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We present a new phenomenological model for the spectral energy distribution of normal star-forming galaxies between 3 and 1100 microns. A sequence of realistic galaxy spectra are constructed from a family of dust emission curves assuming a…

Dust reprocesses the intrinsic radiation of active galactic nuclei (AGNs) to emerge at longer wavelengths. The observed mid-infrared (MIR) luminosity depends fundamentally on the luminosity of the central engine, but in detail it also…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 N. A. Levenson , J. T. Radomski , C. Packham , R. E. Mason , J. J. Schaefer , C. M. Telesco

A subparsec-scale dense plasma torus around an active galactic nucleus (AGN) is unveiled. We report on very-long-baseline interferometry (VLBI) observations at 2.3, 8.4, and 15.4 GHz towards the active galaxy NGC 1052. The convex spectra of…

Astrophysics · Physics 2015-06-24 S. Kameno , S. Sawada-Satoh , M. Inoue , Z. -Q. Shen , K. Wajima

The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of the sample shows that most of the sample's spectral…

Several recent studies have shown that about half of the massive galaxies at z~2 are in a quiescent phase. Moreover, these galaxies are commonly found to be ultra-compact with half-light radii of ~1 kpc. We have obtained a ~29 hr spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-22 Mariska Kriek , Pieter G. van Dokkum , Ivo Labbe , Marijn Franx , Garth D. Illingworth , Danilo Marchesini , Ryan F. Quadri

We present analytic radiative transfer solutions for the spectra of unresolved, spherically symmetric, centrally heated, dusty sources. We find that the dust thermal spectrum possesses scaling relations that provide a natural classification…

Astrophysics · Physics 2009-11-13 Sukanya Chakrabarti , Christopher F. McKee

In order to understand the diversity of classes observed in active galactic nuclei (AGN), a geometrically and optically thick torus of gas and dust is required to obscure the central engine depending on the line of sight to the observer. We…

For an extended sample of Seyfert galaxies we compile from the literature the infrared fluxes in the four IRAS bands, the ground-based small-beam (~ 5-10") fluxes in the standard Q, N, M, L (or L') bands, and the nuclear (non-stellar)…

Astrophysics · Physics 2008-11-26 Dario Fadda , Giuliano Giuricin , Gian Luigi Granato , Donatella Vecchies

We construct a general relativistic radiative transfer (RT) formulation, applicable to particles with or without mass in astrophysical settings. Derived from first principles, the formulation is manifestly covariant. Absorption and…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Ziri Younsi , Kinwah Wu , Steven V. Fuerst

We present model simulations of time-variable infrared (IR) emission from dust as a consequence of variability of the incident radiation. For that we introduce a generalized treatment for temperature variations in a dusty environment, which…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Sebastian F. Hoenig , Makoto Kishimoto

Using the CoDa II simulation, we study the Ly$\alpha$ transmissivity of the intergalactic medium (IGM) during reionization. At $z>6$, a typical galaxy without an active galactic nucleus fails to form a proximity zone around itself due to…

We describe a search for molecular absorption at millimetre wavelengths associated with dusty molecular tori in active galactic nuclei (AGN). The sample observed consists of 11 flat-spectrum radio sources known to have red optical to…

Astrophysics · Physics 2016-08-30 M. Drinkwater , F. Combes , T. Wiklind

We study the inner region of the circumstellar disk around the TTauri star RY Tau. Our aim is to find a physical description satisfying the available interferometric data, obtained with the mid-infrared interferometric instrument at the…

Astrophysics · Physics 2009-11-13 A. A. Schegerer , S. Wolf , Th. Ratzka , Ch. Leinert

We characterize for the first time the torus properties of an ultra-hard X-ray (14-195 keV) volume-limited (DL<40 Mpc) sample of 24 Seyfert (Sy) galaxies (BCS40 sample). The sample was selected from the Swift/BAT nine month catalog. We use…

We compare three different models of clumpy gas disk and show that the Circumnuclear Disk (CND) in the Galactic Center and a putative, geometrically thick, obscuring torus are best explained by a collisional model consisting of…

Astrophysics · Physics 2009-11-10 B. Vollmer , T. Beckert , W. J. Duschl

We present near-to-mid-infrared spectral energy distributions (SEDs) for 21 Seyfert galaxies, using subarcsecond resolution imaging data. Our aim is to compare the properties Seyfert 1 (Sy1) and Seyfert 2 (Sy2) tori using clumpy torus…

We present illustrative models for the UV to millimeter emission of starburst galaxies which are treated as an ensemble of optically thick giant molecular clouds (GMCs) centrally illuminated by recently formed stars. The models follow the…

Astrophysics · Physics 2009-10-31 A. Efstathiou , M. Rowan-Robinson , R. Siebenmorgen

The spectral energy distributions and infrared (IR) spectra of a sample of obscured AGNs selected in the mid-IR are modeled with recent clumpy torus models to investigate the nature of the sources, the properties of the obscuring matter,…

Astrophysics · Physics 2010-03-19 M. Polletta , D. Weedman , S. Hoenig , C. J. Lonsdale , H. E. Smith , J. Houck

Quasars and Active Galactic Nuclei (AGNs) are often obscured by dust and gas. It is normally assumed that the obscuration occurs in an oblate "obscuring torus", that begins at the radius at which the most refractive dust can remain solid.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Martin Elvis

It has been claimed by Taylor et al. that the low-redshift end of the K-z relation for radio galaxies is too bright by about half a magnitude due to contributions from the obscured quasar nuclei. Such a result has major implications for the…

Astrophysics · Physics 2009-10-31 Chris Simpson , Martin Ward , J. V. Wall