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Articles 31 - 35 of 35
Full-Text Articles in Physical Sciences and Mathematics
The Webt Campaign On The Blazar 3c 279 In 2006, Markus Böttcher, Jeff W. Robertson, Stéphane Vennes
The Webt Campaign On The Blazar 3c 279 In 2006, Markus Böttcher, Jeff W. Robertson, Stéphane Vennes
Aerospace, Physics, and Space Science Faculty Publications
The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from 2006 January through April. An optical-IR-radio monitoring campaign by the Whole Earth Blazar Telescope (WEBT) collaboration was organized around target-of-opportunity X-ray and soft γ-ray observations with Chandra and INTEGRAL in 2006 mid-January, with additional X-ray coverage by RXTE and Swift XRT. In this paper we focus on the results of the WEBT campaign. The source exhibited substantial variability of optical flux and spectral shape, with a characteristic timescale of a few days. The variability patterns throughout the optical BVRI bands were very closely correlated with each …
The Mid-Infrared Emission Of M87, Eric S. Perlman, Rachel E. Mason, Christopher C. Packham, Nancy A. Levenson, Moshe Elitzur, Justin J. Schaefer, Masatoshi Imanishi, William B. Sparks, James T. Radomski
The Mid-Infrared Emission Of M87, Eric S. Perlman, Rachel E. Mason, Christopher C. Packham, Nancy A. Levenson, Moshe Elitzur, Justin J. Schaefer, Masatoshi Imanishi, William B. Sparks, James T. Radomski
Aerospace, Physics, and Space Science Faculty Publications
We discuss Subaru and Spitzer Space Telescope imaging and spectroscopy of M87 in the mid-infrared (mid-IR) from 5 to 35 μm. These observations allow us to investigate mid-IR emission mechanisms in the core of M87 and to establish that the flaring, variable jet component HST-1 is not a major contributor to the mid-IR flux. The Spitzer data include a high signal-to-noise ratio 15-35 μm spectrum of the knot A/B complex in the jet, which is consistent with synchrotron emission. However, a synchrotron model cannot account for the observed nuclear spectrum, even when contributions from the jet, necessary due to the …
The Deep X-Ray Radio Blazar Survey. Iii. Radio Number Counts, Evolutionary Properties, And Luminosity Function Of Blazars, Paolo Padovani, Paolo Giommi, Hermine Landt, Eric S. Perlman
The Deep X-Ray Radio Blazar Survey. Iii. Radio Number Counts, Evolutionary Properties, And Luminosity Function Of Blazars, Paolo Padovani, Paolo Giommi, Hermine Landt, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
Our knowledge of the blazar surface densities and luminosity functions, which are fundamental parameters, relies still on samples at relatively high flux limits. As a result, our understanding of this rare class of active galactic nuclei is mostly based on relatively bright and intrinsically luminous sources. We present the radio number counts, evolutionary properties, and luminosity functions of the faintest blazar sample with basically complete (∼95%) identifications. Based on the Deep X-Ray Radio Blazar Survey (DXRBS), it includes 129 flat-spectrum radio quasars ( FSRQs) and 24 BL Lac objects down to a 5 GHz flux and power ∼50 mJy and …
Gemini Mid-Ir Polarimetry Of Ngc 1068: Polarized Structures Around The Nucleus, Christopher C. Packham, Stuart Young, Scott E. Fisher, Kevin M. Volk, Rachel E. Mason, James H. Hough, Patrick F. Roche, Moshe Elitzur, James T. Radomski, Eric S. Perlman
Gemini Mid-Ir Polarimetry Of Ngc 1068: Polarized Structures Around The Nucleus, Christopher C. Packham, Stuart Young, Scott E. Fisher, Kevin M. Volk, Rachel E. Mason, James H. Hough, Patrick F. Roche, Moshe Elitzur, James T. Radomski, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present diffraction-limited, 10 μm imaging polarimetry data for the central regions of the archetypal Seyfert active galactic nucleus NGC 1068. The position angle of polarization is consistent with three dominant polarizing mechanisms. We identify three distinct regions of polarization: (1) north of the nucleus, arising from aligned dust in the narrow emission line region, (2) south, east, and west of the nucleus, consistent with dust being channeled toward the central engine, and (3) a central minimum of polarization consistent with a compact (≤22 pc) torus. These observations provide continuity between the geometrically and optically thick torus and the host …
Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xii. Ground-Based Monitoring Of 3c 390.3, Matthias Dietrich, T. D. Oswalt, Jun Tao
Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xii. Ground-Based Monitoring Of 3c 390.3, Matthias Dietrich, T. D. Oswalt, Jun Tao
Aerospace, Physics, and Space Science Faculty Publications
Results of a ground-based optical monitoring campaign on 3C 390.3 in 1994-1995 are presented. The broadband fluxes (B, V, R, and I), the spectrophotometric optical continuum flux Fλ(5177 Å), and the integrated emission-line fluxes of Hα, Hβ, Hγ, He II λ15876, and He II A4686 all show a nearly monotonic increase with episodes of milder short-term variations superposed. The amplitude of the continuum variations increases with decreasing wavelength (4400-9000 Å). The optical continuum variations follow the variations in the ultraviolet and X-ray with time delays, measured from the centroids of the cross-correlation functions, typically around 5 days, but with uncertainties …