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We fit the near-infrared to radio spectral energy distributions of 30 luminous and ultra-luminous infrared galaxies with pure starburst models or models that include both starburst and AGN components to determine important physical…

Astrophysics · Physics 2009-11-13 O. Vega , M. S. Clemens , A. Bressan , G. L. Granato , L. Silva , P. Panuzzo , --

Using the VLT together with the near infrared instrument ISAAC, we have obtained medium spectral and high spatial resolution observations of a sample of nearby Seyfert galaxies in the H-band. This band is particularly suited for stellar…

Astrophysics · Physics 2009-11-07 C. Boisson , S. Coupe , J. G. Cuby , M. Joly , M. J. Ward

The emission line luminosity function of active galactic nuclei (AGN) is measured from about 3000 AGN included in the main galaxy sample of the Sloan Digital Sky Survey within a redshift range of $0<z<0.15$. The $\Ha$ and [OIII]$\lambda…

Under the unified model for active galactic nuclei (AGNs), narrow-line (Type 2) AGNs are, in fact, broad-line (Type 1) AGNs but each with a heavily obscured accretion disk. We would therefore expect the optical continuum emission from Type…

Although the properties of the narrow-line region (NLR) of active galactic nuclei(AGN) have been deeply studied by many authors in the past three decades, many questions are still open. The main goal of this work is to explore the NLR of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 L. Vaona , S. Ciroi , F. Di Mille , V. Cracco , G. La Mura , P. Rafanelli

This is the second of two papers presenting a detailed long-slit spectroscopic study of the stellar populations in a sample of 36 ULIRGs. In the previous paper we presented the sample, the data and the spectral synthesis modelling while in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Javier Rodriguez-Zaurin , C. N. Tadhunter , R. M. Gonzalez-Delgado

We report here our comparative analysis of active galactic nucleus (AGN) and star formation (SF) characteristics of a sample of narrow-line Seyfert 1 (NLS1) and broad-line Seyfert 1 (BLS1) galaxies. Our sample consisted of 373 BLS1 and 240…

Astrophysics of Galaxies · Physics 2024-06-18 Kshama S. Kurian , C. S. Stalin , S. Rakshit , G. Mountrichas , D. Wylezalek , R. Sagar , M. Kissler-Patig

We determine the stellar population properties - age, metallicity, dust reddening, stellar mass and the star formation history - for all spectra classified as galaxies that were published by the Sloan Digital Sky Survey (SDSS data release…

In modern models and simulations of galactic evolution, the star formation in massive galaxies is regulated by an ad hoc active galactic nuclei (AGN) feedback process. However, the physics and the extension of such effects on the star…

X-ray surveys of active galactic nuclei (AGNs) provide direct constraints on the properties of individual AGNs, such as their emission, obscuration, and accretion rate. Previous AGN population synthesis models have not addressed such…

High Energy Astrophysical Phenomena · Physics 2026-05-19 D. Gerolymatou , S. Paltani , C. Ricci , T. T. Ananna

We present a new tool for the analysis of the optical emission lines of the gas in the Narrow Line Region (NLR) around Active Galactic Nuclei (AGNs). This new tool can be used in large samples of objects in a consistent way using different…

Astrophysics of Galaxies · Physics 2021-07-14 R. García-Benito , E. Pérez-Montero , O. L. Dors , J. M. Vílchez , M. V. Cardaci , G. F. Hägele

Aims: We present a near-infrared spectral atlas of 47 active galactic nuclei (AGN), of all degrees of activity, in the wavelength interval of 0.8-2.4 microns, including the fluxes of the observed emission lines. We analyze the spectroscopic…

Astrophysics · Physics 2009-11-11 R. Riffel , A. Rodriguez-Ardila , M. G. Pastoriza

The stellar population synthesis in unresolved composite objects is a very tricky problem. Indeed, it is a degenerate problem since many parameters affect the observables. The stellar population synthesis issue thus deserves a deep and…

Astrophysics · Physics 2009-11-10 J. Moultaka

Large-scale cosmological simulations suggest that feedback from active galactic nuclei (AGN) plays a crucial role in galaxy evolution. In this study, we directly test this hypothesis utilising SDSS spectra of a sample of 48 low redshift…

Astrophysics of Galaxies · Physics 2024-09-25 Patricia S. Bessiere , Cristina Ramos Almeida , Luke R. Holden , Clive N. Tadhunter , Gabriela Canalizo

We present a comparative test of four widely used full spectral fitting codes, with the aim of answering the question: how robust is the retrieval of the stellar initial mass function (IMF) and other stellar properties of galaxies? We used…

Astrophysics of Galaxies · Physics 2025-08-25 Ilaria Lonoce , Anja Feldmeier-Krause , Alexandra Masegian , Wendy L. Freedman

In order to characterize the amount of recent or ongoing stellar formation in the circumnuclear region of active galaxies on a statistically sound basis, we have studied the stellar component of the nuclear spectra in three different…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 P. Rafanelli , R. D'Abrusco , S. Ciroi , V. Cracco , F. Di Mille , L. Vaona

While emission-line flux ratio diagnostics are the most common technique for identifying active galactic nuclei (AGNs) in optical spectra, applying this approach to single fiber spectra of galaxies can omit entire subpopulations of AGNs.…

We study the host galaxy properties of active galactic nuclei (AGN) that have been detected in X-rays in the nearby Universe ($\rm z<0.2$). For that purpose, we use the catalogue provided by the ROSAT-2RXS in the 0.1-2.4\,keV energy band,…

Astrophysics of Galaxies · Physics 2022-02-02 L. Koutoulidis , G. Mountrichas , I. Georgantopoulos , E. Pouliasis , M. Plionis

High resolution spectral models for simple stellar populations (SSP) developed in the past few years have become a standard ingredient in studies of stellar population of galaxies. As more such models become available, it becomes…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Roberto Cid Fernandes , Rosa M. Gonzalez Delgado

We study a combined sample of 264 star-forming, 51 composite, and 73 active galaxies using optical spectra from SDSS and mid-infrared (mid-IR) spectra from the Spitzer Infrared Spectrograph. We examine optical and mid-IR spectroscopic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Stephanie M. LaMassa , T. M. Heckman , A. Ptak , D. Schiminovich , M. O'Dowd , B. Bertincourt