Subaru spectroscopy and spectral modeling of Cygnus A

Journal Article · Tue Jun 10 00:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/788/1/6· OSTI ID:22356725

Merlo, Matthew J.; Perlman, Eric S. ^[1]; Nikutta, Robert ^[2]; Packham, Christopher ^[3]; Elitzur, Moshe ^[4]; Imanishi, Masatoshi ^[5]; Levenson, N. A. ^[6]; Radomski, James T. ^[7]; Aretxaga, Itziar ^[8]

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1. Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States)
2. Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055 (United States)
3. Department of Physics and Astronomy, University of Texas at San Antonio, 1 UTSA Circle, San Antonio, TX 78249 (United States)
4. Departamento de Ciencias Físicas, Universidad Andrés Bello, Av. República 252, Santiago (Chile)
5. Subaru Telescope, 650 N. A'ohoku Place, Hilo, HI 96720 (United States)
6. Gemini Observatory, Casilla 603, La Serena (Chile)
7. SOFIA/USRA, NASA Ames Research Center, Moffett Field, CA 94035 (United States)
8. Instituto Nacional de Astrofísica, Óptica y Electrónica, Calle Luis Erro 1, Sta. Ma. Tonantzintla, Puebla (Mexico)

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 the spectrum of Cyg A. This foreground absorption prevents a clear view of the central engine and surrounding torus, making it difficult to quantify the extent the torus attributes to the obscuration of the central engine, but does not eliminate the need for a torus in Cyg A.

• OSTI ID: 22356725
• Journal Information: Astrophysical Journal, Vol. 788, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
DUSTS
ENGINES
INTERMEDIATE INFRARED RADIATION
NUCLEI
RADIO GALAXIES
RESOLUTION
SCREENS
SHAPE
SILICATES
SPECTRA
SPECTROSCOPY
TELESCOPES