A<i>HERSCHEL</i>STUDY OF 24<i>μ</i>m-SELECTED AGNs AND THEIR HOST GALAXIES

Xu, Lei; Rieke, G. H.; Egami, Eiichi; Pereira, M. J.; Haines, C. P.; Smith, Graham P.

doi:10.1088/0067-0049/219/2/18

Cited by 38 publications

(101 citation statements)

References 145 publications

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“…Elvis et al (1994),based partly on the PalomarGreen (PG) sample; the same with a far-infrared star-forming component removed (Elvis_noSF) by Xu et al (2015); Richards et al (2006), based on 259 quasars; the radio-quiet quasar template in Shang et al (2011); the starformation-corrected AGN template, based on the radio-quiet PG sample proposed by Symeonidis et al (2016); AGN3 from Kirkpatrick et al (2015) with star formation removed by subtracting the suitably normalized SFG2 from the same source; Netzer et al (2007) with star formation subtraction in the far-IR; that proposed by Hanish et al (2013); and the QSO1 template from Polletta et al (2007). We plot those templates with efforts to remove the star formation contamination as solid lines and marked them with " * " in the legend.…”

Section: Rationalementioning

confidence: 99%

“…Elvis et al (1994): the procedure is most straightforward in the case of the Elvis et al (1994) template. Table 1 shows two results, the first for the original form and the second for the star-formation-removed version from Xu et al (2015). Richards et al (2006): it was necessary to fill out this template for frequencies log(ν) above 17 and below 12.5; this was done by joining on sections of the original Elvis template.…”

Section: Template For Agn Soft X-ray/uv/optical Emissionmentioning

confidence: 99%

“…With the aid of mid-IR spectral decompositions or measurements of the aromatic feaures, many authors have tried to remove the host galaxy contamination in the AGN far-IR emission (e.g., Mullaney et al 2011;Kirkpatrick et al 2012Kirkpatrick et al , 2015Xu et al 2015;Symeonidis et al 2016).…”

Section: The F Agn Mir -F Agn Tir Relationmentioning

confidence: 99%

“…Several groups have attempted to remove this contamination from the AGN template (e.g., Netzer et al 2007;Mullaney et al 2011;Kirkpatrick et al 2015;Xu et al 2015;Symeonidis et al 2016). However, there is still no consensus.…”

Section: Introductionmentioning

confidence: 99%

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The Intrinsic Far-infrared Continua of Type-1 Quasars

Lyu

Rieke

2017

ApJ

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The range of currently proposed active galactic nucleus (AGN) far-infrared templates results in uncertainties in retrieving host galaxy information from infrared observations and also undermines constraints on the outer part of the AGN torus. We discuss how to test and reconcile these templates. Physically, the fraction of the intrinsic AGN IR-processed luminosity compared with that from the central engine should be consistent with the dust-covering factor. In addition, besides reproducing the composite spectral energy distributions (SEDs) of quasars, a correct AGN IR template combined with an accurate library of star-forming galaxy templates should be able to reproduce the IR properties of the host galaxies, such as the luminosity-dependent SED shapes and aromatic feature strengths. We develop tests based on these expected behaviors and find that the shape of the AGN intrinsic far-IR emission drops off rapidly starting at ∼20μm and can be matched by an Elvis et al.-like template with aminor modification. Despite the variations in the near-to mid-IR bands, AGNs in quasars and Seyfert galaxies have remarkably similar intrinsic far-IR SEDs at λ ∼ 20-100μm, suggesting a similar emission character of the outermost region of the circumnuclear torus. The variations of the intrinsic AGN IR SEDs among the type-1 quasar population can be explained by the changing relative strengths of four major dust components with similar characteristic temperatures, and there is evidence for compact AGN-heated dusty structures at sub-kiloparsec scales in the far-IR.

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Section: Rationalementioning

confidence: 99%

Section: Template For Agn Soft X-ray/uv/optical Emissionmentioning

confidence: 99%

Section: The F Agn Mir -F Agn Tir Relationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Intrinsic Far-infrared Continua of Type-1 Quasars

Lyu

Rieke

2017

ApJ

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“…A popular method to distinguish star formation and AGN activity is to rely on Spectral Energy Distribution (SED) models. Some studies involving SED analysis are Elvis et al (1994), Richards et al (2006), Netzer et al (2007), Mor & Netzer (2012), Leipski et al (2013Leipski et al ( , 2014, and Xu et al (2015aXu et al ( , 2015b. In this work, we use a Python-based custom-written SED fitting routine (available upon inquiry).…”

