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We present a sequence of toy models for irradiated planet atmospheres, in which the effects of geometry and energy redistribution are modelled self-consistently. We use separate but coupled grey atmosphere models to treat the ingoing…

Astrophysics · Physics 2009-11-13 Brad Hansen

We explore physically self-consistent models of dusty molecular tori in Active Galactic Nuclei (AGN) with the goal of interpreting VLTI observations and fitting high resolution mid-IR spectral energy distributions (SEDs). The input dust…

We use mid-infrared spectroscopy of unobscured active galactic nuclei (AGNs) to reveal their native dusty environments. We concentrate on Seyfert 1 galaxies, observing a sample of 31 with the Infrared Spectrograph aboard the Spitzer Space…

Astrophysics of Galaxies · Physics 2010-01-15 G. D. Thompson , N. A. Levenson , S. A. Uddin , M. M. Sirocky

From extensive radiative transfer calculations we find that clumpy torus models with \No \about 5--15 dusty clouds along radial equatorial rays successfully explain AGN infrared observations. The dust has standard Galactic composition, with…

Astrophysics · Physics 2011-02-11 Maia Nenkova , Matthew M. Sirocky , Robert Nikutta , Zeljko Ivezic , Moshe Elitzur

Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central source, giving rise to type 1 line spectrum for pole-on viewing and type 2 characteristics in edge-on sources. Infrared radiation at its…

Astrophysics · Physics 2007-05-23 Moshe Elitzur , Maia Nenkova , Zeljko Ivezic

Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central engine. Torus sizes of hundreds of parsecs were deduced from early theoretical modeling efforts, but high-resolution IR observations now…

Astrophysics · Physics 2007-05-23 Moshe Elitzur

We present deep 1.8 cm (16 GHz) radio continuum imaging of seven young stellar objects in the Taurus molecular cloud. These objects have previously been extensively studied in the sub-mm to NIR range and their SEDs modelled to provide…

The radio properties of 11 obscured `radio-intermediate' quasars at redshifts z>~2 have been investigated using the European Very-Long-Baseline-Interferometry Network (EVN) at 1.66 GHz. A sensitivity of ~25 micro Jy per 14x17 mas2 beam was…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 H. -R. Kloeckner , A. Martinez-Sansigre , S. Rawlings , M. A. Garrett

This review describes recent developments related to the unified model of active galactic nuclei (AGN). It focuses on new ideas about the origin and properties of the central obscurer (torus), and the connection with its surrounding. The…

Astrophysics of Galaxies · Physics 2015-09-23 Hagai Netzer

To study large-scale structure in the Universe a full census of the contents are required. This is even more important when the processes of galaxy formation are being investigated. In the last year the population of distant galaxies that…

Astrophysics · Physics 2009-10-31 Andrew W. Blain

We present subarcsecond resolution mid-infrared (mid-IR) photometry in the wavelength range from 8 to 20 micron of eighteen Seyfert galaxies, reporting high spatial resolution nuclear fluxes for the entire sample. We construct spectral…

We present 2-D radiation transfer models of Class I Protostars and show the effect of including more realistic geometries on the resulting spectral energy distributions and images. We begin with a rotationally flattened infalling envelope…

Astrophysics · Physics 2010-04-08 Barbara A. Whitney , Kenneth Wood , J. E. Bjorkman , Michael J. Wolff

We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy,…

Active galactic nuclei (AGNs) are believed to be obscured by an optical thick "torus" that covers a large fraction of solid angles for the nuclei. However, the physical origin of the tori and the differences in the tori among AGNs are not…

Astrophysics of Galaxies · Physics 2019-02-07 Keiichi Wada

Radiative transfer models were developed to understand the optical polarizations in edge-on galaxies, which are observed to occur even outside the geometrically thin dust disk, with a scale height of ~ 0.2 kpc. In order to reproduce the…

Astrophysics of Galaxies · Physics 2018-08-08 Kwang-Il Seon

We describe a complete volume limited sample of nearby active galaxies selected by their 14-195keV luminosity, and outline its rationale for studying the mechanisms regulating gas inflow and outflow. We describe also a complementary sample…

We propose a new diagnostic of the ``dusty torus'' model for Seyfert nuclei. Dust grains in the torus are heated by the nuclear continuum, and reradiate mostly in the mid-infrared wavelengths. From the torus geometry, it is predicted that…

Astrophysics · Physics 2009-10-31 Takashi Murayama , Hideaki Mouri , Yoshiaki Taniguchi

We present near-infrared broad-band polarization images of the nuclear regions of the Circinus galaxy in the J, H and K bands. For the first time the south-eastern reflection cone is detected in polarized light, which is obscured at optical…

Astrophysics · Physics 2009-10-31 M. Ruiz , D. M. Alexander , S. Young , J. Hough , S. L. Lumsden , C. A. Heisler

We present a convariant formulation for radiative transfer in curved space time and demonstrate some applications in the black-hole systems. We calculate the emission from semi-transparent accretion tori around black holes, for opacity…

Astrophysics · Physics 2008-11-14 Kinwah Wu , Warrick Ball , Steven V. Fuerst

We present new mid-infrared (MIR) imaging data for three Type-1 Seyfert galaxies obtained with T-ReCS on the Gemini-South Telescope at subarcsecond resolution. Our aim is to enlarge the sample studied in a previous work to compare the…