scholarly journals Molecular hydrogen and [Fe ii] in active galactic nuclei – III. Low-ionization nuclear emission-line region and star-forming galaxies

2013 ◽  
Vol 430 (3) ◽  
pp. 2002-2017 ◽  
Author(s):  
R. Riffel ◽  
A. Rodríguez-Ardila ◽  
I. Aleman ◽  
M. S. Brotherton ◽  
M. G. Pastoriza ◽  
...  
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Molecular Hydrogen ◽  
Galactic Nuclei ◽  
Star Forming ◽  
Line Region

scholarly journals Constraints on the production and escape of ionizing radiation from the emission-lines of metal-poor star-forming galaxies

2019 ◽  
Vol 15 (S352) ◽  
pp. 121-122
Author(s):  
A. Plat ◽  
S. Charlot ◽  
G. Bruzual ◽  
A. Feltre ◽  
A. Vidal-Garca ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Emission Line ◽  
Active Galactic Nuclei ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Radiative Shocks ◽  
Metal Poor Star

AbstractTo understand how the nature of the ionizing sources and the leakage of ionizing photons in high-redshift galaxies can be constrained from their emission-line spectra, we compare emission-line models of star-forming galaxies including leakage of ionizing radiation, active galactic nuclei (AGN) and radiative shocks, with observations of galaxies at various redshifts with properties expected to approach those of primeval galaxies.

scholarly journals Velocity Diagnostics of the Broad Emission-Line Region of Active Galactic Nuclei

1997 ◽  
Vol 159 ◽  
pp. 175-178 ◽  
Author(s):  
Brian Espey
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Nuclear Region ◽  
Driving Mechanisms ◽  
Broad Emission ◽  
Line Region ◽  
Broad Emission Line ◽  
Ongoing Project

AbstractWe present a brief review of emission-line velocity differences, and describe an ongoing project to determine the driving mechanisms responsible. We conclude with a brief outline of the use of velocity differences as probes of the conditions in the nuclear region of AGNs.

scholarly journals Emission Line Region in a sample of 12 active galactic nuclei

2004 ◽  
Vol 2004 (IAUS222) ◽  
pp. 355-356
Author(s):  
L. C. Popovic ◽  
E. Mediavilla ◽  
E. Bon ◽  
D. Ilic
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Line Region

scholarly journals The Galactic center: not an active galactic nucleus

2013 ◽  
Vol 9 (S303) ◽  
pp. 54-58
Author(s):  
Deokkeun An ◽  
Solange V. Ramírez ◽  
Kris Sellgren
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Active Galactic Nuclei ◽  
Active Galactic Nucleus ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Extensive Area ◽  
Star Forming ◽  
Nearby Galaxies

AbstractWe present 10 μm – 35μm Spitzer spectra of the interstellar medium in the central molecular zone (CMZ), the central 210 pc × 60 pc of the Galactic center (GC). We present maps of the CMZ in ionic and H2 emission, covering a more extensive area than earlier spectroscopic surveys in this region. We compare diagnostic line ratios measured in the Spitzer Infrared Nearby Galaxies Survey to our data. Previous work shows that forbidden line ratios can distinguish star-forming galaxies from low-ionization nuclear emission-line regions (LINERs) and active galactic nuclei (AGNs). Our GC line ratios agree with star-forming galaxies and not with LINERs or AGNs.

scholarly journals Constraints on the outer radius of the broad emission line region of active galactic nuclei

2014 ◽  
Vol 439 (1) ◽  
pp. 1051-1062 ◽  
Author(s):  
Hermine Landt ◽  
Martin J. Ward ◽  
Martin Elvis ◽  
Margarita Karovska
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Outer Radius ◽  
Broad Emission ◽  
Line Region ◽  
Broad Emission Line

scholarly journals Optical spectroscopy of type 2 LINERs

2020 ◽  
Vol 635 ◽  
pp. A50
Author(s):  
L. Hermosa Muñoz ◽  
S. Cazzoli ◽  
I. Márquez ◽  
J. Masegosa
Keyword(s):  
Emission Line ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
True Nature ◽  
Star Forming ◽  
Broad Component ◽  
Line Region ◽  
Line Fitting

