Linking galaxy structural properties and star formation activity to black hole activity with IllustrisTNG

We study the connection between active galactic nuclei (AGN) and their host galaxies through cosmic time in the large-scale cosmological IllustrisTNG simulations. We first compare BH properties, i.e. the hard X-ray BH luminosity function, AGN galaxy occupation fraction, and distribution of Eddington...

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Main Authors: Habouzit, Mélanie (Author) , Genel, Shy (Author) , Somerville, Rachel S (Author) , Kocevski, Dale (Author) , Hirschmann, Michaela (Author) , Dekel, Avishai (Author) , Choi, Ena (Author) , Nelson, Dylan (Author) , Pillepich, Annalisa (Author) , Torrey, Paul (Author) , Hernquist, Lars (Author) , Vogelsberger, Mark (Author) , Weinberger, Rainer (Author) , Springel, Volker (Author)
Format: Article (Journal)
Language:English
Published: 2019 January 16
In: Monthly notices of the Royal Astronomical Society
Year: 2019, Volume: 484, Issue: 4, Pages: 4413-4443
ISSN:1365-2966
DOI:10.1093/mnras/stz102
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1093/mnras/stz102
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Author Notes:Mélanie Habouzit, Shy Genel, Rachel S. Somerville, Dale Kocevski, Michaela Hirschmann, Avishai Dekel, Ena Choi, Dylan Nelson, Annalisa Pillepich, Paul Torrey, Lars Hernquist, Mark Vogelsberger, Rainer Weinberger and Volker Springel
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Summary:We study the connection between active galactic nuclei (AGN) and their host galaxies through cosmic time in the large-scale cosmological IllustrisTNG simulations. We first compare BH properties, i.e. the hard X-ray BH luminosity function, AGN galaxy occupation fraction, and distribution of Eddington ratios, to available observational constraints. The simulations produce a population of BHs in good agreement with observations, but we note an excess of faint AGN in hard X-ray ($L_{\rm x}\sim 10^{43-44}\, \rm erg/s$), and a lower number of bright AGN ($L_{\rm x}\gt 10^{44} \, \rm erg/s$), a conclusion that varies quantitatively but not qualitatively with BH luminosity estimation method. The lower Eddington ratios of the $10^{9}\, \rm M_{\odot }$ BHs compared to observations suggest that AGN feedback may be too efficient in this regime. We study galaxy star formation activity and structural properties, and design sample-dependent criteria to identify different galaxy types (star-forming/quiescent, extended/compact) that we apply both to the simulations and observations from the candels fields. We analyse how the simulated and observed galaxies populate the specific star formation rate - stellar mass surface density diagram. A large fraction of the $z$ = 0 $M_{\star }\geqslant 10^{11}\, \rm M_{\odot }$ quiescent galaxies first experienced a compaction phase (i.e. reduction of galaxy size) while still forming stars, and then a quenching event. We measure the dependence of AGN fraction on galaxies’ locations in this diagram. After correcting the simulations with a redshift and AGN luminosity-dependent model for AGN obscuration, we find good qualitative and quantitative agreement with observations. The AGN fraction is the highest among compact star-forming galaxies ($16-20{{\ \rm per\ cent}}$ at $z$ ∼ 1.5-2), and the lowest among compact quiescent galaxies ($6-10{{\ \rm per\ cent}}$ at $z$ ∼ 1.5-2).
Item Description:Gesehen am 27.07.2022
Physical Description:Online Resource
ISSN:1365-2966
DOI:10.1093/mnras/stz102