census is required; ho we ver , finding heavily obscured A GNs is observationally challenging. Here we use the deep and e xtensiv e 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 ef fecti veness 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

A panchromatic view of infrared quasars: excess star formation and radio emission in the most heavily obscured systems / Andonie, Carolina; M Alexander, David; Rosario, David; Laloux, Brivael; Georgakakis, Antonis; K Morabito, Leah; Villforth, Carolin; Avirett-Mackenzie, Mathilda; Calistro Rivera, Gabriela; Del Moro, Agnese; Fotopoulou, Sotiria; Harrison, Chris; Lapi, Andrea; Petley, James; Petter, Grayson; Shankar, Francesco. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 517:2(2022), pp. 2577-2598. [10.1093/mnras/stac2800]

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

Andrea Lapi;
2022-01-01

Abstract

census is required; ho we ver , finding heavily obscured A GNs is observationally challenging. Here we use the deep and e xtensiv e 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 ef fecti veness 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
517
2
2577
2598
10.1093/mnras/stac2800
https://arxiv.org/abs/2209.13321
Andonie, Carolina; M Alexander, David; Rosario, David; Laloux, Brivael; Georgakakis, Antonis; K Morabito, Leah; Villforth, Carolin; Avirett-Mackenzie, Mathilda; Calistro Rivera, Gabriela; Del Moro, Agnese; Fotopoulou, Sotiria; Harrison, Chris; Lapi, Andrea; Petley, James; Petter, Grayson; Shankar, Francesco
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/130411
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