Context. Type 2 Low-ionization Nuclear Emission-line Regions (LINERs) have been optically classified with the Palomar data as not presenting a broad component in the Balmer emission lines that are associated with the broad-line region (BLR) of the active galactic nuclei (AGN). Aims. We aim to unveil the presence of different kinematic components of emission lines in the nuclear region of a sample of local (z ≤ 0.022) type 2 LINERs. We focus on the analysis of the true nature of LINERs by means of the detection (or nondetection) of a broad component that originated in the BLR of the AGN. Additionally, we search for the possible presence of nonrotational motions such as outflows in these LINERs. Methods. We applied a decomposition of the nuclear emission lines using an spectroscopic analysis of the optical spectra of nine type 2 LINERs of intermediate-resolution spectroscopic data retrieved from the Hubble Space Telescope (HST) archive. The study is completed with archival spectra from the Double Spectrograph from the Palomar Observatory. Results. The emission line fitting reveals the presence of a broad component associated with the BLR in six out of the nine galaxies for the space-based data, and for two out of the eight from the ground-based spectra. The velocity dispersion for two galaxies (NGC 4486 and NGC 4594) measured in HST/STIS data suggest the presence of outflows. Conclusions. The results indicate that the spatial resolution plays a major role in the detection of the BLR, as it appears diluted in the ground-based data (even after removing stellar contribution). This is also true for the emission line diagnostics, as the contaminant light contributes to lower emission line ratios toward the star-forming area of standard BPTs. We propose to reclassify NGC 4594 as a type 1 LINER, since a BLR component is seen in both space- and ground-based spectra. We find ambiguous results for the BLR component of NGC 4486. The modest outflow detection in our sample may indicate that they are not as frequent as seen for type 1 LINERs.

scholarly journals The near-infrared broad emission line region of active galactic nuclei - II. The 1-μm continuum

2011 ◽  
Vol 414 (1) ◽  
pp. 218-240 ◽  
Author(s):  
Hermine Landt ◽  
Martin Elvis ◽  
Martin J. Ward ◽  
Misty C. Bentz ◽  
Kirk T. Korista ◽  
...  
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Near Infrared ◽  
Galactic Nuclei ◽  
Broad Emission ◽  
Line Region ◽  
Broad Emission Line

scholarly journals Fotometria BVRI da galáxia M49 (NGC 4472): Reduções IRAF e MaxIm DL

2019 ◽  
Author(s):  
Vitor De Oliveira Silva
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Line Region

A galáxia Messier 49 (M49, NGC 4472), descoberta por Charles Messier em 1771, éuma galáxia com morfologia elíptica gigante, E2, mas também é classificada como umagaláxia lenticular, S0, (De Vaucouleurs et al. 1991), localizada na constelação deVirgem (ver Figura 1). Foi a primeira galáxia membro do aglomerado de Virgem a serdescoberta e é uma das mais brilhante deste sistema, com magnitude na banda B =9,37±0,06 (De Vaucouleurs et al. 1991). Representa um objeto extragaláctico (z =0,003272±0,00017) com velocidade de recessão de 981±5 km/s. É classficada comnúcleo ativo (AGN – Active Galactic Nuclei), do tipo Seyfert2. Uma classificaçãoLINER (Low-Ionization Nuclear Emission Line Region) também é sugerida. Possucoordenadas equatoriais  = 12h29m46,7s e  = 00’02’’.Fotometria CCD (BVRI) de objetos extensos representa uma linha de pesquisa que estásendo desenvolvida com o telescópio CDK20 (Corrected Dall-Kirkham Astrographtelescope, de 20 polegadas – 50,8cm de diâmetro), instalado no ObservatórioAstronômico Antares (OAA). Apesar de ser um objeto bem estudado na literatura comas técnicas de fotometria e espectroscopia (e.g., Foster et al. (2011), Kim (2010),Sanchez-Blazquez et al. (2007), Michard (1985), King (1978)), em diversoscomprimentos de onda do espectro eletromagnético, M49 representa um excelenteexemplo para iniciar os conceitos de fotometria superficial para os estudantes deIniciação Científica.Em geral, o pacote IRAF (Image Reduction and Analysis Facility), de domínio público,consiste de um sistema de softwares construído para a redução e análise de dadosastronômicos, e vem sendo empregado sistematicamente em nossas reduçõesfotométricas e/ou espectoscópicas. No entanto, apesar da sua ampla validade já assegurapela comunidade astronômica, iremos utilizar um pacote alternativo, MaxIm DL,desenvolvido pela Cyanogen Imaging®. Portanto, uma avaliação quanto a performancepermitirá avaliar o mesmo para o uso em futuras reduções fotométricas, não apenas deobjetos extensos, mas também de estrelas, aglomerados e objetos do Sistema Solar, emparticular, asteróides.

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