The near-to-mid infrared spectrum of quasars

Hernán-Caballero, A.; Hatziminaoglou, E.; Alonso‐Herrero, A.; Mateos, S.

doi:10.1093/mnras/stw2107

Cited by 53 publications

(57 citation statements)

References 72 publications

(84 reference statements)

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“…They found that their objects require two additional dust components to fit the NIR emission. The first component (very hot dust component) has temperatures ranging from 900 K to 1800 K, and the second (warm dust component) has 200 K. Similarly, Hernán-Caballero et al (2016) found a peak in the distribution of the very hot dust temperatures at about 1180 K and of the warm temperatures at 400 K for a sample of luminous quasars at z < 3. While the warm component has been interpreted as dusty clouds in the narrow line region, the very hot dust emission might be related to graphite clouds located at the edge of the dusty torus, thus inside the sublimation radius of silicate (whose sublimation temperature is lower than for pure graphite grains), but outside the broad line region.…”

Section: Hot Dustmentioning

confidence: 63%

The WISSH quasars project

Duras

Bongiorno

Piconcelli

et al. 2017

A&A

122

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Context. Studying the coupling between the energy output produced by the central quasar and the host galaxy is fundamental to fully understand galaxy evolution. Quasar feedback is indeed supposed to dramatically affect the galaxy properties by depositing large amounts of energy and momentum into the interstellar medium (ISM). Aims. In order to gain further insights on this process, we study the spectral energy distributions (SEDs) of sources at the brightest end of the quasar luminosity function, for which the feedback mechanism is assumed to be at its maximum, given their high efficiency in driving powerful outflows. Methods. We modelled the rest-frame UV-to-far-IR SEDs of 16 WISE-SDSS Selected Hyper-luminous (WISSH) quasars at 1.8 < z < 4.6 based on SDSS, 2MASS, WISE and Herschel/SPIRE data. Through an accurate SED-fitting procedure, we separate the different emission components by deriving physical parameters of both the nuclear component (i.e. bolometric and monochromatic luminosities) and the host galaxy (i.e. star formation rate, mass, and temperature of the cold dust). We also use a radiative transfer code to account for the contribution of the quasar-related emission to the far-IR fluxes. Results. Most SEDs are well described by a standard combination of accretion disc plus torus and cold dust emission. However, about 30% of SEDs require an additional emission component in the near-IR, with temperatures peaking at ∼750 K, which indicates that a hotter dust component is present in these powerful quasars. We measure extreme values of both AGN bolometric luminosity (L BOL > 10 47 erg/s) and star formation rate (up to ∼2000 M /yr) based on the quasar-corrected, IR luminosity of the host galaxy. A new relation between quasar and star formation luminosity is derived (L SF ∝ L 0.73 QSO ) by combining several Herschel-detected quasar samples from z ∼ 0 to ∼4. WISSH quasars have masses (∼10 8 M ) and temperatures (∼50 K) of cold dust in agreement with those found for other high-z IR luminous quasars. Conclusions. Thanks to their extreme nuclear and star formation luminosities, the WISSH quasars are ideal targets to shed light on the feedback mechanism and its effect on the evolution of their host galaxies, as well as on the merger-induced scenario that is commonly assumed to explain these exceptional luminosities. Future observations will be crucial to measure the molecular gas content in these systems, probe the effect between quasar-driven outflows and on-going star formation, and reveal merger signatures in their host galaxies.

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Section: Hot Dustmentioning

confidence: 63%

The WISSH quasars project

Duras

Bongiorno

Piconcelli

et al. 2017

A&A

122

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“…This could be related to the NIR bump observed in the spectral energy distributions (SEDs) of some type 1 AGN (∼1-5 µm; Mor, Netzer & Elitzur 2009;Alonso-Herrero et al 2011;Mor & Netzer 2012;Hönig et al 2013;Hernán-Caballero et al 2016;Mateos et al 2016). Various origins have been proposed for this NIR bump: (1) an extra-contribution to the nuclear fluxes from the host galaxy; (2) emission from a compact disc of hot dust detected in interferometric MIR data of some Seyfert galaxies (e.g.…”

