Our Supermassive Black Hole Rivaled the Sun in the Ancient X-ray Sky
Pau Amaro-Seoane, Xian Chen

TL;DR
This paper investigates the historical X-ray outbursts of Sagittarius A*, revealing they could have significantly impacted planetary atmospheres and habitability in the solar system and nearby systems.
Contribution
It provides a calculation of the X-ray luminosity during past outbursts of Sagittarius A* and assesses their potential effects on planetary atmospheres and habitability.
Findings
Past outbursts could produce X-ray flux comparable to the Sun's current emission.
Hard X-ray flux during outbursts exceeds that of X-class solar flares.
Impacts on planetary atmospheres vary with distance and planetary mass.
Abstract
Sagittarius A* (SgrA*) lying in the Galactic Centre kpc from Earth, hosts the closest supermassive black hole known to us. It is now inactive, but there is evidence indicating that about six million years ago it underwent a powerful outburst where the luminosity could have approached the Eddington limit. Motivated by the fact that in extragalaxies the supermassive black holes with similar masses and near-Eddington luminosities are usually strong X-ray emitters, we calculate here the X-ray luminosity of SgrA*. For that, we assume that the outburst was due to accretion of gas or the tidal disruption of a star. We show that these cases could precipitate on Earth a hard X-ray (i.e. ) flux comparable to that from the current quiescent sun. The flux in harder energy band , however, surpasses that from an X-class solar flare, and the…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
