Physical Sciences and Mathematics | Open Access Articles

The Nature Of Deeply Buried Ultraluminous Infrared Galaxies: A Unified Model For Highly Obscured Dusty Galaxy Emission, J. A. Marshall, Moshe Elitzur, L. Armus, T. Diaz-Santos, V. Charmandaris

Physics and Astronomy Faculty Publications

We present models of deeply buried ultraluminous infrared galaxy (ULIRG) spectral energy distributions (SEDs) and use them to construct a three-dimensional diagram for diagnosing the nature of observed ULIRGs. Our goal is to construct a suite of SEDs for a very simple model ULIRG structure, and to explore how well this simple model can (by itself) explain the full range of observed ULIRG properties. We use our diagnostic to analyze archival Spitzer Space Telescope Infrared Spectrograph data of ULIRGs and find that: (1) in general, our model does provide a comprehensive explanation of the distribution of mid-IR ULIRG properties; (2) …

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The Dusty Tori Of Nearby Qsos As Constrained By High-Resolution Mid-Ir Observations, M. Martínez-Paredes, I. Aretxaga, A. Alonso-Herrero, O. González-Martín, E. Lopéz-Rodríguez, C. Ramos Almeida, A. Asensio Ramos, T. Diaz Santos, Moshe Elitzur, P. Esquej, A. Hernán-Caballero, K. Ichikawa, R. Nikutta, C. Packham, M. Pereira-Santaella, C. Telesco

Physics and Astronomy Faculty Publications

We present mid-infrared (MIR; 7.5–13.5 μm) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4-m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs). We find that for the majority of QSOs the MIR emission is unresolved at angular scales ∼0.3 arcsec, corresponding to physical scales ≲ 600 pc. We find that the higher-spatial resolution CC spectra have similar shapes to those obtained with Spitzer/IRS, and hence we can assume that the spectra are not heavily contaminated by extended emission in the host galaxy. We thus take …

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The Differences In The Torus Geometry Between Hidden And Non-Hidden Broad Line Active Galactic Nuclei, Kohei Ichikawa, Christopher Packham, Cristina Ramos Almeida, Andrés Asensio Ramos, Almudena Alonso-Herrero, Omaira González-Martín, Enrique Lopez-Rodriguez, Yoshihiro Ueda, Tanio Díaz-Santos, Moshe Elitzur, Sebastian F. Hönig, Masatoshi Imanishi, Nancy A. Levenson, Rachel E. Mason, Eric S. Perlman, Crystal D. Alsip

Physics and Astronomy Faculty Publications

We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy torus models. We compiled high spatial resolution (~0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy torus models enables us to put constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without …

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An Embedded Active Nucleus In The Oh Megamaser Galaxy Iras16399−0937, Dinalva A. Sales, A. Robinson, D. J. Axon, J. Gallimore, P. Kharb, R. L. Curran, C. O'Dea, S. Baum, Moshe Elitzur, R. Mittal

Physics and Astronomy Faculty Publications

We present a multiwavelength study of the OH megamaser galaxy IRAS16399–0937, based on new Hubble Space Telescope (HST)/Advanced Camera for Surveys F814W and Hα+[N II] images and archive data from HST, Two Micron All Sky Survey, Spitzer, Herschel and the Very Large Array. This system has a double nucleus, whose northern (IRAS16399N) and southern (IRAS16399S) components have a projected separation of ~6'' (3.4 kpc) and have previously been identified based on optical spectra as a low ionization nuclear emission line region (LINER) and starburst nucleus, respectively. The nuclei are embedded in a tidally distorted common envelope, …

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Subaru Spectroscopy And Spectral Modeling Of Cygnus A, Matthew J. Merlo, Erik S. Perlman, Robert Nikutta, Christopher Packham, Moshe Elitzur, Masatoshi Imanishi, N. A. Levenson, James T. Radomski, Itziar Aretxaga

Physics and Astronomy Faculty Publications

We present high angular resolution (~0.''5) MIR spectra of the powerful radio galaxy, Cygnus A (Cyg A), obtained with the Subaru telescope. The overall shape of the spectra agree with previous high angular resolution MIR observations, as well as previous Spitzer spectra. Our spectra, both on and off nucleus, show a deep silicate absorption feature. The absorption feature can be modeled with a blackbody obscured by cold dust or a clumpy torus. The deep silicate feature is best fit by a simple model of a screened blackbody, suggesting that foreground absorption plays a significant, if not dominant, role in shaping …

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The Central Molecular Gas Structure In Liners With Low-Luminosity Active Galactic Nuclei: Evidence For Gradual Disappearance Of The Torus, F. Müller-Sánchez, M. A. Prieto, M. Mezcua, R. I. Davies, M. A. Malkan, Moshe Elitzur

Physics and Astronomy Faculty Publications

We present observations of the molecular gas in the nuclear environment of three prototypical low-luminosity active galactic nuclei (LLAGNs), based on VLT/SINFONI AO-assisted integral-field spectroscopy of H₂ 1-0 S(1) emission at angular resolutions of ~0.''17. On scales of 50-150 pc, the spatial distribution and kinematics of the molecular gas are consistent with a rotating thin disk, where the ratio of rotation (V) to dispersion (σ) exceeds unity. However, in the central 50 pc, the observations reveal a geometrically and optically thick structure of molecular gas (V/σ < 1 and N _H > 10²³ cm^{–2 …}

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The Nuclear Infrared Emission Of Low-Luminosity Active Galactic Nuclei, R. E. Mason, E. Lopez-Rodriguez, C. Packham, A. Alonso-Herrero, N. A. Levenson, J. Radomski, C. Ramos Almeida, L. Colina, Moshe Elitzur, I. Aretxaga, P. F. Roche, N. Oi

