Disc geometry and kHz-QPO connection in 1A 1246−588

Establish the disc geometry of the faint ultra-compact X-ray binary candidate 1A 1246−588 and determine its connection to the source’s kilohertz quasi-periodic oscillation phenomenology using simultaneous soft- and hard-X-ray spectral-timing analysis.

Background

Earlier broadband spectral fits of 1A 1246−588 did not robustly identify a disc-blackbody component, while RXTE observations reported a highly coherent 1258 Hz kilohertz QPO. The absence of a securely detected disc component leaves the inner-disc structure and the physical relationship between the disc and the kilohertz QPO unresolved.

The paper identifies simultaneous AstroSat observations spanning soft and hard X-rays as a way to address this issue through joint spectral and timing constraints.