Kiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow?
NGC 4945 contains a well-known heavily obscured active galactic nucleus (AGN) at its core, with prior reports of strong nuclear and off-nuclear neutral Fe K α emission due to the AGN activity. We report the discovery of very extended Fe K α emission with the XMM-Newton EPIC pn in a ∼5 kpc by ∼10 kpc...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc1ce |
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| author | Kimberly A. Weaver Jenna M. Cann Lynne Valencic Miranda McCarthy Ryan W. Pfeifle K. D. Kuntz Joel F. Campbell Kimberly Engle Ryan Tanner Edmund Hodges-Kluck Isabella Carlton |
| author_facet | Kimberly A. Weaver Jenna M. Cann Lynne Valencic Miranda McCarthy Ryan W. Pfeifle K. D. Kuntz Joel F. Campbell Kimberly Engle Ryan Tanner Edmund Hodges-Kluck Isabella Carlton |
| author_sort | Kimberly A. Weaver |
| collection | DOAJ |
| description | NGC 4945 contains a well-known heavily obscured active galactic nucleus (AGN) at its core, with prior reports of strong nuclear and off-nuclear neutral Fe K α emission due to the AGN activity. We report the discovery of very extended Fe K α emission with the XMM-Newton EPIC pn in a ∼5 kpc by ∼10 kpc region that is misaligned with the plane of the inclined optical galactic disk by ∼60° in projection. After a careful consideration of the crowded center of the galaxy and numerous unresolved hard X-ray sources present, we estimate that ∼15% of the Fe K α is extended on kiloparsec-sized scales. The overall size and misalignment of the region follows an unusual pattern of radio polarization that is not typical of starbursts or normal disk galaxies but has been interpreted as possibly due to AGN activity. We suggest that the extended Fe K α emission arose from a period of AGN eruption several million years ago—a relic of a past AGN ejection episode. |
| format | Article |
| id | doaj-art-3ee9dfbe62004b9bb88e3778c94ae333 |
| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-3ee9dfbe62004b9bb88e3778c94ae3332025-08-20T02:30:50ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198519110.3847/1538-4357/adc1ceKiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow?Kimberly A. Weaver0https://orcid.org/0009-0008-4232-486XJenna M. Cann1https://orcid.org/0000-0003-1051-6564Lynne Valencic2Miranda McCarthy3Ryan W. Pfeifle4https://orcid.org/0000-0001-8640-8522K. D. Kuntz5https://orcid.org/0000-0001-6654-5378Joel F. Campbell6https://orcid.org/0000-0001-8873-7450Kimberly Engle7Ryan Tanner8https://orcid.org/0000-0002-1359-1626Edmund Hodges-Kluck9https://orcid.org/0000-0002-2397-206XIsabella Carlton10https://orcid.org/0000-0003-1172-5018X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; Oak Ridge Associated Universities , NASA NPP Program, Oak Ridge, TN 37831, USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; Johns Hopkins University , USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; Southeastern Universities Research Association , Washington, DC 20005, USA; Center for Research and Exploration in Space Science and Technology , NASA/GSFC, Greenbelt, MD 20771, USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; Oak Ridge Associated Universities , NASA NPP Program, Oak Ridge, TN 37831, USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; Johns Hopkins University , USANASA Langley Research Center , USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; ADNET Systems , Inc., Lanham, MD 20706, USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; Catholic University , Washington, DC 20064, USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USAX-ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA; Southeastern Universities Research Association , Washington, DC 20005, USA; Center for Research and Exploration in Space Science and Technology , NASA/GSFC, Greenbelt, MD 20771, USANGC 4945 contains a well-known heavily obscured active galactic nucleus (AGN) at its core, with prior reports of strong nuclear and off-nuclear neutral Fe K α emission due to the AGN activity. We report the discovery of very extended Fe K α emission with the XMM-Newton EPIC pn in a ∼5 kpc by ∼10 kpc region that is misaligned with the plane of the inclined optical galactic disk by ∼60° in projection. After a careful consideration of the crowded center of the galaxy and numerous unresolved hard X-ray sources present, we estimate that ∼15% of the Fe K α is extended on kiloparsec-sized scales. The overall size and misalignment of the region follows an unusual pattern of radio polarization that is not typical of starbursts or normal disk galaxies but has been interpreted as possibly due to AGN activity. We suggest that the extended Fe K α emission arose from a period of AGN eruption several million years ago—a relic of a past AGN ejection episode.https://doi.org/10.3847/1538-4357/adc1ceActive galaxies |
| spellingShingle | Kimberly A. Weaver Jenna M. Cann Lynne Valencic Miranda McCarthy Ryan W. Pfeifle K. D. Kuntz Joel F. Campbell Kimberly Engle Ryan Tanner Edmund Hodges-Kluck Isabella Carlton Kiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow? The Astrophysical Journal Active galaxies |
| title | Kiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow? |
| title_full | Kiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow? |
| title_fullStr | Kiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow? |
| title_full_unstemmed | Kiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow? |
| title_short | Kiloparsec-scale Neutral Iron Kα Emission in the Starburst-AGN NGC 4945: A Relic AGN Outflow? |
| title_sort | kiloparsec scale neutral iron kα emission in the starburst agn ngc 4945 a relic agn outflow |
| topic | Active galaxies |
| url | https://doi.org/10.3847/1538-4357/adc1ce |
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