EVIDENCE THAT MOST TYPE-1 AGNs ARE REDDENED BY DUST IN THE HOST ISM

Baron, Dalya; Stern, Jonathan; Poznanski, D.; Netzer, H.

doi:10.3847/0004-637x/832/1/8

Cited by 52 publications

(71 citation statements)

References 88 publications

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“…3.2.2. Both values are in line with each other, but significantly lower than the reddening derived from the Baron et al (2016) relation. The lack of a proper calibration between EW (N aD) and dust reddening for normal galaxies certainly plays a role in this discrepancy.…”

Section: Attenuation At Spectral Resolutionsupporting

confidence: 81%

MUSE stares into the shadows: the high-resolution dust attenuation curve of NGC 5626

Viaene

Sarzi

Baes

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The newest generation of integral field unit spectrographs brings three-dimensional mapping of nearby galaxies one step closer. While the focus up to this point was mostly on stars and ionized gas, it is also possible to look at dust in a new, more complete way. Using MUSE science verification observations of NGC 5626, we map the interstellar matter in this dusty lenticular. We use the resolving power of MUSE to measure the optical attenuation with a spectral resolution of 6.25Å, at physical scales of 0.1 − 1 kpc. The integrated attenuation curve of NGC 5626 shows a smooth, slightly steeper than Milky Way and SMC attenuation curves. Several sharp features are superimposed: we measure lower attenuation at spectral emission lines and higher attenuation for the sodium line doublet. No correlation was observed between sodium line strength and reddening by dust on spatially resolved scales. Additionally, the continuum attenuation was found to be independent from the Balmer decrement (tracing ionized gas attenuation). We model and interpret the variations in the attenuation curves of each spatial resolution element of NGC 5626. We find that the amount and distribution of dust along the line-of-sight is highly degenerate with any variation in the intrinsic extinction law. Our analysis shows that the interstellar matter in NGC 5626 resides in a regular and well-settled disk. Our results preach caution in the application of simple recipes to de-redden global galaxy spectra and underlines the need for more realistic dust geometries when constructing such correction formulas.

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Section: Attenuation At Spectral Resolutionsupporting

confidence: 81%

MUSE stares into the shadows: the high-resolution dust attenuation curve of NGC 5626

Viaene

Sarzi

Baes

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Both of these studies have a range of ratios that span a smaller range than ours and could indicate a flaw in our measurements. However, Baron et al (2016) recently found, through an analysis of 5000 AGNs, a much broader range of intrinsic Hα/Hβ ratios (mean of 3.02 and scatter of 1.19), confirming the findings of Schnorr-Müller et al (2016) and in line with the distribution we observe. Furthermore, photoionization modeling of BLR clouds has shown that the intrinsic Hα/Hβ ratio can be as large as 17 for reasonable BLR conditions (Korista & Goad 2004), which is above where the lower limits for the Sy 1.9s extend to.…”

Section: Comparison With Hα/hβ Ratiossupporting

confidence: 71%

BAT AGN Spectroscopic Survey. VIII. Type 1 AGN with Massive Absorbing Columns

Shimizu

Davies

Koss

et al. 2018

ApJ

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The 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-pro t 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 explore the relationship between X-ray absorption and optical obscuration within the BAT AGN Spectroscopic Survey (BASS), which has been collecting and analyzing the optical and X-ray spectra for 641 hard X-ray selected (E>14keV) active galactic nuclei (AGNs). We use the deviation from a linear broad Hα-to-X-ray relationship as an estimate of the maximum optical obscuration toward the broad line region (BLR) and compare the A V to the hydrogen column densities (N H ) found through systematic modeling of their X-ray spectra. We find that the inferred columns implied by A V toward the BLR are often orders of magnitude less than the columns measured toward the X-ray emitting region, indicating a small-scale origin for the X-ray absorbing gas. After removing 30% of Sy 1.9s that potentially have been misclassified due to outflows, we find that 86% (164/190) of the Type 1 population (Sy 1-1.9) are X-ray unabsorbed as expected based on a single obscuring structure. However, 14% (26/190), of which 70% (18/26) are classified as Sy 1.9, are X-ray absorbed, suggesting that the BLR itself is providing extra obscuration toward the X-ray corona. The fraction of X-ray absorbed Type 1 AGNs remains relatively constant with AGN luminosity and Eddington ratio, indicating a stable BLR covering fraction.

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“…We therefore do not apply any dust correction to the narrow line luminosities but emphasize that such a correction will only increase the trend of enhanced [O III] emission. Further support for dust reddening is also provided by stronger absorption of the NaID feature present in the RL stack, indicating a larger amount of dust in the host galaxy (Baron et al 2016). Richards et al (2003) We discuss the emission line properties in more detail in Sec.…”

Section: Rl and Rq Composite Spectramentioning

confidence: 95%

Evidence for Higher Black Hole Spin in Radio-loud Quasars

Schulze

Done

et al. 2017

ApJ

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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. ABSTRACT One of the major unsolved questions on the understanding of the AGN population is the origin of the dichotomy between radio-quiet and radio-loud quasars. The most promising explanation is provided by the spin paradigm, which suggests radio-loud quasars have higher black hole spin. However, the measurement of black hole spin remains extremely challenging. We here aim at comparing the mean radiative efficiencies of carefully matched samples of radio-loud and radio-quiet SDSS quasars at 0.3 < z < 0.8. We use the [O III] luminosity as an indirect average tracer of the ionizing continuum in the extreme-UV regime where differences in the SED due to black hole spin are most pronounced. We find that the radio-loud sample shows an enhancement in [O III] line strength by a factor of at least 1.5 compared to a radio-quiet sample matched in redshift, black hole mass and optical continuum luminosity or accretion rate. We argue that this enhancement is caused by differences in the SED, suggesting higher average bolometric luminosities at fixed accretion rate in the radio-loud population. This suggests that the radio-loud quasar population has on average systematically larger radiative efficiencies and therefore higher black hole spin than the radio-quiet population, providing observational support for the black hole spin paradigm.

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EVIDENCE THAT MOST TYPE-1 AGNs ARE REDDENED BY DUST IN THE HOST ISM

Cited by 52 publications

References 88 publications

MUSE stares into the shadows: the high-resolution dust attenuation curve of NGC 5626

MUSE stares into the shadows: the high-resolution dust attenuation curve of NGC 5626

BAT AGN Spectroscopic Survey. VIII. Type 1 AGN with Massive Absorbing Columns

Evidence for Higher Black Hole Spin in Radio-loud Quasars

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