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A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044

A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044
A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044

We present the first results from a detailed spectral-timing analysis of a long (~130 ks) XMM- Newton observation and quasi-simultaneous NuSTAR and Swift observations of the highly accreting narrow-line Seyfert 1 galaxy Mrk 1044. The broad-band (0.3-50 keV) spectrum reveals the presence of a strong soft X-ray excess emission below ~1.5 keV, iron Kα emission complex at ~6-7 keV and a 'Compton hump' at ~15-30 keV. We find that the relativistic reflection from a high-density accretion disc with a broken power-law emissivity profile can simultaneously explain the soft X-ray excess, highly ionized broad iron line and the Compton hump. At low frequencies ([2 - 6] × 10-5 Hz), the power-law continuum-dominated 1.5- 5 keV band lags behind the reflection-dominated 0.3-1 keV band, which is explained with a combination of propagation fluctuation and Comptonization processes, while at higher frequencies ([1 - 2] × 10-4 Hz), we detect a soft lag which is interpreted as a signature of X-ray reverberation from the accretion disc. The fractional root-mean-squared variability of the source decreases with energy and is well described by two variable components: a less variable relativistic disc reflection and a more variable direct coronal emission. Our combined spectral-timing analyses suggest that the observed broad-band X-ray variability of Mrk 1044 is mainly driven by variations in the location or geometry of the optically thin, hot corona.

accretion, accretion discs, Black hole physics, Galaxies: active, Galaxies: Seyfert, Relativistic processes
0035-8711
615-634
Mallick, L.
15b17e80-7c5f-4cf4-a09e-a8bfcda3cd6e
Alston, W.N.
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Parker, M.L.
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Fabian, A.C.
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Pinto, C.
3331e9ac-b6c6-4967-af51-3bbce228c1c4
Dewangan, G.C.
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Markowitz, A.
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Gandhi, P.
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Kembhavi, A.K.
bd81f9d0-98e8-40a2-bc43-6eded7964d46
Misra, R.
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Mallick, L.
15b17e80-7c5f-4cf4-a09e-a8bfcda3cd6e
Alston, W.N.
7bee626a-854f-4b59-b362-abbab7aeb9ac
Parker, M.L.
5610270f-9c66-4222-bc30-55c5975bb9ee
Fabian, A.C.
0c353376-f159-4129-b03e-d3993c0c5406
Pinto, C.
3331e9ac-b6c6-4967-af51-3bbce228c1c4
Dewangan, G.C.
5ac9d24b-bcbb-45ab-a838-b093e67fc990
Markowitz, A.
6215f211-c545-4c9f-a9d0-a8fd79b8a45c
Gandhi, P.
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Kembhavi, A.K.
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Misra, R.
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Mallick, L., Alston, W.N., Parker, M.L., Fabian, A.C., Pinto, C., Dewangan, G.C., Markowitz, A., Gandhi, P., Kembhavi, A.K. and Misra, R. (2018) A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044. Monthly Notices of the Royal Astronomical Society, 479 (1), 615-634. (doi:10.1093/mnras/sty1487).

Record type: Article

Abstract

We present the first results from a detailed spectral-timing analysis of a long (~130 ks) XMM- Newton observation and quasi-simultaneous NuSTAR and Swift observations of the highly accreting narrow-line Seyfert 1 galaxy Mrk 1044. The broad-band (0.3-50 keV) spectrum reveals the presence of a strong soft X-ray excess emission below ~1.5 keV, iron Kα emission complex at ~6-7 keV and a 'Compton hump' at ~15-30 keV. We find that the relativistic reflection from a high-density accretion disc with a broken power-law emissivity profile can simultaneously explain the soft X-ray excess, highly ionized broad iron line and the Compton hump. At low frequencies ([2 - 6] × 10-5 Hz), the power-law continuum-dominated 1.5- 5 keV band lags behind the reflection-dominated 0.3-1 keV band, which is explained with a combination of propagation fluctuation and Comptonization processes, while at higher frequencies ([1 - 2] × 10-4 Hz), we detect a soft lag which is interpreted as a signature of X-ray reverberation from the accretion disc. The fractional root-mean-squared variability of the source decreases with energy and is well described by two variable components: a less variable relativistic disc reflection and a more variable direct coronal emission. Our combined spectral-timing analyses suggest that the observed broad-band X-ray variability of Mrk 1044 is mainly driven by variations in the location or geometry of the optically thin, hot corona.

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A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044 - Accepted Manuscript
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Accepted/In Press date: 25 May 2018
e-pub ahead of print date: 4 June 2018
Published date: 1 September 2018
Keywords: accretion, accretion discs, Black hole physics, Galaxies: active, Galaxies: Seyfert, Relativistic processes

Identifiers

Local EPrints ID: 424484
URI: http://eprints.soton.ac.uk/id/eprint/424484
ISSN: 0035-8711
PURE UUID: a735c2cc-a5e4-4f08-bac3-682926bed2a1
ORCID for P. Gandhi: ORCID iD orcid.org/0000-0003-3105-2615

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Date deposited: 05 Oct 2018 11:37
Last modified: 07 Oct 2020 02:06

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Contributors

Author: L. Mallick
Author: W.N. Alston
Author: M.L. Parker
Author: A.C. Fabian
Author: C. Pinto
Author: G.C. Dewangan
Author: A. Markowitz
Author: P. Gandhi ORCID iD
Author: A.K. Kembhavi
Author: R. Misra

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