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Full-Text Articles in Physical Sciences and Mathematics
Spitzer Space Telescope Measurements Of Dust Reverberation Lags In The Seyfert 1 Galaxy Ngc 6418, Billy Vazquez, Dan Batcheldor
Spitzer Space Telescope Measurements Of Dust Reverberation Lags In The Seyfert 1 Galaxy Ngc 6418, Billy Vazquez, Dan Batcheldor
Aerospace, Physics, and Space Science Faculty Publications
We present results from a 15 month campaign of high-cadence (∼3 days) mid-infrared Spitzer and optical (B and V) monitoring of the Seyfert 1 galaxy NGC 6418, with the objective of determining the characteristic size of the dusty torus in this active galactic nucleus (AGN). We find that the 3.6 and 4.5 μm flux variations lag behind those of the optical continuum by 37.2 ^+2.4 _-2.2 days and -47.1 ^+3.1 _-3.1 days, respectively. We report a cross-correlation time lag between the 4.5 and 3.6 μm flux of 13.9 ^+0.5 _-0.1 days. The lags indicate that the dust emitting at 3.6 …
Uncovering The Deeply Embedded Active Galactic Nucleus Activity In The Nuclear Regions Of The Interacting Galaxy Arp 299, A Alonso-Herrero, Eric S. Perlman
Uncovering The Deeply Embedded Active Galactic Nucleus Activity In The Nuclear Regions Of The Interacting Galaxy Arp 299, A Alonso-Herrero, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present mid-infrared (MIR) 8-13 μm spectroscopy of the nuclear regions of the interacting galaxy Arp 299 (IC 694+NGC 3690) obtained with CanariCam (CC) on the 10.4 m Gran Telescopio Canarias (GTC). The high angular resolution (∼0.″3-0.″6) of the data allows us to probe nuclear physical scales between 60 and 120 pc, which is a factor of 10 improvement over previous MIR spectroscopic observations of this system. The GTC/CC spectroscopy displays evidence of deeply embedded active galactic nucleus (AGN) activity in both nuclei. The GTC/CC nuclear spectrum of NGC 3690/Arp 299-B1 can be explained as emission from AGN-heated dust in …
Nicmos Polarimetry Of "Polar-Scattered" Seyfert 1 Galaxies, Daniel P. Batcheldor, Andrew Edward Robinson, David J. Axon, Stuart Young, S Quinn, James E. Smith, James H. Hough, David M. Alexander
Nicmos Polarimetry Of "Polar-Scattered" Seyfert 1 Galaxies, Daniel P. Batcheldor, Andrew Edward Robinson, David J. Axon, Stuart Young, S Quinn, James E. Smith, James H. Hough, David M. Alexander
Aerospace, Physics, and Space Science Faculty Publications
The nuclei of Seyfert 1 galaxies exhibit a range of optical polarization characteristics that can be understood in terms of two scattering regions producing orthogonal polarizations: an extended polar scattering region (PSR) and a compact equatorial scattering region (ESR), located within the circum-nuclear torus. Here we present NICMOS 2.0 μm imaging polarimetry of six "polar-scattered" Seyfert 1 (S1) galaxies, in which the PSR dominates the optical polarization. The unresolved nucleus (<058) is significantly polarized in only three objects, but five of the six exhibit polarization in a 058-15 circum-nuclear annulus. In Fairall 51 and ESO 323-G077, the polarization position angle at 2 μm (θ2 μm) is consistent with the average for the optical spectrum(θv), implying that the nuclear polarization is dominated by polar scattering at both wavelengths. The same is probably true for NGC3227. In both NGC 4593 and Mrk 766, there is a large difference between θ2 μm and θv off-nucleus, where polar scattering is expected to dominate. This may be due to contamination by interstellar polarization in NGC4593, but there is no clear explanation in the case of the strongly polarized Mrk766. Lastly, in Mrk1239, a large change (60°) in θ2 μm between the nucleus and the annulus indicates that the unresolved nucleus and its immediate surroundings have different polarization states at 2μm, which we attribute to the ESR and PSR, respectively. A further implication is that the source of the scattered 2 μm emission in the unresolved nucleus is the accretion disk, rather than torus hot dust emission.
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 …