The nature of LINER galaxies: Ubiquitous hot old stars and rare accreting black holes
By R. Singh, Glenn van de Ven, K. Jahnke, M. Lyubenova, J. Falc'on-Barroso, João Alves, R. C. Fernandes, L. Galbany, R. García-Benito, B. Husemann and 11 more. Proceedings of the International Astronomical Union, 2013
226 citations recorded by the source corpus.
Abstract Galaxies, which often contain ionised gas, sometimes also exhibit a so-called low-ionisation nuclear emission line region (LINER). For 30 years, this was attributed to a central mass-accreting supermassive black hole (more commonly known as active galactic nucleus or AGN) of low luminosity, making LINER galaxies the largest AGN sub-population, which dominate in numbers over higher AGN-luminosity Seyfert galaxies and quasars. This, however, poses a serious problem. While the inferred energy balance is plausible, many LINERs clearly do not contain any other independent signatures of an AGN. Using integral field spectroscopic data from the CALIFA survey, we compare the observed radial surface brightness profiles with what is expected from illumination by an AGN. For 48 galaxies with LINER-like emission we show, that the radial emission-line surface brightness profiles are inconsistent with ionisation by a central point-source and hence cannot be due to an AGN alone. The most probable explanation for the excess LINER-like emission is ionisation by evolved stars during the short but very hot and energetic phase known as post-AGB. This leads us to an entirely new interpretation. Post-AGB stars are ubiquitous and their ionising effect should be potentially observable in every galaxy with gas present and with stars older than ~1 Gyr, unless a stronger radiation field from young hot stars or an AGN outshines them. This means, that galaxies with LINER-like emission are not a class defined by a property but rather by the absence of a property. It also explains why LINER emission is observed mostly in massive galaxies with old stars and little star formation.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/4ad14de59576bc9942a694273bc9a46c5b144dc9
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Citations in the corpus
- BLACK HOLE VARIABILITY AND THE STAR FORMATION–ACTIVE GALACTIC NUCLEUS CONNECTION: DO ALL STAR-FORMING GALAXIES HOST AN ACTIVE GALACTIC NUCLEUS? (2013, background): “…low-Eddington optical AGN population are likely to be powered by evolved stellar populations, rather than BH accretion (e.g., Sarzi et al. 2010; Yan & Blanton 2012; Singh et al. 2013), although the effects of this contamination on the derived Eddington ratio distribution are difficult to assess.”
- SDSS IV MaNGA – spatially resolved diagnostic diagrams: a proof that many galaxies are LIERs (2016, methodology): “While observational support for the ‘stellar hypothesis’ for LINER emisson is mounting, previous work has been limited by lack of spatial resolution (e.g. Yan & Blanton 2012), wavelength coverage (e.g. Sarzi et al. 2010) or small sample size (e.g. Singh et al. 2013).”
- SDSS-IV MaNGA : the impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements (2016, background): “…[N ii]/Hα and [S ii]/Hα of DIG would move the position of a star-forming galaxy toward the composite or LI(N)ER region (e.g., Sarzi et al 2006; Stasińska et al. 2008; Yan & Blanton 2012; Kehrig et al. 2012; Singh et al. 2013; Gomes et al. 2016; Belfiore et al. 2016a,b) on the BPT diagrams.”
- Host Galaxy Properties and Offset Distributions of Fast Radio Bursts: Implications for Their Progenitors (2020, background): “Alternatively, the same ionization effect can be produced by a dominating population of post-asymptotic giant branch (postAGB) stars (Yan & Blanton 2012; Singh et al. 2013).”
- Nebular Continuum and Line Emission in Stellar Population Synthesis Models (2016, background): “While some cases are certainly still driven by the presence of a weak AGN, the discovery of spatially extended (∼kpc scales) LIER-like emission has led to work suggesting that hot, evolved stars could be responsible for the ionizing radiation in other cases (Singh et al. 2013; Belfiore et al. 2016).”
- A characteristic oxygen abundance gradient in galaxy disks unveiled with CALIFA (2013, result): “Recent results indicate that it is possible to detect low-intensity (and in most cases low-ionization) gas in all the analyzed CALIFA galaxies (Kehrig et al. 2012; Papaderos et al. 2013; Singh et al. 2013).”