The Close AGN Reference Survey (CARS). What is causing Mrk 1018's return to the shadows after 30 years?
Letter
Husemann, B., Urrutia, T., Tremblay, G.R., Krumpe, M., Dexter, J., Busch, G., Combes, F., Croom, S. M., Davis, T.A., Eckart, A., McElroy, R. E., Pérez-Torres, M., Powell, T.M. and Scharwächter, J.. 2016. "The Close AGN Reference Survey (CARS). What is causing Mrk 1018's return to the shadows after 30 years?" Astronomy and Astrophysics: a European journal. 593, p. L9. https://doi.org/10.1051/0004-6361/201629245
| Article Title | The Close AGN Reference Survey (CARS). What is causing Mrk 1018's return to the shadows after 30 years? |
|---|---|
| ERA Journal ID | 1050 |
| Article Category | Letter |
| Authors | Husemann, B., Urrutia, T., Tremblay, G.R., Krumpe, M., Dexter, J., Busch, G., Combes, F., Croom, S. M., Davis, T.A., Eckart, A., McElroy, R. E., Pérez-Torres, M., Powell, T.M. and Scharwächter, J. |
| Journal Title | Astronomy and Astrophysics: a European journal |
| Journal Citation | 593, p. L9 |
| Number of Pages | 4 |
| Year | 2016 |
| Publisher | EDP Sciences |
| Place of Publication | France |
| ISSN | 0004-6361 |
| 1432-0746 | |
| Digital Object Identifier (DOI) | https://doi.org/10.1051/0004-6361/201629245 |
| Web Address (URL) | https://www.aanda.org/articles/aa/full_html/2016/09/aa29245-16/aa29245-16.html |
| Abstract | We recently discovered that the active galactic nucleus (AGN) of Mrk 1018 has changed optical type again after 30 yr as a type 1 AGN. Here we combine Chandra, NuStar, Swift, Hubble Space Telescope and ground-based observations to explore the cause of this change. The 2-10 keV flux declines by a factor of ~8 between 2010 and 2016. We show with our X-ray observation that this is not caused by varying neutral hydrogen absorption along the line-of-sight up to the Compton-thick level. The optical-UV spectral energy distributions are well fit with a standard geometrically thin optically thick accretion disc model that seems to obey the expected L ~ T<SUP>4</SUP> relation. It confirms that a decline in accretion disc luminosity is the primary origin for the type change. We detect a new narrow-line absorber in Lyα blue-shifted by ~700 km s<SUP>-1</SUP> with respect to the systemic velocity of the galaxy. This new Lyα absorber could be evidence for the onset of an outflow or a companion black hole with associated gas that could be related to the accretion rate change. However, the low column density of the absorber means that it is not the direct cause for Mrk 1018's changing-look nature. <P />Based on Cycle 17 DDT program (ID: 18789, PI: G. Tremblay) approved by the Chandra Director, Dr. Belinda Wilkes. Based on Cycle 23 DDT project with the NASA/ESA Hubble Space Telescope (ID: 14486, PI: B. Husemann) approved by HST Director Dr. Kenneth Sembach. |
| Keywords | accretion; accretion disks; galaxies: nuclei; galaxies: Seyfert; |
| Contains Sensitive Content | Does not contain sensitive content |
| ANZSRC Field of Research 2020 | 510102. Astronomical instrumentation |
| Byline Affiliations | European Southern Observatory (ESO), Germany |
| Leibniz Institute for Astrophysics Potsdam, Germany | |
| Yale University, United States | |
| Max Planck Institute for Extraterrestrial Physics, Germany | |
| University of Cologne, Germany | |
| Sorbonne University, France | |
| University of Sydney | |
| ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions, Australia | |
| Cardiff University, United Kingdom | |
| Max Planck Institute for Radio Astronomy, Germany | |
| Institute of Astrophysics of Andalusia, Spain | |
| Gemini Observatory, United States |
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