A panchromatic view of infrared quasars: Excess star formation and radio emission in the most heavily obscured systems

Carolina Andonie; David M Alexander; David Rosario; Brivael Laloux; Antonis Georgakakis; Leah K Morabito; Carolin Villforth; Mathilda Avirett-mackenzie; Gabriela Calistro Rivera; Agnese Del Moro; Sotiria Fotopoulou; Chris Harrison; Andrea Lapi; James Petley; Grayson Petter; Francesco Shankar

doi:10.1093/mnras/stac2800

A panchromatic view of infrared quasars: Excess star formation and radio emission in the most heavily obscured systems

Carolina Andonie, David M Alexander, David Rosario, Brivael Laloux, Antonis Georgakakis, Leah K Morabito, Carolin Villforth, Mathilda Avirett-mackenzie, Gabriela Calistro Rivera, Agnese Del Moro, Sotiria Fotopoulou, Chris Harrison, Andrea Lapi, James Petley, Grayson Petter, Francesco Shankar

Research output: Contribution to journal › Article › peer-review

14 Citations (SciVal)

Abstract

To understand the active galactic nuclei (AGNs) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multiwavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars (L _AGN,IR > 10 ⁴⁵ erg s ⁻¹) at z < 3, with minimal obscuration bias, using detailed UV-to-far-IR spectral energy distribution (SED) fitting. We complement our SED constraints with X-ray and radio observations to further investigate the properties of the sample. Overall, 322 of the IR quasars are detected by Chandra and have individual X-ray spectral constraints. From a combination of X-ray stacking and L ₂₋₁₀ kev – L _{6 μm} analyses, we show that the majority of the X-ray faint and undetected quasars are heavily obscured (many are likely Compton thick), highlighting the effectiveness of the mid-IR band to find obscured AGNs. We find that 355 (≈61 per cent) IR quasars are obscured (N _H > 10 ²² cm ⁻²) and identify differences in the average properties between the obscured and unobscured quasars: (1) obscured quasars have star formation rates ≈3 times higher than unobscured systems for no significant difference in stellar mass and (2) obscured quasars have stronger radio emission than unobscured systems, with a radio-loudness parameter ≈ 0.2 dex higher. These results are inconsistent with a simple orientation model but in general agreement with either extreme host-galaxy obscuration towards the obscured quasars or a scenario where obscured quasars are an early phase in the evolution of quasars.

Original language	English
Article number	stac2800
Pages (from-to)	2577-2598
Number of pages	22
Journal	Monthly Notices of the Royal Astronomical Society
Volume	517
Issue number	2
Early online date	3 Oct 2022
DOIs	https://doi.org/10.1093/mnras/stac2800
Publication status	Published - 1 Dec 2022

Bibliographical note

Publisher Copyright:
© 2022 The Author(s).

Funding

We thank the referee for his positive and constructive comments. We would also like to express our gratitude to Philip Hopkins for useful research discussions. We want to thank Mara Salvato for sharing her redshift compilation in the COSMOS field, and Stefano Marchesi and Giorgio Lanzuisi for sharing their X-ray spectral fitting results in COSMOS. This work has been supported by the EU H2020-MSCAITN-2019 Project 860744 ‘BiD4BESt: Big Data applications for black hole Evolution STudies.’ DMA thanks the Science Technology Facilities Council (STFC) for support from the Durham consolidated grant (ST/T000244/1). CH acknowledges funding from an United Kingdom Research and Innovation grant (code: MR/V022830/1). AL is partly supported by the PRIN MIUR 2017 prot. 20173ML3WW 002 ‘Opening the ALMA window on the cosmic evolution of gas, stars, and massive black holes’. JP acknowledges support from STFC grants ST/T506047/1 and ST/V506643/1.

Funders	Funder number
United Kingdom Research and Innovation	20173ML3WW 002, ST/V506643/1, MR/V022830/1, ST/T506047/1
Science and Technology Facilities Council	ST/T000244/1
European Commission	860744

Keywords

galaxies: active
infrared: galaxies
quasars: general

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1093/mnras/stac2800Licence: CC BY

Cite this

Andonie, C., Alexander, D. M., Rosario, D., Laloux, B., Georgakakis, A., Morabito, L. K., Villforth, C., Avirett-mackenzie, M., Rivera, G. C., Del Moro, A., Fotopoulou, S., Harrison, C., Lapi, A., Petley, J., Petter, G., & Shankar, F. (2022). A panchromatic view of infrared quasars: Excess star formation and radio emission in the most heavily obscured systems. Monthly Notices of the Royal Astronomical Society, 517(2), 2577-2598. Article stac2800. https://doi.org/10.1093/mnras/stac2800

Andonie, C, Alexander, DM, Rosario, D, Laloux, B, Georgakakis, A, Morabito, LK, Villforth, C , Avirett-mackenzie, M, Rivera, GC, Del Moro, A, Fotopoulou, S, Harrison, C, Lapi, A, Petley, J, Petter, G & Shankar, F 2022, 'A panchromatic view of infrared quasars: Excess star formation and radio emission in the most heavily obscured systems', Monthly Notices of the Royal Astronomical Society, vol. 517, no. 2, stac2800, pp. 2577-2598. https://doi.org/10.1093/mnras/stac2800