Section: Introductionmentioning

confidence: 99%

Herschel Observed Stripe 82 Quasars and Their Host Galaxies: Connections Between Agn Activity and Host Galaxy Star Formation

2016

ApJ

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In this work, we present a study of 207 quasars selected from the Sloan Digital Sky Survey quasar catalogs and the Herschel Stripe 82 survey. Quasars within this sample are high-luminosity quasars with a mean bolometric luminosity of 10 46.4 erg s −1 . The redshift range of this sample is within z < 4, with a mean value of 1.5 ± 0.78. Because we only selected quasars that have been detected in all three Herschel-SPIRE bands, the quasar sample is complete yet highly biased. Based on the multi-wavelength photometric observation data, we conducted a spectral energy distribution (SED) fitting through UV to FIR. Parameters such as active galactic nucleus (AGN) luminosity, far-IR (FIR) luminosity, stellar mass, as well as many other AGN and galaxy properties are deduced from the SED fitting results. The mean star formation rate (SFR) of the sample is 419 M e yr −1 and the mean gas mass is ∼10 11.3 M e . All of these results point to an IR luminous quasar system. Compared with star formation main sequence (MS) galaxies, at least 80 out of 207 quasars are hosted by starburst galaxies. This supports the statement that luminous AGNs are more likely to be associated with major mergers. The SFR increases with the redshift up to z = 2. It is correlated with the AGN bolometric luminosity, where µ  L L FIR Bol 0.46 0.03 . The AGN bolometric luminosity is also correlated with the host galaxy mass and gas mass. Yet the correlation between L FIR and L Bol has higher significant level, implies that the link between AGN accretion and the SFR is more primal. The M BH /M * ratio of our sample is 0.02, higher than the value 0.005 in the local universe. It might indicate an evolutionary trend of the M BH -M * scaling relation.

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A comparison of compact, presumably young with extended, evolved radio active galactic nuclei

Meusinger,

Mhaskey

2024

A&A

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The triggering and evolution of active galactic nuclei (AGNs) and the interaction of the AGN with its host galaxy is an important topic in extragalactic astrophysics. Radio sources with peaked spectra (peaked spectrum sources, PSS) and compact symmetric objects (CSO) are powerful, compact, and presumably young AGNs and therefore particularly suitable to study aspects of the AGN-host connection. We use a statistical approach to investigate properties of a PSS-CSO sample that are related to host galaxies and could potentially shed light on the link between host galaxies and AGNs. The main goal is to compare the PSS-CSO sample with a matching comparison sample of extended sources (ECS) to see if the two have significant differences. We analysed composite spectra, diagnostic line diagrams, multi-band spectral energy distributions (MBSEDs), star formation (SF) indicators, morphologies, and cluster environments for a sample of 121 PSSs and CSOs for which spectra are available from the Sloan Digital Sky Survey (SDSS). The statistical results were compared with those of the ECS sample, where we generally considered the two subsamples of quasi-stellar objects (QSOs) and radio galaxies separately. The analysis is based on a large set of archival data in the spectral range from the ultraviolet to mid-infrared. We find significant differences between the PSS-CSO and the ECS sample. In particular, we find that the ECS sample has a higher proportion of passive galaxies with a lower star formation activity. This applies to both sub-samples (QSOs or radio galaxies) as well as to the entire sample. The star formation rates of the PSS-CSO host galaxies with available data are typically in the range $ 0$ to 5\,$ M $, and the stellar masses are in the range $3 $ to $10^ M Secondly, in agreement with previous results, we find a remarkably high proportion of PSS-CSO host galaxies with merger signatures. The merger fraction of the PSS-CSO sample is $0.61 0.07$, which is significantly higher than that of the comparison sample ($0.15 0.06$). We suggest that this difference can be explained by assuming that the majority of the PSSs and CSOs cannot evolve to extended radio sources and are therefore not represented in our comparison sample.

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AHERSCHELSTUDY OF 24μm-SELECTED AGNs AND THEIR HOST GALAXIES

Cited by 38 publications

References 145 publications

The Intrinsic Far-infrared Continua of Type-1 Quasars

The Intrinsic Far-infrared Continua of Type-1 Quasars

Herschel Observed Stripe 82 Quasars and Their Host Galaxies: Connections Between Agn Activity and Host Galaxy Star Formation

A comparison of compact, presumably young with extended, evolved radio active galactic nuclei

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