Identifying Long Radio Transients with Accompanying X-Ray Emission as Disk-Jet Precessing Black Holes: The Case of ASKAP J1832-0911

Abstract

Aims: In this work we investigate whether the 2 min bursts every 44 min from ASKAP J1832-0911 can be explained by Lense-Thirring precession of an intermediate-mass black hole (IMBH) accretion disk launching a Blandford-Znajek jet, as an alternative to magnetar or white-dwarf models. Methods: We derive the Lense-Thirring period $P_{\mathrm{LT}}=\frac{\pi GM}{a{c}^3}{r}^3$ and solve $P_{\mathrm{LT}}=44$ min for black-hole mass M and dimensionless radius $r=R/R_g$. We estimate the equipartition field B at r, compute the Blandford-Znajek power $P_{\mathrm{BZ}}$, and the power expected from a gap at the black hole magnetosphere, and compare the resulting jet luminosity to the observed radio and X-ray fluxes at $D\approx 4.5$ kpc. We also evaluate expected high-frequency variability and the angular size for Very Long Baseline Interferometry (VLBI) observations. Results: For $a\sim 0.3-0.9$, an IMBH with $M\sim 10^3-10^5{M}_{\odot }$ yields $r\sim 10-40R_g$ and $P_{\mathrm{LT}}=44$ min. Equipartition gives $B\sim 10^5$ G at r, leading to $P_{\mathrm{BZ}}\sim 10^{35-39}$ erg ${\mathrm{s}}^{-1}$. With radiative efficiency ${\epsilon }_j\sim 10^{-2}-10^{-1}$, the predicted $L_{\mathrm{jet}}\sim 10^{34-36}$ erg ${\mathrm{s}}^{-1}$ matches the observed $F_X\sim 10^{-12}$ erg $\mathrm{c}{\mathrm{m}}^{-2}$ ${\mathrm{s}}^{-1}$ and radio flux, variability on $\lesssim 100$ s could be a smoking gun of this model. Conclusions:The IMBH precessing-jet model simultaneously explains the periodicity, energetics, and duty cycle of ASKAP J1832-0911. Only high-time-resolution X-ray timing (to check $\sim$s pulsations) and multi-frequency radio polarimetry can definitively distinguish it from magnetar or white-dwarf scenarios.

5 pages, Submitted to A&A

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