@article{b15c6f96854e40958ed22a5e587b5c83,

title = "A panchromatic view of infrared quasars: Excess star formation and radio emission in the most heavily obscured systems",

abstract = "To understand the active galactic nuclei (AGNs) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multiwavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars (L AGN,IR > 10 45 erg s −1) at z < 3, with minimal obscuration bias, using detailed UV-to-far-IR spectral energy distribution (SED) fitting. We complement our SED constraints with X-ray and radio observations to further investigate the properties of the sample. Overall, 322 of the IR quasars are detected by Chandra and have individual X-ray spectral constraints. From a combination of X-ray stacking and L 2−10 kev – L 6 μm analyses, we show that the majority of the X-ray faint and undetected quasars are heavily obscured (many are likely Compton thick), highlighting the effectiveness of the mid-IR band to find obscured AGNs. We find that 355 (≈61 per cent) IR quasars are obscured (N H > 10 22 cm −2) and identify differences in the average properties between the obscured and unobscured quasars: (1) obscured quasars have star formation rates ≈3 times higher than unobscured systems for no significant difference in stellar mass and (2) obscured quasars have stronger radio emission than unobscured systems, with a radio-loudness parameter ≈ 0.2 dex higher. These results are inconsistent with a simple orientation model but in general agreement with either extreme host-galaxy obscuration towards the obscured quasars or a scenario where obscured quasars are an early phase in the evolution of quasars.",

keywords = "galaxies: active, infrared: galaxies, quasars: general",

author = "Carolina Andonie and Alexander, {David M} and David Rosario and Brivael Laloux and Antonis Georgakakis and Morabito, {Leah K} and Carolin Villforth and Mathilda Avirett-mackenzie and Rivera, {Gabriela Calistro} and {Del Moro}, Agnese and Sotiria Fotopoulou and Chris Harrison and Andrea Lapi and James Petley and Grayson Petter and Francesco Shankar",

note = "Publisher Copyright: {\textcopyright} 2022 The Author(s).",

year = "2022",

month = dec,

day = "1",

doi = "10.1093/mnras/stac2800",

language = "English",

volume = "517",

pages = "2577--2598",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "2",

}

TY - JOUR

T1 - A panchromatic view of infrared quasars: Excess star formation and radio emission in the most heavily obscured systems

AU - Andonie, Carolina

AU - Alexander, David M

AU - Rosario, David

AU - Laloux, Brivael

AU - Georgakakis, Antonis

AU - Morabito, Leah K

AU - Villforth, Carolin

AU - Avirett-mackenzie, Mathilda

AU - Rivera, Gabriela Calistro

AU - Del Moro, Agnese

AU - Fotopoulou, Sotiria

AU - Harrison, Chris

AU - Lapi, Andrea

AU - Petley, James

AU - Petter, Grayson

AU - Shankar, Francesco

PY - 2022/12/1

Y1 - 2022/12/1

N2 - To understand the active galactic nuclei (AGNs) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multiwavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars (L AGN,IR > 10 45 erg s −1) at z < 3, with minimal obscuration bias, using detailed UV-to-far-IR spectral energy distribution (SED) fitting. We complement our SED constraints with X-ray and radio observations to further investigate the properties of the sample. Overall, 322 of the IR quasars are detected by Chandra and have individual X-ray spectral constraints. From a combination of X-ray stacking and L 2−10 kev – L 6 μm analyses, we show that the majority of the X-ray faint and undetected quasars are heavily obscured (many are likely Compton thick), highlighting the effectiveness of the mid-IR band to find obscured AGNs. We find that 355 (≈61 per cent) IR quasars are obscured (N H > 10 22 cm −2) and identify differences in the average properties between the obscured and unobscured quasars: (1) obscured quasars have star formation rates ≈3 times higher than unobscured systems for no significant difference in stellar mass and (2) obscured quasars have stronger radio emission than unobscured systems, with a radio-loudness parameter ≈ 0.2 dex higher. These results are inconsistent with a simple orientation model but in general agreement with either extreme host-galaxy obscuration towards the obscured quasars or a scenario where obscured quasars are an early phase in the evolution of quasars.

AB - To understand the active galactic nuclei (AGNs) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multiwavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars (L AGN,IR > 10 45 erg s −1) at z < 3, with minimal obscuration bias, using detailed UV-to-far-IR spectral energy distribution (SED) fitting. We complement our SED constraints with X-ray and radio observations to further investigate the properties of the sample. Overall, 322 of the IR quasars are detected by Chandra and have individual X-ray spectral constraints. From a combination of X-ray stacking and L 2−10 kev – L 6 μm analyses, we show that the majority of the X-ray faint and undetected quasars are heavily obscured (many are likely Compton thick), highlighting the effectiveness of the mid-IR band to find obscured AGNs. We find that 355 (≈61 per cent) IR quasars are obscured (N H > 10 22 cm −2) and identify differences in the average properties between the obscured and unobscured quasars: (1) obscured quasars have star formation rates ≈3 times higher than unobscured systems for no significant difference in stellar mass and (2) obscured quasars have stronger radio emission than unobscured systems, with a radio-loudness parameter ≈ 0.2 dex higher. These results are inconsistent with a simple orientation model but in general agreement with either extreme host-galaxy obscuration towards the obscured quasars or a scenario where obscured quasars are an early phase in the evolution of quasars.

KW - galaxies: active

KW - infrared: galaxies

KW - quasars: general

UR - http://www.scopus.com/inward/record.url?scp=85145250539&partnerID=8YFLogxK

U2 - 10.1093/mnras/stac2800

DO - 10.1093/mnras/stac2800

M3 - Article

SN - 0035-8711

VL - 517

SP - 2577

EP - 2598

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 2

M1 - stac2800

ER -

A panchromatic view of infrared quasars: Excess star formation and radio emission in the most heavily obscured systems

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this