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The absence of a thin disc in M81

The absence of a thin disc in M81
The absence of a thin disc in M81
We present the results of simultaneous Suzaku and NuSTAR observations of the nearest low-luminosity active galactic nucleus (LLAGN), M81*. The spectrum is well described by a cut-off power law plus narrow emission lines from Fe K α, Fe  xxv, and Fe  xxvi. There is no evidence of Compton reflection from an optically thick disc, and we obtain the strongest constraint on the reflection fraction in M81* to date, with a best-fitting value of R = 0.0 with an upper limit of R < 0.1. The Fe K α line may be produced in optically thin, NH=1×1023cm−2 , gas located in the equatorial plane that could be the broad line region. The ionized iron lines may originate in the hot, inner accretion flow. The X-ray continuum shows significant variability on ∼40 ks time-scales suggesting that the primary X-ray source is ∼100 s of gravitational radii in size. If this X-ray source illuminates any putative optically thick disc, the weakness of reflection implies that such a disc lies outside a few ×103 gravitational radii. An optically thin accretion flow inside a truncated optically thick disc appears to be a common feature of LLAGN that are accreting at only a tiny fraction of the Eddington limit.
0035-8711
5698-5703
Young, A.J.
3bde9f79-98e5-4d0c-a15d-16b366c9db31
Mchardy, Ian
4f215137-9cc4-4a08-982e-772a0b24c17e
Emmanoulopoulos, Dimitrios
ee2db4c6-3379-4604-8711-f779fb74f538
Connolly, Samuel, Dominic
73b7ee98-bf7c-4064-a04d-e7ece13061e4
Young, A.J.
3bde9f79-98e5-4d0c-a15d-16b366c9db31
Mchardy, Ian
4f215137-9cc4-4a08-982e-772a0b24c17e
Emmanoulopoulos, Dimitrios
ee2db4c6-3379-4604-8711-f779fb74f538
Connolly, Samuel, Dominic
73b7ee98-bf7c-4064-a04d-e7ece13061e4

Young, A.J., Mchardy, Ian, Emmanoulopoulos, Dimitrios and Connolly, Samuel, Dominic (2018) The absence of a thin disc in M81. Monthly Notices of the Royal Astronomical Society, 476 (4), 5698-5703. (doi:10.1093/mnras/sty509).

Record type: Article

Abstract

We present the results of simultaneous Suzaku and NuSTAR observations of the nearest low-luminosity active galactic nucleus (LLAGN), M81*. The spectrum is well described by a cut-off power law plus narrow emission lines from Fe K α, Fe  xxv, and Fe  xxvi. There is no evidence of Compton reflection from an optically thick disc, and we obtain the strongest constraint on the reflection fraction in M81* to date, with a best-fitting value of R = 0.0 with an upper limit of R < 0.1. The Fe K α line may be produced in optically thin, NH=1×1023cm−2 , gas located in the equatorial plane that could be the broad line region. The ionized iron lines may originate in the hot, inner accretion flow. The X-ray continuum shows significant variability on ∼40 ks time-scales suggesting that the primary X-ray source is ∼100 s of gravitational radii in size. If this X-ray source illuminates any putative optically thick disc, the weakness of reflection implies that such a disc lies outside a few ×103 gravitational radii. An optically thin accretion flow inside a truncated optically thick disc appears to be a common feature of LLAGN that are accreting at only a tiny fraction of the Eddington limit.

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Accepted/In Press date: 13 February 2018
e-pub ahead of print date: 13 March 2018
Published date: June 2018
Additional Information: Author confirmed Arxiv record 1803.10050 is AM

Identifiers

Local EPrints ID: 422271
URI: http://eprints.soton.ac.uk/id/eprint/422271
ISSN: 0035-8711
PURE UUID: f6672686-0b43-43a8-80a0-9ba20a8a5bf2
ORCID for Dimitrios Emmanoulopoulos: ORCID iD orcid.org/0000-0002-3335-2446

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Date deposited: 20 Jul 2018 16:30
Last modified: 07 May 2020 00:31

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Author: A.J. Young
Author: Ian Mchardy
Author: Samuel, Dominic Connolly

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