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AGN luminosity and stellar age: two missing ingredients forAGN unification as seen with iPTF supernovae
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy. Uppsala Univ, CIM, SE-75106 Uppsala, Sweden.
Department of Astronomy and The Oskar Klein Centre, Stockholm University, SE-106 91 Stockholm, Sweden.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
Univ Oulu, Astron Res Unit, FI-90014 Oulu, Finland.
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2017 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 837, no 2, 110Article in journal (Refereed) Published
Abstract [en]

Active galactic nuclei (AGNs) are extremely powerful cosmic objects, driven by accretion of hot gas upon super-massive black holes. The zoo of AGN classes is divided into two major groups, with Type-1 AGNs displaying broad Balmer emission lines and Type-2 narrow ones. For a long time it was believed that a Type-2 AGN is a Type-1 AGN viewed through a dusty kiloparsec-sized torus, but an emerging body of observations suggests more than just the viewing angle matters. Here we report significant differences in supernova (SN) counts and classes in the first study to date of SNe near Type-1 and Type-2 AGN host galaxies, using data from the intermediate Palomar Transient Factory, the Sloan Digital Sky Survey Data Release 7, and Galaxy Zoo. We detect many more SNe in Type-2 AGN hosts (size of effect similar to 5.1 sigma) compared to Type-1 hosts, which shows that the two classes of AGN are located inside host galaxies with different properties. In addition, Type-1 and Type-2 AGNs that are dominated by star formation according to Wide-field Infrared Survey Explorer colors m(W1) - m(W2) < 0.5 and are matched in 22 mu m absolute magnitude differ by a factor of ten in L[O III] lambda 5007 luminosity, suggesting that when residing in similar types of host galaxies Type-1 AGNs are much more luminous. Our results demonstrate two more factors that play an important role in completing the current picture: the age of stellar populations and the AGN luminosity. This has immediate consequences for understanding the many AGN classes and galaxy evolution.

Place, publisher, year, edition, pages
2017. Vol. 837, no 2, 110
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:uu:diva-308356DOI: 10.3847/1538-4357/aa5d5aISI: 000401172400008OAI: oai:DiVA.org:uu-308356DiVA: diva2:1049485
Funder
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Available from: 2016-11-24 Created: 2016-11-24 Last updated: 2017-06-15Bibliographically approved
In thesis
1. Active Galactic Nuclei in galaxy surveys: Empirical paths to the fiery hearts of cosmic beasts
Open this publication in new window or tab >>Active Galactic Nuclei in galaxy surveys: Empirical paths to the fiery hearts of cosmic beasts
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Some galaxies emit excessive amounts of light from their centers, caused by accretion of gas onto super-massive black holes (SMBH). These galactic cores are often referred to as Active Galactic Nuclei (AGN) and they come in many different forms, distinguishable by their emission properties. The AGN classes fall into two major categories: those with narrow Balmer lines, and those with broad Balmer lines. The AGN Unification theory of radio-quiet AGN predicts the two classes to differ mainly in the viewing angle of the observer who may, or may not, see the central engine due to dust obscuration in the foreground.

In this PhD thesis, I explore the limits of the radio-quiet AGN Unification. In its most famous and simple form, the obscurer is a parsec-sized dust doughnut surrounding the accretion disk. I show that the galaxy neighbours to the two types of AGN are different, in disagreement with the simplest form of unification (Paper I). The two AGN classes differ in their [OIII]5007 luminosity, as well as in their star-formation history (Paper II), suggesting that we must incorporate galactic dust into the concept of AGN Unification, as well as differences in the luminosity of the central engine. I also present a novel, data-driven method to pinpoint the relative spatial origin of certain emission lines in AGN (Paper III). Finally, we conclude the thesis by discussing an anti-transient survey targeted at finding signatures of extra-terrestrial intelligence (Paper IV). This survey can, as a side effect, also be useful to find extreme, variable AGN that challenge both AGN Unification and evolutionary theories.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 47 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1458
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Astronomy
Identifiers
urn:nbn:se:uu:diva-308359 (URN)978-91-554-9765-1 (ISBN)
Public defence
2017-01-13, Polhemsalen, Ångströmslaboratoriet, Lägerhyddsv. 1, Uppsala, 13:30 (English)
Opponent
Supervisors
Available from: 2016-12-22 Created: 2016-11-24 Last updated: 2016-12-28Bibliographically approved

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