Press Release

Rapid Flares in Normal Looking Galaxies Hint at the Ubiquity of Supermassive Black Holes

April 1, 2005

The following release was received from Kyoto University and is reprinted here in its entirety for the convenience of our readers:
(Original Article:

This page is made by Tomonori Totani, on behalf of the research group.


We discovered flares of the nuclei in apparently normal galaxies by a search for transient objects using the Subaru telescope. These galaxies are about 4 billion light years away, and flares occur just within a few days. This radiation is likely coming from accretion disk that is rotating with a speed close to that of light, at a distance of about 1 billion km from supermassive black holes that are about 100 million times heavier than the Sun. These black holes are even much heavier than the black hole in the center of the Milky Way, which is about 3 millon solar masses. It is for the first time that such violent activity is observed from such heavy black holes in visible wavebands. It gives a further support for the notion that black hole existence is ubiquitous in centers of almost all galaxies, which is becoming a standard idea among astronomers.

Figure 1

Figure 1: The region we observed in this project. The area is roughly the same size with the full moon. The locations of the six AGNs are indicated.

Figure 2

Figure 2: The close-up of the object 1.

Figure 3

Figure 3: The six galaxies and their differential images showing variability for four days. You can see that the nuclei of the galaxies are changing their luminosity. The object 2 is showing particularly strong flare within the four days.

This work has been publised in the Astrophysical Journal Letters. This is also highlightened by the journal Nature, in Research Highlight section of Feb 17 issue, 2005.



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