V359: more likely very unusual IP below the period minimum

I have analyzed thr ZTF data and confirmed the two periods found by G. Murawski.

https://www.aavso.org/vsx/index.php?view=detail.top&oid=1498507

The amplitudes, however, are too large for an AM CVn star. The 0.0351788-d period has an amplitude of 1.5 mag. The 0.0239743-d period has an amplitude of 1.1 mag. The beat period of 0.0756893 d has to maxima per cycle. It is also unusual for an AM CVn star to have a secondary period much shorter than the orbital one. The profile of the light curve is boxy rather than sinusoidal (suggesting emission from magnetic poles). This object looks more likely an IP below the period minimum, but with polar-like large variations like Romanov V48 we suggested.

See https://arxiv.org/abs/2204.02598

MGAB-V359 also has a bright ROSAT counterpart:

122016.2 +565454 (2000.0) 2RXP_J122016.3+565455 0.2251P -0.81 -0.41 931030 122016.4 +565451 (2000.0) 1RXPJ122016+5654.8 0.2160 -0.81 -0.43