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Active galactic nuclei as scaled-up Galactic black holes

Active galactic nuclei as scaled-up Galactic black holes
Active galactic nuclei as scaled-up Galactic black holes
A long-standing question is whether active galactic nuclei (AGN) vary like Galactic black hole systems when appropriately scaled up by mass1,2,3. If so, we can then determine how AGN should behave on cosmological timescales by studying the brighter and much faster varying Galactic systems. As x-ray emission is produced very close to the black holes, it provides one of the best diagnostics of their behaviour. A characteristic timescale—which potentially could tell us about the mass of the black hole—is found in the x-ray variations from both AGN and Galactic black holes1,2,3,4,5,6, but whether it is physically meaningful to compare the two has been questioned7. Here we report that, after correcting for variations in the accretion rate, the timescales can be physically linked, revealing that the accretion process is exactly the same for small and large black holes. Strong support for this linkage comes, perhaps surprisingly, from the permitted optical emission lines in AGN whose widths (in both broad-line AGN and narrow-emission-line Seyfert 1 galaxies) correlate strongly with the characteristic x-ray timescale, exactly as expected from the AGN black hole masses and accretion rates. So AGN really are just scaled-up Galactic black holes.
0028-0836
730-732
McHardy, I.
4f215137-9cc4-4a08-982e-772a0b24c17e
Koerding, E.
17fc4980-d334-4114-932d-90b6e99a01b7
Knigge, C.
ac320eec-631a-426e-b2db-717c8bf7857e
Uttley, P.
db770bd7-d97e-43f5-99d4-a585bccd352a
Fender, R.P.
c802ddfc-25a3-4c0e-899d-11c405c705d1
McHardy, I.
4f215137-9cc4-4a08-982e-772a0b24c17e
Koerding, E.
17fc4980-d334-4114-932d-90b6e99a01b7
Knigge, C.
ac320eec-631a-426e-b2db-717c8bf7857e
Uttley, P.
db770bd7-d97e-43f5-99d4-a585bccd352a
Fender, R.P.
c802ddfc-25a3-4c0e-899d-11c405c705d1

McHardy, I., Koerding, E., Knigge, C., Uttley, P. and Fender, R.P. (2006) Active galactic nuclei as scaled-up Galactic black holes. Nature, 444 (7120), 730-732. (doi:10.1038/nature05389).

Record type: Article

Abstract

A long-standing question is whether active galactic nuclei (AGN) vary like Galactic black hole systems when appropriately scaled up by mass1,2,3. If so, we can then determine how AGN should behave on cosmological timescales by studying the brighter and much faster varying Galactic systems. As x-ray emission is produced very close to the black holes, it provides one of the best diagnostics of their behaviour. A characteristic timescale—which potentially could tell us about the mass of the black hole—is found in the x-ray variations from both AGN and Galactic black holes1,2,3,4,5,6, but whether it is physically meaningful to compare the two has been questioned7. Here we report that, after correcting for variations in the accretion rate, the timescales can be physically linked, revealing that the accretion process is exactly the same for small and large black holes. Strong support for this linkage comes, perhaps surprisingly, from the permitted optical emission lines in AGN whose widths (in both broad-line AGN and narrow-emission-line Seyfert 1 galaxies) correlate strongly with the characteristic x-ray timescale, exactly as expected from the AGN black hole masses and accretion rates. So AGN really are just scaled-up Galactic black holes.

Full text not available from this repository.

More information

Published date: 7 December 2006
Additional Information: Proves that AGN are defintely scaled-up Galactic black holes, with scaling (of characteristic timescale) going exactly as mass/accretion rate. Also finds, and explains, a surprising relationship between AGN optical linewidth and characteristic timescales (explaining Narrow Line Seyfert 1 Galaxies). McHardy led this research, carried out much of the analysis and wrote the paper.

Identifiers

Local EPrints ID: 45362
URI: http://eprints.soton.ac.uk/id/eprint/45362
ISSN: 0028-0836
PURE UUID: ce67dfa7-9531-4b14-a054-d33e078163f6

Catalogue record

Date deposited: 21 Mar 2007
Last modified: 13 Mar 2019 21:05

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