Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
Abstract
The cores of most galaxies are thought to harbour supermassive black holes, which power galactic nuclei by converting the gravitational energy of accreting matter into radiation (ref 1). Sagittarius A*, the compact source of radio, infrared and X-ray emission at the centre of the Milky Way, is the closest example of this phenomenon, with an estimated black hole mass that is 4 million times that of the Sun (refs. 2,3). A long-standing astronomical goal is to resolve structures in the innermost accretion flow surrounding Sgr A* where strong gravitational fields will distort the appearance of radiation emitted near the black hole. Radio observations at wavelengths of 3.5 mm and 7 mm have detected intrinsic structure in Sgr A*, but the spatial resolution of observations at these wavelengths is limited by interstellar scattering (refs. 4-7). Here we report observations at a wavelength of 1.3 mm that set a size of 37 (+16, -10; 3-sigma) microarcseconds on the intrinsic diameter of Sgr A*. This is less than the expected apparent size of the event horizon of the presumed black hole, suggesting that the bulk of SgrA* emission may not be not centred on the black hole, but arises in the surrounding accretion flow.
Cite
@article{arxiv.0809.2442,
title = {Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre},
author = {Sheperd Doeleman and Jonathan Weintroub and Alan E. E. Rogers and Richard Plambeck and Robert Freund and Remo P. J. Tilanus and Per Friberg and Lucy M. Ziurys and James M. Moran and Brian Corey and Ken H. Young and Daniel L. Smythe and Michael Titus and Daniel P. Marrone and Roger J. Cappallo and Douglas C. J. Bock and Geoffrey C. Bower and Richard Chamberlin and Gary R. Davis and Thomas P. Krichbaum and James Lamb and Holly Maness and Arthur E. Niell and Alan Roy and Peter Strittmatter and Daniel Werthimer and Alan R. Whitney and David Woody},
journal= {arXiv preprint arXiv:0809.2442},
year = {2008}
}
Comments
12 pages including 2 figures