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The role of AGN and obscuration in the position of the host galaxy relative to the main sequence

The role of AGN and obscuration in the position of the host galaxy relative to the main sequence
The role of AGN and obscuration in the position of the host galaxy relative to the main sequence

We use X-ray active galactic nuclei (AGN) observed by the Chandra X-ray Observatory within the 9.3 deg2 Boötes field of the NDWFS to study whether there is a correlation between X-ray luminosity (LX) and star formation rate (SFR) of the host galaxy, at 0.5 < z < 2.0, with respect to the position of the galaxy to the main sequence (SFRnorm). About half of the sources in the X-ray sample have spectroscopic redshifts. We also construct a reference galaxy catalogue. For both datasets we use photometric data from the optical to the far-infrared compiled by the HELP project, and apply spectral energy distribution fitting, using the X-CIGALE code. We exclude quiescent sources from both the X-ray and the reference samples. We also account for the mass completeness of our dataset, in different redshifts bins. Our analysis highlights the importance of studying the SFR-LX relation in a uniform manner, taking into account systematics and selection effects. Our results suggest, in less massive galaxies (log [M∗(Mo˙)] ∼ 11), that an AGN enhances the SFR of the host galaxy by ∼50% compared to non-AGN systems. A flat relation is observed for the most massive galaxies. The SFRnorm does not evolve with redshift. The results, although tentative, are consistent with a scenario where, in less massive systems, both AGN and star formation are fed by cold gas supplied by a merger event. In more massive galaxies the flat relation could be explained by a different supermasssive black hole fuelling mechanism that is decoupled from the star formation of the host galaxy (e.g., hot diffuse gas). Finally, we compare the host galaxy properties of X-ray absorbed and unabsorbed sources. Our results show no difference, which suggests that X-ray absorption is not linked with the properties of the galaxy.

Galaxies: active, Galaxies: star formation, Quasars: supermassive black holes, X-rays: galaxies, X-rays: general
0004-6361
Shirley, Raphael
fb6bc6f3-f593-4cf5-9f68-a63587ab8135
Mountrichas, G.
33670ac9-a8f9-47d8-ab05-0470abda2363
Buat, Veronique
c3e069af-ff40-42b5-8c8d-78aa0a283ac3
Yang, G.
48876be3-7355-4e04-b11a-93a47d7787ad
Boquien, M.
9700eced-7828-4790-b00b-55aa1dbea5e4
Burgarella, Denis
4293fe39-6051-494c-946d-649f87b652bc
Ciesla, L.
2b71f062-abe5-4a87-bfc3-a5c92ffe7964
Malek, K.
702eeff2-219c-4dd7-b802-c412f49e05ea
Shirley, Raphael
fb6bc6f3-f593-4cf5-9f68-a63587ab8135
Mountrichas, G.
33670ac9-a8f9-47d8-ab05-0470abda2363
Buat, Veronique
c3e069af-ff40-42b5-8c8d-78aa0a283ac3
Yang, G.
48876be3-7355-4e04-b11a-93a47d7787ad
Boquien, M.
9700eced-7828-4790-b00b-55aa1dbea5e4
Burgarella, Denis
4293fe39-6051-494c-946d-649f87b652bc
Ciesla, L.
2b71f062-abe5-4a87-bfc3-a5c92ffe7964
Malek, K.
702eeff2-219c-4dd7-b802-c412f49e05ea

Shirley, Raphael, Mountrichas, G., Buat, Veronique, Yang, G., Boquien, M., Burgarella, Denis, Ciesla, L. and Malek, K. (2021) The role of AGN and obscuration in the position of the host galaxy relative to the main sequence. Astronomy & Astrophysics, 653, [A74]. (doi:10.1051/0004-6361/202140630).

Record type: Article

Abstract

We use X-ray active galactic nuclei (AGN) observed by the Chandra X-ray Observatory within the 9.3 deg2 Boötes field of the NDWFS to study whether there is a correlation between X-ray luminosity (LX) and star formation rate (SFR) of the host galaxy, at 0.5 < z < 2.0, with respect to the position of the galaxy to the main sequence (SFRnorm). About half of the sources in the X-ray sample have spectroscopic redshifts. We also construct a reference galaxy catalogue. For both datasets we use photometric data from the optical to the far-infrared compiled by the HELP project, and apply spectral energy distribution fitting, using the X-CIGALE code. We exclude quiescent sources from both the X-ray and the reference samples. We also account for the mass completeness of our dataset, in different redshifts bins. Our analysis highlights the importance of studying the SFR-LX relation in a uniform manner, taking into account systematics and selection effects. Our results suggest, in less massive galaxies (log [M∗(Mo˙)] ∼ 11), that an AGN enhances the SFR of the host galaxy by ∼50% compared to non-AGN systems. A flat relation is observed for the most massive galaxies. The SFRnorm does not evolve with redshift. The results, although tentative, are consistent with a scenario where, in less massive systems, both AGN and star formation are fed by cold gas supplied by a merger event. In more massive galaxies the flat relation could be explained by a different supermasssive black hole fuelling mechanism that is decoupled from the star formation of the host galaxy (e.g., hot diffuse gas). Finally, we compare the host galaxy properties of X-ray absorbed and unabsorbed sources. Our results show no difference, which suggests that X-ray absorption is not linked with the properties of the galaxy.

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2106.10678 - Accepted Manuscript
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Accepted/In Press date: 19 June 2021
e-pub ahead of print date: 10 September 2021
Published date: 10 September 2021
Additional Information: Funding Information: Acknowledgements. The authors thank the anonymous referee for their detailed report that improved the quality of the paper. GM acknowledges support by the Funding Information: The authors thank the anonymous referee for their detailed report that improved the quality of the paper. GM acknowledges support by the Agencia Publisher Copyright: © ESO 2021.
Keywords: Galaxies: active, Galaxies: star formation, Quasars: supermassive black holes, X-rays: galaxies, X-rays: general

Identifiers

Local EPrints ID: 453197
URI: http://eprints.soton.ac.uk/id/eprint/453197
ISSN: 0004-6361
PURE UUID: b9d4acf9-a5ff-4350-900d-5791854ca001

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Date deposited: 10 Jan 2022 18:04
Last modified: 16 Mar 2024 15:12

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Contributors

Author: Raphael Shirley
Author: G. Mountrichas
Author: Veronique Buat
Author: G. Yang
Author: M. Boquien
Author: Denis Burgarella
Author: L. Ciesla
Author: K. Malek

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