The flaring drill in the Galactic centre. Did the IRS 13 cluster carve out the mini-cavity in the mini-spiral?
Jaroslav Haas, Pavel Kroupa, Florian Pei{ss}ker, Mark R. Morris
arXiv:2606.17131v1 Announce Type: new
Abstract: The mini-cavity is a low-density region observed in the complex of streams of ionized gas around the Galactic central supermassive black hole, Sgr A$^star$, known as the mini-spiral. Its near-circular shape is suggestive of a formation due to the effect of stellar winds. No suitable stars are currently observed within the mini-cavity, however. In this study we assessed whether the mini-cavity could have been formed by the winds of the stars from the neighbouring IRS 13 cluster that were located at the position of the mini-cavity in the past but moved away from it later on owing to their orbital motions around Sgr A$^star$. Furthermore, we estimated the rate of accretion of the then-abundant interstellar medium onto the putative intermediate-mass black hole that has been proposed to reside in the IRS 13 cluster and the corresponding X-ray luminosity of this black hole. The estimates were obtained analytically using the astrophysical properties reported for the involved objects and the environment. Based on our results, we suggest that the mini-cavity was formed by the winds of the IRS 13 cluster member stars about 300 years ago, when this cluster went through the Bar region of the mini-spiral. The accompanying accretion of the interstellar medium onto the putative intermediate-mass black hole in this cluster may have produced multiple X-ray flares with luminosities of $approx10^{39}$ erg/s. Such flares are compatible with the X-ray reflections currently observed on the molecular clouds in the complexes Sgr A, B, and C, including the necessary light-travel time delay.arXiv:2606.17131v1 Announce Type: new
Abstract: The mini-cavity is a low-density region observed in the complex of streams of ionized gas around the Galactic central supermassive black hole, Sgr A$^star$, known as the mini-spiral. Its near-circular shape is suggestive of a formation due to the effect of stellar winds. No suitable stars are currently observed within the mini-cavity, however. In this study we assessed whether the mini-cavity could have been formed by the winds of the stars from the neighbouring IRS 13 cluster that were located at the position of the mini-cavity in the past but moved away from it later on owing to their orbital motions around Sgr A$^star$. Furthermore, we estimated the rate of accretion of the then-abundant interstellar medium onto the putative intermediate-mass black hole that has been proposed to reside in the IRS 13 cluster and the corresponding X-ray luminosity of this black hole. The estimates were obtained analytically using the astrophysical properties reported for the involved objects and the environment. Based on our results, we suggest that the mini-cavity was formed by the winds of the IRS 13 cluster member stars about 300 years ago, when this cluster went through the Bar region of the mini-spiral. The accompanying accretion of the interstellar medium onto the putative intermediate-mass black hole in this cluster may have produced multiple X-ray flares with luminosities of $approx10^{39}$ erg/s. Such flares are compatible with the X-ray reflections currently observed on the molecular clouds in the complexes Sgr A, B, and C, including the necessary light-travel time delay.

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