RT Cru, is the prototype of the δ X-ray type of symbiotics.
It was also the first symbiotic to be detected with INTEGRAL and Swift at energies greater that ∼50 keV

RT Cru

Position: FK5 coord. (ep=J2000 eq=2000) : R.A.= 12 34 53.73; DEC: -64 33 56.09

Swift/BAT Hard X-ray Transient Monitor daily ligth curve, with 100 days bins.

AAVSO+ASAS Optical light curve (left Y axis) and Swift BAT 100days/bin light curve (right Y axis). The moving vertical line indicates the dates of the Swift XRT observations whose spectra are shown in the bottom panel. The optical/XRT/BAT flux cleary vary in tandem.

References:

Simbad query results