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Full-Text Articles in Physical Sciences and Mathematics
Dusty Structure Around Type-I Active Galactic Nuclei: Clumpy Torus Narrow-Line Region And Near-Nucleus Hot Dust, Rivay Mor, Hagai Netzer, Moshe Elitzur
Dusty Structure Around Type-I Active Galactic Nuclei: Clumpy Torus Narrow-Line Region And Near-Nucleus Hot Dust, Rivay Mor, Hagai Netzer, Moshe Elitzur
Physics and Astronomy Faculty Publications
We fitted Spitzer/IRS ~ 2-35 μm spectra of 26 luminous quasi-stellar objects in an attempt to define the main emission components. Our model has three major components: a clumpy torus, dusty narrow-line region (NLR) clouds, and a blackbody-like dust. The models utilize the clumpy torus of Nenkova et al. and are the first to allow its consistent check in type-I active galactic nuclei (AGNs). Single torus models and combined torus-NLR models fail to fit the spectra of most sources, but three-component models adequately fit the spectra of all sources. We present torus inclination, cloud distribution, covering factor, and …
Simultaneous Multiwavelength Observations Of Markarian 421 During Outburst, P. T. Reynolds, Veritas, Magic
Simultaneous Multiwavelength Observations Of Markarian 421 During Outburst, P. T. Reynolds, Veritas, Magic
Physical Sciences Publications
We report on the results of two coordinated multiwavelength campaigns that focused on the blazar Markarian 421 during its 2006 and 2008 outbursts. These campaigns obtained UV and X-ray data using the XMM-Newton satellite, while the gamma-ray data were obtained utilizing three imaging atmospheric Cerenkov telescopes, the Whipple 10 m telescope and VERITAS, both based in Arizona, as well as the MAGIC telescope, based on La Palma in the Canary Islands. The coordinated effort between the gamma-ray groups allowed for truly simultaneous data in UV/X-ray/gamma-ray wavelengths during a significant portion of the XMM-Newton observations. This simultaneous coverage allowed for a …
Veritas Observations Of The Bl Lac Object 1es 1218+304, P. T. Reynolds, Et. Al.
Veritas Observations Of The Bl Lac Object 1es 1218+304, P. T. Reynolds, Et. Al.
Physical Sciences Publications
The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from the high-frequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z = 0.182. A gamma-ray signal was detected with a statistical significance of 10.4 standard deviations (10.4σ) for the observations taken during the first three months of 2007, confirming the discovery of this object made by the MAGIC collaboration. The photon spectrum between ~160 GeV and ~1.8 TeV is well described by a power law with an index of Γ = 3.08 ± 0.34stat ± 0.2sys. The integral flux is Φ(E>200GeV) = (12.2 ± 2.6) × …
Properties Of Warm Absorbers In Active Galaxies: A Systematic Stability Curve Analysis, Susmita Chakravorty, Ajit K. Kembhavi, Martin Elvis, Gary J. Ferland
Properties Of Warm Absorbers In Active Galaxies: A Systematic Stability Curve Analysis, Susmita Chakravorty, Ajit K. Kembhavi, Martin Elvis, Gary J. Ferland
Physics and Astronomy Faculty Publications
Signatures of warm absorbers are seen in soft X-ray spectra of about half of all type 1 Seyfert galaxies observed and in some quasars and blazars. We use the thermal equilibrium curve to study the influence of the shape of the ionizing continuum, density and the chemical composition of the absorbing gas on the existence and nature of the warm absorbers. We describe circumstances in which a stable warm absorber can exist as a multiphase medium or one with continuous variation in pressure. In particular, we find the following results: (i) the warm absorber exists only if the spectral index …
The Spitzer Infrared Nearby Galaxies Survey: A High-Resolution Spectroscopy Anthology, Da Dale, Jdt Smith, Ea Schlawin, L Armus, Ba Buckalew, Sa Cohen, G Helou, Th Jarrett, Lc Johnson, J Moustakas, Ej Murphy, H Roussel, K Sheth, S Staudaher, C Bot, D Calzetti, Cw Engelbracht, Kd Gordon, Dj Hollenbach, Rc Kennicutt, S Malhotra
The Spitzer Infrared Nearby Galaxies Survey: A High-Resolution Spectroscopy Anthology, Da Dale, Jdt Smith, Ea Schlawin, L Armus, Ba Buckalew, Sa Cohen, G Helou, Th Jarrett, Lc Johnson, J Moustakas, Ej Murphy, H Roussel, K Sheth, S Staudaher, C Bot, D Calzetti, Cw Engelbracht, Kd Gordon, Dj Hollenbach, Rc Kennicutt, S Malhotra
Astronomy Department Faculty Publication Series
High-resolution mid-infrared spectra are presented for 155 nuclear and extranuclear regions from the Spitzer Infrared Nearby Galaxies Survey (SINGS). The fluxes for nine atomic forbidden and three molecular hydrogen mid-infrared emission lines are also provided, along with upper limits in key lines for infrared-faint targets. The SINGS sample shows a wide range in the ratio of [S III] 18.71 μm/[S III] 33.48 μm, but the average ratio of the ensemble indicates a typical interstellar electron density of 300-400 cm–3 on ~23'' × 15'' scales and 500-600 cm–3 using ~11'' × 9'' apertures, independent of whether the region probed is a …