Physics and Astronomy Faculty Publications

We present high-resolution mid-infrared (MIR) imaging, nuclear spectral energy distributions (SEDs), and archival Spitzer spectra for 22 low-luminosity active galactic nuclei (LLAGNs; L_bol ≲ 10⁴² erg s^–1). Infrared (IR) observations may advance our understanding of the accretion flows in LLAGNs, the fate of the obscuring torus at low accretion rates, and, perhaps, the star formation histories of these objects. However, while comprehensively studied in higher-luminosity Seyferts and quasars, the nuclear IR properties of LLAGNs have not yet been well determined. We separate the present LLAGN sample into three categories depending on their Eddington ratio and radio …

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On The Unification Of Active Galactic Nuclei, Moshe Elitzur

Physics and Astronomy Faculty Publications

The inevitable spread in properties of the toroidal obscuration of active galactic nuclei (AGNs) invalidates the widespread notion that type 1 and 2 AGNs are intrinsically the same objects, drawn randomly from the distribution of torus covering factors. Instead, AGNs are drawn preferentially from the distribution; type 2 are more likely drawn from the distribution higher end, type 1 from its lower end. Type 2 AGNs have a higher IR luminosity, lower narrow-line luminosity, and a higher fraction of Compton thick X-ray obscuration than type 1. Meaningful studies of unification statistics cannot be conducted without first determining the intrinsic distribution …

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Emission From Hot Dust In The Infrared Spectra Of Gamma-Ray Bright Blazars, Michael P. Malmrose, Alan P. Marscher, Svetlana G. Jorstad, Robert Nikutta, Moshe Elitzur

Physics and Astronomy Faculty Publications

A possible source of γ-ray photons observed from the jets of blazars is inverse Compton scattering by relativistic electrons of infrared seed photons from a hot, dusty torus in the nucleus. We use observations from the Spitzer Space Telescope to search for signatures of such dust in the infrared spectra of four γ-ray bright blazars, the quasars 4C 21.35, CTA102, and PKS 1510-089, and the BL Lacertae object ON231. The spectral energy distribution (SED) of 4C 21.35 contains a prominent infrared excess indicative of dust emission. After subtracting a non-thermal component with a power-law spectrum, we fit a …

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Dusty Tori Of Luminous Type 1 Quasars At Z ~ 2, Rajesh P. Deo, Gordon T. Richards, Robert Nikutta, Moshe Elitzur, Sarah C. Gallagher, Željko Ivezić, Dean Hines

Physics and Astronomy Faculty Publications

We present Spitzer infrared (IR) spectra and ultraviolet (UV) to mid-IR spectral energy distributions (SEDs) of 25 luminous type 1 quasars at z ~ 2. In general, the spectra show a bump peaking around 3 μm and the 10 μm silicate emission feature. The 3 μm emission is identified with hot dust emission at its sublimation temperature. We explore two approaches to modeling the SED: (1) using the CLUMPY model SED from Nenkova et al. and (2) the CLUMPY model SED and an additional blackbody component to represent the 3 μm emission. In the first case, …

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Full-Text Articles in Physical Sciences and Mathematics

The Nature Of Deeply Buried Ultraluminous Infrared Galaxies: A Unified Model For Highly Obscured Dusty Galaxy Emission, J. A. Marshall, Moshe Elitzur, L. Armus, T. Diaz-Santos, V. Charmandaris

Physics and Astronomy Faculty Publications

Physics and Astronomy Faculty Publications

Physics and Astronomy Faculty Publications

An Embedded Active Nucleus In The Oh Megamaser Galaxy Iras16399−0937, Dinalva A. Sales, A. Robinson, D. J. Axon, J. Gallimore, P. Kharb, R. L. Curran, C. O'Dea, S. Baum, Moshe Elitzur, R. Mittal

Physics and Astronomy Faculty Publications

Subaru Spectroscopy And Spectral Modeling Of Cygnus A, Matthew J. Merlo, Erik S. Perlman, Robert Nikutta, Christopher Packham, Moshe Elitzur, Masatoshi Imanishi, N. A. Levenson, James T. Radomski, Itziar Aretxaga

Physics and Astronomy Faculty Publications

The Central Molecular Gas Structure In Liners With Low-Luminosity Active Galactic Nuclei: Evidence For Gradual Disappearance Of The Torus, F. Müller-Sánchez, M. A. Prieto, M. Mezcua, R. I. Davies, M. A. Malkan, Moshe Elitzur

Physics and Astronomy Faculty Publications

The Nuclear Infrared Emission Of Low-Luminosity Active Galactic Nuclei, R. E. Mason, E. Lopez-Rodriguez, C. Packham, A. Alonso-Herrero, N. A. Levenson, J. Radomski, C. Ramos Almeida, L. Colina, Moshe Elitzur, I. Aretxaga, P. F. Roche, N. Oi

Physics and Astronomy Faculty Publications

On The Unification Of Active Galactic Nuclei, Moshe Elitzur

Physics and Astronomy Faculty Publications

Emission From Hot Dust In The Infrared Spectra Of Gamma-Ray Bright Blazars, Michael P. Malmrose, Alan P. Marscher, Svetlana G. Jorstad, Robert Nikutta, Moshe Elitzur

Physics and Astronomy Faculty Publications

Dusty Tori Of Luminous Type 1 Quasars At Z ~ 2, Rajesh P. Deo, Gordon T. Richards, Robert Nikutta, Moshe Elitzur, Sarah C. Gallagher, Željko Ivezić, Dean Hines

Physics and Astronomy Faculty Publications