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We extend the analysis presented in Tran (2001) of a spectropolarimetric survey of the CfA and 12micron samples of Seyfert 2 galaxies (S2s). We confirm that S2s with hidden broad line regions (HBLRs) tend to have hotter circumnuclear dust…

天体物理学 · 物理学 2009-11-07 Hien D. Tran

To study the impact of active galactic nuclei (AGN) feedback on the galactic ISM, we present Magellan long-slit spectroscopy of 12 luminous nearby type 2 AGN (L_bol~10^{45.0-46.5} erg/s, z~0.1). These objects are selected from a parent…

星系天体物理 · 物理学 2017-02-08 Ai-Lei Sun , Jenny E. Greene , Nadia L. Zakamska

For the first time, a calibration between the HeI $\lambda5876$/H$\beta$ emission line ratio and the helium abundance $y$=12+log(He/H) for Narrow line regions (NLRs) of Seyfert~2 Active Galactic Nuclei (AGN) is proposed. In this context,…

We present a comprehensive spectroscopic imaging survey of the distribution and kinematics of atomic hydrogen (HI) in 16 nearby spiral galaxies hosting low luminosity AGN, observed with high spectral and spatial resolution (resolution: ~20…

天体物理学 · 物理学 2008-11-26 S. Haan , E. Schinnerer , C. G. Mundell , S. Garcia-Burillo , F. Combes

(Abridged) The two-dimensional distribution and kinematics of the molecular, ionized, and highly ionized gas in the nuclear regions of Seyfert 1 galaxies have been measured using high spatial resolution (~0''.09) near-infrared spectroscopy…

天体物理学 · 物理学 2009-11-13 E. K. S. Hicks , M. A. Malkan

We have analyzed archival \textit{Chandra} and \textit{XMM-Newton} data for two nearly complete homogeneously selected samples of type 2 Seyfert galaxies (Sy2s). These samples were selected based on intrinsic Active Galactic Nuclei (AGN)…

宇宙学与河外天体物理 · 物理学 2015-05-20 Stephanie M. LaMassa , T. M. Heckman , A. Ptak , L. Martins , V. Wild , P. Sonnentrucker , A. Hornschemeier

A survey for H2O megamaser emission from 354 active galaxies has resulted in the detection of 10 new sources, making 16 known altogether. The galaxies surveyed include a distance-limited sample (covering Seyferts and LINERs with recession…

天体物理学 · 物理学 2009-10-30 J. A. Braatz , A. S. Wilson , C. Henkel

We present an imaging molecular line survey in the 3-mm band (85-114 GHz) focused on one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068, based on observations taken with the Atacama Large Millimeter/submillimeter…

We present the results of the optical identifications of a set of X-ray sources from the all-sky surveys of INTEGRAL and SWIFT observatories. Optical data were obtained with Russian-Turkish 1.5-m Telescope (RTT150). Nine X-ray sources were…

The origin of He II emission in galaxies remains a debated topic, requiring ionizing photons with energies exceeding 54 eV. While massive stars, such as Wolf-Rayet stars, have been considered potential sources, their UV flux often fails to…

星系天体物理 · 物理学 2025-04-16 K. Kouroumpatzakis , J. Svoboda

A thorough study of radio emission in Active Galactic Nuclei (AGN) is of fundamental importance to understand the physical mechanisms responsible for the emission and the interplay between accretion and ejection processes. High frequency…

星系天体物理 · 物理学 2020-05-27 E. Chiaraluce , F. Panessa , G. Bruni , R. D. Baldi , E. Behar , F. Vagnetti , F. Tombesi , I. McHardy

We report results from a FUSE survey of interstellar molecular hydrogen (H2) along 45 sight lines to AGN at high Galactic latitudes (|b| > 20 degrees). Most (39 of 45) of the sight lines show detectable Galactic H2 absorption from Lyman and…

天体物理学 · 物理学 2009-11-13 Kristen Gillmon , J. Michael Shull , Jason Tumlinson , Charles Danforth

We present near-infrared K- (1.9-2.5 micrometer) and L- (2.8-4.2 micrometer) band spectroscopy of 22 Seyfert nuclei. We use two methods to investigate the presence of nuclear starbursts: (1) the Polycyclic Aromatic Hydrocarbon (PAH)…

星系天体物理 · 物理学 2015-05-20 Nagisa Oi , Masatoshi Imanishi , Keisuke Imase

We present near-infrared (NIR) spectroscopic observations of 28 X-ray and mid-infrared selected sources at a median redshift of z~0.8 in the Extended Groth Strip (EGS). To date this is the largest compilation of NIR spectra of active…

The central regions of galaxies harbouring active galactic nuclei (AGNs) can be quite complex, especially at high activity, presenting, besides variability, a variety of phenomena related, e.g. to ionization/excitation mechanisms. A…

We present measurements of interstellar H_2 absorption lines in the continuum spectra of seven early-type stars in the Galactic disk at distances between 1 and 4 kpc. Five of these stars provide lines of sight through the Sagittarius spiral…

天体物理学 · 物理学 2009-10-30 W. Van Dyke Dixon , Mark Hurwitz , Stuart Bowyer

New observations are reported of J-band spectra (1.04micron -- 1.4 micron) of three Seyfert 2 galaxies, Mkn 34, Mkn 78 and NGC 5929. In each case the spectral range includes the near-infrared lines of [FeII], [PII], HeI and Pa beta. Each…

天体物理学 · 物理学 2008-11-26 N. Jackson , R. Beswick

(Abridged) We present Herschel/HIFI spectra of the H2O 1113 GHz and H2O+ 1115 GHz lines toward five nearby prototypical starburst/AGN systems, and OH+ 971 GHz spectra toward three of these. The beam size of 20" corresponds to resolutions…

星系天体物理 · 物理学 2016-09-14 Floris van der Tak , Axel Weiss , Lijie Liu , Rolf Guesten

We present spectroscopic observations obtained with the infrared Spitzer Space Telescope, which provide insight into the H$_2$ physics and gas energetics in photodissociation Regions (PDRs) of low to moderate far-ultraviolet (FUV) fields…

We analysed the centre of NGC 1566, which hosts a well-studied active galactic nucleus (AGN), known for its variability. With the aid of techniques such as Principal Component Analysis Tomography, analysis of the emission-line spectra,…

星系天体物理 · 物理学 2017-07-11 Patrícia da Silva , J. E. Steiner , R. B. Menezes