The Near‐Infrared Broad Emission Line Region of Active Galactic Nuclei. I. The Observations

Landt, Hermine; Bentz, Misty C.; Ward, M. J.; Elvis, M.; Peterson, B. M.; Korista, K. T.; Karovska, M.

doi:10.1086/522373

Cited by 128 publications

(217 citation statements)

References 57 publications

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“…All data were obtained through a slit of 0.8 × 15 ′′ giving an average spectral resolution of full width at half maximum (FWHM) ∼ 400 km s −1 . The four epochs spanning the years 2004 − 2007 are our own data and were discussed and presented in Landt et al (2008) and Landt et al (2011). The near-IR spectrum from 2002 was discussed by Riffel et al (2006).…”

Section: Near-ir and Optical Spectroscopymentioning

confidence: 99%

Strong variability of the coronal line region in NGC 5548

Landt¹,

Ward²,

Steenbrugge³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present the second extensive study of the coronal line variability in an active galaxy. Our data set for the well-studied Seyfert galaxy NGC 5548 consists of five epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about five years and three epochs of X-ray spectroscopy overlapping in time with it. Whereas the broad emission lines and hot dust emission varied only moderately, the coronal lines varied strongly. However, the observed high variability is mainly due to a flux decrease. Using the optical [Fe VII] and X-ray O VII emission lines we estimate that the coronal line gas has a relatively low density of n e ∼ 10 3 cm −3 and a relatively high ionisation parameter of log U ∼ 1. The resultant distance of the coronal line gas from the ionising source of about eight light years places this region well beyond the hot inner face of the dusty torus. These results imply that the coronal line region is an independent entity. We find again support for the X-ray heated wind scenario of Pier & Voit; the increased ionising radiation that heats the dusty torus also increases the cooling efficiency of the coronal line gas, most likely due to a stronger adiabatic expansion. The much stronger coronal line variability of NGC 5548 relative to that of NGC 4151 can also be explained within this picture. NGC 5548 has much stronger coronal lines relative to the low ionisation lines than NGC 4151 indicating a stronger wind, in which case a stronger adiabatic expansion of the gas and so fading of the line emission is expected.

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Section: Near-ir and Optical Spectroscopymentioning

confidence: 99%

Strong variability of the coronal line region in NGC 5548

Landt¹,

Ward²,

Steenbrugge³

et al. 2015

Mon. Not. R. Astron. Soc.

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“…In the case of the narrow lines we assumed ratio Paβ/Hα = 0.06 from atomic physics (Osterbrock 1989). Since the broad-line galaxies are known not to conform to case B we have used the observed near-infrared broad-line region ratios observed in type 1 AGN by Riffel et al (2006) and Landt et al (2008) to estimate the contamination in the F160W filter. This analysis shows the contamination to be 15% for broad-line objects (BLOs) and 4% for narrow-line objects and in both cases that is small enough not to affect our conclusions regarding the origin of the nuclear NIR emission.…”

Section: Sample and Hst Observationsmentioning

confidence: 99%

THE 1.6 μm NEAR-INFRARED NUCLEI OF 3C RADIO GALAXIES: JETS, THERMAL EMISSION, OR SCATTERED LIGHT?

Baldi¹,

Chiaberge²,

Capetti³

et al. 2010

ApJ

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Using HST NICMOS 2 observations we have measured 1.6 μm near-infrared nuclear luminosities of 100 3CR radio galaxies with z < 0.3, by modeling and subtracting the extended emission from the host galaxy. We performed a multiwavelength statistical analysis (including optical and radio data) of the properties of the nuclei following classification of the objects into FR I and FR II, and low-ionization galaxies (LIGs), high-ionization galaxies (HIGs), and broad-line objects (BLOs) using the radio morphology and optical spectra, respectively. The correlations among near-infrared, optical, and radio nuclear luminosity support the idea that the nearinfrared nuclear emission of FR Is has a non-thermal origin. Despite the difference in radio morphology, the multiwavelength properties of FR II LIG nuclei are statistically indistinguishable from those of FR Is, an indication of a common structure of the central engine. All BLOs show an unresolved near-infrared nucleus and a large near-infrared excess with respect to FR II LIGs and FR Is of equal radio core luminosity. This requires the presence of an additional (and dominant) component other than the non-thermal light. Considering the shape of their spectral energy distribution, we ascribe the origin of their near-infrared light to hot circumnuclear dust. A near-infrared excess is also found in HIGs, but their nuclei are substantially fainter than those of BLO. This result indicates that substantial obscuration along the line of sight to the nuclei is still present at 1.6 μm. Nonetheless, HIG nuclei cannot simply be explained in terms of dust obscuration: a significant contribution from light reflected in a circumnuclear scattering region is needed to account for their multiwavelength properties.

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“…Optical spectra of 14 high-redshift AGNs in the BAT sample were obtained through the Monitoring of Jets in AGN with VLBA Experiments (MOJAVE) project, targeting AGNs selected at 2 cm (Torrealba et al 2012). Ten sources are based on flux-calibrated optical spectra of broad-line AGNs observed with FAST (Landt et al 2008). We also used spectra obtained to follow-up the Palermo BAT catalog, which has produced its own BAT AGN catalog, which has significant overlap with this sample ( = N 62; Parisi et al 2009Parisi et al , 2012Parisi et al , 2014.…”

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confidence: 99%

BAT AGN Spectroscopic Survey. I. Spectral Measurements, Derived Quantities, and AGN Demographics

Koss

Trakhtenbrot

Ricci

et al. 2017

ApJ

264

308

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We present the first catalog and data release of the Swift-BAT AGN Spectroscopic Survey. We analyze optical spectra of the majority of the detected AGNs (77%, 642/836)based on their 14-195 keV emission in the 70-month Swift-BATall-sky catalog. This includes redshift determination, absorption and emission-line measurements, and black hole mass and accretion rate estimates for the majority of obscured and unobscured AGNs (74%, 473/642), with 340 measured for the first time. With ∼90% of sources at < z 0.2, the survey represents a significant advance in the census of hard X-ray-selected AGNs in the local universe. In this first catalog paper, we describe the spectroscopic observations and data sets, and our initial spectral analysis. The FWHMs of the emission lines show broad agreement with the X-ray obscuration (∼94%), such that Sy 1-1.8 have < N 10 H 21.9 cm −2 , and Seyfert 2 have > N 10 H 21.9 cm −2 . Seyfert 1.9, however, show a range of column densities. Compared to narrow-line AGNs in the SDSS, the X-ray-selected AGNs have a larger fraction of dusty host galaxies ( a b > H H 5), suggesting that these types of AGN are missed in optical surveys. Using the [O III] λ5007/Hβ and [N II] λ6583/Hα emission-line diagnostic, about half of the sources are classified as Seyferts; ∼15% reside in dusty galaxies that lack an Hβ detection, but for which the upper limits on line emission imply either a Seyfert or LINER,~15% are in galaxies with weak or no emission lines despite high-quality spectra, and a few percent each are LINERS, composite galaxies, H II regions, or in known beamed AGNs.

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The Near‐Infrared Broad Emission Line Region of Active Galactic Nuclei. I. The Observations

Cited by 128 publications

References 57 publications

Strong variability of the coronal line region in NGC 5548

Strong variability of the coronal line region in NGC 5548

THE 1.6 μm NEAR-INFRARED NUCLEI OF 3C RADIO GALAXIES: JETS, THERMAL EMISSION, OR SCATTERED LIGHT?

BAT AGN Spectroscopic Survey. I. Spectral Measurements, Derived Quantities, and AGN Demographics

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