Section: Discussionmentioning

confidence: 97%

The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei

García-Bernete¹,

Almeida²,

Landt³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Citation for published item:qr¡ %EferneteD sF nd mos elmeidD gF nd vndtD rF nd rdD wF tF nd flokovi¡ D wF nd eostEulidoD tF eF @PHIUA 9he infrred to Ery orreltion spetr of unosured type I tive glti nuleiF9D wonthly noties of the oyl estronomil oietyFD RTW @IAF ppF IIHEIPTF Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTWe use new X-ray data obtained with the Nuclear Spectroscopic Telescope Array (NuSTAR), near-infrared (NIR) fluxes and mid-infrared (MIR) spectra of a sample of 24 unobscured type 1 active galactic nuclei (AGN) to study the correlation between various hard X-ray bands between 3 and 80 keV and the infrared (IR) emission. The IR to X-ray correlation spectrum (IRXCS) shows a maximum at ∼15-20 µm, coincident with the peak of the AGN contribution to the MIR spectra of the majority of the sample. There is also an NIR correlation peak at ∼2 µm, which we associate with the NIR bump observed in some type 1 AGN at ∼1-5 µm and is likely produced by nuclear hot dust emission. The IRXCS shows practically the same behaviour in all the X-ray bands considered, indicating a common origin for all of them. We finally evaluated correlations between the X-ray luminosities and various MIR emission lines. All the lines show a good correlation with the hard X-rays (ρ ≥ 0.7), but we do not find the expected correlation between their ionization potentials and the strength of the IRXCS.

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“…Previous work has often argued that a single black body plus a power-law SED is enough to reproduce the quasar continuum at λ ∼0.5-3 µm (e.g., Glikman et al 2006;Kim et al 2015;Hernán-Caballero et al 2016). Since dust temperature is a strong function of distance, the dust grains responsible for the λ ∼1-3 µm emission should be located at similar radii.…”

Section: Classical Clumpy Modelmentioning

confidence: 97%

Mid-IR Variability and Dust Reverberation Mapping of Low-z Quasars. I. Data, Methods, and Basic Results

Lyu

Rieke

Smith

2019

ApJ

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The continued operation of the Wide-field Infrared Survey Explorer (WISE) combined with several groundbased optical transient surveys (e.g., CRTS, ASAS-SN and PTF) offer an unprecedented opportunity to explore the dust structures in luminous AGNs. We use these data for a mid-IR dust reverberation mapping (RM) study of 87 archetypal Palomar-Green quasars at z 0.5. To cope with various contaminations of the photometry data and the sparse time sampling of the light curves, procedures to combine these datasets and retrieve the dust RM signals have been developed. We find that ∼70% of the sample (with a completeness correction, up to 95%) has convincing mid-IR time lags in the WISE W 1 (∼ 3.4 µm) and W 2 (∼ 4.5 µm) bands and they are proportional to the square root of the AGN luminosity. Combined with previous K-band (∼ 2.2 µm) RM results in the literature, the inferred dust emission size ratios are R K : R W 1 : R W 2 = 0.6 : 1 : 1.2. Under simple assumptions, we put preliminary constraints on the projected dust surface density at these bands and reveal the possibly different torus structures among hot-dust-deficient, warm-dust-deficient and normal quasars from the reverberation signals. With multi-epoch Spitzer data and later WISE photometry, we also explore AGN IR variability at 10-24 µm over a 5 yr time-scale. Except for blazars and flat-spectrum radio sources, the majority of AGNs have typical variation amplitudes at 24 µm of no more than 10% of that in the W 1 band, indicating that the dust reverberation signals damp out quickly at longer wavelengths. In particular, steep-spectrum radio quasars also lack strong 24 µm variability, consistent with the unification picture of radio-loud AGNs.

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The near-to-mid infrared spectrum of quasars

Cited by 53 publications

References 72 publications

The WISSH quasars project

The WISSH quasars project

The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei

Mid-IR Variability and Dust Reverberation Mapping of Low-z Quasars. I. Data, Methods, and Basic Results

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