Variable accretion and emission from the stellar winds in the Galactic centre

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dc.creatorCuadra, Jorge
dc.creatorNayakshin, Sergei
dc.creatorMartins, Fabrice
dc.date2007-05-05
dc.date2007-10-10
dc.date.accessioned2026-07-07T12:49:30Z
dc.date.available2026-07-07T12:49:30Z
dc.descriptionWe present numerical simulations of stellar wind dynamics in the central parsec of the Galactic centre, studying in particular the accretion of gas on to Sgr A*, the super-massive black hole. Unlike our previous work, here we use state-of-the-art observational data on orbits and wind properties of individual wind-producing stars. Since wind velocities were revised upwards and non-zero eccentricities were considered, our new simulations show fewer clumps of cold gas and no conspicuous disc-like structure. The accretion rate is dominated by a few close `slow wind stars' v_w < 750 km/s, and is consistent with the Bondi estimate, but variable on time-scales of tens to hundreds of years. This variability is due to the stochastic in-fall of cold clumps of gas, as in earlier simulations, and to the eccentric orbits of stars. The present models fail to explain the high luminosity of Sgr A* a few hundred years ago implied by Integral observations, but we argue that the accretion of a cold clump with a small impact parameter could have caused it. Finally, we show the possibility of constraining the total mass-loss rate of the `slow wind stars' using near infra-red observations of gas in the central few arcseconds.
dc.descriptionMNRAS, accepted. 10 pages, 11 figures. PS version is better (Fig 11 gets blurred in PDF)
dc.identifierhttps://arxiv.org/abs/0705.0769
dc.identifierhttp://arxiv.org/abs/0705.0769
dc.identifierMon.Not.Roy.Astron.Soc. 383 (2008) 458-466
dc.identifierdoi:10.1111/j.1365-2966.2007.12573.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/222424
dc.subjectAstrophysics
dc.titleVariable accretion and emission from the stellar winds in the Galactic centre
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