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Main Authors: Yin, Charles, Lawrence, Andy, Ward, Martin, Homan, David, Kollatschny, Wolfram
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2506.04337
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author Yin, Charles
Lawrence, Andy
Ward, Martin
Homan, David
Kollatschny, Wolfram
author_facet Yin, Charles
Lawrence, Andy
Ward, Martin
Homan, David
Kollatschny, Wolfram
contents We present flux measurements of the coronal lines [Fe VII] and [Fe X] spanning three decades, in the highly variable Active Galactic Nucleus (AGN) MKN 110. These coronal lines are sensitive to the spectral energy distribution (SED) of AGNs in the extreme ultraviolet (EUV). Neither [Fe VII] nor [Fe X] demonstrates variability in the short term on a weekly or monthly timescale. However, by taking advantage of a long term decrease in the continuum flux of MKN 110 on the order of years, we were able to track the [Fe VII] and [Fe X] fluxes as they respond to the continuum. We were able to detect a lag for [Fe VII] relative to the continuum at 5100 Å, with a modal lag of 652 days, but were unable to detect a significant lag in the [Fe x] flux, though there exist significant uncertainties in the [Fe X] fit. These two lag results are not consistent and the line widths for the two line species also do not match. This provides strong evidence for stratification within the coronal line region (CLR). There is also evidence of a non-varying component within the coronal line flux, probably a result of a more extended region of origin. Taken together, these results suggest a CLR where the bulk of the [Fe VII] originates on parsec scales, but a portion of the [Fe VII] flux originates further out, at or beyond a 10 pc scale. These results also indicate the limitations of single-cloud models in describing the physical conditions of the CLR.
format Preprint
id arxiv_https___arxiv_org_abs_2506_04337
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Long Term Reverberation Mapping of Iron Coronal Lines in MKN 110
Yin, Charles
Lawrence, Andy
Ward, Martin
Homan, David
Kollatschny, Wolfram
Astrophysics of Galaxies
We present flux measurements of the coronal lines [Fe VII] and [Fe X] spanning three decades, in the highly variable Active Galactic Nucleus (AGN) MKN 110. These coronal lines are sensitive to the spectral energy distribution (SED) of AGNs in the extreme ultraviolet (EUV). Neither [Fe VII] nor [Fe X] demonstrates variability in the short term on a weekly or monthly timescale. However, by taking advantage of a long term decrease in the continuum flux of MKN 110 on the order of years, we were able to track the [Fe VII] and [Fe X] fluxes as they respond to the continuum. We were able to detect a lag for [Fe VII] relative to the continuum at 5100 Å, with a modal lag of 652 days, but were unable to detect a significant lag in the [Fe x] flux, though there exist significant uncertainties in the [Fe X] fit. These two lag results are not consistent and the line widths for the two line species also do not match. This provides strong evidence for stratification within the coronal line region (CLR). There is also evidence of a non-varying component within the coronal line flux, probably a result of a more extended region of origin. Taken together, these results suggest a CLR where the bulk of the [Fe VII] originates on parsec scales, but a portion of the [Fe VII] flux originates further out, at or beyond a 10 pc scale. These results also indicate the limitations of single-cloud models in describing the physical conditions of the CLR.
title Long Term Reverberation Mapping of Iron Coronal Lines in MKN 110
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2506.04337