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We systematically determine the electron density and electron temperature of active galaxies and star-forming galaxies using spectroscopy from the SDSS DR7, while mainly focusing on the NLRs. Density and temperature are determined through…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-18 Zhitai Zhang , Yanchun Liang , François Hammer

We show that the recently observed suppression of the gap between the broad line region (BLR) and the narrow line region (NLR) in some AGN can be fully explained by an increase of the gas density in the emitting region. Our model predicts…

Astrophysics of Galaxies · Physics 2016-11-17 T. P. Adhikari , A. Różańska , B. Czerny , K. Hryniewicz , G. J. Ferland

Broad-line regions (BLR) are one of the main components that constitute the phenomenological picture of active galaxies near the vicinity of the accreting supermassive black holes. Both theoretical and observational studies have shown that…

High Energy Astrophysical Phenomena · Physics 2019-11-13 Swayamtrupta Panda

We apply a new method of determination of the size of the broad emission-line region (BLR) in active galactic nuclei. This method relates the radius of the broad-line region of AGN to the soft X-ray luminosity and spectral index. Comparing…

Astrophysics · Physics 2016-01-27 Amri Wandel , Thomas Boller

Outflows in active galactic nuclei (AGNs) are crucial to understand in investigating the co-evolution of supermassive black holes (SMBHs) and their host galaxies since outflows may play an important role as an AGN feedback mechanism. Based…

Astrophysics of Galaxies · Physics 2019-01-04 Jaejin Shin , Tohru Nagao , Jong-Hak Woo

The broad-line region (BLR) of active galactic nuclei (AGNs) traces gas close to the central supermassive black hole (BH). Recent reverberation mapping (RM) and interferometric spectro-astrometry data have enabled detailed investigations of…

We have completed an optical spectroscopic survey of the nuclear regions (r < 200 pc) of a large sample of nearby galaxies. Although the main objectives of the survey are to search for low-luminosity active galactic nuclei and to quantify…

Astrophysics · Physics 2011-06-15 Luis C. Ho , Alexei V. Filippenko , Wallace L. W. Sargent

While [OIII] narrow-band imaging is commonly used to measure the size of the narrow-line regions (NLRs) in active galactic nuclei (AGNs), it can be contaminated by emission from surrounding starbursts. Recently, we have shown that long-slit…

Astrophysics · Physics 2009-11-11 Nicola Bennert , Bruno Jungwiert , Stefanie Komossa , Martin Haas , Rolf Chini

Here we describe the \emph{Siding Spring Southern Seyfert Spectroscopic Snapshot Survey} (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph (WiFeS) mounted on the ANU 2.3m…

We derive the nitrogen and oxygen abundances in the Narrow Line Regions (NLRs) of a sample of 38 local ($z \: < \: 0.4$) Seyfert~2 nuclei. For that, we consider narrow optical emission line intensities and direct estimates of the electron…

This is the first paper in a series dedicated to the study of the emission-line and continuum properties of narrow line Seyfert 1 galaxies (NLS1s). We carried out a systematic search for NLS1s from objects assigned as ``QSOs'' or…

Astrophysics · Physics 2009-07-28 Hongyan Zhou , Tinggui Wang , Weimin Yuan , Honglin Lu , Xiaobo Dong , Junxian Wang , Youjun Lu

We present measurements of radial velocities for the narrow-line region gas (NLR) in the Seyfert 2 galaxy Mrk 3 out to ~1 kpc from the nucleus. The observations consist of two datasets, both using the Space Telescope Imaging Spectrograph on…

We present high quality (high signal-to-noise ratio and moderate spectral resolution) near-infrared (near-IR) spectroscopic observations of 23 well-known broad-emission line active galactic nuclei (AGN). Additionally, we obtained…

The extended narrow line region (NLR) of Active Galactic Nuclei (AGN) provides a valuable laboratory for exploring the relationship between AGN and their host galaxies, often appearing as an "ionization cone" that can extend out to the very…

The structure of the broad line region (BLR) is an essential ingredient in the determination of active galactic nuclei (AGN) virial black hole masses, which in turn are important to study the role of black holes in galaxy evolution.…

Astrophysics of Galaxies · Physics 2020-02-05 S. I. Raimundo , M. Vestergaard , M. R. Goad , C. J. Grier , P. R. Williams , B. M. Peterson , T. Treu

We present the addition of nebular emission from the narrow-line regions (NLR) surrounding active galactic nuclei (AGN) to BEAGLE (BayEsian Analysis of GaLaxy sEds). Using a set of idealised spectra, we fit to a set of observables…

Astrophysics of Galaxies · Physics 2022-11-28 A. Vidal-García , A. Plat , E. Curtis-Lake , A. Feltre , M. Hirschmann , J. Chevallard , S. Charlot

Galaxies with active galactic nuclei (AGN) exhibit broad emission lines as a key spectral feature. The shape of emission-line profiles depends on the complex dynamics of discrete clouds within a spatially extended region known as the Broad…

Astrophysics of Galaxies · Physics 2025-10-08 M. H. Naddaf , M. L. Martinez-Aldama , D. Hutsemekers , D. Savic , B. Czerny

We discuss the polarization of broad emission lines in the type 1 active galactic nuclei (AGNs). The polarization depends on the geometry of the broad line region (BLR), and also on the polarization mechanism, or distribution of the…

Astrophysics of Galaxies · Physics 2021-11-12 L. C. Popović , E. Shablovinskaya , Dj. Savić

It is known that the spectral energy distribution (SED) of the nuclear radiation of narrow-line Seyfert 1 galaxies (NLS1s) has different shapes with respect to that of ordinary broad-line Seyfert 1 galaxies (BLS1s), particularly in…

Astrophysics · Physics 2009-10-31 T. Nagao , T. Murayama , Y. Taniguchi

Emission-line studies in the active galactic nuclei (AGNs), particularly those utilizing high spatial resolution, provide the most accurate method to determine critical quantities of the central engine and of the gas a few tens of parsecs…

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