MODELING THE INFRARED EMISSION IN CYGNUS A

Journal Article · Thu Mar 01 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/747/1/46· OSTI ID:22016320

Privon, G C; Baum, S A; Noel-Storr, J ^[1]; O'Dea, C P; Axon, D J; Robinson, A ^[2]; Gallimore, J ^[3]

---

1. Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, Rochester, NY 14623 (United States)
2. Department of Physics, Rochester Institute of Technology, Rochester, NY 14623 (United States)
3. Department of Physics, Bucknell University, Lewisburg, PA 17837 (United States)

We present new Spitzer IRS spectroscopy of Cygnus A, one of the most luminous radio sources in the local universe. Data on the inner 20'' are combined with new reductions of MIPS and IRAC photometry as well as data from the literature to form a radio through mid-infrared spectral energy distribution (SED). This SED is then modeled as a combination of torus reprocessed active galactic nucleus (AGN) radiation, dust enshrouded starburst, and a synchrotron jet. This combination of physically motivated components successfully reproduces the observed emission over almost 5 dex in frequency. The bolometric AGN luminosity is found to be 10{sup 12} L{sub Sun} (90% of L{sub IR}), with a clumpy AGN-heated dust medium extending to {approx}130 pc from the supermassive black hole. Evidence is seen for a break or cutoff in the core synchrotron emission. The associated population of relativistic electrons could in principle be responsible for some of the observed X-ray emission though the synchrotron self-Compton mechanism. The SED requires a cool dust component, consistent with dust-reprocessed radiation from ongoing star formation. Star formation contributes at least 6 Multiplication-Sign 10{sup 10} L{sub Sun} to the bolometric output of Cygnus A, corresponding to a star formation rate of {approx}10 M{sub Sun} yr{sup -1}.

• OSTI ID: 22016320
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 747; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
BOLOMETERS
COMPUTERIZED SIMULATION
DUSTS
ENERGY SPECTRA
GALAXIES
LUMINOSITY
PHOTOMETRY
PHOTON EMISSION
RELATIVISTIC RANGE
SPECTROSCOPY
STARS
UNIVERSE